Polarization in Meson Production Reactions
Knutson, L.D.
2000-12-31
A comprehensive formalism for describing polarization observables in meson production reactions is presented. Particular attention is given to the complications that arise when the final state contains three particles. A general formula for the partial wave expansion of the polarization observables is presented, and a number of applications of the formalism are discussed.
Electroweak meson production reaction in the nucleon resonance region
Sato, Toru
2015-10-15
We report on our recent study of the the neutrino-nucleon reaction in the nucleon resonance region. The dynamical reaction model of meson production reaction on the nucleon for the pion and photon induced reaction has been developed in order to investigate the spectrum of nucleon excited state. We have extended this model in order to describe the weak meson production reactions with the πN, ηN, KΛ, KΣ and ππN final states. We also studied the role of the final state interaction in the photon and the neutrino induced pion production reaction on the deuteron around the Δ(1232) resonance region.
X (3872) production from reactions involving D and D* mesons
NASA Astrophysics Data System (ADS)
Martínez Torres, A.; Khemchandani, K. P.; Navarra, F. S.; Nielsen, M.; Abreu, Luciano M.
2015-07-01
In this proceeding we show the results found for the cross sections of the processes D → πX(3872), *D → πX(3872) and *D* → πX(3872), information needed for calculations of the X (3872) abundance in heavy ion collisions. Our formalism is based on the generation of X(3872) from the interaction of the hadrons 0D*0 — c.c, D-D*+ — c.c and D-sD*+s — c.c. The evaluation of the cross section associated with processes having D* meson(s) involves an anomalous vertex, X*D*, which we have determined by considering triangular loops motivated by the molecular nature of X (3872). We find that the contribution of this vertex is important. Encouraged by this finding we estimate the X*D* coupling, which turns out to be 1.95 ± 0.22. We then use it to obtain the cross section for the reaction *D* → πX and find that the X*D* vertex is also relevant in this case. We also discuss the role of the charged components of X in the determination of the production cross sections.
Effect of in-medium parameters of ρ meson in its photoproduction reactions on nuclei
Das, Swapan
2015-03-15
There exist model calculations showing the modification of the hadronic parameters of ρ meson in the nuclear environment. From these parameters, we extract the ρ-meson-nucleus optical potential and show the medium effect due to this potential on the ρ-meson mass distribution spectra in the photonuclear reactions. The calculated results reproduced reasonably the measured e{sup +}e{sup −} invariant mass, i.e., ρ-meson mass, distribution spectra in γ, ρ{sup 0} → e{sup +}e{sup −} reactions on nuclei.
Nucleon resonances in exclusive reactions of photo- and electroproduction of mesons
Skorodumina, Iu. A.; Burkert, V. D.; Golovach, E. N.; Gothe, R. W.; Isupov, E. L.; Ishkhanov, B. S.; Mokeev, V. I.; Fedotov, G. V.
2015-11-01
Methods for extracting nucleon resonance parameters from experimental data are reviewed. The formalism for the description of exclusive reactions of meson photo- and electroproduction off nucleons is discussed. Recent experimental data on exclusive meson production in the scattering of electrons and photons off protons are analyzed.
Dynamical coupled-channels study of meson production reactions from EBAC@Jlab
Hiroyuki Kamano
2011-10-01
We present the current status of a combined and simultaneous analysis of meson production reactions based on a dynamical coupled-channels (DCC) model, which is conducted at Excited Baryon Analysis Center (EBAC) of Jefferson Lab.
Extraction of Nucleon Resonances From Global Analysis of Meson Production Reactions at EBAC
Hiroyuki Kamano
2011-10-01
We report the current status of exploring the dynamical aspect of the excited nucleon states through the comprehensive coupled-channels analysis of meson production reactions at the Excited Baryon Analysis Center of Jefferson Lab.
Light meson decays from photon-induced reactions with CLAS
NASA Astrophysics Data System (ADS)
Kunkel, Michael C.
2016-05-01
Photo-production experiments with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Laboratory produce data sets with unprecedented statistics for light mesons. With these data sets, measurements of transition form factors for η, ω, and η' mesons via conversion decays can be performed using the invariant mass distribution of the final state dileptons. Tests of fundamental symmetries and information on the light quark mass difference can be performed using a Dalitz plot analysis of the meson decay. An overview of the first results, from existing CLAS data, and future prospects within the newly upgraded CLAS12 apparatus are given.
Dynamical Coupled-Channel Model of Meson Production Reactions in the Nucleon Resonance Region
T.-S. H. Lee; A. Matsuyama; T. Sato
2006-11-15
A dynamical coupled-channel model is presented for investigating the nucleon resonances (N*) in the meson production reactions induced by pions and photons. Our objective is to extract the N* parameters and to investigate the meson production reaction mechanisms for mapping out the quark-gluon substructure of N* from the data. The model is based on an energy-independent Hamiltonian which is derived from a set of Lagrangians by using a unitary transformation method.
Light Meson Decays from Photon-Induced Reactions with CLAS
NASA Astrophysics Data System (ADS)
Kunkel, Michael; CLAS Collaboration; Light Meson Decay (LMD) Team
2015-04-01
Photo-production experiments with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Laboratory produce data sets with unprecedented statistics of light mesons. With these data sets, measurements of transition form factors for η, ω, and η ' via conversion decays can be performed using a line shape analysis on the invariant mass of the final state dileptons. Tests of fundamental symmetries and information on the light quark mass difference can be performed using a Dalitz plot analysis of the meson decay. In addition, the data allows for a search for dark matter, such as the heavy photon via conversion decays of light mesons and physics beyond the Standard Model can be searched for via invisible decays of η mesons. An overview of the first results and future prospects will be given.
Meson structure in soft hadronic reactions at COMPASS
Colantoni, M.
2006-02-11
The measurement of the electric ({alpha}-bar{pi}) and magnetic ({beta}-bar{pi}) pion polarizabilities supplies a significant test of QCD predictions in particular in the framework of the chiral perturbation theory.In this perspective we have measured with the COMPASS spectrometer the t-dependence of the cross section for the reactions: {pi}- + Z {yields} {pi}- + Z + {gamma}, and {mu}- + Z {yields} {mu}- + Z + {gamma} selecting events corresponding to the Compton {pi}{gamma} and {mu}{gamma} scattering respectively. From a fit of the data of the first reaction we can extract {alpha}-bar{pi} and {beta}-bar{pi}, from those of the second the point-like contribution. This procedure minimizes the systematic errors. Details on the experiment and the present status of the analysis of the data collected in 2004 will be discussed.
Meson-exchange model for πN scattering and γN-->πN reaction
NASA Astrophysics Data System (ADS)
Sato, T.; Lee, T.-S. H.
1996-11-01
An effective Hamiltonian consisting of bare Δ⇆πN, γN vertex interactions and energy-independent meson-exchange πN⇆πN,γN transition operators is derived by applying a unitary transformation to a model Lagrangian with N,Δ,π, ρ, ω, and γ fields. With appropriate phenomenological form factors and coupling constants for ρ and Δ, the model can give a good description of πN scattering phase shifts up to the Δ excitation energy region. It is shown that the best reproduction of the recent LEGS data of the photon-asymmetry ratios in γp-->π0p reactions provides rather restricted constraints on the coupling strengths GE of the electric E2 and GM of the magnetic M1 transitions of the bare Δ⇆γN vertex and the less well-determined coupling constant gωNN of ω meson. Within the ranges that GM=1.9+/-0.05, GE=0.0+/-0.025, and 7<=gωNN<=10.5, the predicted differential cross sections and photon-asymmetry ratios are in an overall good agreement with the data of γp-->π0p, γp-->π+n, and γn-->π-p reactions from 180 MeV to the Δ excitation region. The predicted M1+ and E1+ multipole amplitudes are also in good agreement with the empirical values determined by the amplitude analyses. The constructed effective Hamiltonian is free of the nucleon renormalization problem and hence is suitable for nuclear many-body calculations. We have also shown that the assumptions made in the K-matrix method, commonly used in extracting empirically the γN-->Δ transition amplitudes from the data, are consistent with our meson-exchange dynamical model. It is found that the helicity amplitudes calculated from our bare γN-->Δ vertex are in good agreement with the predictions of the constituent quark model. The differences between these bare amplitudes and the dressed amplitudes, which are closer to the empirical values listed by the Particle Data Group, are shown to be due to the nonresonant meson exchange mechanisms. Within the range 7<=gωNN<=10.5 of the ω meson coupling
Role of pentaquark components in ϕ meson production proton-antiproton annihilation reactions
NASA Astrophysics Data System (ADS)
Srisuphaphon, S.; Kaewsnod, A.; Limphirat, A.; Khosonthongkee, K.; Yan, Y.
2016-02-01
The pentaquark component uuds s ¯ is included in the proton wave functions to study ϕ meson production proton-antiproton annihilation reactions. With all possible configurations of the uuds subsystem proposed for describing the strangeness spin and magnetic moment of the proton, we estimate the branching ratios of the annihilation reactions at rest p p ¯→ϕ X (X =π0,η ,ρ0,ω ) from atomic p p ¯ S - and P -wave states by using effective quark line diagrams incorporating the 3P0 model. The best agreement of theoretical prediction with the experimental data is found when the pentaquark configuration of the proton wave function takes the flavor-spin symmetry [4] FS[22] F[22] S .
Extraction of Meson Resonances from Three-pions Photo-production Reactions
S. X. Nakamura, H. Kamano, T.-S. H. Lee, T. Sato
2012-12-01
We have investigated the model dependence of meson resonance properties extracted from the Dalitz-plot analysis of the three-pions photoproduction reactions on the nucleon. Within a unitary model developed in Phys. Rev. D 84, 114019 (2011), we generate Dalitz-plot distributions as data to perform an isobar model fit that is similar to most of the previous analyses of three-pion production reactions. It is found that the resonance positions from the two models agree well when both fit the data accurately, except for the resonance poles near branch points. The residues of the resonant amplitudes extracted from the two models and by the usual Breit-Wigner procedure agree well only for the isolated resonances with narrow widths. For overlapping resonances, most of the extracted residues could be drastically different. Our results suggest that even with high precision data, the resonance extraction should be based on models within which the amplitude parametrization is constrained by three-particle unitarity condition.
Meson Exchange Contributions to the pparrow ppπ^0 Reaction
NASA Astrophysics Data System (ADS)
van Kolck, U.; Miller, G. A.; Riska, D. O.
1996-10-01
The reaction pparrow pp π^0 remains a challenging theoretical problem. Long--range contributions as dictated from chiral perturbation theory from the impulse and pion rescattering diagrams interfere destructively and fail to account for the observed cross--section near threshold ( T.D. Cohen, J.L. Friar, G.A. Miller, and U. van Kolck, Phys. Rev. C 53) (1996) 2661; B.-Y. Park, F. Myhrer, J.R. Morones, T. Meissner, and K. Kubodera, Phys. Rev. C 53 (1996) 1519.. Here we discuss shorter--ranged mechanisms in which the pion is emitted by heavier mesons that are exchanged between nucleons. In particular, we show that ρ-ω and η-a0 exchanges, when combined with previously suggested ( T.-S.H. Lee and D.O. Riska, Phys. Rev. Lett. 70) (1993) 2237; C.J. Horowitz, H.O. Meyer, and D.K. Griegel, Phys. Rev. C 49 (1994) 1337. σ, ω pair diagrams, can reproduce the observed cross--section, within the theoretical uncertainty associated with long--range mechanisms and the two--nucleon wave function.
Near threshold two meson production with the pd→3Heπ+π- and pd→3HeK+K- reactions
NASA Astrophysics Data System (ADS)
Bellemann, F.; Berg, A.; Bisplinghoff, J.; Bohlscheid, G.; Ernst, J.; Henrich, C.; Hinterberger, F.; Ibald, R.; Jahn, R.; Jarczyk, L.; Joosten, R.; Kozela, A.; Machner, H.; Magiera, A.; Maschuw, R.; Mayer-Kuckuk, T.; Mertler, G.; Munkel, J.; von Neumann-Cosel, P.; Rosendaal, D.; von Rossen, P.; Schnitker, H.; Scho, K.; Smyrski, J.; Strzalkowski, A.; Tölle, R.; Wilkin, C.
2000-06-01
Near threshold two meson production via the reactions pd→3Heπ+π- and pd→3HeK+K- was measured kinematically complete with the MOMO experiment at COSY. The obtained two pion invariant mass spectra and angular distributions depict a remarkable deviation from phase space. The two kaon data are consistent with phase space topped by a clear signal of the φ meson.
Investigation of near-threshold eta-meson production in the reaction {pi}{sup -}p{yields} {eta}n
Bayadilov, D. E.; Beloglazov, Yu. A.; Gridnev, A. B.; Kozlenko, N. G.; Kruglov, S. P.; Kulbardis, A. A.; Lopatin, I. V.; Novinskiy, D. V.; Radkov, A. K.; Sumachev, V. V.; Filimonov, E. A.; Shvedchikov, A. V.
2012-08-15
Differential and total cross sections for eta-meson production in the reaction {pi}{sup -}p {yields} {eta}n were measured within the experimental program eta-meson physics implemented in the pion channel of the synchrocyclotron of the Petersburg Nuclear Physics Institute (PNPI, Gatchina). These measurements were performed at incident-pion momenta (700, 710, 720, and 730 MeV/c) in the vicinity of the threshold for the process under study by using the neutral-meson spectrometer designed and created at the Meson Physics Laboratory of PNPI. It is shown that, in the immediate vicinity of the threshold (685 MeV/c), the process of eta-meson production proceeds predominantly via S{sub 11}(1535)-resonance formation followed by the decay S{sub 11}(1535) {yields} {eta}n (the respective branching fraction is Br Almost-Equal-To 60%), but that, as the momentum of incident pions increases, the role of the D wave becomes ever more important. A detailed analysis of this effect indicates that it is due to the increasing contribution of the D{sub 13}(1520) resonance. Although the branching fraction of the decay of this resonance through the {eta}n channel is assumed to be very small (BR Almost-Equal-To 0.24%), the effect is enhanced owing to the interference between the D wave and the dominant resonance S{sub 11}(1535).
Formation of η{^'(958) meson bound states by the 6Li(γ,d) reaction
NASA Astrophysics Data System (ADS)
Miyatani, M.; Ikeno, N.; Nagahiro, H.; Hirenzaki, S.
2016-07-01
We have investigated the 6Li( γ, d) reaction theoretically for the formation of the η^'(958) mesic nucleus close to the recoilless kinematics. We have developed the theoretical formula and reported the quantitative results of the formation spectra for various cases in this article. We have found that the formation cross sections are reduced by the effects of the fragile deuteron form factor.
B. Julia-Diaz, H. Kamano, T.-S. H. Lee, A. Matsuyama, T. Sato, N. Suzuki
2009-04-01
Within the relativistic quantum field theory, we analyze the differences between the $\\pi N$ reaction models constructed from using (1) three-dimensional reductions of Bethe-Salpeter Equation, (2) method of unitary transformation, and (3) time-ordered perturbation theory. Their relations with the approach based on the dispersion relations of S-matrix theory are dicusssed.
COSY-MOMO Collaboration
2000-12-31
Near-threshold two-meson production via the reactions pd {yields} {sup 3}He{pi}{sup +}{pi}{sup {minus}} and pd {yields} {sup 3}HeK{sup +}K{sup {minus}} was measured kinematically complete with the MOMO experiment at COSY. The obtained two-pion variant mass spectra and angular distributions depict a remarkable deviation from phase space. The two-kaon data are consistent with phase space topped by a clear signal of the {phi} meson.
Techniques in meson spectroscopy
Longacre, R.S.
1991-12-31
This report contains lectures on the following topics: the quark model and beyond using quantum chromodynamics; analysis of formation reactions; energy dependence of the partial wave amplitudes; where the data for the t-matrix analysis comes from; and coupled channel analysis of isoscalar mesons.
Overview of coupled-channels analyses of meson production reactions: The way to the N*s
Julia-Diaz, Bruno
2011-10-24
We provide a brief review of the main existing theoretical efforts to extract and interpret the properties of baryon resonances from the experimental data for hadro-, photo- and electro-production of mesons on the nucleon. The focus is set on the dynamical coupled-channels models. An effort is made to highlight the relevant aspects of the different approaches, within the space limitations of these proceedings.
Physics opportunities with meson beams
Briscoe, William J.; Doring, Michael; Haberzettl, Helmut; Manley, D. Mark; Naruki, Megumi; Strakovsky, Igor I.; Swanson, Eric S.
2015-10-20
Over the past two decades, meson photo- and electro-production data of unprecedented quality and quantity have been measured at electromagnetic facilities worldwide. By contrast, the meson-beam data for the same hadronic final states are mostly outdated and largely of poor quality, or even nonexistent, and thus provide inadequate input to help interpret, analyze, and exploit the full potential of the new electromagnetic data. To reap the full benefit of the high-precision electromagnetic data, new high-statistics data from measurements with meson beams, with good angle and energy coverage for a wide range of reactions, are critically needed to advance our knowledge in baryon and meson spectroscopy and other related areas of hadron physics. To address this situation, a state of-the-art meson-beam facility needs to be constructed. Furthermore, the present paper summarizes unresolved issues in hadron physics and outlines the vast opportunities and advances that only become possible with such a facility.
NASA Astrophysics Data System (ADS)
Tang, A. H.; Wang, G.
2016-08-01
The electromagnetic (EM) field pattern created by spectators in relativistic heavy-ion collisions plants a seed of positive (negative) magnetic helicity in the hemisphere above (below) the reaction plane. Owing to the chiral anomaly, the magnetic helicity interacts with the fermionic helicity of the collision system and causes photons emitted in upper and lower hemispheres to have different preferences in the circular polarization. Similar helicity separation for massive particles, owing to the global vorticity, is also possible. In this paper, we lay out a procedure to measure the variation of the circular polarization with respect to the reaction plane in relativistic heavy-ion collisions for massless photons, as well as similar polarization patterns for vector mesons decaying into two daughters. We propose to study the yield differentially and compare the yield between upper and lower hemispheres to identify and quantify such effects.
NASA Astrophysics Data System (ADS)
Kleefeld, F.
A new crossing symmetric unitarization scheme conveniently applied to meson-meson and meson-baryon scattering amplitudes is shortly proposed which can be not only used by theoreticians to unitarize arbitrary theoretical reaction amplitudes resulting from phenomenological Lagrangeans for mesons and baryons, yet also by experimentalists to generate realistic unitary fitting formulae for meson-meson and meson-baryon scattering observables sharing on one hand all the features of the underlying theoretical amplitudes, on the other hand allowing direct comparison to these amplitudes. The new unitarization scheme has been inspired by the Dalitz and Tuan representation, the basic ansatz of which is that "... the phases caused by different sources add ..." (using the words of B.S. Zou, D.V. Bugg, Phys. Rev. D 50 (1994) 591).
NASA Astrophysics Data System (ADS)
Meyer, C. A.; Swanson, E. S.
2015-05-01
A review of the theoretical and experimental status of hybrid hadrons is presented. The states π1(1400) , π1(1600) , and π1(2015) are thoroughly reviewed, along with experimental results from GAMS, VES, Obelix, COMPASS, KEK, CLEO, Crystal Barrel, CLAS, and BNL. Theoretical lattice results on the gluelump spectrum, adiabatic potentials, heavy and light hybrids, and transition matrix elements are discussed. These are compared with bag, string, flux tube, and constituent gluon models. Strong and electromagnetic decay models are described and compared to lattice gauge theory results. We conclude that while good evidence for the existence of a light isovector exotic meson exists, its confirmation as a hybrid meson awaits discovery of its iso-partners. We also conclude that lattice gauge theory rules out a number of hybrid models and provides a reference to judge the success of others.
Steffen Strauch
2009-10-01
This is a brief and selective discussion of meson photoproduction measurements with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Meson photo- production is being used as a tool for various investigations, including the spectroscopy of baryons and mesons and the search for vector-meson medium modifications.
Evidence for a scalar meson resonance in the {pi}{sup -}p{yields}n{omega}{phi} reaction
Ivashin, A.; Ekimov, A.; Gouz, Yu.; Kachaev, I.; Karyukhin, A.; Konstantinov, V.; Makouski, M.; Matveev, V.; Myagkov, A.; Polyakov, B.; Ryabchikov, D.; Shalanda, N.; Soldatov, M.; Solodkov, A. A.; Solodkov, A. V.; Solovianov, O.; Sugonyaev, V.; Salomatin, Yu.; Volkov, E.; Khokhlov, Yu.
2010-08-05
The charge-exchange reaction {pi}{sup -}p{yields}n{omega}(780){phi}(1020) is studied with the VES setup. The ({omega}{phi}) system is observed at relatively low background. Its invariant mass distribution peaks near threshold. The two-particles partial wave analyses shows that the J{sup pc} = 0{sup ++} state dominates. This wave is compared with 0{sup ++} component in the ({omega}{omega}) system at the comparable mass, which was measured earlier.
Physics opportunities with meson beams
Briscoe, William J.; Doring, Michael; Haberzettl, Helmut; Manley, D. Mark; Naruki, Megumi; Strakovsky, Igor I.; Swanson, Eric S.
2015-10-20
Over the past two decades, meson photo- and electro-production data of unprecedented quality and quantity have been measured at electromagnetic facilities worldwide. By contrast, the meson-beam data for the same hadronic final states are mostly outdated and largely of poor quality, or even nonexistent, and thus provide inadequate input to help interpret, analyze, and exploit the full potential of the new electromagnetic data. To reap the full benefit of the high-precision electromagnetic data, new high-statistics data from measurements with meson beams, with good angle and energy coverage for a wide range of reactions, are critically needed to advance our knowledgemore » in baryon and meson spectroscopy and other related areas of hadron physics. To address this situation, a state of-the-art meson-beam facility needs to be constructed. Furthermore, the present paper summarizes unresolved issues in hadron physics and outlines the vast opportunities and advances that only become possible with such a facility.« less
Meson Photoproduction Experiments with CLAS
Eugene Pasyuk
2012-12-01
A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to light baryon spectroscopy. Meson photoprodcution experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams and frozen spin polarized targets provide unique conditions for this type of experiments. This combination of experimental tools gives a remarkable opportunity to measure double polarization observables for different pseudo-scalar meson photoproduction processes. For the first time, a complete or nearly complete measurement became possible and will facilitate model independent extraction of the reaction amplitude. An overview of the experimental program and its current status together with recent results on double polarization measurements in π{sup +} photoproduction are presented.
The Meson Spectroscopy Program at the Jefferson Laboratory
Filippi, Alessandro
2015-06-01
The experimental techniques that will be applied by the next generation meson spectroscopy experiments at JLab are described. For the first time, these experiments will be able to exploit the features of a photon beam of unprecedented intensity and momentum resolution, that will allow to perform precision studies of meson states with masses below 3 GeV/c^{2}. Photon induced reactions will enhance the production of spin-1 mesons, that are of particular interest according to the most recent Lattice QCD calculations of the lightest exotic hybrid meson.
Monte Carlo Nucleon Meson Transport Code System.
2000-11-17
Version 00 NMTC/JAERI97 is an upgraded version of the code system NMTC/JAERI, which was developed in 1982 at JAERI and is based on the CCC-161/NMTC code system. NMTC/JAERI97 simulates high energy nuclear reactions and nucleon-meson transport processes.
Charged {rho}-meson production in neutrino-induced reactions at
Agababyan, N. M.; Ammosov, V. V.; Grigoryan, N.; Gulkanyan, H.; Ivanilov, A. A.; Karamyan, Zh.; Korotkov, V. A.
2011-02-15
The production of charged {rho} mesons on nuclei and nucleons is investigated in charged current neutrino interactions at moderate energies (
Semay, Claude; Buisseret, Fabien; Silvestre-Brac, Bernard
2009-05-01
A hybrid meson is a quark-antiquark pair in which, contrary to ordinary mesons, the gluon field is in an excited state. In the framework of constituent models, the interaction potential is assumed to be the energy of an excited string. An approximate, but accurate, analytical solution of the Schroedinger equation with such a potential is presented. When applied to hybrid charmonia and bottomonia, towers of states are predicted in which the masses are a linear function of a harmonic oscillator band number for the quark-antiquark pair. Such a formula could be a reliable guide for the experimental detection of heavy hybrid mesons.
NASA Astrophysics Data System (ADS)
Gupta, Virendra
It is suggested that the narrow meson state seen in the the SELEX experiment is a (cbar {s} sbar {s}) tetraquark state. Characteristics of other possible tetraquarks formed out of c and s quarks and antiquarks are considered.
Low-energy {omega} ({yields}{pi}{sup 0}{gamma}) meson photoproduction in the nucleus
Das, Swapan
2011-06-15
The {pi}{sup 0{gamma}} invariant mass distribution spectra in the ({gamma},{pi}{sup 0{gamma}}) reaction were measured by the TAPS/ELSA Collaboration to look for the hadron parameters of the {omega} meson in the Nb nucleus. We study the mechanism for this reaction, where we consider that the elementary reaction in the Nb nucleus proceeds as {gamma}N{yields}{omega}N;{omega}{yields}{pi}{sup 0}{gamma}. The {omega}-meson photoproduction amplitude for this reaction is extracted from the measured four-momentum transfer distribution in the {gamma}p{yields}{omega}p reaction. The propagation of the {omega} meson and the distorted wave function for the {pi}{sup 0} meson in the final state are described by the eikonal form. The {omega} and {pi}{sup 0} mesons' nucleus optical potentials, appearing in the {omega} meson propagator and {pi}{sup 0} meson distorted wave function respectively, are estimated using the t{rho} approximation. The effects of pair correlation and color transparency are also studied. The calculated results do not show medium modification for the {omega} meson produced in the nucleus for momentum greater than 200 MeV. It occurs because the {omega} meson predominantly decays outside the nucleus. The dependence of the cross section on the final-state interaction is also investigated. The broadening of the {omega}-meson mass distribution spectra is shown to occur due to the large resolution width associated with the detector used in the experiment.
Vector meson dominance and the {rho} meson
Benayoun, M.; OConnell, H.B.; Williams, A.G.
1999-04-01
We discuss the properties of vector mesons, in particular the {rho}{sup 0}, in the context of the hidden local symmetry (HLS) model. This provides a unified framework to study several aspects of the low energy QCD sector. First, we show that in the HLS model the physical photon is massless, without requiring off field diagonalization. We then demonstrate the equivalence of HLS and the two existing representations of vector meson dominance, VMD1 and VMD2, at both the tree level and one loop order. Finally the S matrix pole position is shown to provide a model and process independent means of specifying the {rho} mass and width, in contrast with the real axis prescription currently used in the Particle Data Group tables. {copyright} {ital 1999} {ital The American Physical Society}
Observation of the chi_c2(2P) meson in the reaction gamma gamma -> D Dbar at BaBar
Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G. /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Paris U., VI-VII /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /INFN, Naples /Naples U. /INFN, Naples /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /Pennsylvania U. /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison
2010-05-26
A search for the Z(3930) resonance in {gamma}{gamma} production of the D{bar D} system has been performed using a data sample corresponding to an integrated luminosity of 384 fb{sup -1} recorded by the BABAR experiment at the PEP-II asymmetric-energy electron-positron collider. The D{bar D} invariant mass distribution shows clear evidence of the Z(3930) state with a significance of 5.8{sigma}. We determine mass and width values of (3926.7 {+-} 2.7 {+-} 1.1)MeV/c{sup 2} and (21.3 {+-} 6.8 {+-} 3.6)MeV, respectively. A decay angular analysis provides evidence that the Z(3930) is a tensor state with positive parity and C-parity (J{sup PC} = 2{sup ++}); therefore we identify the Z(3930) state as the {chi}{sub c2}(2P) meson. The value of the partial width {Lambda}{sub {gamma}{gamma}} x {Beta}(Z(3930) {yields} D{bar D}) is found to be (0.24 {+-} 0.05 {+-} 0.04) keV.
Meson Spectroscopy in the Light Quark Sector
De Vita, R.; Lunardi, S.; Bizzeti, P. G.; Bucci, C.; Chiari, M.; Dainese, A.; Di Nezza, P.; Menegazzo, R.; Nannini, A.; Signorini, C.; Valiente-Dobon, J. J.
2014-01-01
Understanding the hadron spectrum is one of the fundamental issues in modern particle physics. We know that existing hadron configurations include baryons, made of three quarks, and mesons, made of quark-antiquark pairs. However most of the mass of the hadrons is not due to the mass of these elementary constituents but to their binding force. Studying the hadron spectrum is therefore a tool to understand one of the fundamental forces in nature, the strong force, and Quantum Chromo Dynamics (QCD), the theory that describes it. This investigation can provide an answer to fundamental questions as what is the origin of the mass of hadrons, what is the origin of quark confinement, what are the relevant degrees of freedom to describe these complex systems and how the transition between the elementary constituents, quarks and gluons, and baryons and mesons occurs. In this field a key tool is given by meson spectroscopy. Mesons, being made by a quark and an anti-quark, are the simplest quark bound system and therefore the ideal benchmark to study the interaction between quarks and understand what the role of gluons is. In this investigation, it is fundamental to precisely determine the spectrum and properties of mesons but also to search for possible unconventional states beyond the configuration q{anti q} as tetraquarks (qq{anti qq}), hybrids (q{anti q}g) and glueballs. These states can be distinguished unambiguously from regular mesons when they have exotic quantum numbers, i.e. combinations of total angular momentum, spin and parity that are not allowed for q{anti q} states. These are called exotic quantum numbers and the corresponding states are referred to as exotics. The study of the meson spectrum and the search for exotics is among the goals of several experiments in the world that exploit different reaction processes, as e{sup +}e{sup -} annihilation, p{anti p} annihilation, pion scattering, proton-proton scattering and photo-production, to produce meson states
Liu Yunhu; Shao Jianxin; Wang Xiaogang; Zhang Ziying; Li Demin
2008-02-01
Based on the main assumption that the D{sub sJ}(2860) belongs to the 2{sup 3}P{sub 0} qq multiplet, the masses of the scalar meson nonet are estimated in the framework of the relativistic independent quark model, Regge phenomenology, and meson-meson mixing. We suggest that the a{sub 0}(1005), K{sub 0}*(1062), f{sub 0}(1103), and f{sub 0}(564) constitute the ground scalar meson nonet; it is supposed that these states would likely correspond to the observed states a{sub 0}(980), {kappa}(900), f{sub 0}(980), and f{sub 0}(600)/{sigma}, respectively. Also a{sub 0}(1516), K{sub 0}*(1669), f{sub 0}(1788), and f{sub 0}(1284) constitute the first radial scalar meson nonet, it is supposed that these states would likely correspond to the observed states a{sub 0}(1450), K{sub 0}*(1430), f{sub 0}(1710), and f{sub 0}(1370), respectively. The scalar state f{sub 0}(1500) may be a good candidate for the ground scalar glueball. The agreement between the present findings and those given by other different approaches is satisfactory.
Absorption of the omega and phi Mesons in Nuclei
M. H. Wood, R. Nasseripour, M. Paolone, C. Djalali, D. P. Weygand, the CLAS Collaboration
2010-09-01
Due to their long lifetimes, the $\\omega$ and $\\phi$ mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from $^{2}$H, C, Ti, Fe, and Pb targets. This paper reports the first measurement of the ratio of nuclear transparencies for the $e^{+}e^{-}$ channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels.
Meson Production and Space Radiation
NASA Astrophysics Data System (ADS)
Norbury, John; Blattnig, Steve; Norman, Ryan; Aghara, Sukesh
-nucleus reactions will be presented. The NCRP has also recom-mended that more attention should be paid to neutron and light ion transport. The coupling of neutrons, light ions, mesons and other hadrons will be discussed.
B Decays Involving Light Mesons
NASA Astrophysics Data System (ADS)
Eschrich, Ivo Gough
Recent BABAR results for decays of B-mesons to combinations of non-charm mesons are presented. This includes B decays to two vector mesons, B → η‧(π, K, ρ) modes, and a comprehensive Dalitz Plot analysis of B → KKK decays.
B Decays Involving Light Mesons
Eschrich, Ivo Gough; /UC, Irvine
2007-01-09
Recent BABAR results for decays of B-mesons to combinations of non-charm mesons are presented. This includes B decays to two vector mesons, B {yields} {eta}{prime}({pi}, K, {rho}) modes, and a comprehensive Dalitz Plot analysis of B {yields} KKK decays.
Quarkonium and Bc mesons from Pb + Pb at LHC energies
NASA Astrophysics Data System (ADS)
Norbeck, Edwin; Nachtman, Jane; Onel, Yasar
2013-08-01
The bbar b(Upsilon) mesons appear to be produced in the initial PbPb collision at 2.76 TeV per nucleon pair followed by partial melting in the hot quark-gluon plasma. In sharp contrast, the cbar c(J/Ψ) mesons seem more likely to be formed by recombination at the hadronization stage. The Bc mesons, with one quark of each kind are seldom seen in pp collisions because a particle-antiparticle pair requires the simultaneous production of four heavy quarks. Although a family of Bc mesons have been predicted, only the ground state has been seen. If the cbar c mesons are produced by recombination, it could be expected that Bc mesons would be abundant with PbPb. Because the quark and antiquark have different flavor, the Bc are relatively long lived, 0.45 ps (to be compared with about 1.5 ps for the lighter B mesons). They would be seen with PbPb reactions by B±c → J/Ψ(μ+μ-)π± looking at muons and pions from displaced vertices.
Absorption of the {omega} and {phi} Mesons in Nuclei
Wood, M. H.; Nasseripour, R.; Berman, B. L.; Briscoe, W. J.; Munevar, E.; Strakovsky, I. I.; Paolone, M.; Djalali, C.; Gothe, R. W.; Graham, L.; Tedeschi, D. J.; Tkachenko, S.; Zhao, Z. W.; Weygand, D. P.; Batourine, V.; Burkert, V. D.; Carman, D. S.; Deur, A.; Guo, L.; Nadel-Turonski, P.
2010-09-10
Because of their long lifetimes, the {omega} and {phi} mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from {sup 2}H, C, Ti, Fe, and Pb targets. This Letter reports the first measurement of the ratio of nuclear transparencies for the e{sup +}e{sup -} channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels. The absorption of the {omega} meson is stronger than that reported by the CBELSA-TAPS experiment and cannot be explained by recent theoretical models.
Bianco, Stefano
2006-02-11
The scenario of heavy quark meson spectroscopy underwent recently a major revolution, after the observation of BABAR and CLEO, confirmed by BELLE, of DsJ L=1 excited states, and by further evidences by SELEX. These experimental results have cast doubts on the incarnations of the ideas of Heavy Quark Effective Theory in heavy quark spectroscopy. I shall review the status of experimental data, discuss implications and sketch an outlook.
Deeply Virtual Pseudoscalar Meson Production with CLAS
Valery Kubarovsky, Paul Stoler, Ivan Bedlinsky
2011-05-01
One of the primary goals of the CLAS12 program is to double the Q^{2} range of the available data into a region where approached with lower twist corrections become more reliable. Since the extraction of GPDs from electroproduction data can be difficult, a detailed understanding of the reaction mechanism is essential before one can compare with theoretical calculations. It is not yet clear at what values of Q^{2} the application of GPDs to meson electroproduction becomes valid.1–5 However, detailed measurements of observables may test model-independent features of the reaction mechanism.
Electroproduction of tensor mesons in QCD
NASA Astrophysics Data System (ADS)
Braun, V. M.; Kivel, N.; Strohmaier, M.; Vladimirov, A. A.
2016-06-01
Due to multiple possible polarizations hard exclusive production of tensor mesons by virtual photons or in heavy meson decays offers interesting possibilities to study the helicity structure of the underlying short-distance process. Motivated by the first measurement of the transition form factor γ∗γ → f 2(1270) at large momentum transfers by the BELLE collaboration we present an improved QCD analysis of this reaction in the framework of collinear factorization including contributions of twist-three quark-antiquark-gluon operators and an estimate of soft end-point corrections using light-cone sum rules. The results appear to be in good agreement with the data, in particular the predicted scaling behavior is reproduced in all cases.
Rare B Meson Decays With Omega Mesons
Zhang, Lei; /Colorado U.
2006-04-24
Rare charmless hadronic B decays are particularly interesting because of their importance in understanding the CP violation, which is essential to explain the matter-antimatter asymmetry in our universe, and of their roles in testing the ''effective'' theory of B physics. The study has been done with the BABAR experiment, which is mainly designed for the study of CP violation in the decays of neutral B mesons, and secondarily for rare processes that become accessible with the high luminosity of the PEP-II B Factory. In a sample of 89 million produced B{bar B} pairs on the BABAR experiment, we observed the decays B{sup 0} {yields} {omega}K{sup 0} and B{sup +} {yields} {omega}{rho}{sup +} for the first time, made more precise measurements for B{sup +} {yields} {omega}h{sup +} and reported tighter upper limits for B {yields} {omega}K* and B{sup 0} {yields} {omega}{rho}{sup 0}.
Scalar isovector resonance photoproduction through the final state meson-meson interactions
NASA Astrophysics Data System (ADS)
Bibrzycki, Łukasz; Kamiński, Robert
2016-08-01
We construct the amplitudes of πη photoproduction taking into account the effects of the πη-KK¯ interchannel coupling. The idea of our model is to describe the scalar isovectors as dynamically produced in the final state while the initial stage of the reaction being described in terms of meson exchanges. Meson loops which arise this way include not only pseudoscalars but also vector mesons. These amplitudes are used to calculate the S-wave cross-sections and mass distributions in the πη effective mass region corresponding to the scalar resonances a0(980) and a0(1450). The values we obtained for a0(980) are comparable with predictions of other models while the cross-section for a0(1450) is about an order of magnitude larger than prediction based on the quark model. We show that the amplitudes with loops containing vector mesons calculated in the on-shell approximation are not suppressed in contrast to amplitudes containing only pseudoscalar loops. We also estimate the cross-sections for the P- and D-waves in the πη channel.
The light meson spectroscopy program
Smith, Elton S.
2014-06-01
Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.
Exotic meson spectroscopy with CLAS
Adams, G.; Napolitano, J.
1994-04-01
The identification and study of mesons with explicit gluonic degrees of freedom will provide major constraints on nonperturbative QCD and models thereof. CLAS will provide a unique opportunity for studying these resonances by measuring photoproduction of multi-meson final states.
Meson spectroscopy at the Tevatron
Yi, Kai
2010-04-01
The Tevatron experiments have each accumulated about 6 fb{sup -1} good data since the start of RUN II. This large dataset provided good opportunities for meson spectroscopy studies at the Tevatron. This article will cover the recent new {Upsilon}(nS) polarization studies as well as exotic meson spectroscopy studies.
Cross sections for inelastic meson-meson scattering via quark-antiquark annihilation
NASA Astrophysics Data System (ADS)
Shen, Zhen-Yu; Xu, Xiao-Ming; Weber, H. J.
2016-08-01
We study inelastic meson-meson scattering that is governed by quark-antiquark annihilation and creation involving a quark and an antiquark annihilating into a gluon, and subsequently the gluon creating another quark-antiquark pair. The resultant hadronic reactions include for I =1 : π π →ρ ρ , K K ¯→K*K¯*, K K¯*→K*K¯*, K*K ¯→K*K¯*, as well as π π →K K ¯, π ρ →K K¯*, π ρ →K*K ¯, and K K ¯→ρ ρ . In each reaction, one or two Feynman diagrams are involved in the Born approximation. We derive formulas for the unpolarized cross section, the transition amplitude, and the transition potential for quark-antiquark annihilation and creation. The unpolarized cross sections for the reactions are calculated at six temperatures, and prominent temperature dependence is found. It is due to differences among mesonic temperature dependence in hadronic matter.
Meson radiobiology and therapy.
Kligerman, M M
1975-01-01
High-linear energy transfer radiation (neutrons, heavy ions, and pions) have a greater relative biological effectiveness than low-linear energy transfer radiation by depositing a high density of ionization in irradiated cells. This overcomes the protective effect of oxygen; decreases the variation in sensitivity among the several stages of the cell cycles; and, inhibits the repair of sublethal damage as compared to x-rays, gamma rays, electrons and protons. Negative pi mesons (pions), appear particularly suited for radiation therapy as their penetration and depth-dose profile lend themselves to shaping the high dose area to the tumor size and location. Preliminary biological experiments with pions produced at the Los Alamos Meson Physics Facility studied cell survival at various radiation depths and cell cycle sensitivity. Histologic study of data from the first human experiments indicated severe tumor cell destruction by pions as compared to x-rays in treating malignant melanoma skin nodules, without increased effects on dermal elements. PMID:1201774
Luth, Vera G.; /SLAC
2012-01-03
Semileptonic decays of B mesons play a critical role in the determination of the magnitude of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements V{sub cb} and V{sub ub}. These two quantities are fundamental parameters of the Standard Model and have to be determined experimentally. Over the past decade, the vast samples of B mesons recorded at the B factories at LEP at Cornell University, KEK at Tsukuba, and SLAC at Stanford University have allowed for detailed studies of semileptonic B decays. These decays proceed via first-order weak interactions; thus, they are expected to be free of non-Standard Model contributions and therefore are well suited for the extraction of the quark-mixing parameters. Differential decay rates are combined with theoretical calculations of hadronization effects, leading to a substantially improved knowledge of |V{sub cb}| and |V{sub ub}|. The results are used to constrain the parameters of the CKM matrix and to test the Standard Model predictions for CP-violating effects.
Gabareen Mokhtar, Arafat; Olsen, Stephen Lars; /Seoul Natl. U.
2011-08-12
A brief review of the experimental situation concerning the electrically charged charmoniumlike meson candidates, Z{sup -}, is presented. The Belle Collaboration reported peaks in the {psi}{prime}{pi}{sup -} and {chi}{sub c1}{pi}{sup -} invariant mass distributions in B {yields} {psi}{prime}{pi}{sup -}K and B {yields} {chi}{sub c1}{pi}{sup -}K, respectively. If these peaks are meson resonances, they would have a minimal quark substructure of c{bar c}d{bar u} and be unmistakeably exotic. However, even though the Belle signals have more than 5{sigma} statistical significance, the experimental situation remains uncertain in that none of these peaks have yet been confirmed by other experiments. An analysis by the BABAR Collaboration of B {yields} {psi}{prime}{pi}{sup -}K neither confirms nor contradicts the Belle claim for the Z(4430){sup -} {yields} {psi}{prime}{pi}{sup -}. In the BABAR analysis, B {yields} J/{psi}{pi}{sup -}K decays were also studied, and no evidence for Z(4430){sup -} {yields} J/{psi}{pi}{sup -} was found. In this paper, we review and compare Belle and BABAR results on searches for charged charmonium-like states.
Crowe, K.M.
1992-01-01
The activities of this group are primarily concerned with experiments using the Crystal Barrel Detector. This detector is installed and operating at the Low Energy Antiproton Ring (LEAR) at CERN. QCD, the modem theory of the strong interaction, is reasonably well understood at high energies, but unfortunately, low-energy QCD is still not well understood, and is far from being adequately tested. The Crystal Barrel experiments are designed to provide some of the tests. The basic line of research involves meson spectroscopy, analyses bearing on the quark and/or gluon content of nuclear states, and the exploration of mechanisms and rules which govern p[bar p] annihilation dynamics. The Crystal Barrel Detector detects and identifies charged and neutral particles with a geometric acceptance close to 100%. The principal component of the detector is an array of 1,380 CsI(TI) crystals. These crystals surround a Jet Drift Chamber (JDC), located in a 1.5 Tesla magnetic field, which measures the momentum and dE/dx of charged particles. One of the very interesting physics goals of the detector is a search for exotic mesonic states -- glueballs and hybrids. Annihilation at rest will be studied with both liquid and gaseous hydrogen targets. The gaseous target offers the possibility of triggering on atomic L-shell X rays so that specific initial angular momentum states can be studied.These topics as well as other related topics are discussed in this report.
Crowe, K.M.
1992-12-01
The activities of this group are primarily concerned with experiments using the Crystal Barrel Detector. This detector is installed and operating at the Low Energy Antiproton Ring (LEAR) at CERN. QCD, the modem theory of the strong interaction, is reasonably well understood at high energies, but unfortunately, low-energy QCD is still not well understood, and is far from being adequately tested. The Crystal Barrel experiments are designed to provide some of the tests. The basic line of research involves meson spectroscopy, analyses bearing on the quark and/or gluon content of nuclear states, and the exploration of mechanisms and rules which govern p{bar p} annihilation dynamics. The Crystal Barrel Detector detects and identifies charged and neutral particles with a geometric acceptance close to 100%. The principal component of the detector is an array of 1,380 CsI(TI) crystals. These crystals surround a Jet Drift Chamber (JDC), located in a 1.5 Tesla magnetic field, which measures the momentum and dE/dx of charged particles. One of the very interesting physics goals of the detector is a search for exotic mesonic states -- glueballs and hybrids. Annihilation at rest will be studied with both liquid and gaseous hydrogen targets. The gaseous target offers the possibility of triggering on atomic L-shell X rays so that specific initial angular momentum states can be studied.These topics as well as other related topics are discussed in this report.
Meson Production in p+d Reactions
GEM Collaboration
2000-12-31
Pion and {eta} production on the deuteron are studied at energies in the vicinity of the absolute threshold. The data are expected to be sensitive to high momentum components in the deuteron wavefunction as well as to two-step processes.
Backward-meson photoproduction at SPring-8/LEPS
Sumihama, Mizuki
2011-10-21
Photoproductions of {pi}{sup 0} and {eta} mesons from protons were measured at backward angles. Bump structures were observed in both reaction, and a strong angular distribution of photon asymmetries was found in {pi}{sup 0} production. These structures are discussed connecting with baryon resonances.
Status of Meson Photoproduction Experiments with CLAS
Pasyuk, Eugene A.
2014-01-01
A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to baryon spectroscopy. Meson photoproduction experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams in combination with longitudinally and transversely polarized frozen spin targets provide unique conditions for this type of experiments. For the first time, a complete or nearly complete measurement became possible and will allow model independent extraction of the reaction amplitude. The measurements were complete with both proton and deuteron targets. An overview of the collected experimental data will be presented.
PSEUDOVECTOR MESONS, HYBRIDS AND GLUEBALLS
L. BURAKOVSKY; P. PAGE
2000-06-01
The authors consider glueball-(hybrid) meson mixing for the low-lying four pseudovector states. The h{sub 1}{prime}(1380) decays dominantly to K*K with some presence in {rho}{pi} and {omega}{eta}. The newly observed h{sub 1}(1600) has a D- to S-wave width ratio to {omega}{eta} which makes its interpretation as a conventional meson unlikely. They predict the decay pattern of the isopartner conventional or hybrid meson b{sub 1}(1650). A notably narrow s{bar s} partner h{sub 1}{prime}(1810) is predicted.
Photoproduction of hybrid mesons
Barnes, T. |
1998-11-01
In this contribution the author discusses prospects for photoproducing hybrid mesons at CEBAF, based on recent model results and experimental indications of possible hybrids. One excellent opportunity appears to be a search for I = 1, J{sup PC} = 2{sup +{minus}} ``b{sub 2}{sup o}`` hybrids in (a{sub 2}{pi}){sup o} through diffraction photoproduction. Other notable possibilities accessible through {pi}{sup +}; {pi}{sub J}{sup +}(1770) in f{sub 2}{pi}{sup +} and (b{sub 1}{pi}){sup +}; {pi}{sup +}(1800) in f{sub 0}{pi}{sup +}, f{sub 2}{pi}{sup =}, {rho}{sup +}{omega} and ({rho}{pi}){sup +}; a{sub 1} in f{sub 1}{pi}{sup +} and f{sub 2}{pi}{sup +}; and {omega} in ({rho}{pi}){sup o}, {omega}{eta} and K{sub 1}K.
Electromagnetic structure of vector mesons
NASA Astrophysics Data System (ADS)
Adamuščín, C.; Dubnička, S.; Dubničková, A. Z.
2014-11-01
Electromagnetic structure of the complete nonet of vector mesons (ρ0, ρ+, ρ-, ω, ϕ, K*0, K*+, K¯*0, K*-) is investigated in the framework of the Unitary and Analytic model and insufficient experimental information on it is discussed.
Strange meson production in Al+Al collisions at 1.9 A GeV
NASA Astrophysics Data System (ADS)
Gasik, P.; Piasecki, K.; Herrmann, N.; Leifels, Y.; Matulewicz, T.; Andronic, A.; Averbeck, R.; Barret, V.; Basrak, Z.; Bastid, N.; Benabderrahmane, M. L.; Berger, M.; Buehler, P.; Cargnelli, M.; Čaplar, R.; Crochet, P.; Czerwiakowa, O.; Deppner, I.; Dupieux, P.; Dželalija, M.; Fabbietti, L.; Fodor, Z.; Gašparić, I.; Grishkin, Y.; Hartmann, O. N.; Hildenbrand, K. D.; Hong, B.; Kang, T. I.; Kecskemeti, J.; Kim, Y. J.; Kirejczyk, M.; Kiš, M.; Koczon, P.; Kotte, R.; Lebedev, A.; Le Fèvre, A.; Liu, J. L.; Lopez, X.; Manko, V.; Marton, J.; Münzer, R.; Petrovici, M.; Rami, F.; Reischl, A.; Reisdorf, W.; Ryu, M. S.; Schmidt, P.; Schüttauf, A.; Seres, Z.; Sikora, B.; Sim, K. S.; Simion, V.; Siwek-Wilczyńska, K.; Smolyankin, V.; Suzuki, K.; Tymiński, Z.; Wagner, P.; Weber, I.; Widmann, E.; Wiśniewski, K.; Xiao, Z. G.; Yushmanov, I.; Zhang, Y.; Zhilin, A.; Zinyuk, V.; Zmeskal, J.
2016-06-01
The production of K+, K- and φ (1020) mesons is studied in Al+Al collisions at a beam energy of 1.9A GeV which is close to or below the production threshold in NN reactions. Inverse slopes, anisotropy parameters, and total emission yields of K± mesons are obtained. A comparison of the ratio of kinetic energy distributions of K- and K+ mesons to the HSD transport model calculations suggests that the inclusion of the in-medium modifications of kaon properties is necessary to reproduce the ratio. The inverse slope and total yield of φ mesons are deduced. The contribution to K- production from φ meson decays is found to be [17 ± 3(stat)^{+2}_{-7}(syst)]%. The results are in line with the previous K± and φ data obtained for different colliding systems at similar incident beam energies.
Medium Modification of Vector Mesons
Chaden Djalali, Michael Paolone, Dennis Weygand, Michael H. Wood, Rakhsha Nasseripour
2011-03-01
The theory of the strong interaction, Quantum Chromodynamics (QCD), has been remarkably successful in describing high-energy and short-distance-scale experiments involving quarks and gluons. However, applying QCD to low energy and large-distance scale experiments has been a major challenge. Various QCD-inspired models predict a partial restoration of chiral symmetry in nuclear matter with modifications of the properties of hadrons from their free-space values. Measurable changes such as a shift in mass and/or a change of width are predicted at normal nuclear density. Photoproduction of vector mesons off nuclei have been performed at different laboratories. The properties of the ρ, ω and φ mesons are investigated either directly by measuring their mass spectra or indirectly through transparency ratios. The latest results regarding medium modifications of the vector mesons in the nuclear medium will be discussed.
NASA Astrophysics Data System (ADS)
Godfrey, Stephen; Moats, Kenneth; Swanson, Eric S.
2016-09-01
Properties of bottom and bottom-strange mesons are computed in two relativized quark models. Model masses and wave functions are used to predict radiative transition rates, and the 3P0 quark pair creation model is used to compute strong decay widths. A comparison to recently observed bottom and bottom-strange states is made. We find that there are numerous excited B and Bs mesons that have relatively narrow widths and significant branching ratios to simple final states such as B π , B*π , B K , and B*K that could be observed in the near future.
Quantum Electrodynamics for Vector Mesons
Djukanovic, Dalibor; Schindler, Matthias R.; Scherer, Stefan; Gegelia, Jambul
2005-07-01
Quantum electrodynamics for {rho} mesons is considered. It is shown that, at the tree level, the value of the gyromagnetic ratio of the {rho}{sup +} is fixed to 2 in a self-consistent effective quantum field theory. Further, the mixing parameter of the photon and the neutral vector meson is equal to the ratio of electromagnetic and strong couplings, leading to the mass difference M{sub {rho}}{sub {sup 0}}-M{sub {rho}}{sub {sup {+-}}}{approx}1 MeV at tree order.
Interaction of eta mesons with nuclei.
Kelkar, N G; Khemchandani, K P; Upadhyay, N J; Jain, B K
2013-06-01
Back in the mid-1980s, a new branch of investigation related to the interaction of eta mesons with nuclei came into existence. It started with the theoretical prediction of possible exotic states of eta mesons and nuclei bound by the strong interaction and later developed into an extensive experimental program to search for such unstable states as well as understand the underlying interaction via eta-meson producing reactions. The vast literature of experimental as well as theoretical works that studied various aspects of eta-producing reactions such as the π(+)n → ηp, pd → (3)Heη, p (6)Li → (7)Be η and γ (3)He → η X, to name a few, had but one objective in mind: to understand the eta-nucleon (ηN) and hence the η-nucleus interaction which could explain the production data and confirm the existence of some η-mesic nuclei. In spite of these efforts, there remain uncertainties in the knowledge of the ηN and hence the η-nucleus interaction. Therefore, this review is an attempt to bind together the findings in these works and draw some global and specific conclusions which can be useful for future explorations.The ηN scattering length (which represents the strength of the η-nucleon interaction) using different theoretical models and analyzing the data on η production in pion, photon and proton induced reactions was found to be spread out in a wide range, namely, 0.18 ≤ Re aηN ≤ 1.03 fm and 0.16 ≤ Rm aηN ≤ 0.49 fm. Theoretical searches of heavy η-mesic nuclei based on η-nucleus optical potentials and lighter ones based on Faddeev type few-body approaches predict the existence of several quasibound and resonant states. Although some hints of η-mesic states such as (3)(η)He and (25)(η)Mg do exist from previous experiments, the promise of clearer signals for the existence of η-mesic nuclei lies in the experiments to be performed at the J-PARC, MAMI and COSY facilities in the near future. This review is aimed at giving an overall status
Electromagnetic Meson Production in the Nucleon Resonance Region
Volker Burkert; T.-S. H. Lee
2004-10-01
Recent experimental and theoretical advances in investigating electromagnetic meson production reactions in the nucleon resonance region are reviewed. The article gives a description of current experimental facilities with electron and photon beams and presents a unified derivation of most of the phenomenological approaches being used to extract the resonance parameters from the data. The analyses of {pi} and {eta} production data and the resulting transition form factors for the {Delta}(1232)P{sub 33}, N(1535)S{sub 11}, N(1440)P{sub 11}, and N(1520)D{sub 13} resonances are discussed in detail. The status of our understanding of the reactions with production of two pions, kaons, and vector mesons is also reviewed.
Theoretical overview: The New mesons
Quigg, Chris; /Fermilab
2004-11-01
After commenting on the state of contemporary hadronic physics and spectroscopy, I highlight four areas where the action is: searching for the relevant degrees of freedom, mesons with beauty and charm, chiral symmetry and the D{sub sJ} levels, and X(3872) and the lost tribes of charmonium.
Photon-tagged heavy meson production in high energy nuclear collisions
Kang, Z.B.; Vitev, I.
2011-07-26
We study the photon-triggered light and heavy meson production in both p+p and A+A collisions. We find that a parton energy loss approach that successfully describes inclusive hadron attenuation in nucleus-nucleus reactions at RHIC can simultaneously describe well the experimentally determined photon-triggered light hadron fragmentation functions. Using the same framework, we generalize our formalism to study photon-triggered heavy meson production. We find that the nuclear modification of photon-tagged heavy meson fragmentation functions in A+A collision is very different from that of the photon-tagged light hadron case. While photon-triggered light hadron fragmentation functions in A+A collisions are suppressed relative to p+p, photon-triggered heavy meson fragmentation functions can be either enhanced or suppressed, depending on the specific kinematic region. The anticipated smaller energy loss for b-quarks manifests itself as a flatter photon-triggered B-meson fragmentation function compared to that for the D-meson case. We make detailed predictions for both RHIC and LHC energies. We conclude that a comprehensive comparative study of both photon-tagged light and heavy meson production can provide new insights in the details of the jet quenching mechanism.
Has an isotensor meson been seen in pp --> π+/-X-/+?
NASA Astrophysics Data System (ADS)
Dover, Carl B.
1984-10-01
We suggest that the narrow meson X recently observed in the pp --> π+/-X-/+ reaction may have quantum numbers JπC(IG) = 1+/-(2-). Other reactions which test this isotensor assignment are discussed. Laboratoire associé au CNRS.
Recent results on mesonic and non-mesonic weak decays
NASA Astrophysics Data System (ADS)
Botta, Elena
2010-04-01
Recent results from the FINUDA experiment on the Mesonic Weak Decay (MWD) and Non-Mesonic Weak Decay (NMWD) channels of p-shell Λ-hypernuclei are presented and discussed. Magnetic analysis of π's from MWD was performed for the first time for LiΛ7, BeΛ9, BΛ11 and NΛ15; decay rates were evaluated and a spin-parity assignment J=3/2 for NΛ15 ground-state was derived. Spectra of protons from NMWD were obtained for HeΛ5, LiΛ7, BeΛ9, BΛ11, CΛ12, CΛ13, NΛ15 and OΛ16. An estimation of the contributions of both Final State Interactions (FSI) and two-nucleon induced (2N) decay processes was done, following a model independent approach.
Semihadronic and hadronic decays of ρ0 and ω mesons coherently photoproduced in isoscalar nuclei
NASA Astrophysics Data System (ADS)
Das, Swapan
2016-08-01
The interference of ρ0 and ω mesons has been studied in the hadronic and leptonic decay channels, i.e., dipion and dilepton decay channels respectively, but this interference has not been studied yet in the semihadronic or semileptonic decay channel, e.g., V →π0γ . V denotes either a ρ0 or ω meson. To look for this interference in the π0γ decay channel as well as the contribution of the ρ meson to the cross section, the correlated π0γ invariant mass distribution spectra are calculated in the photonuclear reaction in the multi-GeV region. It is assumed that these bosons arise in the final state due to the decay of ρ0 and ω mesons which are photoproduced coherently in the isoscalar nucleus. The elementary reaction in the nucleus is considered to proceed as γ N →V N , V →π0γ . The forward propagation of the ρ and ω mesons and the near forward emission of pions are considered, so that they can be described by the eikonal form. The meson-nucleus interactions are evaluated using the t ϱ approximation. Replacing the decay vertex V →π0γ by V →π+π- in the above formalism, it is also used to study the ρ -ω interference in the π+π- decay channel.
Scalar Mesons and Chiral States
NASA Astrophysics Data System (ADS)
Ishida, M.; Ishida, S.
2004-08-01
The essential points and physical backgrounds of the covariant level-classification scheme, based on Ū(12)SF⊗O(3, 1)L, are reviewed: This scheme is extended from the non-relativistic SU(6)SF⊗O(3)L scheme by introducing the new SU(2)-spin (ρ-spin) degree of freedom, which is necessary for covariant description of composite hadrons. Our scheme predicts the existence of new type of chiral mesons and baryons (Chiralons) out of the conventional SU(6)SF⊗O(3)L scheme. The σ nonet is a typical example of chiralons to be assigned to the (qq¯) relativistic S-wave state. The new narrow mesons Ds(2317)/Ds(2463) are naturally assigned as the ground-state scalar and axial-vector chiralons in the (cs¯) system.
Photoproduction of $\\pi^+ \\pi^-$ meson pairs on the proton
Marco A. Battaglieri; DeVita, Raffaella; Szczepaniak, Adam P.
2009-10-01
The exclusive reaction $\\gamma p \\to p \\pi^+ \\pi^-$ was studied in the photon energy range 3.0 - 3.8 GeV and momentum transfer range $0.4<-t<1.0$ GeV$^2$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was about 20 pb$^{-1}$. The reaction was isolated by detecting the $\\pi^+$ and proton in CLAS, and reconstructing the $\\pi^-$ via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the $S$, $P$, and $D$-waves in the $M_{\\pi^+\\pi^-}$ mass range $0.4-1.4$ GeV were derived performing a partial wave expansion of the extracted moments. Besides the dominant contribution of the $\\rho(770)$ meson in the $P$-wave, evidence for the $f_0(980)$ and the $f_2(1270)$ mesons was found in the $S$ and $D$-waves, respectively. The differential production cross sections $d\\sigma/dt$ for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the $f_0(980)$ has been measured in a photoproduction experiment.
Lazzaro, Alfio; /Milan U. /INFN, Milan
2007-05-11
Symmetries and their conservation laws play a fundamental role in Physics. Among them, the discrete symmetries corresponding to charge (C), parity (P), and time (T) transformations are extensively used in the theory of the elementary particles and their interactions (so called Standard Model (SM)) to give the basis of the fundamental physical description of nature. Eventual discoveries of violations of these symmetries become a crucial test for our understanding of the nature. It was assumed that the three discrete symmetries were not violated until 1956 when it was found that P is violated in the weak interaction. Soon it was understood that also the C is violated in the weak interaction. At that time these two violated symmetries were replaced by their combination, CP, which was considered a new fundamental symmetry. In 1964 also the CP was found violated in the case of the neutral K meson system. Since that year there were many achievements in theories and experiments in order to explain this symmetry violation. In the last five years the main contribution comes from the discovery of the CP violation in B meson system. In this note we will describe briefly how the CP violation is described in the SM and the main experimental results obtained in the B mesons system.
Confirmation of the sigma meson
Toernqvist, N.A.; Roos, M.
1996-03-01
A very general model and an analysis of data on the lightest 0{sup ++} meson nonet shows that the {ital f}{sub 0}(980) and {ital f}{sub 0}(1300) resonance poles are two manifestations of the same {bar {ital ss}} state. On the other hand, the {bar {ital uu}}+{bar {ital dd}} state, when unitarized and strongly distorted by hadronic mass shifts, becomes an extremely broad (880 MeV) and light (860 MeV) resonance, with its pole at {ital s}=0.158{minus}{ital i}0.235 GeV{sup 2}. This is the {sigma} meson required by models for spontaneous breaking of chiral symmetry. It has been named the Higgs meson of QCD, because it generates most of the light hadron masses. It dominates {pi}{pi} scattering below 900 MeV and it is also the resonance required by nuclear physics. {copyright} {ital 1996 The American Physical Society.}
Cranking in hedgehog models with vector mesons
NASA Astrophysics Data System (ADS)
Broniowski, Wojciech; Cohen, Thomas D.
1986-09-01
A cranking calculation is performed in a massive SU(2) × SU(2) × U(1) model with valence quarks and the σ, π, ϱ, A and ω mesons. The nucleon moment of inertia, the N-Δ mass splitting and the proton and neutron charge distributions are obtained. The general framework and the specific ansatz for the cranked fields can be used in any hedgehog model with vector mesons. A possible role of η and δ mesons is also discussed.
Meson Spectroscopy at CLAS and CLAS12
Carlos Salgado
2011-10-01
We report on meson spectroscopy using the CLAS at Jefferson Lab. We study photo-production of exotic mesons and strangeonia on the largest data sample ever to be produced at photon energies of about 5 GeV. We also describe an experiment to continue meson spectroscopy at CLAS12 (CLAS energy upgrade) using electroproduction at very low Q2 ('quasireal photons') up to photon energies of 10 GeV.
D and E mesons and possible KKK enhancements
Bromberg, C.; Dickey, J.; Fox, G.; Gomez, R.; Kropac, W.; Pine, J.; Stampke, S.; Haggerty, H.; Malamud, E.; Abrams, R.; Delzenero, R.; Goldberg, H.; Lopez, F.; Margulies, S.; McLeod, D.; Solomon, J.; Dzierba, A.; Fredericksen, F.; Heinz, R.; Krider, J.; Martin, H.; Petersen, D.
1981-01-01
Results are presented from the study of multikaon final states in the reactions ..pi../sup -/p..-->..K/sup 0/K/sup + -/..pi..minus-or-plusX, K/sup 0/K/sup +/KX at 50 and 100 GeV/c. Here X is semi-inclusive, because a specific forward topology and an interaction registering in the counters sourrounding the target are required. The D(1285) meson is seen in the dr mode, while the E(1420) meson is observed in both the dr and the KK modes. In addition, there are two possible enhancements in the three kaon final state. The first (Mapprox.1840 MeV) is associated with the K/sup 0/f mode and is consistent with being the charmed D/sup 0/. The second, a K state (M = 2003 +- 14 MeV, G = 87 +- 43 MeV), decays into KA/sub 2/.
D and E mesons and possible KKK enhancements
NASA Astrophysics Data System (ADS)
Bromberg, C.; Dickey, J.; Fox, G.; Gomez, R.; Kropac, W.; Pine, J.; Stampke, S.; Haggerty, H.; Malamud, E.; Abrams, R.; Delzenero, R.; Goldberg, H.; Lopez, F.; Margulies, S.; McLeod, D.; Solomon, J.; Dzierba, A.; Fredericksen, F.; Heinz, R.; Krider, J.; Martin, H.; Petersen, D.
1981-01-01
Results are presented from the study of multikaon final states in the reactions r-p→K0K±r∓X˜, K0K+KX˜ at 50 and 100 GeV/c. Here X˜ is semi-inclusive, because a specific forward topology and an interaction registering in the counters sourrounding the target are required. The D(1285) meson is seen in the dr mode, while the E(1420) meson is observed in both the dr and the KK modes. In addition, there are two possible enhancements in the three kaon final state. The first (M∠1840 MeV) is associated with the K0f mode and is consistent with being the charmed D0. The second, a K state (M = 2003±14 MeV, G = 87±43 MeV), decays into KA2.
Meson's correlation functions in a nuclear medium
NASA Astrophysics Data System (ADS)
Park, Chanyong
2016-09-01
We investigate meson's spectrum, decay constant and form factor in a nuclear medium through holographic two- and three-point correlation functions. To describe a nuclear medium composed of protons and neutrons, we consider a hard wall model on the thermal charged AdS geometry and show that due to the isospin interaction with a nuclear medium, there exist splittings of the meson's spectrum, decay constant and form factor relying on the isospin charge. In addition, we show that the ρ-meson's form factor describing an interaction with pseudoscalar fluctuation decreases when the nuclear density increases, while the interaction with a longitudinal part of an axial vector meson increases.
Spin alignment of vector mesons in heavy ion and proton-proton collisions
NASA Astrophysics Data System (ADS)
Ayala, Alejandro; Cuautle, Eleazar; Corral, G. Herrera; Magnin, J.; Montaño, Luis Manuel
2010-01-01
The spin alignment matrix element ρ00 for the vector mesons K and ϕ(1020) has been measured in RHIC at central rapidities. These measurements are consistent with the absence of polarization with respect to the reaction plane in mid-central Au+Au collisions whereas, when measured with respect to the production plane in the same reactions and in p+p collisions, a non-vanishing and p⊥-dependent ρ00 is found. We show that this behavior can be understood in a simple model of vector meson production where the spin of their constituent quarks is oriented during hadronization as the result of Thomas precession.
Photoproduction of ω mesons off the proton
NASA Astrophysics Data System (ADS)
Wilson, A.; Crede, V.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Brinkmann, K. T.; Castelijns, R.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Fuchs, M.; Funke, Chr.; Gregor, R.; Gridnev, A.; Gutz, E.; Hannappel, J.; Hillert, W.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Jude, T.; Junkersfeld, J.; Kalinowsky, H.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Kotulla, M.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schmidt, C.; Schmieden, H.; Shende, S.; Sokhoyan, V.; Sparks, N.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch.; Wiedner, U.
2015-10-01
The differential cross sections and unpolarized spin-density matrix elements for the reaction γp → pω were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV. These observables were measured from the radiative decay of the ω meson, ω →π0 γ. The cross sections cover the full angular range and show the full extent of the t-channel forward rise. The overall shape of the angular distributions in the differential cross sections and unpolarized spin-density matrix elements are in fair agreement with previous data. In addition, for the first time, a beam of linearly-polarized tagged photons in the energy range from 1150 MeV to 1650 MeV was used to extract polarized spin-density matrix elements. These data were included in the Bonn-Gatchina partial wave analysis (PWA). The dominant contribution to ω photoproduction near threshold was found to be the 3 /2+ partial wave, which is primarily due to the sub-threshold N (1720) 3 /2+ resonance. At higher energies, pomeron-exchange was found to dominate whereas π-exchange remained small. These t-channel contributions as well as further contributions from nucleon resonances were necessary to describe the entire dataset: the 1 /2-, 3 /2-, and 5 /2+ partial waves were also found to contribute significantly.
NASA Astrophysics Data System (ADS)
Roe, Natalie A.
2001-04-01
Our world manifestly violates CP, the symmetry between matter and antimatter; there is no observational evidence for any significant amount of antimatter in the Universe. Andrei Sakharov was the first to point out that, in the context of Big Bang theory, a matter-dominated universe requires CP violation at the quantum level. Indeed, CP violation was subsequently observed as a tiny effect in K-meson decays, and it can be naturally accommodated in the Standard Model of fundamental particles with 3 generations of quarks. However, to produce the observed baryon asymmetry, baryogenesis calculations require more CP violation than the Standard Model affords. This is an intriguing puzzle whose solution will require input from both particle physics and cosmology, and it has inspired particle physicists to study CP violation with greater precision in a new generation of experiments. We are now entering this exciting new era in CP violation studies. Several new or upgraded experiments plan a program of detailed measurements of CP violating effects in B mesons. The predicted asymmetries are large, observable in a variety of decay channels, and the theoretical uncertainties are small for the best modes. Some interesting experimental results have recently been announced, and more precise measurements will soon follow. Future experiments are already planned to make even more definitive measurements. In this talk I will review the theoretical predictions and the connection to cosmology, survey the experimental scene, and describe how the study of CP violation in B mesons will allow us to make stringent tests of the Standard Model.
Are the exotic mesons and baryons, recently observed, a signature of quark-hadron duality ?
NASA Astrophysics Data System (ADS)
Tatischeff, Boris
2002-06-01
Narrow low mass exotic hadronic structures were recently observed in mesons, baryons and dibaryons. Narrow mesons, in the mass range 300less-than-or-equal]M[less-than-or-equal 750 MeV, were observed using the pp [right arrow] ppX reaction. Narrow baryons in the mass range 1000less-than-or-equal]M[less-than-or-equal 1400 MeV were observed using the pp [right arrow] ppi+X and dp [right arrow] ppX reactions. The statistical significances of these structures vary up to 4.6 standard deviations (S.D.) for mesons and up to 16.9 S.D. for baryons. These exotic states are associated with precursor quark deconfinement.
Measurement of the meson lifetime using decays
NASA Astrophysics Data System (ADS)
Aaij, R.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Cartelle, P. Alvarez; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; Anderlini, L.; Anderson, J.; Andreassen, R.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Gutierrez, O. Aquines; Archilli, F.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Balagura, V.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Bauer, Th.; Bay, A.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Belogurov, S.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Bizzeti, A.; Bjørnstad, P. M.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Brambach, T.; van den Brand, J.; Bressieux, J.; Brett, D.; Britsch, M.; Britton, T.; Brook, N. H.; Brown, H.; Bursche, A.; Busetto, G.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Callot, O.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Campana, P.; Campora Perez, D.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carranza-Mejia, H.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cenci, R.; Charles, M.; Charpentier, Ph.; Cheung, S.-F.; Chiapolini, N.; Chrzaszcz, M.; Ciba, K.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coca, C.; Coco, V.; Cogan, J.; Cogneras, E.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Counts, I.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dalseno, J.; David, P.; David, P. N. Y.; Davis, A.; De Bonis, I.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Silva, W.; De Simone, P.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Di Canto, A.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dorosz, P.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Falabella, A.; Färber, C.; Farinelli, C.; Farry, S.; Ferguson, D.; Fernandez Albor, V.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Fitzpatrick, C.; Fontana, M.; Fontanelli, F.; Forty, R.; Francisco, O.; Frank, M.; Frei, C.; Frosini, M.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gandelman, M.; Gandini, P.; Gao, Y.; Garofoli, J.; Garra Tico, J.; Garrido, L.; Gaspar, C.; Gauld, R.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianelle, A.; Gibson, V.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gordon, H.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Hafkenscheid, T. W.; Haines, S. C.; Hall, S.; Hamilton, B.; Hampson, T.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; Hartmann, T.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Hunt, P.; Huse, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Iakovenko, V.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jans, E.; Jaton, P.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kaballo, M.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Kenyon, I. R.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Klaver, S.; Kochebina, O.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Korolev, M.; Kozlinskiy, A.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucharczyk, M.; Kudryavtsev, V.; Kurek, K.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanciotti, E.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leo, S.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Liu, G.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lopez-March, N.; Lowdon, P.; Lu, H.; Lucchesi, D.; Luisier, J.; Luo, H.; Luppi, E.; Lupton, O.; Machefert, F.; Machikhiliyan, I. V.; Maciuc, F.; Maev, O.; Malde, S.; Manca, G.; Mancinelli, G.; Manzali, M.; Maratas, J.; Marconi, U.; Marino, P.; Märki, R.; Marks, J.; Martellotti, G.; Martens, A.; Martín Sánchez, A.; Martinelli, M.; Martinez Santos, D.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathe, Z.; Matteuzzi, C.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; McSkelly, B.; Meadows, B.; Meier, F.; Meissner, M.; Merk, M.; Milanes, D. A.; Minard, M.-N.; Molina Rodriguez, J.; Monteil, S.; Moran, D.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Mountain, R.; Mous, I.; Muheim, F.; Müller, K.; Muresan, R.; Muryn, B.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nasteva, I.; Needham, M.; Neubert, S.; Neufeld, N.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Nicol, M.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; Oblakowska-Mucha, A.; Obraztsov, V.; Oggero, S.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, G.; Orlandea, M.; Otalora Goicochea, J. M.; Owen, P.; Oyanguren, A.; Pal, B. K.; Palano, A.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L.; Parkes, C.; Parkinson, C. J.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pavel-Nicorescu, C.; Pazos Alvarez, A.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perez Trigo, E.; Perret, P.; Perrin-Terrin, M.; Pescatore, L.; Pesen, E.; Pessina, G.; Petridis, K.; Petrolini, A.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Pistone, A.; Playfer, S.; Plo Casasus, M.; Polci, F.; Polok, G.; Poluektov, A.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Powell, A.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Rachwal, B.; Rademacker, J. H.; Rakotomiaramanana, B.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redford, S.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, A.; Rinnert, K.; Rives Molina, V.; Roa Romero, D. A.; Robbe, P.; Roberts, D. A.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruffini, F.; Ruiz, H.; Ruiz Valls, P.; Sabatino, G.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santovetti, E.; Sapunov, M.; Sarti, A.; Satriano, C.; Satta, A.; Savrie, M.; Savrina, D.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmidt, B.; Schneider, O.; Schopper, A.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Seco, M.; Semennikov, A.; Senderowska, K.; Sepp, I.; Serra, N.; Serrano, J.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, O.; Shevchenko, V.; Shires, A.; Silva Coutinho, R.; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, N. A.; Smith, E.; Smith, E.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Sparkes, A.; Spinella, F.; Spradlin, P.; Stagni, F.; Stahl, S.; Steinkamp, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Stroili, R.; Subbiah, V. K.; Sun, L.; Sutcliffe, W.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szilard, D.; Szumlak, T.; T'Jampens, S.; Teklishyn, M.; Tellarini, G.; Teodorescu, E.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Tran, M. T.; Tresch, M.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ubeda Garcia, M.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; Voss, H.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Webber, A. D.; Websdale, D.; Whitehead, M.; Wicht, J.; Wiechczynski, J.; Wiedner, D.; Wiggers, L.; Wilkinson, G.; Williams, M. P.; Williams, M.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wu, S.; Wyllie, K.; Xie, Y.; Xing, Z.; Yang, Z.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, F.; Zhang, L.; Zhang, W. C.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.; Zvyagin, A.
2014-05-01
The lifetime of the meson is measured using semileptonic decays having a meson and a muon in the final state. The data, corresponding to an integrated luminosity of , are collected by the LHCb detector in collisions at a centre-of-mass energy of 8 TeV. The measured lifetime is where the first uncertainty is statistical and the second is systematic.
Meson-photon transition form factors
Balakireva, Irina; Lucha, Wolfgang; Melikhov, Dmitri
2012-10-23
We present the results of our recent analysis of the meson-photon transition form factors F{sub P{gamma}}(Q{sup 2}) for the pseudoscalar mesons P {pi}{sup 0},{eta},{eta} Prime ,{eta}{sub c}, using the local-duality version of QCD sum rules.
Nonrelativistic quark-antiquark potential for mesons
NASA Astrophysics Data System (ADS)
Leeb, H.; Fiedeldey, H.; Sofianos, S. A.; Lipperheide, R.; de la Ripelle, M. Fabre
1990-02-01
A flavour- and nearly model-independent quark-antiquark potential has been determined by fitting the masses of the vector mesons. The uncertainties in the potential, obtained by an error analysis of the fitting procedure, clearly indicate that the spectra of known mesons determine the potential only between r = 0.7 fm and r = 1.8 fm.
Excited light meson spectroscopy from lattice QCD
Christopher Thomas, Hadron Spectrum Collaboration
2012-04-01
I report on recent progress in calculating excited meson spectra using lattice QCD, emphasizing results and phenomenology. With novel techniques we can now extract extensive spectra of excited mesons with high statistical precision, including spin-four states and those with exotic quantum numbers. As well as isovector meson spectra, I will present new calculations of the spectrum of excited light isoscalar mesons, something that has up to now been a challenge for lattice QCD. I show determinations of the flavor content of these mesons, including the eta-eta' mixing angle, providing a window on annihilation dynamics in QCD. I will also discuss recent work on using lattice QCD to map out the energy-dependent phase shift in pi-pi scattering and future applications of the methodology to the study of resonances and decays.
Light Vector Mesons in the Nuclear Medium
Wood, Michael; Nasseripour, Rakhsha; Weygand, Dennis; Djalali, Chaden; Tur, Clarisse; Mosel, Ulrich; Muehlich, Pascal; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Ambrozewicz, Pawel; Anghinolfi, Marco; Asryan, Gegham; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, James; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Carnahan, Bryan; Casey, Liam; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dharmawardane, Kahanawita; Dickson, Richard; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Feldman, Gerald; Feuerbach, Robert; Fradi, Ahmed; Funsten, Herbert; Garcon, Michel; Gavalian, Gagik; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gordon, Christopher; Gothe, Ralf; Griffioen, Keith; Guidal, Michel; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hakobyan, Rafael; Hanretty, Charles; Hardie, John; Hassall, Neil; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Kellie, James; Khandaker, Mahbubul; Khetarpal, Puneet; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Krahn, Zebulun; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Lachniet, Jeff; Laget, Jean; Langheinrich, Jorn; Lawrence, David; Li, Ji; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Prok, Yelena; Protopopescu, Dan; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Ronchetti, Federico; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Smith, Elton; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinsky, Aleksey; Stepanyan, Stepan; Stepanyan, Samuel; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Williams, Michael; Wolin, Elliott; Yegneswaran, Amrit; Zana, Lorenzo; Zhang, Bin; Zhang, Jixie; Zhao, Bo; Zhao, Zhiwen
2008-07-01
The light vector mesons ($\\rho$, $\\omega$, and $\\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\\rho$ meson mass spectrum was extracted after the $\\omega$ and $\\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body eff
Rescattering in Meson Photoproduction off Few Body Systems
Jean-Marc Laget
2006-04-01
Exclusive reactions induced at high momentum transfer in few body systems allow to adjust the formation time of the produced particles to the distance between two nucleons in the target. They are the best windows to study the propagation of exotic configurations of hadrons such as for instance the onset of color transparency. It may appear earlier in meson photo-production reactions, in the strange sector more particularly, than in more classical quasi elastic scattering of electrons. More generally, those reactions provide them with the best tool to determine the cross section of the scattering of various hadrons (strange particles, vector mesons) with nucleon, to better understand the mechanisms of their formation in cold hadronic matter, and to access the production of possible exotic states. At the top of the unitary rescattering peak (triangular logarithmic singularity), the reaction amplitude is on solid ground since it depends only on on-shell elementary amplitudes and on low momentum components of the nuclear wave function.
Light scalar mesons in central production at COMPASS
NASA Astrophysics Data System (ADS)
Austregesilo, Alexander
2016-05-01
COMPASS is a fixed-target experiment at the CERN SPS that studies the spectrum of light-quark hadrons. In 2009, it collected a large dataset using a 190 GeV/c positive hadron beam impinging on a liquid-hydrogen target in order to measure the central exclusive production of light scalar mesons. One of the goals is the search for so-called glueballs, which are hypothetical meson-like objects without valence-quark content. We study the decay of neutral resonances by selecting centrally produced pion pairs from the COMPASS dataset. The angular distributions of the two pseudoscalar mesons are decomposed in terms of partial waves, where particular attention is paid to the inherent mathematical ambiguities. The large dataset allows us to perform a detailed analysis in bins of the two squared four-momentum transfers carried by the exchange particles in the reaction. Possible parameterisations of the mass dependence of the partial-wave amplitudes in terms of resonances are also discussed.
SUITABILITY OF A NEW CALORIMETER FOR EXOTIC MESON SEARCHES
Bookwalter, C.; Ostrovidov, A.; Eugenio, P.
2007-01-01
Exotic mesons, particles that have quantum numbers that are inaccessible to conventional quark-model mesons, are predicted by quantum chromodynamics (QCD), but past experiments seeking to identify exotic candidates have produced controversial results. The HyCLAS experiment (E04005) at Thomas Jefferson National Accelerator Facility (TJNAF) proposes the use of the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) in Hall B to study the photoproduction of exotic mesons. However, the base detector package at CLAS is not ideal for observing and measuring neutral particles, particularly at forward angles. The Deeply Virtual Compton Scattering (DVCS) experiment at TJNAF has commissioned a new calorimeter for detecting small-angle photons, but studies must be performed to determine its suitability for a meson spectroscopy experiment. The ηπ system has been under especial scrutiny in the community as a source for potential exotics, so the new calorimeter’s ability at reconstructing these resonances must be evaluated. To achieve this, the invariant mass of showers in the calorimeter are reconstructed. Also, two electroproduction reaction channels analogous to photoproduction channels of interest to HyCLAS are examined in DVCS data. It is found that, while not ideal, the new calorimeter will allow access to additional reaction channels, and its inclusion in HyCLAS is warranted. Results in basic shower reconstruction show that the calorimeter has good effi ciency in resolving π° decays, but its η reconstruction is not as strong. When examining ep → epπ°η, preliminary reconstruction of the ηπ° system shows faint signals in the a0(980) region. In the ep → e n π+ η channel, preliminary reconstruction of the ηπ+ system gave good signals in the a0(980) and a2(1320) regions, but statistics were poor. While more analyses are necessary to improve statistics and remove background, these preliminary results support the claim
Photoproduction of the rho meson and its magnetic moments
Kaneko, Hiromi; Hosaka, Atsushi; Scholten, Olaf
2011-10-21
We study photoproduction of {rho} meson in a model of hidden local symmetry. We introduce the {rho} meson on a hidden gauge boson and phenomenological {rho} meson-nucleon Lagrangian is constructed respecting chiral symmetry. It turns out that the {sigma}-exchange interaction plays an important role in neutral {rho} meson photoproduction to reproduce the experimental cross sections. In charged {rho} meson photoproduction, the model takes into account the {rho} meson magnetic moments from the three-point vertex in the kinetic terms. We show that the magnetic moment of the charged {rho} meson has a significant effect on the total cross sections in proportion to the photon energies.
A search for the Bs meson in Υ(5S) decays
NASA Astrophysics Data System (ADS)
Shipsey, Ian
2004-05-01
The CLEO III detector has recorded approximately 0.5 fb-1 of e^+ e^- annihilation data at the Υ(5S) resonance. Using this data sample, we have searched for fully reconstructed Bs mesons in the reaction Υ(5S) arrow B_s^(*) barB_s^(*)
GlueX: Meson Spectroscopy in Photoproduction
Salgado, Carlos; Smith, Elton S.
2014-03-01
The goal of the GlueX experiment \\cite{gluex} is to provide crucial data to help understand the soft gluonic fields responsible for binding quarks in hadrons. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. Photoproduction is expected to be effective in producing exotic hybrids but there is little data on the photoproduction of light mesons. GlueX will use the new 12-GeV electron beam at Jefferson Lab to produce a 9-GeV beam of linearly polarized photons using the technique of coherent bremsstrahlung. A solenoid-based hermetic detector is under construction, which will be used to collect data on meson production and decays. These data will also be used to study the spectrum of conventional mesons, including the poorly understood excited vector mesons. This talk will give an update on the experiment as well as describe theoretical developments \\cite{Dudek:2011bn} to help understand how these data can provide insights into the fundamental theory of strong interactions.
1988 CELLO, JADE, and PLUTO contributions to ''exotic'' meson spectroscopy
Feindt, M.
1989-04-25
This article reviews selected recent results on resonance formation in ..gamma gamma.. reactions obtained with the CELLO, JADE, and PLUTO spectrometers at the /ital e//sup +//ital e/minus// storage ring PETRA. New stringent limits on the ..gamma gamma.. coupling of glueball candidates as well as new results on tensor and scalar mesons are presented. The recent observation of ..pi../sub 2/(1680) formation is confirmed by the CELLO group. Finally the two spin 1 states observed in ..gamma gamma../sup */ interactions, in particular the parity of the /ital X//sub 1/(1420) and the model dependence of present analyses are discussed.
Photoproduction of ω mesons off nuclei and impact of polarization on the meson-nucleon interaction
Chudakov, Eugene A.; Gevorkyan, Sergey; Somov, Alexander
2016-01-25
We consider photoproduction of ω mesons off complex nuclei to study interactions of transversely and longitudinally polarized vector mesons with nucleons. Whereas the total cross section for interactions of the transversely polarized vector mesons with nucleons σT = σ(VTN) can be obtained from coherent photoproduction, measurements of vector meson photoproduction in the incoherent region provide a unique opportunity to extract the not-yet-measured total cross section for longitudinally polarized mesons σL = σ(VLN). The predictions for the latter strongly depend on the theoretical approaches. Furthermore, this work is stimulated by the construction of the new experiment GlueX at Jefferson Lab, designedmore » to study the photoproduction of mesons in a large beam energy range up to 12 GeV.« less
Some New Features in the Pseudoscalar Meson and Vector Meson Photoproductions
NASA Astrophysics Data System (ADS)
Yu, Byung Geel; Park, Yong Jae; Choi, Ki-Seok; Nam, Seung-il; Choi, Tae-Keun; Oh, Yongseok
2013-08-01
We investigate the role of the t-channel meson exchange in various photoproduction processes to discuss features of the respective production mechanism. For the less model-dependent analysis we work with the t-channel meson pole reggeized in the Born approximation amplitude. With the meson-baryon coupling constants chosen consistently with symmetry prediction we show that the Reggeized pole model could reproduce the experimental data to a good degree in the lower energy region. Numerical consequences show the significance of the tensor meson exchange in the γ p → K +Λ, the dominance of the pseudoscalar meson exchange in the πΔ (and KΣ*) processes, and the sizable role of the vector-meson magnetic moment in the charged ρ (and K*) photoproductions, respectively. These new features from the present analyses could provide a useful guide for future study of the N* resonances in the low energy region.
Charge asymmetry in charmed-meson photoproduction
Berezhnoy, A. V. Likhoded, A. K.
2006-01-15
Within the perturbative-recombination model, the charge asymmetries in the D*{sup +}-D*{sup -}, D*{sup 0}-D*{sup 0}, and D{sup +}{sub s}-D{sup -}{sub s} yields are estimated under the kinematical conditions of the COMPASS experiment. Corrections that arise owing to the mass of a light quark in a charmed meson are taken into account. The yield of D{sup +}{sub s} mesons is predicted to be large in relation to the yield of D{sup -}{sub s} mesons.
From the {psi} to charmed mesons
Goldhaber, G. |
1994-11-01
This talk deals with the author`s recollections about the discoveries of the J/{psi} the {psi}{prime} as well as psion spectroscopy and charmed mesons. He gives a chronology for the {psi} and {psi}{prime} discoveries. He also discusses the events which led to the charmed meson discovery as well as detailed discussions on the proof that the resonance observed in the K{sup {minus}} {pi}{sup +} system, at 1,865 MeV, was indeed the predicted charmed meson.
Meson spectroscopy and properties using dyson-schwinger equations.
Krassnigg, A.; Roberts, C. D.; Wright, S. V.; Physics; Univ. of Graz
2007-01-30
We study pseudoscalar and scalar mesons using a practical and symmetry preserving truncation of QCD's Dyson-Schwinger equations. We investigate and compare properties of ground and radially excited meson states. In addition to exact results for radial meson excitations we also present results for meson masses and decay constants from the chiral limit up to the charm-quark mass, e.g., the mass of the {chi}{sub c0}(2P) meson.
Skarha, J.E.; CDF Collaboration
1994-08-01
Measurements of the B{sub u}, B{sub d}, and B{sub s} meson lifetime using semileptonic B{sub U} {yields} e{nu}D* X, B{sub s} {yields} l{nu}D{sub s}X events and exclusive B{sub u} {yields} {psi}({prime})K({sub s})(*)B{sub s} {yields} {psi}{phi} events are presented. These results used the precise position measurements of the CDF SVX silicon vertex detector and were obtained from a 19.3 pb{sup {minus}1} sample of 1.8 TeV {bar p}p collisions collected in 1992--93 at the Fermilab Tevatron collider. Comparisons with previous measurements will be shown.
Tetraquarks in the 1 /N expansion and meson-meson resonances
NASA Astrophysics Data System (ADS)
Maiani, L.; Polosa, A. D.; Riquer, V.
2016-06-01
Diquarks are found to have the right degrees of freedom to describe the tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact tetraquarks result as intermediate states in non-planar diagrams of the 1 /N expansion and the corresponding resonances are narrower than what estimated before. The proximity of tetraquarks to meson-thresholds has an apparent role in this analysis and, in the language of meson molecules, an halving rule in the counting of states is obtained.
Recent progress on light scalar mesons
Peláez, J. R.
2014-07-23
This is a brief account of the recent developments on the determination of the mass and widths of the much debated scalar mesons, paying particular attention to the causes of major revision of the σ or f{sub 0}(500) meson in the last edition of the Review of Particle Physics, which has finally acknowledged that the situation concerning the mass and width of this controversial state has been settled, although this was already well-known to scalar meson practitioners for about a decade. I will briefly comment on the dispersive approach, followed by several groups, which seems to have been the most decisive in support of the existence and precise determinations of scalar meson properties.
Gubler, Philipp; Hattori, Koichi; Lee, Su Houng; Oka, Makoto; Ozaki, Sho; Suzuki, Kei
2016-03-15
In this paper, we investigate the mass spectra of open heavy flavor mesons in an external constant magnetic field within QCD sum rules. Spectral Ansatze on the phenomenological side are proposed in order to properly take into account mixing effects between the pseudoscalar and vector channels, and the Landau levels of charged mesons. The operator product expansion is implemented up to dimension-5 operators. As a result, we find for neutral D mesons a significant positive mass shift that goes beyond simple mixing effects. In contrast, charged D mesons are further subject to Landau level effects, which together with the mixingmore » effects almost completely saturate the mass shifts obtained in our sum rule analysis.« less
On meson melting in the quark medium
NASA Astrophysics Data System (ADS)
Fadafan, K. Bitaghsir; Azimfard, E.
2012-10-01
We consider a heavy quark-antiquark (qq¯) pair as a heavy meson in the medium composed of light quarks and gluons. By using the AdS/CFT correspondence, the properties of this system are investigated. In particular, we study the inter-quark distance and it is shown that the mechanism of melting in the quark-gluon plasma and in the hadronic phase is the same. It is found that by considering finite-coupling corrections, the inter-quark distance of a heavy meson decreases. As a result a heavy meson like J/ψ will melt at higher temperatures. By considering rotating heavy mesons, we discuss melting of exited states like χc and ψ'.
Deeply Virtual Compton Scattering and Meson Production at Jlab/CLAS
Hyon-Suk Jo
2012-04-01
This report reviews the recent experimental results from the CLAS collaboration (Hall B of Jefferson Lab, or JLab) on Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) and discusses their interpretation in the framework of Generalized Parton Distributions (GPDs). The impact of the experimental data on the applicability of the GPD mechanism to these exclusive reactions is discussed. Initial results obtained from JLab 6 GeV data indicate that DVCS might already be interpretable in this framework while GPD models fail to describe the exclusive meson production (DVMP) data with the GPD parameterizations presently used. An exception is the {phi} meson production for which the GPD mechanism appears to apply. The recent global analyses aiming to extract GPDs from fitting DVCS CLAS and world data are discussed. The GPD experimental program at CLAS12, planned with the upcoming 12 GeV upgrade of JLab, is briefly presented.
Electroproduction of the {phi}(1020) Vector Meson at 4 GeV
Konstantin Loukachine
2000-02-01
We studied the reaction ep {yields} e{prime}p{prime}{phi} with a 4.2 GeV incident electron beam in the region of the electroproduction variables Q{sup 2} from 0.7 to 2.2 GeV{sup 2} and W from 2.0 to 2.6 GeV. The data were taken and analyzed at the Thomas Jefferson National Accelerator Facility. For the first time, we observe the expected t-slope dependence on Q{sup 2} and {Delta}{tau} in {phi} vector meson production. We find that the width of the forward {phi}-meson diffraction peak increases rapidly as the interaction time decreases below c{Delta}{tau} of 1 fm. Within a simple optical model framework, the data show that {phi} meson has a smaller size than the {rho}. The measured {phi} cross-section dependence on Q{sup 2} is in a good agreement with previous measurements and well-described by the phenomenological Pomeron exchange model. Our cross-section data do not favor the standard Vector Meson Dominance and s{bar s}-knockout model predictions. From the angular distribution of the decay {phi} {yields} K{sup +} K{sup -}, assuming the s-channel helicity conservation, we extracted the longitudinal-to-transverse cross-section ratio, R, and Vector Meson Dominance scaling parameter, {xi}{sup 2}, which are consistent with the previous measurements and the model expectations.
Strangeness in the Meson Cloud Model
Signal, A. I.
2010-07-27
I review progress in calculating strange quark and antiquark distributions of the nucleon using the meson cloud model. This progress parallels that of the meson cloud model, which is now a useful theoretical basis for understanding symmetry breaking in nucleon parton distribution functions. I examine the breaking of symmetries involving strange quarks and antiquarks, including quark--antiquark symmetry in the sea, SU(3) flavour symmetry and SU(6) spin-flavour symmetry.
Meson and baryon spectroscopy on the lattice
David Richards
2010-12-01
Recent progress at understanding the excited state spectrum of mesons and baryons is described. I begin by outlining the application of the variational method to compute the spectrum, and the program of anisotropic clover lattice generation designed for hadron spectroscopy. I present results for the excited meson spectrum, with continuum quantum numbers of the states clearly delineated. I conclude with recent results for the low lying baryon spectrum, and the prospects for future calculations.
Rare meson decays into very light neutralinos
O'Leary, Ben
2010-02-10
Results are presented for the two-body decays of mesons into light neutralinos and from the first complete calculation of the loop-induced decays of kaons to pions plus light neutralinos and of B mesons to kaons plus light neutralinos. The branching ratios are shown to be strongly suppressed within the MSSM with minimal flavor violation, and no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed.
Andreas S. Kronfeld
2000-10-17
Computational and theoretical developments in lattice QCD calculations of B and D mesons are surveyed. Several topical examples are given: new ideas for calculating the HQET parameters {bar {Lambda}} and {lambda}{sub 1}; form factors needed to determine {vert_bar}V{sub cb}{vert_bar} and {vert_bar}V{sub ub}{vert_bar}; bag parameters for the mass differences of the B mesons; and decay constants. Prospects for removing the quenched approximation are discussed.
Branching ratios of B{sub c} meson decays into tensor meson in the final state
Sharma, Neelesh
2010-01-01
Two-body hadronic weak decays of B{sub c} meson involving tensor meson in the final state are studied by using the Isgur-Scora-Grinstein-Wise II model. Decay amplitudes are obtained using the factorization scheme in the spectator quark model. Branching ratios for the charm changing and bottom changing decay modes are predicted.
Photoproduction and Decay of Light Mesons in CLAS
Amaryan, Moskov Jamalovich
2013-08-01
We present preliminary experimental results on photoproduction and decay of light mesons measured with CLAS setup at JLAB . This include Dalitz decay of pseudoscalar and vector mesons, radiative decay of pseudoscalar mesons as well hadronic decays of pseudoscalar and vector mesons. The collected high statistics in some of decay channels exceeds the world data by an order of magnitude and some other decay modes are observed for the first time. It is shown how the CLAS data will improve the world data on transition form factors of light mesons, Dalitz plot analyses, branching ratios of rare decay modes and other fundamental properties potentially accessible through the light meson decays.
Scalar meson spectroscopy with lattice staggered fermions
Bernard, Claude; DeTar, Carleton; Fu Ziwen; Prelovsek, Sasa
2007-11-01
With sufficiently light up and down quarks the isovector (a{sub 0}) and isosinglet (f{sub 0}) scalar meson propagators are dominated at large distance by two-meson states. In the staggered-fermion formulation of lattice quantum chromodynamics, taste-symmetry breaking causes a proliferation of two-meson states that further complicates the analysis of these channels. Many of them are unphysical artifacts of the lattice approximation. They are expected to disappear in the continuum limit. The staggered-fermion fourth-root procedure has its purported counterpart in rooted staggered chiral perturbation theory (rS{chi}PT). Fortunately, the rooted theory provides a strict framework that permits the analysis of scalar meson correlators in terms of only a small number of low-energy couplings. Thus the analysis of the point-to-point scalar meson correlators in this context gives a useful consistency check of the fourth-root procedure and its proposed chiral realization. Through numerical simulation we have measured correlators for both the a{sub 0} and f{sub 0} channels in the 'Asqtad' improved staggered-fermion formulation in a lattice ensemble with lattice spacing a=0.12 fm. We analyze those correlators in the context of rS{chi}PT and obtain values of the low-energy chiral couplings that are reasonably consistent with previous determinations.
B meson decays to charmless meson pairs containing η or η' mesons
NASA Astrophysics Data System (ADS)
Aubert, B.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D. N.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Osipenkov, I. L.; Tackmann, K.; Tanabe, T.; Hawkes, C. M.; Soni, N.; Watson, A. T.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Fulsom, B. G.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Barrett, M.; Khan, A.; Randle-Conde, A.; Blinov, V. E.; Bukin, A. D.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Bondioli, M.; Curry, S.; Eschrich, I.; Kirkby, D.; Lankford, A. J.; Lund, P.; Mandelkern, M.; Martin, E. C.; Stoker, D. P.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Yasin, Z.; Sharma, V.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Mazur, M. A.; Richman, J. D.; Beck, T. W.; Eisner, A. M.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schalk, T.; Schumm, B. A.; Seiden, A.; Wang, L.; Winstrom, L. O.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Fang, F.; Hitlin, D. G.; Narsky, I.; Ongmongkolkul, P.; Piatenko, T.; Porter, F. C.; Andreassen, R.; Mancinelli, G.; Meadows, B. T.; Mishra, K.; Sokoloff, M. D.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Hirschauer, J. F.; Nagel, M.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Wilson, R. J.; Feltresi, E.; Hauke, A.; Jasper, H.; Karbach, T. M.; Merkel, J.; Petzold, A.; Spaan, B.; Wacker, K.; Kobel, M. J.; Nogowski, R.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Latour, E.; Verderi, M.; Clark, P. J.; Playfer, S.; Watson, J. E.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cecchi, A.; Cibinetto, G.; Fioravanti, E.; Franchini, P.; Luppi, E.; Munerato, M.; Negrini, M.; Petrella, A.; Piemontese, L.; Santoro, V.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Pacetti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Tosi, S.; Chaisanguanthum, K. S.; Morii, M.; Adametz, A.; Marks, J.; Schenk, S.; Uwer, U.; Bernlochner, F. U.; Klose, V.; Lacker, H. M.; Lueck, T.; Volk, A.; Bard, D. J.; Dauncey, P. D.; Tibbetts, M.; Behera, P. K.; Charles, M. J.; Mallik, U.; Cochran, J.; Crawley, H. B.; Dong, L.; Eyges, V.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gao, Y. Y.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Béquilleux, J.; D'Orazio, A.; Davier, M.; Derkach, D.; da Costa, J. Firmino; Grosdidier, G.; Le Diberder, F.; Lepeltier, V.; Lutz, A. M.; Malaescu, B.; Pruvot, S.; Roudeau, P.; Schune, M. H.; Serrano, J.; Sordini, V.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Bingham, I.; Burke, J. P.; Chavez, C. A.; Fry, J. R.; Gabathuler, E.; Gamet, R.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Clarke, C. K.; di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Paramesvaran, S.; Wren, A. C.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Hafner, A.; Alwyn, K. E.; Bailey, D.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; West, T. J.; Yi, J. I.; Anderson, J.; Chen, C.; Jawahery, A.; Roberts, D. A.; Simi, G.; Tuggle, J. M.; Dallapiccola, C.; Salvati, E.; Cowan, R.; Dujmic, D.; Fisher, P. H.; Henderson, S. W.; Sciolla, G.; Spitznagel, M.; Yamamoto, R. K.; Zhao, M.; Patel, P. M.; Robertson, S. H.; Schram, M.; Biassoni, P.; Lazzaro, A.; Lombardo, V.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Zhao, H. W.; Simard, M.; Taras, P.; Nicholson, H.; de Nardo, G.; Lista, L.; Monorchio, D.; Onorato, G.; Sciacca, C.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Knoepfel, K. J.; Losecco, J. M.; Wang, W. F.; Corwin, L. A.; Honscheid, K.; Kagan, H.; Kass, R.; Morris, J. P.; Rahimi, A. M.; Sekula, S. J.; Wong, Q. K.; Blount, N. L.; Brau, J.; Frey, R.; Igonkina, O.; Kolb, J. A.; Lu, M.; Rahmat, R.; Sinev, N. B.; Strom, D.; Strube, J.; Torrence, E.; Castelli, G.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Voci, C.; Del Amo Sanchez, P.; Ben-Haim, E.; Bonneaud, G. R.; Briand, H.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Perez, A.; Prendki, J.; Sitt, S.; Gladney, L.; Biasini, M.; Manoni, E.; Angelini, C.; Batignani, G.; Bettarini, S.; Calderini, G.; Carpinelli, M.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Morganti, M.; Neri, N.; Paoloni, E.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Baracchini, E.; Cavoto, G.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Jackson, P. D.; Li Gioi, L.; Mazzoni, M. A.; Morganti, S.; Piredda, G.; Renga, F.; Voena, C.; Ebert, M.; Hartmann, T.; Schröder, H.; Waldi, R.; Adye, T.; Franek, B.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Esteve, L.; Hamel de Monchenault, G.; Kozanecki, W.; Vasseur, G.; Yèche, Ch.; Zito, M.; Allen, M. T.; Aston, D.; Bartoldus, R.; Benitez, J. F.; Cenci, R.; Coleman, J. P.; Convery, M. R.; Dingfelder, J. C.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Field, R. C.; Franco Sevilla, M.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.; Kaminski, J.; Kelsey, M. H.; Kim, H.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Li, S.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; Macfarlane, D. B.; Marsiske, H.; Messner, R.; Muller, D. R.; Neal, H.; Nelson, S.; O'Grady, C. P.; Ofte, I.; Perl, M.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Schwiening, J.; Snyder, A.; Su, D.; Sullivan, M. K.; Suzuki, K.; Swain, S. K.; Thompson, J. M.; Va'Vra, J.; Wagner, A. P.; Weaver, M.; West, C. A.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Wulsin, H. W.; Yarritu, A. K.; Young, C. C.; Ziegler, V.; Chen, X. R.; Liu, H.; Park, W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Bellis, M.; Burchat, P. R.; Edwards, A. J.; Miyashita, T. S.; Ahmed, S.; Alam, M. S.; Ernst, J. A.; Pan, B.; Saeed, M. A.; Zain, S. B.; Soffer, A.; Spanier, S. M.; Wogsland, B. J.; Eckmann, R.; Ritchie, J. L.; Ruland, A. M.; Schilling, C. J.; Schwitters, R. F.; Wray, B. C.; Drummond, B. W.; Izen, J. M.; Lou, X. C.; Bianchi, F.; Gamba, D.; Pelliccioni, M.; Bomben, M.; Bosisio, L.; Cartaro, C.; Della Ricca, G.; Lanceri, L.; Vitale, L.; Azzolini, V.; Lopez-March, N.; Martinez-Vidal, F.; Milanes, D. A.; Oyanguren, A.; Albert, J.; Banerjee, Sw.; Bhuyan, B.; Choi, H. H. F.; Hamano, K.; King, G. J.; Kowalewski, R.; Lewczuk, M. J.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Gershon, T. J.; Harrison, P. F.; Ilic, J.; Latham, T. E.; Mohanty, G. B.; Puccio, E. M. T.; Band, H. R.; Chen, X.; Dasu, S.; Flood, K. T.; Pan, Y.; Prepost, R.; Vuosalo, C. O.; Wu, S. L.
2009-12-01
We present updated measurements of the branching fractions for B0 meson decays to ηK0, ηη, ηϕ, ηω, η'K0, η'η', η'ϕ, and η'ω, and branching fractions and CP-violating charge asymmetries for B+ decays to ηπ+, ηK+, η'π+, and η'K+. The data represent the full data set of 467×106 BB¯ pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory. Besides large signals for the four charged B decay modes and for B0→η'K0, we find evidence for three B0 decay modes at greater than 3.0σ significance. We find B(B0→ηK0)=(1.15-0.38+0.43±0.09)×10-6, B(B0→ηω)=(0.94-0.30+0.35±0.09)×10-6, and B(B0→η'ω)=(1.01-0.38+0.46±0.09)×10-6, where the first (second) uncertainty is statistical (systematic). For the B+→ηK+ decay mode, we measure the charge asymmetry Ach(B+→ηK+)=-0.36±0.11±0.03.
Review of meson spectroscopy: quark states and glueballs
Chanowitz, M.S.
1981-11-01
A group of three lectures on hadron spectroscopy are presented. Topics covered include: light L = 0 mesons, light L = 1 mesons, antiquark antiquark quark quark exotics, a catalogue of higher quark antiquark excitations, heavy quarkonium, and glueballs. (GHT)
Unitary coupled-channels model for three-mesons decays of heavy mesons
Hiroyuki Kamano; Nakamura, Satoshi X.; Lee, Tsung-Shung H.; Sato, Toru
2011-12-16
In this study, a unitary coupled-channels model is presented for investigating the decays of heavy mesons and excited meson states into three light pseudoscalar mesons. The model accounts for the three-mesons final state interactions in the decay processes, as required by both the three-body and two-body unitarity conditions. In the absence of the Z-diagram mechanisms that are necessary consequences of the three-body unitarity, our decay amplitudes are reduced to a form similar to those used in the so-called isobar-model analysis. We apply our coupled-channels model to the three-pions decays of α_{1}(1260), π_{2}(1670), π_{2}(2100), and D^{0} mesons, and show that the Z-diagram mechanisms can contribute to the calculated Dalitz plot distributions by as much as 30% in magnitudes in the regions where f_{0}(600), ρ(770), and f_{2}(1270) dominate the distributions. Also, by fitting to the same Dalitz plot distributions, we demonstrate that the decay amplitudes obtained with the unitary model and the isobar model can be rather different, particularly in the phase that plays a crucial role in extracting the CKM CP-violating phase from the data of B meson decays. Our results indicate that the commonly used isobar model analysis must be extended to account for the final state interactions required by the three-body unitarity to reanalyze the three-mesons decays of heavy mesons, thereby exploring hybrid or exotic mesons, and signatures of physics beyond the standard model.
Unitary coupled-channels model for three-mesons decays of heavy mesons
Hiroyuki Kamano; Nakamura, Satoshi X.; Lee, Tsung-Shung H.; Sato, Toru
2011-12-16
In this study, a unitary coupled-channels model is presented for investigating the decays of heavy mesons and excited meson states into three light pseudoscalar mesons. The model accounts for the three-mesons final state interactions in the decay processes, as required by both the three-body and two-body unitarity conditions. In the absence of the Z-diagram mechanisms that are necessary consequences of the three-body unitarity, our decay amplitudes are reduced to a form similar to those used in the so-called isobar-model analysis. We apply our coupled-channels model to the three-pions decays of α1(1260), π2(1670), π2(2100), and D0 mesons, and show that themore » Z-diagram mechanisms can contribute to the calculated Dalitz plot distributions by as much as 30% in magnitudes in the regions where f0(600), ρ(770), and f2(1270) dominate the distributions. Also, by fitting to the same Dalitz plot distributions, we demonstrate that the decay amplitudes obtained with the unitary model and the isobar model can be rather different, particularly in the phase that plays a crucial role in extracting the CKM CP-violating phase from the data of B meson decays. Our results indicate that the commonly used isobar model analysis must be extended to account for the final state interactions required by the three-body unitarity to reanalyze the three-mesons decays of heavy mesons, thereby exploring hybrid or exotic mesons, and signatures of physics beyond the standard model.« less
Azimuthal Asymmetries in Meson Electroproduction at HERMES
NASA Astrophysics Data System (ADS)
Hasch, Delia
2003-07-01
The measurement of single-spin azimuthal asymmetries for pseudoscalar meson production in semi-inclusive deep-inelastic scattering of 27.6 GeV electrons off a longitudinally polarised hydrogen and deuterium target is reported by the HERMES experiment. A significant target-spin asymmetry amplitude in the azimuthal distribution of charged and neutral pions and positively charged kaons relative to the lepton scattering plane has been observed. The dependence on the relevant kinematic variables which are the Bjorken variable x, the meson fractional energy z and the meson transverse momentum P⊥ has been investigated as well. The results are compared to predictions of model calculations which are base on a fragmentation function that varies with the transverse polarisation of the struck quark. In addition, data from the measurement of a single beam-spin azimuthal asymmetry in the electroproduction of positive pions in semi-inclusive and semi-exclusive deep-inelastic scattering will be presented.
δ Meson Effects on Asymmetric Nuclear Matter
NASA Astrophysics Data System (ADS)
Liu, B.; di Toro, M.; Greco, V.
The impact of a δ meson field (the scalar-isovector channel) on asymmetric nuclear matter is studied within relativistic mean-field (RMF) models with both constant and density dependent (DD) nucleon-meson couplings. The Equation of State (EOS) for asymmetric nuclear matter and the neutron star properties by the different models are compared. We find that the δ-field in the constant coupling scheme leads to a larger repulsion in dense neutron-rich matter and to a definite splitting of proton and neutron effective masses, finally influencing the stability of the neutron stars. A broader analysis of possible δ-field effects is achieved considering also density dependent nucleon-meson coupling. A remarkable effect on the relation between mass and radius for the neutron stars is seen, showing a significant reduction of the radius along with a moderate mass reduction due to the increase of the effective δ coupling in high density regions.
Magnetic properties of ground-state mesons
NASA Astrophysics Data System (ADS)
Šimonis, V.
2016-04-01
Starting with the bag model a method for the study of the magnetic properties (magnetic moments, magnetic dipole transition widths) of ground-state mesons is developed. We calculate the M1 transition moments and use them subsequently to estimate the corresponding decay widths. These are compared with experimental data, where available, and with the results obtained in other approaches. Finally, we give the predictions for the static magnetic moments of all ground-state vector mesons including those containing heavy quarks. We have a good agreement with experimental data for the M1 decay rates of light as well as heavy mesons. Therefore, we expect our predictions for the static magnetic properties ( i.e., usual magnetic moments) to be of sufficiently high quality, too.
Massive mesons in Weyl-Dirac theory
NASA Astrophysics Data System (ADS)
Mirabotalebi, S.; Ahmadi, F.; Salehi, H.
2008-01-01
In order to study the mass generation of the vector fields in the framework of a conformal invariant gravitational model, the Weyl-Dirac theory is considered. The mass of the Weyl’s meson fields plays a principal role in this theory, it connects basically the conformal and gauge symmetries. We estimate this mass by using the large-scale characteristics of the observed universe. To do this we firstly specify a preferred conformal frame as a cosmological frame, then in this frame, we introduce an exact possible solution of the theory. We also study the dynamical effect of the massive vector meson fields on the trajectories of an elementary particle. We show that a local change of the cosmological frame leads to a Hamilton-Jacobi equation describing a particle with an adjustable mass. The dynamical effect of the massive vector meson field presents itself in the form of a correction term for the mass of the particle.
Electroproduction of baryon-meson states and strangeness suppression
NASA Astrophysics Data System (ADS)
Santopinto, E.; García-Tecocoatzi, H.; Bijker, R.
2016-08-01
We describe the electroproduction ratios of baryon-meson states from nucleon, inferring from the sea quarks in the nucleon using an extension of the quark model that takes into account the sea. As a result we provide, with no adjustable parameters, the predictions of ratios of exclusive meson-baryon final states: ΛK+, Σ* K, ΣK, pπ0, and nπ+. These predictions are in agreement with the new JLab experimental data showing that sea quarks play an important role in the electroproduction. We also predicted further ratios of exclusive reactions that can be measured and tested in future experiments. In particular, we suggested new experiments on deuterium and tritium. Such measurements can provide crucial tests of different predictions concerning the structure of nucleon and its sea quarks helping to solve an outstanding problem. Finally, we compute the so called strangeness suppression factor, λs, that is the suppression of strange quark-antiquark pairs compared to nonstrange pairs, and we found that our finding with this simple extension of the quark model is in good agreement with the results of JLab and CERN experiments.
Nucleon Resonance Electrocouplings from the CLAS Meson Electroproduction Data.
Inna Aznauryan, Volker Burkert, Viktor Mokeev
2012-04-01
Transition helicity amplitudes {gamma}{sub {nu}}NN* (electrocouplings) were determined for prominent excited proton states with masses less than 1.8 GeV in independent analyses of major meson electroproduction channels: {pi}{sup +}n, {pi}{sup 0}p and {pi}{sup +}{pi}{sup -}p. Consistent results on resonance electrocouplings obtained from analyses of these exclusive reactions with very different non-resonant contributions demonstrated reliable extraction of these fundamental quantities for states that have significant decays for either N{pi} or N{pi}{pi} channels. Preliminary results on electrocouplings of N* states with masses above 1.6 GeV have become available from the CLAS data on {pi}{sup +}{pi}{sup -}p electroproduction off protons for the first time. Comparison with quark models and coupled channel approaches strongly suggest that N* structure is determined by contributions from an internal core of three constituent quarks and an external meson-baryon cloud at the distance scales covered in measurements with the CLAS detector.
Further evidence for magnetic charge from meson spectroscopy
Akers, D.
1987-12-01
Recently evidence was presented for the existence of magnetic charge from Zeeman splitting in meson states. The model by Akers predicted the existence of a new eta meson at 1814 MeV with I/sup G/ (J/sup PC/) = O/sup +/ (O/sup - +/). Experimental evidence for this new meson is cited and discussed.
Scalar mesons in a linear sigma model with (axial-)vector mesons
Parganlija, D.; Kovacs, P.; Wolf, Gy.; Giacosa, F.; Rischke, D. H.
2013-03-25
The structure of the scalar mesons has been a subject of debate for many decades. In this work we look for qq states among the physical resonances using an extended Linear Sigma Model that contains scalar, pseudoscalar, vector, and axial-vector mesons both in the non-strange and strange sectors. We perform global fits of meson masses, decay widths and amplitudes in order to ascertain whether the scalar qq states are below or above 1 GeV. We find the scalar states above 1 GeV to be preferred as qq states.
CP violation in B meson decays
NASA Astrophysics Data System (ADS)
Noguchi, S.; Belle Group
2003-06-01
CP violation in neutral B meson decays has been observed confirming the prediction of the Kobayashi-Maskawa model where introduction of six quaks naturally induces CP violation in the weak interaction. The measurements of CP asymmetryc in B meson decays were made at the newly constructed Asymmetric B factories, which consist of high luminosity, ebergy-asymmetric e+e- colliders (KEKB and PEP-II) and detectors (Belle and BaBar). The results are in good agreement and are consistent with other experimental results within the framework of the Standard Model.
Scalar mesons and polarizability of the nucleon
Schumacher, Martin
2008-08-31
It is shown that the scalar mesons {sigma}, f{sub 0}(980) and a{sub 0}(980) as t-channel exchanges quantitatively solve the problem of diamagnetism and give an explanation of the large missing part of the electric polarizability {alpha} showing up when only the pion cloud is taken into account. The electric polarizability of the proton {alpha}{sub p} confirms a two-photon width of the {sigma} meson of {gamma}{sub {sigma}}{sub {gamma}}{sub {gamma}} = (2.58{+-}0.26) keV.
Meson spectrum in strong magnetic fields
NASA Astrophysics Data System (ADS)
Andreichikov, M. A.; Kerbikov, B. O.; Orlovsky, V. D.; Simonov, Yu. A.
2013-05-01
We study the relativistic quark-antiquark system embedded in a magnetic field (MF). The Hamiltonian containing confinement, one gluon exchange, and spin-spin interaction is derived. We analytically follow the evolution of the lowest meson states as a function of MF strength. Calculating the one gluon exchange interaction energy ⟨VOGE⟩ and spin-spin contribution ⟨aSS⟩ we have observed that these corrections remain finite at large MF, preventing the vanishing of the total ρ meson mass at some Bcrit, as previously thought. We display the ρ masses as functions of the MF in comparison with recent lattice data.
Shape of mesons in holographic QCD
Torabian, Mahdi; Yee, Ho-Ung
2009-10-15
Based on the expectation that the constituent quark model may capture the right physics in the large N limit, we point out that the orbital angular momentum of the quark-antiquark pair inside light mesons of low spins in the constituent quark model may provide a clue for the holographic dual string model of large N QCD. Our discussion, relying on a few suggestive assumptions, leads to a necessity of world-sheet fermions in the bulk of dual strings that can incorporate intrinsic spins of fundamental QCD degrees of freedom. We also comment on the interesting issue of the size of mesons in holographic QCD.
Exotic nuclei with open heavy flavor mesons
Yasui, Shigehiro; Sudoh, Kazutaka
2009-08-01
We propose stable exotic nuclei bound with D and B mesons with respect to heavy quark symmetry. We indicate that an approximate degeneracy of D(B) and D*(B*) mesons plays an important role, and discuss the stability of DN and BN bound states. We find the binding energies 1.4 MeV and 9.4 MeV for each state in the J{sup P}=1/2{sup -} with the I=0 channel. We discuss also possible existence of exotic nuclei DNN and BNN.
Light O++ Mesons: Scalargators in Florida
NASA Astrophysics Data System (ADS)
Pennington, M. R.
2010-08-01
Light scalar mesons abound in hadron processes, like the alligators in the Florida Everglades. Moreover, scalars are intimately tied to the vacuum structure of QCD. They are the product of many decays. Consequently, a rich source of recent information about them has come from experiments producing heavy flavour mesons. Indeed, scalars will continue to dominate many of the processes to be studied at forthcoming facilities like BESIII in Beijing, FAIR at GSI Darmstadt and the GlueX experiment at JLab, making an understanding (or at least an excellent and theoretically consistent description) essential for the physics missions of these facilities.
Excited light isoscalar mesons from lattice QCD
Christopher Thomas
2011-07-01
I report a recent lattice QCD calculation of an excited spectrum of light isoscalar mesons, something that has up to now proved challenging for lattice QCD. With novel techniques we extract an extensive spectrum with high statistical precision, including spin-four states and, for the first time, light isoscalars with exotic quantum numbers. In addition, the hidden flavour content of these mesons is determined, providing a window on annihilation dynamics in QCD. I comment on future prospects including applications to the study of resonances.
Sharma, Neelesh; Verma, R. C.; Dhir, Rohit
2011-01-01
In this paper, we investigate phenomenologically two-body weak decays of the bottom mesons emitting pseudoscalar/vector meson and a tensor meson. Form factors are obtained using the improved Isgur-Scora-Grinstein-Wise II model. Consequently, branching ratios for the Cabibbo-Kobayashi-Maskawa-favored and Cabibbo-Kobayashi-Maskawa-suppressed decays are calculated.
Issues in light meson spectroscopy: The case for meson spectroscopy at CEBAF
Godfrey, S.
1994-04-01
The author reviews some outstanding issues in meson spectroscopy. The most important qualitative issue is whether hadrons with explicit gluonic degrees of freedom exist. To answer this question requires a much better understanding of conventional q{bar q} mesons. The author therefore begins by examining the status of conventional meson spectroscopy and how the situation can be improved. The expected properties of gluonic excitations are discussed with particular emphasis on hybrids to give guidance to experimental searches. Multiquark systems are commented upon as they are likely to be important in the mass region under study and will have to be understood better. In the final section the author discusses the opportunities that CEBAF can offer for the study of meson spectroscopy.
NASA Astrophysics Data System (ADS)
Roy, P.
2016-05-01
Baryon spectroscopy is an indispensable tool for investigating the nature of strong interaction within baryons. The study of vector-meson photoproduction is expected to improve our understanding of the properties of known baryon resonances and also immensely aid in discovering new higher-mass resonances. Polarization observables, in addition to unpolarized cross sections, are required to identify the contributing resonances to these reactions with minimal ambiguities. Preliminary results from the FROST experiment on beam-polarization observables in γ →p →→p ω as well as γ →p →→p π+π- using a linearly-polarized beam and a transversely-polarized FROzen Spin butanol Target will be presented. The latter reaction will provide important information on N* to (broad) ρ vector-meson decay modes, which is difficult to extract directly from the data.
Meson distribution amplitudes in holographic models
NASA Astrophysics Data System (ADS)
Hwang, Chien-Wen
2012-07-01
We study the wave functions of light and heavy mesons in both hard-wall (HW) and soft-wall (SW) holographic models which use AdS/CFT correspondence. In the case of massless constituents, the asymptotic behaviors of the electromagnetic form factor, the distribution amplitudes, and the decay constants for the two models are the same, if the relation between the dilaton scale parameter and the size of meson is an inverse proportion. On the other hand, by introducing a quark mass dependence in the wave function, the differences of the distribution amplitudes between the two models are obvious. In addition, for the SW model, the dependences of the decay constants of meson on the dilaton scale parameter κ differ; especially fQq˜κ3/mQ2 is consistent with the prediction of the heavy quark effective theory if κ˜mQ1/2. Thus the parameters of the two models are fit by the decay constants of the distinct mesons; the distribution amplitudes and the ξ-moments are calculated and compared.
Charmonium meson and hybrid radiative transitions
Guo, Peng; Yépez-Martínez, Tochtli; Szczepaniak, Adam P.
2014-06-01
We consider the non-relativistic limit of the QCD Hamiltonian in the Coulomb gauge, to describe radiative transitions between conventional charmonium states and from the lowest multiplet of cc¯ hybrids to charmonium mesons. The results are compared to potential quark models and lattices calculations.
Extracting excited mesons from the finite volume
Doring, Michael
2014-12-01
As quark masses come closer to their physical values in lattice simulations, finite volume effects dominate the level spectrum. Methods to extract excited mesons from the finite volume are discussed, like moving frames in the presence of coupled channels. Effective field theory can be used to stabilize the determination of the resonance spectrum.
CPT violation and B-meson oscillations
Kostelecky, V. Alan; Van Kooten, Richard J.
2010-11-15
Recent evidence for anomalous CP violation in B-meson oscillations can be interpreted as resulting from CPT violation. This yields the first sensitivity to CPT violation in the B{sub s}{sup 0} system, with the relevant coefficient for CPT violation constrained at the level of parts in 10{sup 12}.
Meson Spectroscopy at JLab@12 GeV
Celentano, Andrea
2013-03-01
Meson, being the simplest hadronic bound system, is the ideal "laboratory" to study the interaction between quarks, to understand the role of the gluons inside hadrons and to investigate the origin of color confinement. To perform such studies it is important to measure the meson spectrum, with precise determination of resonance masses and properties, looking for rare qbar q states and for unconventional mesons with exotic quantum numbers (i.e. mesons with quantum numbers that are not compatible with a qbar q structure). With the imminent advent of the 12 GeV upgrade of Jefferson Lab a new generation of meson spectroscopy experiments will start: "Meson-Ex" in Hall B and "GLUEX" in Hall D. Both will use photo-production to explore the spectrum of mesons in the light-quark sector, in the energy range of few GeVs.
Predictions of three-body-decays of mesons from pole-dominated dispersion relations
NASA Technical Reports Server (NTRS)
Thews, R. L.
1974-01-01
The investigation shows that the method of finite dispersion relations (FDR) as developed by Aviv and Nussinov (1970) is consistent with a wide range of three-body meson decays. The specific results vary with each reaction. For each possibility a definite form for the t-channel Regge-pole terms is selected. The results of the investigation indicate the basic reliability of an approach based on the FDR method and the finite-energy sum rules.
NASA Astrophysics Data System (ADS)
Kageya, Tsuneo
2014-01-01
Psuedo-scalar meson photo production measurements have been carried out with longitudinally-polarized neutrons using the circularly and linearly polarized photon beams and the CLAS at Thomas Jefferson National Accelerator Facility (Jlab). The experiment aims to obtain a complete set of spin observables on an efficient neutron target. Preliminary E asymmetries for the exclusive reaction, γ + n(p) → π- + p(p), selecting quasi free neutron kinematics are discussed.
Vector meson production in ultra-peripheral collisions at the LHC
Fiore, R.; Jenkovszky, L.; Salii, A.; Libov, V.; Machado, M. V. T.
2015-04-10
By using a Regge-pole model for vector meson production (VMP), that successfully describes the HERA data, we analyse the connection of VMP cross sections in photon-induced reactions at HERA with those in ultra-peripheral collisions at the Large Hadron Collider (LHC). The role of the low-energy behaviour of VMP cross sections in γp collisions is scrutinized.
Probing Nucleon Structure with Meson Electro-production in Hall C
Wood, Stephen
2011-02-01
Meson electro-production is used in Hall C at Jefferson Lab to probe nucleon, baryon and nuclear structure. The experimental program in Hall C includes studies of semi-inclusive pion production, p, d(e, e'π±)X, where low energy factorization has been observed, suggesting that these reactions can be used to probe nucleon structure, including transverse momentum distributions of quarks, at energies available at JLab after the upcoming 12 GeV upgrade.
Quark-exchange versus meson-exchange in D(e,e'p)Delta
L. Ya. Glozman; A. Faessler
1994-05-01
We demonstrate that the meson-exchange contribution to D(e,e'p)Delta(T{sub p} {approx} 0.7-1 GeV and being at rest) is small compared to the six-quark contribution. The cross-section is large enough to be measured at CEBAF. It means that through this reaction we could observe and study the quark degrees of freedom in the deuteron.
The Evolution of t dependence in Meson Photoproduction
NASA Astrophysics Data System (ADS)
Puentes, Daniel; Raue, Brian; Guo, Lei; Freese, Adam
2016-03-01
Studies of single-meson photoproduction off the proton over the past few decades have yielded tremendous amounts of data on differential cross sections. The wealth of data can be used to understand the exchange mechanisms responsible for the production of specific final-state hadrons. At low momentum transfer the differential cross section dσ / dt can be parameterized by the t-slope parameter b, where dσ / dt ~e-bt . We have determined b as a function of photon beam energy for the reactions γp -->K+Σ0 , γp -->K+ Λ , γp -->p ω , γp -->p η , γp -->pη' , γp -->pρ0 , γp -->pπ0 , and γp -->p ϕ . Preliminary results will be presented.
Neutrino-Induced Meson Productions
NASA Astrophysics Data System (ADS)
Nakamura, Satoshi X.
We develop a dynamical coupled-channels (DCC) model for neutrino-nucleon reactions in the resonance region, by extending the DCC model that we have previously developed through an analysis of π N,γ N to π N,η N,KΛ ,KΣ reaction data for W ≤ 2.1 GeV. We analyze electron-induced reaction data for both proton and neutron targets to determine the vector current form factors up to Q2 ≤ 3.0 (GeV/c)2. Axial-current matrix elements are derived in accordance with the Partially Conserved Axial Current (PCAC) relation to the πN interactions of the DCC model. As a result, we can uniquely determine the interference pattern between resonant and non-resonant amplitudes. Our calculated cross sections for neutrino-induced single-pion productions are compared with available data, and are found to be in reasonable agreement with the data. We also calculate the double-pion production cross sections in the resonance region, for the first time, with relevant resonance contributions and channel couplings. The result is compared with the double-pion production data. For a future development of a neutrino-nucleus reaction model and/or a neutrino event generator for analyses of neutrino experiments, the DCC model presented here can give a useful input.
Spin O decay angular distribution for interfering mesons in electroproduction
Funsten, H.; Gilfoyle, G.
1994-04-01
Self analyzing meson electroproduction experiments are currently being planned for the CEBAF CLAS detector. These experiments deduce the spin polarization of outgoing unstable spin s (?)0 mesons from their decay angular distribution, W({theta},{psi}). The large angular acceptance of the CLAS detector permits kinematic tracking of a sufficient number of these events to accurately determine electroproduction amplitudes from the deduced polarization. Maximum polarization information is obtained from W({theta},{psi}) for decay into spin 0 daughters. The helicity of the decaying meson is transferred to the daughter`s relative orbital angular momentum m-projection; none is {open_quotes}absorbed{close_quotes} into daughter helicities. The decaying meson`s helicity maximally appears in W({theta},{psi}). W({theta},{psi}) for spin 0 daughters has been derived for (1) vector meson electroproduction and (2) general interfering mesons produced by incident pions. This paper derives W({theta},{psi}) for electroproduction of two interfering mesons that decay into spin 0 daughters. An application is made to the case of interfering scalar and vector mesons. The derivation is an extension of work by Schil using the general decay formalism of Martin. The expressions can be easily extended to the case of N interfering mesons since interference occurs pairwise in the observable W ({theta},{psi}), a quadratic function of the meson amplitudes. The derivation uses the virtual photon density matrix of Schil which is transformed by a meson electroproduction transition operator, T. The resulting density matrix for the interfering mesons is then converted into a corresponding statistical tensor and contracted into the efficiency tensor for spin 0 daughters.
Exploring X(5568) as a meson molecule
NASA Astrophysics Data System (ADS)
Agaev, S. S.; Azizi, K.; Sundu, H.
2016-10-01
The parameters, i.e. the mass and current coupling of the exotic X(5568) state observed by the D0 Collaboration as well as the decay width of the process X → B_s0π+, are explored using the Boverline{K} molecule assumption on its structure. Employed computational methods include QCD two-point and light-cone sum rules, the latter being considered in the soft-meson approximation. The obtained results are compared with the data of the D0 Collaboration as well as with the predictions of the diquark-antidiquark model. This comparison strengthens a diquark-antidiquark picture for the X(5568) state rather than a meson molecule structure.
The lightest hybrid meson supermultiplet in QCD
Dudek, Jozef J
2011-10-01
We interpret the spectrum of meson states recently obtained in non-perturbative lattice QCD calculations in terms of constituent quark-antiquark bound states and states, called 'hybrids', in which the q{bar q} pair is supplemented by an excitation of the gluonic field. We identify a lightest supermultiplet of hybrid mesons with J{sup PC} = (0,1,2){sup {-+}}, 1{sup -} built from a gluonic excitation of chromomagnetic character coupled to q{bar q} in an S-wave. The next lightest hybrids are suggested to be quark orbital excitations with the same gluonic excitation, while the next distinct gluonic excitation is significantly heavier. Existing models of gluonic excitations are compared to these findings and possible phenomenological consequences explored.
The lightest hybrid meson supermultiplet in QCD
Dudek, Jozef J.
2011-10-01
We interpret the spectrum of meson states recently obtained in nonperturbative lattice QCD calculations in terms of constituent quark-antiquark bound states and states, called ''hybrids'', in which the qq pair is supplemented by an excitation of the gluonic field. We identify a lightest supermultiplet of hybrid mesons with J{sup PC}=(0,1,2){sup -+},1{sup --} built from a gluonic excitation of chromomagnetic character coupled to qq in an S-wave. The next lightest hybrids are suggested to be quark orbital excitations with the same gluonic excitation, while the next distinct gluonic excitation is significantly heavier. Existing models of gluonic excitations are compared to these findings and possible phenomenological consequences explored.
Meson exchange and neutral weak currents
Beck, D.H.
1994-04-01
Measurements of parity-violating electron scattering asymmetries to determine weak neutral currents in nuclei will be effected by the presence of meson exchange currents. Present low momentum transfer calculations, based on a flavor independent framework, show these effects to be small. In general, however, as the momentum transfer increases to values typical of deep-inelastic scattering, fragmentation functions show a clear flavor dependence. It is suggested that a good experimental starting point for understanding the flavor dependence of meson production and exchange currents is the Q{sup 2} dependence of parity-violating asymmetry in inclusive single pion electroproduction. A CEBAF facility with doubled energy is necessary to approach momentum transfers where this process begins to scale.
Non-conventional mesons at PANDA
NASA Astrophysics Data System (ADS)
Giacosa, Francesco
2015-04-01
Non-conventional mesons, such as glueballs and tetraquarks, will be in the focus of the PANDA experiment at the FAIR facility. In this lecture we recall the basic properties of QCD and describe some features of unconventional states. We focus on the search of the not-yet discovered glueballs and the use of the extended Linear Sigma Model for this purpose, and on the already discovered but not-yet understood X, Y, Z states.
Strangeness and meson-nucleon sigma terms
Dahiya, Harleen; Sharma, Neetika
2011-10-21
The chiral constituent quark model ({chi}CQM) has been extended to calculate the flavor structure of the nucleon through the meson-nucleon sigma terms which have large contributions from the quark sea and are greatly affected by chiral symmetry breaking and SU(3) symmetry breaking. The hidden strangeness component in the nucleon has also been investigated and its significant contribution is found to be consistent with the recent available experimental observations.
Understanding the baryon and meson spectra
Pennington, Michael R.
2013-10-01
A brief overview is given of what we know of the baryon and meson spectra, with a focus on what are the key internal degrees of freedom and how these relate to strong coupling QCD. The challenges, experimental, theoretical and phenomenological, for the future are outlined, with particular reference to a program at Jefferson Lab to extract hadronic states in which glue unambiguously contributes to their quantum numbers.
Helicity operators for mesons in flight on the lattice
Christopher E. Thomas; Edwards, Robert G.; Dudek, Jozef J.
2012-01-20
Motivated by the desire to construct meson-meson operators of definite relative momentum in order to study resonances in lattice QCD, we present a set of single-meson interpolating fields at non-zero momentum that respect the reduced symmetry of a cubic lattice in a finite cubic volume. These operators follow from the subduction of operators of definite helicity into irreducible representations of the appropriate little groups. We show their effectiveness in explicit computations where we find that the spectrum of states interpolated by these operators is close to diagonal in helicity, admitting a description in terms of single-meson states of identified JPC.more » Lastly, the variationally determined optimal superpositions of the operators for each state give rapid relaxation in Euclidean time to that state, ideal for the construction of meson-meson operators and for the evaluation of matrix elements at finite momentum.« less
Helicity operators for mesons in flight on the lattice
Christopher E. Thomas; Edwards, Robert G.; Dudek, Jozef J.
2012-01-20
Motivated by the desire to construct meson-meson operators of definite relative momentum in order to study resonances in lattice QCD, we present a set of single-meson interpolating fields at non-zero momentum that respect the reduced symmetry of a cubic lattice in a finite cubic volume. These operators follow from the subduction of operators of definite helicity into irreducible representations of the appropriate little groups. We show their effectiveness in explicit computations where we find that the spectrum of states interpolated by these operators is close to diagonal in helicity, admitting a description in terms of single-meson states of identified J^{PC}. Lastly, the variationally determined optimal superpositions of the operators for each state give rapid relaxation in Euclidean time to that state, ideal for the construction of meson-meson operators and for the evaluation of matrix elements at finite momentum.
Time reversal violation for entangled neutral mesons
Bernabeu, J.
2014-07-23
A direct evidence for Time Reversal Violation (TRV) means an experiment that, considered by itself, clearly shows TRV independent of, and unconnected to, the results for CP Violation. No existing result before the recent BABAR experiment with entangled neutral B mesons had demonstrated TRV in this sense. There is a unique solution for the test of TRV with unstable particles thanks to the Einstein-Podolsky-Rosen (EPR) Entanglement between the two neutral mesons in B, and φ, Factories. The two quantum effects of the decays as filtering measurements of the meson states and the transfer of information of the first decay to the still living partner allow performing a genuine TRV asymmetry with the exchange of “in” and “out” states. With four independent TRV asymmetries, BABAR observes a large deviation of T-invariance with a statistical significance of 14 standard deviations, far more than needed to declare the result as a discovery. This is the first direct observation of TRV in the time evolution of any system. The perspectives for future additional studies of TRV are discussed.
Asymmetric vector mesons produced in nuclear collisions
NASA Astrophysics Data System (ADS)
Dremin, I. M.; Nechitailo, V. A.
2016-09-01
It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high-energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further described in quantum mechanics as the interference of direct and continuum states in the Fano-Feshbach effect. To reveal the nature of the interaction it is proposed to use a phenomenological model of the additional contribution due to Cherenkov gluons. They can be created because of the excess of the refractivity index over 1 just in the low-mass wing as required by the classical Cherenkov treatment. In quantum mechanics, this requirement is related to the positive real part of the interaction amplitude in this wing. The corresponding parameters are found from the comparison with ρ-meson data and admit reasonable explanation.
Hard Exclusive Meson Production at COMPASS
NASA Astrophysics Data System (ADS)
Ter Wolbeek, Johannes
2016-02-01
The concept of Generalized Parton Distributions (GPDs) combines two-dimensional spatial information given by form factors, with longitudinal momentum information from Parton Distribution Functions. GPDs provide comprehensive description of the nucleon structure involving a wealth of new information. For instance, according to Ji’s sum rule, the GPDs H and E enable access to the total angular momenta of quarks, antiquarks and gluons. While H can be approached using measurements of electroproduction cross sections, asymmetry measurements in hard exclusive meson production off transversely polarized targets can help to constrain the GPD E and chiral-odd GPDs. In 2007 and 2010 the COMPASS experiment at CERN collected data by scattering a 160GeV/c muon beam off a transversely polarized NH3 target. Exclusive vector-meson production μ + p → μ‧ + p + V with a ρ0 or ω meson in the final state is studied and five single-spin and three double-spin azimuthal asymmetries are measured.
Topological theory of hadrons. I. Mesons
NASA Astrophysics Data System (ADS)
Stapp, Henry P.
1983-05-01
Spin is incorporated into the hadronic topological expansion scheme. Spin analogs of Chan-Paton factors are introduced in a way that avoids the troubles encountered in earlier attempts. Those troubles, at the meson level, were, first, the occurrence of twice the wanted number of pseudoscalar and vector mesons; second, the occurrence of parity-doublet partners of the pseudoscalar and vector mesons; and third, the occurrence of these parity-doublet partners as particles of negative metric, called ghosts. These troubles are all avoided by introducing a new topological level, called zero entropy, that lies below the ordered level. At the zero-entropy level quarks of opposite chirality are treated as distinct particles. The theory has been extended to all hadrons, and the basic particles are exactly those of the constituent-quark model, which for baryons start with the (56+) and (70-). The theory is formulated in the M-function framework, where the "quarks" are represented by two-component spinors, and it entails SU(6)W symmetry of the hadronic vertices at a low level of the topological expansion.
Exclusive electroproduction of strange mesons with JLab 12 GeV
Strikman, Mark; Weiss, Christian
2009-01-01
We summarize the physics topics which can be addressed by measurements of high-Q^2 exclusive electroproduction of strange mesons, gamma* N -> phi N, K* Lambda, K Lambda, K Sigma, at Jefferson Lab with 11 GeV beam energy. The proposed investigations are aimed both at exploring the reaction mechanism (dominance of point-like configurations) and extracting information about baryon structure from the data (generalized parton distributions, or GPDs). They include (a) probing the t-dependence of the nucleon's gluon GPD (transverse spatial distribution of gluons) in phi meson production; (b) separating the nucleon helicity-flip and nonflip quark GPDs in K* Lambda production with measurement of the Lambda recoil polarization; (c) probing strangeness polarization in the nucleon in K Lambda and K Sigma production. These studies rely only on the analysis of cross section ratios, which are less affected by the theoretical uncertainties of present GPD-based calculations than absolute cross sect
{phi}-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies
Salamanca, Julian; Cole, Philip L.
2007-10-26
The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how {phi}-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the {gamma}-vectorp{yields}{phi}p reaction, with {phi}{yields}K{sup +}K{sup -}, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.
Φ-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies
Salamanca, Julian; Cole, Philip L
2007-10-01
The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how Φ-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the γp → Φp reaction, with Φ → K^{+}K^{-}, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.
Nonleptonic two-body decays of charmed mesons
NASA Astrophysics Data System (ADS)
Yu, Fu-Sheng; Wang, Xiao-Xia; Lü, Cai-Dian
2011-10-01
Nonleptonic decays of charmed mesons into two pseudoscalar mesons or one pseudoscalar meson and one vector meson are studied on the basis of a generalized factorization method considering the resonance effects in the pole model for the annihilation contributions. Large strong phases between different topological diagrams are considered in this work, simply taking the phase in the coefficients ai. We find that the annihilation-type contributions calculated in the pole model are large in both of the PP and PV modes, which make our numerical results agree with the experimental data better than those previous calculations.
Phi meson propagation in a hot hadronic gas
Alvarez-Ruso, Luis; Koch, Volker
2002-02-20
The Hidden Local Symmetry Lagrangian is used to study the interactions of phi mesons with other pseudoscalar and vector mesons in a hadronic gas at finite temperature. We have found a significantly small phi mean free path (less than 2.4 fm at T > 170 MeV) due to large collision rates with rho mesons, kaons and predominantly K* in spite of their heavy mass. This implies that phi mesons produced after hadronization in relativistic heavy ion collisions will not leave the hadronic system without scattering. The effect of these interactions on the time evolution of the phi density in the expanding hadronic fireball is investigated.
Search for gluonic excitations in light unconventional mesons
Paul Eugenio
2007-07-01
Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenologicalmodels for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.
The hybrid mesons quest: the MesonEx experiment at Jefferson Laboratory
NASA Astrophysics Data System (ADS)
Rizzo, A.; CLAS Collaboration
2016-02-01
The meson spectroscopy plays nowadays a central role in the investigation of hadron structure thanks to the possible existence of exotic hybrid mesons, quark-antiquark-gluon bound states. Their explicit gluonic degrees of freedom which should clearly emerge from a Partial Wave Analysis (PWA) of the corresponding Dalitz plot of the exotic particle decay, may result in final JPC configurations not allowed in the constituent quark model. Besides this clear signature, hybrid mesons are also expected to have a large particle multiplicity decays, requiring for their search an experimental apparatus with high performances in terms of rate capability, resolution and almost a full acceptance to apply PWA methods. New-generation experiments are planned at Thomas Jefferson National Laboratory (VA, USA) for which an unprecedented statistics of large multiplicity decay events with fully reconstructed kinematics will be available. In particular for the MesonEx (CLAS12) experiment in Hall B, a wide scientific program that will start in 2016 has been deployed to study the meson spectrum at energies up to 11 GeV. A key role in such program is played by the Forward Tagger apparatus of the experiment, which will allow to extend the study of meson electro-production to very low Q2 values, in a quasi-real photo production kinematical region, where the production of hybrid mesons is expected to be favorite. Currently a new analysis framework for the search of the hybrid mesons is being set up by the HASPECT network, an international structure which gather people involved into theoretical and experimental hadronic physics all over the world. The goals of the network is to develop new analysis models and statistical techniques to unfold the signal and background distributions in high-statistics datasets. In this work are briefly presented the first preliminary results from the application of a statistical technique, namely the sPlot, to the data already acquired by the CLAS experiment for
Electroproduction of pseudoscalar mesons above the resonance region
Niczyporuk, B.B.
1994-04-01
In this paper, the author has revisited twenty year old data considering the progress achieved in related fields. To make further progress in our understanding of strong interactions, one needs much better quality of exclusive electroproduction data. A measurement of the differential cross section {sigma}(t, W, Q{sup 2}) for the reactions e{sup {minus}} + p {r_arrow} e{sup {minus}} + {pi}{sup +}(K{sup +}) + n({Lambda}{degrees}) at a beam energy of {ge} 4 GeV is proposed. Data will be collected simultaneously for both reactions using the CLAS detector at CEBAF in the following kinematical region: Q{sup 2} > 1 GeV{sup 2} and W > 2 GeV. One of the most interesting aspects of electroproduction is that it can be used to measure photoproduction amplitudes as functions of the photon mass squared Q{sup 2} and momentum transfer t. Emphasis is given to measuring the differential cross sections for t {approximately} m{sup 2}{sub {pi},{kappa}}. Above the resonance region (W > 2 GeV), the cross section is dominated by the amplitudes for scalar photons. Measured angular distributions of produced mesons will be used to estimate the contribution of various amplitudes to the cross sections. High statistics and good quality data collected simultaneously using a large acceptance detector will improve our understanding of nucleon structure as well as the hadronic properties of the photon.
Leptonic Decays of Charged Pseudoscalar Mesons - 2015
Rosner, Jonathan L.; Stone, Sheldon; Van de Water, Ruth S.
2015-09-07
We review the physics of purely leptonic decays of $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and antiquark wave-functions in the meson, called the decay constant $f_P$. The leptonic decay constants for $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ mesons can be obtained with controlled theoretical uncertainties and high precision from {\\it ab initio} lattice-QCD simulations. The combination of experimental leptonic decay-rate measurements and theoretical decay-constant calculations enables the determination of several elements of the CKM matrix within the standard model. These determinations are competitive with those obtained from semileptonic decays, and also complementary because they are sensitive to different quark flavor-changing currents. They can also be used to test the unitarity of the first and second rows of the CKM matrix. Conversely, taking the CKM elements predicted by unitarity, one can infer "experimental" values for $f_P$ that can be compared with theory. These provide tests of lattice-QCD methods, provided new-physics contributions to leptonic decays are negligible at the current level of precision. This review is the basis of the article in the Particle Data Group's 2016 edition, updating the versions in Refs. [1-3].
New-particle spectroscopy, quarkonium and gluonic mesons
Bloom, E.D.
1982-10-01
Recent experimental results on quarkonium and gluonic mesons are presented and discussed. Comparisons with theory are made. Quarkonium predictions seem to agree well with experiment. The question of the experimental verification of gluonic mesons is clouded by the difficulty of the theoretical interpretation.
Beauty vector meson decay constants from QCD sum rules
NASA Astrophysics Data System (ADS)
Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano
2016-01-01
We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.
Investigation of semileptonic B meson decays to P-wave charm mesons
NASA Astrophysics Data System (ADS)
Bellerive, Alain
This thesis presents an investigation of semileptonic B meson decays with a narrow P-wave charm meson in the final state. The data sample consists of 3.29 × 106 BB¯ events collected with the CLEO II detector at the Cornell Electron-positron Storage Ring. The P-wave charm mesons are reconstructed in the chain of decays: D0J-->D*+p- ,D*+-->D0p+,D 0-->K-p+ or D0-->K- p+p 0 . Study of the decay B- -->D*+p0l -nl reveals useful information about the deficit observed in inclusive charm semileptonic B decays and the effective couplings of the W boson to heavy quark mesons. The results obtained for the exclusive semileptonic product branching fractions are B(B- --> D01l-nl ) B(D01-->D*+p -) = (0.373 +/- 0.085 +/- 0.052 +/- 0.024)% and B(B- -->D*0 2l- nl )B(D*0 2-->D*+p-) < 0.16% (90% C.L.). The assumption B(D01-->D* +p-) = 67% and B(D*02-->D *+p-) = 20% implies B(B- -->D01 l- nl) (0.56 0.13 +/- 0.08 +/- 0.04)% and B(B---> D*0 2lnl) < 0.8% (90% C.L.). These results indicate that at least 18% of the total B semileptonic rate is still unaccounted for by the observed exclusive decays, B-->D0l- nl, B-->D*ln l,B -->D1ln l, and B-->D*2 lnl . Furthermore, the first measurement of the q 2 spectrum for B- -->D01ln l is presented. The present analysis also suggests that the Λ QCD/mQ corrections beyond the HQS prescriptions might be significant in the theoretical treatment of the dynamics of B semileptonic decays to excited charm mesons.
Scalar Mesons, Multiquark States and Supersymmetry
Catto, Sultan
2008-08-31
Quark models with potentials derived from QCD, including the quark-diquark model for excited hadrons leading to a symmetry between mesons and baryons gives mass formulae in very good agreement with experiment and goes a long way in explaining the approximate symmetries and supersymmetries of the hadronic spectrum, including the symmetry breaking mechanism. We give a description of the only algebra describing color degrees of freedom based on split octonionic units and leading to a mathematical understanding of formation of diquarks as well as multiquark states.
Meson Photoproduction Experiments at ELPH, Tohoku University
NASA Astrophysics Data System (ADS)
Ishikawa, Takatsugu; Fujimura, Hisako; Fukasawa, Hiroshi; Hashimoto, Ryo; He, Qinghua; Honda, Yuki; Iwata, Takahiro; Kaida, Shun; Kasagi, Jirohta; Kawano, Atsushi; Kuwasaki, Shuzo; Maeda, Kazushige; Masumoto, Shin'ichi; Miyabe, Manabu; Miyahara, Fusashi; Mochizuki, Kei'ichi; Muramatsu, Norihito; Nakamura, Akihiko; Nawa, Ken'ichi; Ogushi, Shoei; Okada, Yasuyuki; Onodera, Yoshihito; Ozawa, Kyoichiro; Sakamoto, Yasunobu; Sato, Mamoru; Shimizu, Hajime; Sugai, Hiroyuki; Suzuki, Koutaku; Tajima, Yasuhisa; Takahashi, Shin'ichiro; Taniguchi, Yusuke; Tsuchikawa, Yusuke; Yamazaki, Hirohito; Yamazaki, Ryuji; Yoshida, Hiroshi Y.
Meson photoproduction experiments have been conducted with an electromagnetic (EM) calorimeter FOREST at Research Center for Electron Photon Science (ELPH), Tohoku University. A narrow resonance observed at W = 1670 MeV in η photoproduction on the neutron is of great interest, which is a candidate of an anti-decuplet pentaquark baryon although its origin is still controversial. The preliminary results of the cross sections for π0 and η photoproduction on the deuteron are presented. The next generation FOREST experiments have been planned to study S11(1535) properties in the nuclear medium by searching for η-mesic nucleus states. The planned experiments are also shown in this contribution.
Isoscalar meson spectroscopy from lattice QCD
Jozef Dudek, Robert Edwards, David Richards, Christopher Thomas, Balint Joo, Michael Peardon
2011-06-01
We extract to high statistical precision an excited spectrum of single-particle isoscalar mesons using lattice QCD, including states of high spin and, for the first time, light exotic JPC isoscalars. The use of a novel quark field construction has enabled us to overcome the long-standing challenge of efficiently including quark-annihilation contributions. Hidden-flavor mixing angles are extracted and while most states are found to be close to ideally flavor mixed, there are examples of large mixing in the pseudoscalar and axial sectors in line with experiment. The exotic JPC isoscalar states appear at a mass scale comparable to the exotic isovector states.
Charmed-strange mesons revisited: Mass spectra and strong decays
NASA Astrophysics Data System (ADS)
Song, Qin-Tao; Chen, Dian-Yong; Liu, Xiang; Matsuki, Takayuki
2015-03-01
Inspired by the present experimental status of charmed-strange mesons, we perform a systematic study of the charmed-strange meson family in which we calculate the mass spectra of the charmed-strange meson family by taking a screening effect into account in the Godfrey-Isgur model and investigate the corresponding strong decays via the quark pair creation model. These phenomenological analyses of charmed-strange mesons not only shed light on the features of the observed charmed-strange states, but also provide important information on future experimental search for the missing higher radial and orbital excitations in the charmed-strange meson family, which will be a valuable task in LHCb, the forthcoming Belle II, and PANDA.
Pion double charge exchange in a composite-meson model
Kezerashvili, R. Ya.; Boyko, V. S.
2007-01-15
The pion double charge exchange amplitude is evaluated in a composite-meson model based on the four-quark interaction. The model assumes that the mesons are two-quark systems and can interact with each other only through quark loops. To evaluate the meson exchange current contribution, the form factors of the two-pion decay modes of the {rho},{sigma}, and f{sub 0} mesons have been used in the calculations. The contribution of the four-quark box diagram has been taken into account as well as a contact diagram. The contributions of the {rho},{sigma}, and f{sub 0} mesons increase the forward scattering cross section, which depends weakly on the energy.
Probing the perturbative dynamics of exclusive meson pair production
NASA Astrophysics Data System (ADS)
Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.; Stirling, W. J.
2013-10-01
We present the results of a recent novel application of the 'hard exclusive' perturbative formalism to the process gg → MMbar at large angles, where M (Mbar) is a light meson (anti-meson). As well as discussing the important theoretical features of the relevant leading-order gg → qqbar (gg) qqbar (gg) 6-parton amplitudes, we also comment on their phenomenological implications. In particular, we consider the central exclusive production of meson pairs at comparatively large transverse momentum k⊥, which is expected to proceed via this mechanism. We show that this leads to various non-trivial predictions for a range of exclusive processes, and that the cross sections for the η‧ and η mesons display significant sensitivity to any valence gg component of the meson wavefunctions.
QCD description of backward vector meson hard electroproduction
NASA Astrophysics Data System (ADS)
Pire, B.; Semenov-Tian-Shansky, K.; Szymanowski, L.
2015-05-01
We consider backward vector meson exclusive electroproduction off nucleons in the framework of collinear QCD factorization. Nucleon to vector meson transition distribution amplitudes (TDAs) arise as building blocks for the corresponding factorized amplitudes. In the near-backward kinematics, the suggested factorization mechanism results in the dominance of the transverse cross section of vector meson production (σT≫σL ) and in the characteristic 1 /Q8-scaling behavior of the cross section. We evaluate nucleon to vector meson TDAs in the cross-channel nucleon exchange model and present estimates of the differential cross section for backward ρ0, ω and ϕ meson production off protons. The resulting cross sections are shown to be measurable in the forthcoming JLab@12 GeV experiments.
How sensitive are di-leptons from {rho} mesons to the high baryon density region?
Vogel, S.; Schmidt, K.; Santini, E.; Sturm, C.; Bleicher, M.; Petersen, H.; Aichelin, J.
2008-10-15
We show that the measurement of dileptons might provide only a restricted view into the most dense stages of heavy-ion reactions. Thus, possible studies of meson and baryon properties at high baryon densities, as, e.g., done at the GSI High Acceptance DiElectron Spectrometer (HADES) and envisioned for the Facility for Antiproton and Ion Research (FAIR) compressed baryonic matter experiments, might observe weaker effects than currently expected in certain approaches. We argue that the strong absorption of resonances in the high-baryon-density region of the heavy-ion collision masks information from the early hot and dense phase due to a strong increase of the total decay width because of collisional broadening. To obtain additional information, we also compare the currently used approaches to extract dileptons from transport simulations, i.e., shining, only vector mesons from final baryon resonance decays and instant emission of dileptons and find a strong sensitivity on the method employed in particular at FAIR and the CERN Super Proton Synchrotron energies. It is shown explicitly that a restriction to {rho} meson (and therefore dilepton) production only in final-state baryon resonance decays provide a strong bias toward rather low baryon densities. The results presented are obtained from ultrarelativistic quantum molecular dynamics v2.3 calculations using the standard setup.
Sharma, Neelesh; Verma, R. C.
2010-11-01
Two-body hadronic weak decays of B{sub c} meson emitting pseudoscalar and heavy scalar mesons are investigated using the Spectator Quark Model. Decay amplitudes are obtained using the factorization scheme; consequently, branching ratios are predicted in the Isgur-Scora-Grinstein-Wise (ISGW II) model.
Weak Decays of Excited B Mesons.
Grinstein, B; Martin Camalich, J
2016-04-01
We investigate the decays of the excited (bq[over ¯]) mesons as probes of the short-distance structure of the weak ΔB=1 transitions. These states are unstable under the electromagnetic or strong interactions, although their widths are typically suppressed by phase space. Compared to the pseudoscalar B meson, the purely leptonic decays of the vector B^{*} are not chirally suppressed and are sensitive to different combinations of the underlying weak effective operators. An interesting example is B_{s}^{*}→ℓ^{+}ℓ^{-}, which has a rate that can be accurately predicted in the standard model. The branching fraction is B∼10^{-11}, irrespective of the lepton flavor and where the main uncertainty stems from the unmeasured and theoretically not well known B_{s}^{*} width. We discuss the prospects for producing this decay mode at the LHC and explore the possibility of measuring the B_{s}^{*}→ℓℓ amplitude, instead, through scattering experiments at the B_{s}^{*} resonance peak. PMID:27104698
Meson Electro-/Photo-Production from QCD
NASA Astrophysics Data System (ADS)
Briceño, Raúl A.
2016-07-01
Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the discovery of new excited nucleon and Δ states using multi-channel partial wave analyses procedures. The internal structure of several prominent excited states has been revealed employing meson electroproduction processes. On the theoretical front, lattice QCD is now predicting the baryon spectrum with very similar characteristics as the constituent quark model, and continuum QCD, such as is represented in the Dyson-Schwinger equations approach and in light front relativistic quark models, describes the non-perturbative behavior of resonance excitations at photon virtuality of Q^2 > 1.5 GeV^2 . In this talk I discuss the need to continue a vigorous program of nucleon spectroscopy and the study of the internal structure of excited states as a way to reveal the effective degrees of freedom underlying the excited states and their dependence on the distance scale probed.
Weak Decays of Excited B Mesons.
Grinstein, B; Martin Camalich, J
2016-04-01
We investigate the decays of the excited (bq[over ¯]) mesons as probes of the short-distance structure of the weak ΔB=1 transitions. These states are unstable under the electromagnetic or strong interactions, although their widths are typically suppressed by phase space. Compared to the pseudoscalar B meson, the purely leptonic decays of the vector B^{*} are not chirally suppressed and are sensitive to different combinations of the underlying weak effective operators. An interesting example is B_{s}^{*}→ℓ^{+}ℓ^{-}, which has a rate that can be accurately predicted in the standard model. The branching fraction is B∼10^{-11}, irrespective of the lepton flavor and where the main uncertainty stems from the unmeasured and theoretically not well known B_{s}^{*} width. We discuss the prospects for producing this decay mode at the LHC and explore the possibility of measuring the B_{s}^{*}→ℓℓ amplitude, instead, through scattering experiments at the B_{s}^{*} resonance peak.
NASA Astrophysics Data System (ADS)
Papandreou, Zisis
2006-02-01
A study of several rare η decays near threshold was carried out at the C-6 (π-) beamline of the Alternating Gradient Synchrotron at Brookhaven National Laboratory with the Crystal Ball detector, an electromagnetic calorimeter with nearly 4π geometric acceptance that is comprised of 672 optically isolated NaI(Tl) crystals with a thickness of 15.7 radiation lengths. Results from the search for the CP forbidden decay η → 4π0 and the investigation of the quadratic slope parameter in η → 3π0 decay will be profiled, among others. The focus of the talk will be on the η → π0γγ rare decay: its relative branching ratio was extracted to be B1 = (8.3 ± 2.8 ± 1.2) × 10-4, based on the analysis of 3 × 107 detected η mesons. This leads to a partial width for the eta meson of Γ(η → π0γγ) = (0.32 ± 0.15) eV/c2, a value much lower than past measurements and in line with Chiral Perturbation Theory calculations.
Flavor symmetry breaking and meson masses
Bhagwat, Mandar S.; Roberts, Craig D.; Chang Lei; Liu Yuxin; Tandy, Peter C.
2007-10-15
The axial-vector Ward-Takahashi identity is used to derive mass formulas for neutral pseudoscalar mesons. Flavor symmetry breaking entails nonideal flavor content for these states. Adding that the {eta}{sup '} is not a Goldstone mode, exact chiral-limit relations are developed from the identity. They connect the dressed-quark propagator to the topological susceptibility. It is confirmed that in the chiral limit the {eta}{sup '} mass is proportional to the matrix element which connects this state to the vacuum via the topological susceptibility. The implications of the mass formulas are illustrated using an elementary dynamical model, which includes an Ansatz for that part of the Bethe-Salpeter kernel related to the non-Abelian anomaly. In addition to the current-quark masses, the model involves two parameters, one of which is a mass-scale. It is employed in an analysis of pseudoscalar- and vector-meson bound-states. While the effects of SU(N{sub f}=2) and SU(N{sub f}=3) flavor symmetry breaking are emphasized, the five-flavor spectra are described. Despite its simplicity, the model is elucidative and phenomenologically efficacious; e.g., it predicts {eta}-{eta}{sup '} mixing angles of {approx}-15 deg. and {pi}{sup 0}-{eta} angles of {approx}1 deg.
Meson properties in a nonlocal SU(3) chiral quark model at finite temperature
Contrera, G. A.; Gomez Dumm, D.; Scoccola, N. N.
2010-11-12
Finite temperature meson properties are studied in the context of a nonlocal SU(3) quark model which includes flavor mixing and the coupling of quarks to the Polyakov loop (PL). We analyze the behavior of scalar and pseudoscalar meson masses and mixing angles, as well as quark-meson couplings and pseudoscalar meson decay constants.
NASA Technical Reports Server (NTRS)
Takahashi, Y.; Eby, P. B.
1985-01-01
Possibilities of observing abundances of phi mesons and narrow hadronic pairs, as results of QGP and Chiral transitions, are considered for nucleus-nucleus interactions. Kinematical requirements in forming close pairs are satisfied in K+K decays of S(975) and delta (980) mesons with small phi, and phi (91020) mesons with large PT, and in pi-pi decays of familiar resonance mesons only in a partially restored chiral symmetry. Gluon-gluon dominance in QGP can enhance phi meson production. High hadronization rates of primordial resonance mesons which form narrow hadronic pairs are not implausible. Past cosmic ray evidences of anomalous phi production and narrow pair abundances are considered.
Strange meson spectroscopy in K[omega] and K[phi] at 11 GeV/c and Cherenkov ring imaging at SLD
Kwon, Youngjoon.
1993-01-01
This thesis consists of two independent parts; development of Cherenkov Ring Imaging Detector (CRID) system and analysis of high-statistics data of strange meson reactions from the LASS spectrometer. Part 1: The CRID system is devoted to charged particle identification in the SLAC Large Detector (SLD) to study e[sup +]e[sup [minus
Kageya, Tsuneo
2014-01-01
Psuedo-scalar meson photo production measurements have been carried out with longitudinally-polarized neutrons using the circularly and linearly polarized photon beams and the CLAS at Thomas Jefferson National Accelerator Facility (Jlab). The experiment aims to obtain a complete set of spin observables on an efficient neutron target. Preliminary E asymmetries for the exclusive reaction, gamma + n(p)--> pi- + p(p), selecting quasi free neutron kinematics are discussed.
Exotic Meson Decay to {omega}{pi}{sup 0}{pi}{sup -}
M. Lu; G.S. Adams; T. Adams; Z. Bar-Yam; J.M. Bishop; V.A. Bodyagin; D.S. Brown; N.M. Cason; S.U. Chung; J.P. Cummings; K. Danyo; A.I. Demianov; S.P. Denisov; V. Dorofeev; J.P. Dowd; P. Eugenio; X.L. Fan; A.M. Gribushin; R.W. Hackenburg; M. Hayek; J. Hu; E.I. Ivanov; D. Joffe; I. Kachaev; W. Kern; E. King; O.L. Kodolova; V.L. Korotkikh; M.A. Kostin; J. Kuhn; V.V. Lipaev; J.M. LoSecco; J.J. Manak; J. Napolitano; M. Nozar; C. Olchanski; A.I. Ostrovidov; T.K. Pedlar; A.V. Popov; D.I. Ryabchikov; L.I. Sarycheva; K.K. Seth; N. Shenhav; X. Shen; W.D. Shephard; N.B. Sinev; D.L. Stienike; J.S. Suh; S.A. Taegar; A. Tomaradze; I.N. Vardanyan; D.P. Weygand; D.B. White; H.J. Willutzki; M. Witkowski; A.A. Yershov
2004-05-01
A partial-wave analysis of the mesons from the reaction {pi}{sup -} p {yields} {pi}{sup +}{pi}{sup -}{pi}{sup -}{pi}{sup 0}{pi}{sup 0}p has been performed. The data show b{sub 1}{pi} decay of the spin-exotic states {pi}{sub 1}(1600) and {pi}{sub 1}(2000). Three isovector 2{sup -+} states were seen in the {omega}{rho}{sup -} decay channel. In addition to the well known {pi}{sub 2}(1670), signals were also observed for {pi}{sub 2}(1880) and {pi}{sub 2}(1970).
The Determination of Pseudoscalar Meson Photoproduction Amplitudes from Complete Experiments
A. M. Sandorfi, S. Hoblit, H. Kamano, and T-S. H. Lee
2011-10-01
A new generation of complete experiments is currently underway with the goal of performing a high precision extraction of pseudoscalar meson photo-production amplitudes. Here we review the most general analytic form of the cross section, dependent upon the three polarization vectors of the beam, target and recoil baryon, including all single, double and triple-polarization terms involving 16 spin-dependent observables. Analytic expressions that determine the recoil baryon polarization are also presented. Different conventions are in use in the literature and we have used a numerical calculation of cross sections from Chew-Goldberger-Low-Nambu amplitudes with arbitrary spin projections to clarify apparent sign differences. As an illustration of the use of this machinery, we carry out a multipole analysis of the gammap --> K+Lambda reaction and examine the impact of recently published polarization measurements. In fitting multipoles, we use a combined Monte Carlo sampling of the amplitude space, with gradient minimization, and find a shallow chi2 valley pitted with a very large number of local minima, despite the inclusion of recent data on 8 different observables. We conclude that, while a mathematical solution to the problem of determining an amplitude free of ambiguities may require 8 observables, as has been pointed out in the literature, experiments with realistically achievable uncertainties will require a significantly larger number.
The chiral S = -1 meson-baryon interaction with new constraints on the NLO contributions
NASA Astrophysics Data System (ADS)
Ramos, A.; Feijoo, A.; Magas, V. K.
2016-10-01
We present a study of the S = - 1 meson-baryon interaction, employing a chiral SU(3) Lagrangian up to next-to-leading order (NLO) and implementing unitarization in coupled channels. The parameters of the model have been fitted to a large set of experimental scattering data in different two-body channels, to threshold branching ratios, and to the precise SIDDHARTA value of the energy shift and width of kaonic hidrogen. In contrast to other groups, we have taken into consideration the K- p →K+Ξ- ,K0Ξ0 reaction data, since we found in a previous work to be especially sensitive to the NLO parameters of the chiral Lagrangian. In the present work we also include the Born terms, which usually have very little effect, and find them to be non-negligible in the K- p → KΞ channels, correspondingly causing significant modifications to the NLO parameters. We furthermore show that the importance of the Born terms becomes more visible in the isospin projected amplitudes of the K- p → KΞ reactions. The measurement of processes that filter single isospin components, like the KL0 p →K+Ξ0 reaction that could be measured at the proposed secondary KL0 beam at Jlab, would put valuable constraints on the chiral models describing the meson-baryon interaction in the S = - 1 sector.
Determining pseudoscalar meson photoproduction amplitudes from complete experiments
NASA Astrophysics Data System (ADS)
Sandorfi, A. M.; Hoblit, S.; Kamano, H.; Lee, T.-S. H.
2011-05-01
A new generation of complete experiments is focused on a high precision extraction of pseudoscalar meson photoproduction amplitudes. Here, we review the development of the most general analytic form of the cross section, dependent upon the three polarization vectors of the beam, target and recoil baryon, including all single-, double- and triple-polarization terms involving 16 spin-dependent observables. We examine the different conventions that have been used by different authors, and we present expressions that allow the direct numerical calculation of any pseudoscalar meson photoproduction observables with arbitrary spin projections from the Chew-Goldberger-Low-Nambu amplitudes. We use this numerical tool to clarify apparent sign differences that exist in the literature, in particular with the definitions of six double-polarization observables. We also present analytic expressions that determine the recoil baryon polarization, together with examples of their potential use with quasi-4π detectors to deduce observables. As an illustration of the use of the consistent machinery presented in this review, we carry out a multipole analysis of the γp → K+Λ reaction and examine the impact of recently published polarization measurements. When combining data from different experiments, we utilize the Fierz identities to fit a consistent set of scales. In fitting multipoles, we use a combined Monte Carlo sampling of the amplitude space, with gradient minimization, and find a shallow χ2 valley pitted with a very large number of local minima. This results in broad bands of multipole solutions that are experimentally indistinguishable. While these bands have been noticeably narrowed by the inclusion of new polarization measurements, many of the multipoles remain very poorly determined, even in sign, despite the inclusion of data on eight different observables. We have compared multipoles from recent PWA codes with our model-independent solution bands and found that such
Determining pseudoscalar meson photoproduction amplitudes from complete experiments
Sandorfi, A.M.; Hoblit, S.; Sandorfi,A.M.; Hoblit,S.; Kamano,H.; Lee,T-S.H.
2011-04-06
A new generation of complete experiments is focused on a high precision extraction of pseudoscalar meson photoproduction amplitudes. Here, we review the development of the most general analytic form of the cross section, dependent upon the three polarization vectors of the beam, target and recoil baryon, including all single-, double- and triple-polarization terms involving 16 spin-dependent observables. We examine the different conventions that have been used by different authors, and we present expressions that allow the direct numerical calculation of any pseudoscalar meson photoproduction observables with arbitrary spin projections from the Chew-Goldberger-Low-Nambu amplitudes. We use this numerical tool to clarify apparent sign differences that exist in the literature, in particular with the definitions of six double-polarization observables. We also present analytic expressions that determine the recoil baryon polarization, together with examples of their potential use with quasi-4{pi} detectors to deduce observables. As an illustration of the use of the consistent machinery presented in this review, we carry out a multipole analysis of the {gamma}p {yields} K{sup +}{Lambda} reaction and examine the impact of recently published polarization measurements. When combining data from different experiments, we utilize the Fierz identities to fit a consistent set of scales. In fitting multipoles, we use a combined Monte Carlo sampling of the amplitude space, with gradient minimization, and find a shallow {chi}{sup 2} valley pitted with a very large number of local minima. This results in broad bands of multipole solutions that are experimentally indistinguishable. While these bands have been noticeably narrowed by the inclusion of new polarization measurements, many of the multipoles remain very poorly determined, even in sign, despite the inclusion of data on eight different observables. We have compared multipoles from recent PWA codes with our model
Neutrino-induced meson productions off nucleon at forward limit in nucleon resonance region
Nakamura, S. X.; Kamano, H.; Lee, T.-S. H.; Sato, T.
2015-05-15
We study forward neutrino-induced meson production off the nucleon in the resonance region. Our calculation is based on a dynamical coupled-channels (DCC) model that reasonably describes π(γ)N → πN, ηN, KΛ, KΣ data in the resonance region. We apply the PCAC hypothesis to the DCC model to relate the πN reaction amplitude to the forward neutrino reaction amplitude. In this way, we give a prediction for νN → πN, ππN, ηN, KΛ, KΣ reaction cross sections. The predicted νN → ππN, ηN, KΛ, KΣ cross sections are, for the first time, based on a model extensively tested by data. We compare our results with those from the Rein-Sehgal model that has been very often used in the existing Monte Carlo simulators for neutrino experiments. We find a significant difference between them.
Model discrimination in pseudoscalar-meson photoproduction
NASA Astrophysics Data System (ADS)
Nys, J.; Ryckebusch, J.; Ireland, D. G.; Glazier, D. I.
2016-08-01
To learn about a physical system of interest, experimental results must be able to discriminate among models. We introduce a geometrical measure to quantify the distance between models for pseudoscalar-meson photoproduction in amplitude space. Experimental observables, with finite precision, map to probability distributions in amplitude space, and the characteristic width scale of such distributions needs to be smaller than the distance between models if the observable data are going to be useful. We therefore also introduce a method for evaluating probability distributions in amplitude space that arise as a result of one or more measurements, and show how one can use this to determine what further measurements are going to be necessary to be able to discriminate among models.
eta and eta' Mesons from Lattice QCD
Christ, N.H.; Izubuchi, T.; Dawson, C.; Jung, C.; Liu, Q.; Mawhinney, R.D.; Sachrajda, C.T.; Soni, A.; Zhou, R.
2010-12-08
The large mass of the ninth pseudoscalar meson, the {eta}{prime}, is believed to arise from the combined effects of the axial anomaly and the gauge field topology present in QCD. We report a realistic, 2+1-flavor, lattice QCD calculation of the {eta} and {eta}{prime} masses and mixing which confirms this picture. The physical eigenstates show small octet-singlet mixing with a mixing angle of {theta} = -14.1(2.8){sup o}. Extrapolation to the physical light quark mass gives, with statistical errors only, m{sub {eta}} = 573(6) MeV and m{sub {eta}} = 947(142) MeV, consistent with the experimental values of 548 and 958 MeV.
Meson Spectroscopy At Jlab At 12 Gev
Fegan, Stuart
2014-12-01
The 12 GeV upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab will enable a new generation of experiments in hadronic nuclear physics, seeking to address fundamental questions in our understanding of QCD. The existence of exotic states, suggested by both quark models and lattice calculations, would allow gluonic degrees of freedom to be explored, and may help explain the role played by gluons in the QCD interaction. This article will review the meson spectroscopy program being planned at the lab following the 12 GeV upgrade, utilising real and quasi-real photon beams in two of the lab's four experimental halls, whose distinct capabilities will enable an extensive set of spectroscopy experiments to be performed at the same facility.
Meson photoproduction from the nucleon at CLAS
Daniel P. Watts
2012-01-01
The excitation spectrum of the nucleon provides a stringent constraint on the dynamics and interactions of its internal constituents and therefore probes the mechanism of confinement in the light quark sector. Our detailed knowlege of this excitation spectrum is poor, with many predicted states not yet observed in experiment and many 'established' states having poorly known properties. To address these shortcomings a worldwide effort is currently underway exploiting the latest generation of electron and photon beams in detailed studies of meson photoproduction from nucleon targets. A major contribution to this effort will come from the experimental programme at Jefferson Lab exploiting the frozen spin target (FROST) with the CLAS spectrometer. The status of this project will be presented along with preliminary results and analyses.
Meson-meson bound state in a 2+1 lattice QCD model with two flavors and strong coupling
Faria da Veiga, Paulo A.; O'Carroll, Michael; Neto, Antonio Francisco
2005-08-01
We consider the existence of bound states of two mesons in an imaginary-time formulation of lattice QCD. We analyze an SU(3) theory with two flavors in 2+1 dimensions and two-dimensional spin matrices. For a small hopping parameter and a sufficiently large glueball mass, as a preliminary, we show the existence of isoscalar and isovector mesonlike particles that have isolated dispersion curves (upper gap up to near the two-particle threshold {approx}-4ln{kappa}). The corresponding meson masses are equal up to and including O({kappa}{sup 3}) and are asymptotically of order -2ln{kappa}-{kappa}{sup 2}. Considering the zero total isospin sector, we show that there is a meson-meson bound state solution to the Bethe-Salpeter equation in a ladder approximation, below the two-meson threshold, and with binding energy of order b{kappa}{sup 2}{approx_equal}0.02359{kappa}{sup 2}. In the context of the strong coupling expansion in {kappa}, we show that there are two sources of meson-meson attraction. One comes from a quark-antiquark exchange. This is not a meson exchange, as the spin indices are not those of the meson particle, and we refer to this as a quasimeson exchange. The other arises from gauge field correlations of four overlapping bonds, two positively oriented and two of opposite orientation. Although the exchange part gives rise to a space range-one attractive potential, the main mechanism for the formation of the bound state comes from the gauge contribution. In our lattice Bethe-Salpeter equation approach, this mechanism is manifested by an attractive distance-zero energy-dependent potential. We recall that no bound state appeared in the one-flavor case, where the repulsive effect of Pauli exclusion is stronger.
Leptonic and semileptonic decays of B mesons
NASA Astrophysics Data System (ADS)
Dingfelder, Jochen; Mannel, Thomas
2016-07-01
Semileptonic decays are ideally suited to study the weak interaction as well as strong interaction effects in B -meson decays. In the last decade, precision studies of semileptonic B decays have been made possible by the large samples of B mesons collected at the B factories KEKB in Japan and PEP-II in the USA. Measurements of the charged-current semileptonic transitions b →q ℓν (q =u , c ) allow for a determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix elements Vc b and Vu b and the masses of the b and c quarks, which are fundamental parameters of the standard model of particle physics. The values of |Vc b| and |Vu b| are determined from measurements of inclusive B decays in combination with calculations of partial decay rates or from exclusive decays combined with theoretical predictions of hadronic form factors. Purely leptonic B decays B →ℓν (ℓ=e , μ , τ ) also provide access to |Vu b|. They are theoretically simpler, but the available signal samples are still small. Decays involving a τ lepton, B →τ ν and B →D(*)τ ν , are sensitive to new physics, in particular, to charged Higgs bosons in models with an extended Higgs sector, and provide a window to the physics of the third generation. In this article, the measurements and theoretical descriptions of charged-current leptonic and semileptonic B decays and the status of |Vc b| and |Vu b| determinations are reviewed. An overview of the theoretical approaches and the experimental techniques used in the study of these decays is also provided.
Nucleon Resonance Structure from Exclusive Meson Electroproduction with CLAS and CLAS12
Philip L. Cole, Volker D. Burkert, Ralf W. Gothe, Victor I. Mokeev
2012-12-01
The CLAS detector at Jefferson Lab is a unique instrument, which has provided the lion's share of the world's data on meson photo- and electroproduction in the resonance excitation region. The electroexcitation amplitudes for the low-lying resonances P{sub 33} (1232), P{sub 11} (1440), D{sub 13} (1520), and S {sub 11} (1535) were determined over a wide range of Q{sub 2} < 5.0 GeV{sub 2} in a comprehensive analysis of exclusive single-meson ( {pi}{sup +} n, {pi}{sup 0} p) reactions in the electroproduction off protons. Further, we were able to precisely measure {pi}{sup +}{pi}{sup -}p electroproduction differential cross sections provided by the nearly full kinematic coverage of the CLAS detector. And, for the first time, the electrocouplings of the P{sub 11} (1440), D{sub 13} (1520) excited states are determined from the exclusive-{pi}{sup +}{pi}{sup -}p reaction. Consistent results on the electrocouplings from two-independent analyses (single- and double-pion electroproduction) have provided compelling evidence for the reliable extraction of the N* electrocouplings. And preliminary results on the electrocouplings of the S{sub 31} (1620), S{sub 11} (1650), D{sub 33} (1700), and P{sub 13} (1720) states, which decay preferentially to the N{pi} {pi} final states, have recently become available. Theoretical analyses of these results have revealed that there are two major contributions to the resonance structure: a) an internal quark core and b) an external meson-baryon cloud. These CLAS results have had considerable impact on QCD-based studies on N* structure and in the search for manifestations of the dynamical masses of the dressed quarks. Future CLAS12 N* structure studies at high photon virtualities will considerably extend our capabilities in exploring the nature of confinement in baryons.
Analysis tools for MesonEx at CLAS12
NASA Astrophysics Data System (ADS)
Glazier, D. I.
2016-05-01
The JLAB upgrade will soon be completed and the new CLAS12 detector system will collect large volumes of data allowing detailed investigations of many aspects of hadron physics. The focus of the MesonEx experiment is on the production of mesonic states by low Q2 virtual photons, or quasi-real photons. Studying such mesonic states is a particularly challenging data analysis problem, requiring well understood detector systems, clean signal and background separation, handling of large volumes of data and crucially a close collaboration between experimentalists and theorists to ensure the most sophisticated theoretical methods are used to interrogate the data. Here we briefly outline some of the analysis and methods that are being used to prepare for the MesonEx experiment.
Search for medium modification of the $\\rho$ meson
R. Nasseripour; M. H. Wood; C. Djalali; D. P. Weygand; C. Tur; U. Mosel; P. Muehlich; CLAS Collaboration
2007-08-01
The photoproduction of vector mesons on various nuclei has been studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory. The vector mesons, $\\rho$, $\\omega$, and $\\phi$, are observed via their decay to $e^+e^-$, in order to reduce the effects of final state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the $\\rho$ meson. The $\\rho$ spectral function is extracted from the data on various nuclei, carbon, iron, and titanium, and compared to the spectrum from liquid deuterium, which is relatively free of nuclear effects. We observe no significant mass shift for the $\\rho$ meson; however, there is some widening of the resonance in titanium and iron, which is consistent with expected collisional broadening.
Staggered chiral perturbation theory for heavy-light mesons
NASA Astrophysics Data System (ADS)
Aubin, C.; Bernard, C.
2006-01-01
We incorporate heavy-light mesons into staggered chiral perturbation theory (SχPT), working to leading order in 1/mQ, where mQ is the heavy-quark mass. At first nontrivial order in the chiral expansion, staggered taste violations affect the chiral logarithms for heavy-light quantities only through the light-meson propagators in loops. There are also new analytic contributions coming from additional terms in the Lagrangian involving heavy-light and light mesons. Using this heavy-light SχPT, we perform the one-loop calculation of the B (or D) meson leptonic decay constant in the partially quenched and full QCD cases. In our treatment, we assume the validity both of the “fourth root trick” to reduce four staggered tastes to one, and of the SχPT prescription to represent this trick by insertions of factors of 1/4 for each sea-quark loop.
Toward the excited isoscalar meson spectrum from lattice QCD
Dudek, Jozef J.; Edwards, Robert G.; Guo, Peng; Thomas, Christopher E.
2013-11-18
We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about ~400 MeV. The distillation method enables us to evaluate the required disconnected contributions with high statistical precision for a large number of meson interpolating fields. We find relatively little mixing between light and strange in most JPC channels; one notable exception is the pseudoscalar sector where the approximate SU(3)F octet, singlet structure of the η, η' is reproduced. We extract exotic JPC states, identifiedmore » as hybrid mesons in which an excited gluonic field is coupled to a color-octet qqbar pair, along with non-exotic hybrid mesons embedded in a qq¯-like spectrum.« less
Toward the excited isoscalar meson spectrum from lattice QCD
Dudek, Jozef J.; Edwards, Robert G.; Guo, Peng; Thomas, Christopher E.
2013-11-18
We report on the extraction of an excited spectrum of isoscalar mesons using lattice QCD. Calculations on several lattice volumes are performed with a range of light quark masses corresponding to pion masses down to about ~400 MeV. The distillation method enables us to evaluate the required disconnected contributions with high statistical precision for a large number of meson interpolating fields. We find relatively little mixing between light and strange in most J^{PC} channels; one notable exception is the pseudoscalar sector where the approximate SU(3)_{F} octet, singlet structure of the η, η' is reproduced. We extract exotic J^{PC} states, identified as hybrid mesons in which an excited gluonic field is coupled to a color-octet qqbar pair, along with non-exotic hybrid mesons embedded in a qq¯-like spectrum.
Selection rules for hadronic transitions of XYZ mesons.
Braaten, Eric; Langmack, Christian; Smith, D Hudson
2014-06-01
Many of the XYZ mesons discovered in the last decade can be identified as bound states of a heavy quark and antiquark in Born-Oppenheimer (BO) potentials defined by the energy of gluon and light-quark fields in the presence of static color sources. The mesons include quarkonium hybrids, which are bound states in excited flavor-singlet BO potentials, and quarkonium tetraquarks, which are bound states in BO potentials with light-quark+antiquark flavor. The deepest hybrid potentials are known from lattice QCD calculations. The deepest tetraquark potentials can be inferred from lattice QCD calculations of static adjoint mesons. Selection rules for hadronic transitions are derived and used to identify XYZ mesons that are candidates for ground-state energy levels in the BO potentials for charmonium hybrids and tetraquarks.
Selection rules for hadronic transitions of XYZ mesons.
Braaten, Eric; Langmack, Christian; Smith, D Hudson
2014-06-01
Many of the XYZ mesons discovered in the last decade can be identified as bound states of a heavy quark and antiquark in Born-Oppenheimer (BO) potentials defined by the energy of gluon and light-quark fields in the presence of static color sources. The mesons include quarkonium hybrids, which are bound states in excited flavor-singlet BO potentials, and quarkonium tetraquarks, which are bound states in BO potentials with light-quark+antiquark flavor. The deepest hybrid potentials are known from lattice QCD calculations. The deepest tetraquark potentials can be inferred from lattice QCD calculations of static adjoint mesons. Selection rules for hadronic transitions are derived and used to identify XYZ mesons that are candidates for ground-state energy levels in the BO potentials for charmonium hybrids and tetraquarks. PMID:24949759
Semileptonic B and Bs decays into orbitally excited charmed mesons
NASA Astrophysics Data System (ADS)
Segovia, J.; Albertus, C.; Entem, D. R.; Fernández, F.; Hernández, E.; Pérez-García, M. A.
2011-11-01
The BABAR Collaboration has recently reported products of branching fractions that include B meson semileptonic decays into final states with charged and neutral D1(2420) and D2*(2460), two narrow orbitally excited charmed mesons. We evaluate these branching fractions, together with those concerning D0*(2400) and D1'(2430) mesons, within the framework of a constituent quark model. The calculation is performed in two steps, one of which involves a semileptonic decay and the other is mediated by a strong process. Our results are in agreement with the experimental data. We also extend the study to semileptonic decays of Bs into orbitally excited charmed-strange mesons, providing predictions to the possible measurements to be carried out at LHC.
Search for scalar glueballs from heavy meson decays
Lue Caidian; Shen Yuelong; Wang Wei
2010-08-05
We investigate the transition form factors of B meson decays into a scalar glueball in the light-cone formalism. Compared with form factors of B to ordinary scalar mesons, the B-to-glueball form factors have the same power in the expansion of 1/m{sub B}. Taking into account the leading twist light-cone distribution amplitude, we find that they are numerically smaller than those form factors of B to ordinary scalar mesons. In the presence of mixing between glueballs and ordinary scalar mesons, the possibility to extract the mixing parameters from semileptonic B decays and nonleptonic B decays are explored. We also point out a clean way to identify a glueball through B{sub c} decays.
Finite temperature effect in infrared-improved AdS/QCD model with back reaction of bulk vacuum
NASA Astrophysics Data System (ADS)
Cui, Ling-Xiao; Fang, Zhen; Wu, Yue-Liang
2016-06-01
Based on an IR-improved soft-wall AdS/QCD model for mesons, which provides a consistent prediction for the mass spectra of resonance scalar, pseudoscalar, vector and axial-vector mesons, we investigate its finite temperature effect. By analyzing the spectral function of mesons and fitting it with a Breit-Wigner form, we perform an analysis for the critical temperature of mesons. The back-reaction effects of bulk vacuum are considered and the thermal mass spectral function of resonance mesons is calculated based on the back-reaction improved action. A reasonable melting temperature is found to be T c ≈ 150 ± 7 MeV, which is consistent with the recent results from lattice QCD simulations. Supported by National Nature Science Foundation of China (NSFC)(10975170, 10905084, 10821504), and Project of Knowledge Innovation Program (PKIP) of Chinese Academy of Science
Leading Twist Parton Distribution Amplitudes in Heavy Vector Mesons
NASA Astrophysics Data System (ADS)
Gao, Fei; Ding, Minghui; Chang, Lei; Liu, Yu-Xin; Roberts, Craig D.
2016-03-01
We employed QCD's Dyson-Schwinger equations (DSEs) for heavy quarks and obtained the leading twist parton distribution amplitudes (PDAs) in heavy vector mesons J/Ψ and ϒ. We found that all of the amplitudes are narrower than the asymptotic form, while they deviate from δ function. This indicates that the interaction between the two continent quarks are still important in the mesons consisted of charm and bottom quarks.
Using anti pp annihilation to find exotic mesons
Sharpe, S.R.
1987-10-01
Present data suggests that a number of mesons have been found which cannot be accommodated in standard anti qq multiplets. Theory suggests that such exotic mesons should exist in the spectrum of Quantum Chromodynamics, but provides little guide to their properties. It is argued that a high luminosity, low energy anti pp machine would be a powerful tool with which to search for such exotics.
Inter-Meson Potentials in Dual Ginzburg-Landau Theory
NASA Astrophysics Data System (ADS)
Kodama, H.; Matsubara, Y.; Ohno, S.; Suzuki, T.
1997-12-01
We calculate inter-meson potentials numerically by solving classical equations of motion derived from dual Ginzburg-Landau (DGL) theory. Inter-meson potentials in DGL theory are shown to be similar to those of the string-flip model and reproduce behavior of the short-range interaction quite well at the classical level. We also compare our results with those from lattice QCD Monte Carlo calculations in the SU(2) case.
Eta Meson Production in Proton-Proton and Nuclear Collisions
NASA Technical Reports Server (NTRS)
Norbury, John W.; Dick, Frank
2008-01-01
Total cross sections for eta meson production in proton - proton collisions are calculated. The eta meson is mainly produced via decay of the excited nucleon resonance at 1535 MeV. A scalar quantum field theory is used to calculate cross sections, which also include resonance decay. Comparison between theory and experiment is problematic near threshold when resonance decay is not included. When the decay is included, the comparison between theory and experiment is much better.
Highly excited and exotic meson spectroscopy from lattice QCD
Christopher Thomas
2011-05-01
I will discuss recent progress in extracting highly excited and exotic meson spectra using lattice QCD. New results in the light meson sector will be presented, where a combination of techniques have enabled us to confidently identify the spin of extracted states. Highlights include many states with exotic quantum numbers and, for the first time in a lattice QCD calculation, spin-four states. I will conclude with comments on future prospects.
Mesons in strong magnetic fields: (I) General analyses
NASA Astrophysics Data System (ADS)
Hattori, Koichi; Kojo, Toru; Su, Nan
2016-07-01
We study properties of neutral and charged mesons in strong magnetic fields | eB | ≫ ΛQCD2 with ΛQCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger-Dyson and Bethe-Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number of meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compared to the case without a magnetic field; this simple picture would offer a gauge invariant and intuitive explanation of the inverse magnetic catalysis.
Mesons in strong magnetic fields: (I) General analyses
Hattori, Koichi; Kojo, Toru; Su, Nan
2016-03-21
Here, we study properties of neutral and charged mesons in strong magnetic fields |eB| >> Λ2QCD with ΛQCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger–Dyson and Bethe–Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number ofmore » meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compared to the case without a magnetic field; this simple picture would offer a gauge invariant and intuitive explanation of the inverse magnetic catalysis.« less
Medium Modification of the Light Vector Mesons in Nuclei
Nasseripour, R.; Djalali, C.; Wood, M.; Weygand, D.
2008-10-13
Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the {rho} vector mesons were investigated via their rare leptonic decay to e+e{sup -}. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The {rho} meson mass distributions were extracted for each of the targets. Statistically significant results regarding medium modification of the rho meson in the nuclear medium rule out large medium effects. Transparency studies of the {omega} and {phi} vector mesons allows a determination of their widths in the medium.
Honma, A.K.
1980-11-01
The results from a high-statistics study of K..pi.. elastic scattering in the reaction K/sup -/p ..-->.. K/sup -/..pi../sup +/n are presented. The data for this analysis are taken from an 11-GeV/c K/sup -/p experiment performed on the Large Aperture Solenoidal Spectrometer (LASS) facility at the Stanford Linear Accelerator Center (SLAC). By selecting the very forward produced K/sup -/..pi../sup +/ events, a sample consisting of data for the K..pi.. ..-->.. K..pi.. elastic scattering reaction was extracted. The angular distribution for this meson-meson scattering is studied by use of both a spherical harmonic moments analysis and a partial-wave analysis (PWA). The previously established leading natural spin-parity strange meson resonances (the J/sup P/ = 1/sup -/ K*(895), the 2/sup +/ K*(1430), and the 3/sup -/ K*(1780)) are observed in the results from both the moments analysis and the PWA. In addition, evidence for a new spin 4/sup -/ K* resonance with a mass of 2080 MeV and a width of about 225 MeV is presented. The results from the PWA confirm the existence of a 0/sup +/ kappa (1490) and propose the existence of a second scalar meson resonance, the 0/sup +/ kappa' (1900). Structure in the P-wave amplitude indicates resonance behavior in the mass region near 1700 MeV. In two of the four ambiguous solutions for the mass region above 1800 MeV, there is strong evidence for another P-wave resonant structure near 2100 MeV. The observed strange meson resonances are found to have a natural interpretation in terms of states predicted by the quark model. In particular, the mass splittings of the leading trajectory natural spin-parity strange meson states and the mass splittings between the spin-orbit triplet states are discussed. 59 figures, 17 tables.
Residual meson-meson interaction from lattice gauge simulation in a simple QED{sub 2+1} model
J. Canosa; H. Fiebig
1995-08-01
The residual interaction for a meson-meson system is computed utilizing the cumulant, or cluster, expansion of the momentum-space time correlation matrix. The cumulant expansion serves to define asymptotic, or free, meson-meson operators. The definition of an effective interaction is then based on a comparison of the full (interacting) and the free (noninteracting) time correlation matrices. The proposed method, which may straight forwardly be transcribed to other hadron-hadron systems, here is applied to a simple 2+1 dimensional U(1) lattice gauge model tuned such that it is confining. Fermions are treated in the staggered scheme. The effective interaction exhibits a repulsive core and attraction at intermediate relative distances. These findings are consistent with an earlier study of the same model utilizing L{umlt u}scher's method where scattering phase shifts are obtained directly.
On Decays of B Mesons to a Strange Meson and an Eta or Eta' Meson at Babar
Hirschauer, James Francis
2009-01-01
We describe studies of the decays of B mesons to final states ηK*(892), ηK*_{0}(S-wave), ηK*_{2}(1430), and η'K based on data collected with the BABAR detector at the PEP-II asymmetric-energy e^{+}e^{-} collier at the Stanford Linear Accelerator Center. We measure branching fractions and charge asymmetries for the decays B → ηK*, where K* indicates a spin 0, 1, or 2 Kπ system, making first observations of decays to final states ηK^{0*}_{0}(S-wave), ηK^{+*}_{0} (S-wave), and ηK^{0*}_{2}(1430). We measure the time-dependent CP-violation parameters S and C for the decays B^{0} → η'K^{0}, observing CP violation in a charmless B decay with 5σ significance considering both statistical and systematic uncertainties.
Cheng Haiyang; Chua Chunkhiang; Yang Kweichou
2006-01-01
The hadronic charmless B decays into a scalar meson and a pseudoscalar meson are studied within the framework of QCD factorization. Based on the QCD sum rule method, we have derived the leading-twist light-cone distribution amplitudes of scalar mesons and their decay constants. Although the light scalar mesons f{sub 0}(980) and a{sub 0}(980) are widely perceived as primarily the four-quark bound states, in practice it is difficult to make quantitative predictions based on the four-quark picture for light scalars. Hence, predictions are made in the 2-quark model for the scalar mesons. The short-distance approach suffices to explain the observed large rates of f{sub 0}(980)K{sup -} and f{sub 0}(980)K{sup 0} that receive major penguin contributions from the b{yields}sss process. When f{sub 0}(980) is assigned as a four-quark bound state, there exist extra diagrams contributing to B{yields}f{sub 0}(980)K. Therefore, a priori the f{sub 0}(980)K rate is not necessarily suppressed for a four-quark state f{sub 0}(980). The predicted B{sup 0}{yields}a{sub 0}{sup {+-}}(980){pi}{sup {+-}} and a{sub 0}{sup +}(980)K{sup -} rates exceed the current experimental limits, favoring a four-quark nature for a{sub 0}(980). The penguin-dominated modes a{sub 0}(980)K and a{sub 0}(1450)K receive predominant weak annihilation contributions. There exists a twofold experimental ambiguity in extracting the branching ratio of B{sup -}{yields}K{sub 0}*{sup 0}(1430){pi}{sup -}, which can be resolved by measuring other K{sub 0}*(1430){pi} modes in conjunction with the isospin symmetry consideration. Large weak annihilation contributions are needed to explain the K{sub 0}*(1430){pi} data. The decay B{sup 0}{yields}{kappa}{sup +}K{sup -} provides a nice ground for testing the 4-quark and 2-quark nature of the {kappa} meson. It can proceed through W-exchange and hence is quite suppressed if {kappa} is made of two quarks, while it receives a tree contribution if {kappa} is predominately a four
Two-body hadronic charmed meson decays
NASA Astrophysics Data System (ADS)
Cheng, Hai-Yang; Chiang, Cheng-Wei
2010-04-01
In this work we study the two-body hadronic charmed meson decays, including both the PP and VP modes. The latest experimental data are first analyzed in the diagrammatic approach. The magnitudes and strong phases of the flavor amplitudes are extracted from the Cabibbo-favored decay modes using χ2 minimization. The best-fitted values are then used to predict the branching fractions of the singly Cabibbo-suppressed and doubly Cabibbo-suppressed decay modes in the flavor SU(3) symmetry limit. We observe significant SU(3) breaking effects in some of the singly Cabibbo-suppressed channels. In the case of VP modes, we point out that the AP and AV amplitudes cannot be completely determined based on currently available data. We conjecture that the quoted experimental results for both Ds+→K¯0K*+ and Ds+→ρ+η' are overestimated. We compare the sizes of color-allowed and color-suppressed tree amplitudes extracted from the diagrammatical approach with the effective parameters a1 and a2 defined in the factorization approach. The ratio |a2/a1| is more or less universal among the D→K¯π, K¯*π, and K¯ρ modes. This feature allows us to discriminate between different solutions of topological amplitudes. For the long-standing puzzle about the ratio Γ(D0→K+K-)/Γ(D0→π+π-), we argue that, in addition to the SU(3) breaking effect in the spectator amplitudes, the long-distance resonant contribution through the nearby resonance f0(1710) can naturally explain why D0 decays more copiously to K+K- than π+π- through the W-exchange topology. This has to do with the dominance of the scalar glueball content of f0(1710) and the chiral-suppression effect in the decay of a scalar glueball into two pseudoscalar mesons. The same final-state interaction also explains the occurrence of D0→K0K¯0 and its vanishing amplitude when SU(3) flavor symmetry is exact. Owing to the G-parity selection rule, Ds+→π+ω does not receive contributions from the short-distance W
Biplab Dey, Michael E. McCracken, David G. Ireland, Curtis A. Meyer
2011-05-01
The complete expression for the intensity in pseudo-scalar meson photoproduction with a polarized beam, target, and recoil baryon is derived using a density matrix approach that offers great economy of notation. A Cartesian basis with spins for all particles quantized along a single direction, the longitudinal beam direction, is used for consistency and clarity in interpretation. A single spin-quantization axis for all particles enables the amplitudes to be written in a manifestly covariant fashion with simple relations to those of the well-known CGLN formalism. Possible sign discrepancies between theoretical amplitude-level expressions and experimentally measurable intensity profiles are dealt with carefully. Our motivation is to provide a coherent framework for coupled-channel partial-wave analysis of several meson photoproduction reactions, incorporating recently published and forthcoming polarization data from Jefferson Lab.
NASA Astrophysics Data System (ADS)
Olivas, Alexander Raymond, Jr.
The decays of B0 mesons to hadronic final states remains a rich area of physics on BaBar. Not only do the cc¯ -K final states (e.g. B0 → psi(2 S)K0) allow for the measurement of CP Violation, but the branching fractions provide a sensitive test of the theoretical methods used to account for low energy non-perturbative QCD effects. We present the measurement of the branching fraction for the decay B0 → psi(2S)K s. The data set consists of 88.8 +/- 1.0 x 10 6 BB¯ pairs collected on the e +e- → Upsilon(4 S) resonance on BaBar/PEP-II at the Stanford Linear Accelerator Center (SLAC). This analysis features a modification of present cuts, with respect to those published so far on BaBar, on the Ks → pi +pi- and psi(2S) → J/psipi+pi- which aim at reducing the background while keeping the signal intact. Various data selection criteria are studied for the lepton modes (e+ e- and mu+mu- ) of the J/psi and psi(2S) to improve signal purity as well as study the stability of the resultant branching fractions.
NASA Astrophysics Data System (ADS)
He, Liang
2016-08-01
Experiments at the Relativistic Heavy Ion Collider (RHIC) indicate that a novel QCD matter consistent with a strongly-coupled Quark-Gluon Plasma (sQGP) has been created. Heavy quarks are predominantly created in initial hard scatterings, and thus experience the entire evolution of the system including the sQGP phase. The sensitivity of heavy quarks to the transport properties of sQGP is encoded in experimental observables such as elliptic flow (v2). In this presentation, we present the first measurement of v2 of D 0 mesons reconstructed with the STAR Heavy Flavor Tracker (HFT) in Au+Au collisions at √sNN =200 GeV, for a wide transverse momentum range. The measured D 0 v2 in 0-80% most central collisions is finite and suggests that the charm quark exhibits collective behavior. Several theoretical calculations with dimensionless spacial diffusion coefficient (2πTDs ) for charm quarks in the range of ∼⃒2-12 can simultaneously reproduce our D0 s v2 result as well as the previously published D0 nuclear modification factor.
Leskovec, Luka; Lang, C. B.; Mohler, Daniel; Prelovsek, Sasa; Woloshyn, R. M.
2015-11-12
We study the positive parity charmed strange mesons using lattice QCD, the only reliable ab initio method to study QCD at low energies. Especially the experimentally observed $D_{s0}^*(2317)$ and $D_{s1}(2460)$ have challenged theory for quite some time. The dynamical lattice QCD simulations are performed at two distinct pion masses, $m_{\\pi}$ = 266 MeV and 156 MeV, using both $\\bar{c}s$ as well as $DK$ and $D^*K$ scattering operators in the construction of the correlation matrix in order to take into the account threshold effects. While the $J^P = 0^+$ channel benefited most from the inclusion of scattering operators, it was also crucial for the case of the $D_{s1}(2460)$. Using the L\\"uscher method, which relates the finite volume spectrum to the infinite volume scattering matrix, we were able to determine the near threshold behavior of the scattering amplitude. From it we extracted the binding momenta and the masses of the below-threshold bound states $D_{s0}^*(2317)$ and $D_{s1}(2460)$ by determining the pole positions of the scattering amplitudes. Our results compare well with experiment, resolving a long standing discrepancy between theory and experiment.
Electromagnetic Studies of Mesons, Nucleons, and Nuclei
Baker, Oliver K.
2013-08-20
Professor Baker was a faculty member at Hampton University in Hampton, Virginia, and, jointly, a Staff Physicist at Jefferson Lab in nearby Newport News from September 1989 to July 2006. The Department of Energy (DOE) funded the grant DE-FG02-97ER41035 Electromagnetic Studies of Mesons, Nucleons, and Nuclei, while Baker was in this joint appointment. Baker sent a closeout report on these activities to Hampton University’s Sponsored Research Office some years ago, shortly after joining Yale University in 2006. In the period around 2001, the research grant with Baker as the Principal Investigator (PI) was put under the supervision of Professor Liguang Tang at Hampton University. Baker continued to pursue the research while in this join appointment, however the administrative responsibilities with the DOE and with Hampton University rested with Professor Tang after 2001, to my recollection. What is written in this document is from Baker’s memory of the research activities, which he has not pursued since joining the Yale University faculty.
Flux-bubble models and mesonic molecules
NASA Astrophysics Data System (ADS)
Boyce, M. M.; Treurniet, J.; Watson, P. J. S.
1999-06-01
It has been shown that the string-flip potential model reproduces most of the bulk properties of nuclear matter, with the exception of nuclear binding. Furthermore, it was postulated that this model with the inclusion of the colour-hyperfine interaction should produce binding. In some recent work a modified version of the string-flip potential model was developed, called the flux-bubble model, which would allow for the addition of perturbative QCD interactions. In attempts to construct a simple q overlineq nucleon system using the flux-bubble model (which only included colour-Coulomb interactions) difficulties arise with trying to construct a many-body variational wave function that would take into account the locality of the flux-bubble interactions. In this paper we look at a toy system, a mesonic molecule, in order to understand these difficulties. En route, a new variational wave function is proposed that may have a sufficient impact on the old string-flip potential model results that the inclusion of perturbative effects may not be needed.
Dark photons from charm mesons at LHCb
NASA Astrophysics Data System (ADS)
Ilten, Philip; Thaler, Jesse; Williams, Mike; Xue, Wei
2015-12-01
We propose a search for dark photons A' at the LHCb experiment using the charm meson decay D*(2007 )0→D0A'. At nominal luminosity, D*0→D0γ decays will be produced at about 700 kHz within the LHCb acceptance, yielding over 5 trillion such decays during Run 3 of the LHC. Replacing the photon with a kinetically mixed dark photon, LHCb is then sensitive to dark photons that decay as A'→e+e-. We pursue two search strategies in this paper. The displaced strategy takes advantage of the large Lorentz boost of the dark photon and the excellent vertex resolution of LHCb, yielding a nearly background-free search when the A' decay vertex is significantly displaced from the proton-proton primary vertex. The resonant strategy takes advantage of the large event rate for D*0→D0A' and the excellent invariant-mass resolution of LHCb, yielding a background-limited search that nevertheless covers a significant portion of the A' parameter space. Both search strategies rely on the planned upgrade to a triggerless-readout system at LHCb in Run 3, which will permit the identification of low-momentum electron-positron pairs online during data taking. For dark photon masses below about 100 MeV, LHCb can explore nearly all of the dark photon parameter space between existing prompt-A' and beam-dump limits.
Studying meson baryon systems with strangeness +1
NASA Astrophysics Data System (ADS)
Khemchandani, K. P.; Martinez Torres, A.; Navarra, F. S.; Nielsen, M.; Tolos, L.
2015-07-01
We discuss the results of our recent study of the s-wave KN-K*N coupled interaction. The K*N amplitude is obtained by calculating t- and u- channel diagrams and a contact interaction. For the KN amplitude we calculate the Weinberg-Tomozawa term obtained from the lowest order chiral Lagrangian. The KN ↔ K*N amplitudes are calculated by replacing the photon by a vector meson in the standard Kroll-Ruderman term. The subtraction constants required to calculate the loops are fixed by demanding the KN amplitudes to fit the data available on the isospin 0 and 1 s-wave phase shifts. We find that the coupling between the two channels plays an important in the isospin 0 configuration. We obtain updated amplitudes and cross sections for the KN and K*N systems, which can be used to understand some recent findings of K, K* production in p-p and p-A collisions studied by the Hades collaboration. We also look for resonances in these systems but find none.
ϕ-meson photoproduction on hydrogen in the neutral decay mode
NASA Astrophysics Data System (ADS)
Seraydaryan, H.; Amaryan, M. J.; Gavalian, G.; Baghdasaryan, H.; Weinstein, L.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Anderson, M. D.; Pereira, S. Anefalos; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Collins, P.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; Fassi, L. El; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Gevorgyan, N.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lewis, S.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munevar, E.; Camacho, C. Munoz; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Protopopescu, D.; Puckett, A. J. R.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration
2014-05-01
We report the first measurement of the photoproduction cross section of the ϕ meson in its neutral decay mode in the reaction γp →pϕ(KSKL). The experiment was performed with a tagged photon beam of energy 1.6≤Eγ≤3.6 GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The pϕ final state is identified via reconstruction of KS in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction γp →pKSX to be KL. The presented results significantly enlarge the existing data on ϕ photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of ϕ photoproduction.
Simultaneous photoproduction of eta and pi0 mesons on the proton.
Ajaka, J; Assafiri, Y; Bartalini, O; Bellini, V; Bouchigny, S; Castoldi, M; D'Angelo, A; Didelez, J P; Di Salvo, R; Döring, M; Fantini, A; Fichen, L; Gervino, G; Ghio, F; Girolami, B; Giusa, A; Guidal, M; Hourany, E; Kunne, R; Lapik, A; Sandri, P Levi; Moricciani, D; Mushkarenkov, A; Nedorezov, V; Oset, E; Randieri, C; Rudnev, N; Russo, G; Schaerf, C; Sperduto, M; Sutera, M; Turinge, A
2008-02-01
The analysis of the gammap-->etapi(0)p reaction has been performed using data from the GRAAL experiment. The total and differential cross sections and the beam asymmetry have been obtained from threshold up to 1.5 GeV of beam energy. The two resonances S11(1535) and Delta(1700) are expected to be excited in the intermediate states of this reaction. The results are used to test predictions based on the assumption that both resonances are dynamically generated from the meson-baryon interaction provided by chiral Lagrangians. The term involving the Delta(1700) excitation, followed by the decay into etaDelta(1232), is found to be dominant.
phi-meson photoproduction on Hydrogen in the neutral decay mode
Seraydaryan, Helena; Amaryan, Moscov J.; Gavalian, Gagik; Baghdasaryan, Hovhannes A.; Weinstein, Larry
2014-05-01
We report the first measurement of the photoproduction cross section of the $\\phi$ meson in its neutral decay mode in the reaction $\\gamma p \\to p\\phi(K_SK_L)$. The experiment was performed with a tagged photon beam of energy $1.6 \\le E_\\gamma \\le 3.6$ GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The $p \\phi$ final state is identified via reconstruction of $K_S$ in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction $\\gamma p \\to p K_S X$ to be $K_L$. The presented results significantly enlarge the existing data on $\\phi$-photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of $\\phi$ photoproduction.
Hadronic D decays involving even-parity light mesons
Cheng, H.-Y.; Chiang, C.-W.
2010-04-01
We study the hadronic D meson decays into a pseudoscalar meson P and an even-parity meson M, where M represents a scalar meson S, an axial-vector meson A, or a tensor meson T. These decays are first analyzed in the flavor-diagram approach. Fits to the SP modes with S being a nonstrange scalar meson show that neither the simple qq picture nor the q{sup 2}q{sup 2} scheme is favored by data. Current measurements on the AP decays are insufficient for a meaningful analysis. Some TP data are inconsistent with the others. In certain cases, the W-annihilation diagrams indicated by the data are unexpectedly large. As a comparison, we also compute their decay rates in the factorization approach using form factors extracted from the covariant light-front model. We find that factorization works well for Cabibbo-allowed D{sup +{yields}}SP, AP decays free of the weak annihilation contributions (W-exchange or W-annihilation). For the other SP and AP modes, it is necessary to include weak annihilation contributions to account for the data. However, factorization fails for D{yields}TP decays for some unknown reason; the predicted rates are in general too small by at least 2 orders of magnitude compared to experiment. We also examine the finite-width effects of resonances. Some decay modes which are kinematically forbidden become physically allowed due to the finite width of the resonance. We show that the branching fraction of D{sup +{yields}{sigma}{pi}+} extracted from three-body decays is enhanced by a factor of 2, whereas B(D{sup 0{yields}}f{sub 2}(1270)K{sup 0}) is reduced by a factor of 4 by finite-width effects.
Yukawa Meson, Sakata Model and Baryon-Lepton Symmetry Revisited
NASA Astrophysics Data System (ADS)
Marshak, R. E.
It is difficult for me to grasp that this symposium is celebrating the jubilee of meson theory since I was a junior at Columbia College in 1935. I recall hearing a colloquium by Paul Dirac that year telling an enraptured audience about the infinite sea of negative energy states but I do not recall any special note being taken of the birth of an equally revolutionary concept, the Yukawa meson. Perhaps the reason was the publication of Hideki Yukawa's paper in an inaccessible Japanese journal, perhaps Dirac's electron theory was dealing with the well-known electromagnetic force whereas Yukawa' meson theory was put forth to understand the nature of two new forces - the nuclear and the weak. Whatever the reason, the situation changed drastically when I migrated to Cornell (to do my thesis under Hans Bethe during the years 1937sim39) and found a deep interest in meson theory. Thus, my own scientific career has almost spanned the period since the birth of meson theory but, what is more to the point, it has been strongly influenced by the work of Yukawa and his collaborators. It therefore gives me great pleasure to be able to talk at this MESON 50 symposium. As one of the oldest speakers, I shall respond in a loose way to Professor Maki's invitation to cover ``topics concerning the historical developments of hadron physics''. I shall select several major themes from the Japanese work that have had special interest for me. My remarks will fall under the four headings: (A) Yukawa Meson; (B) Sakata Model; (C) Baryon-Lepton Symmetry; and (D) Extensions of Baryon-Lepton Symmetry.
Decoherence induced CPT violation and entangled neutral mesons
Bernabeu, J.; Mavromatos, Nick E.; Sarkar, Sarben
2006-08-15
We discuss two classes of semimicroscopic theoretical models of stochastic spacetime foam in quantum gravity and the associated effects on entangled states of neutral mesons, signalling an intrinsic breakdown of CPT invariance. One class of models deals with a specific model of foam, initially constructed in the context of noncritical (Liouville) string theory, but viewed here in the more general context of effective quantum-gravity models. The relevant Hamiltonian perturbation, describing the interaction of the meson with the foam medium, consists of off-diagonal stochastic metric fluctuations, connecting distinct mass eigenstates (or the appropriate generalization thereof in the case of K-mesons), and it is proportional to the relevant momentum transfer (along the direction of motion of the meson pair). There are two kinds of CPT-violating effects in this case, which can be experimentally disentangled: one (termed '{omega}-effect') is associated with the failure of the indistinguishability between the neutral meson and its antiparticle, and affects certain symmetry properties of the initial state of the two-meson system; the second effect is generated by the time evolution of the system in the medium of the spacetime foam, and can result in time-dependent contributions of the {omega}-effect type in the time profile of the two-meson state. Estimates of both effects are given, which show that, at least in certain models, such effects are not far from the sensitivity of experimental facilities available currently or in the near future. The other class of quantum-gravity models involves a medium of gravitational fluctuations which behaves like a 'thermal bath'. In this model both of the above-mentioned intrinsic CPT violation effects are not valid.
Relative rates of B meson decays into {psi}(2S) and J/{psi} mesons
Abazov, V. M.; Alexeev, G. D.; Kharzheev, Y. M.; Malyshev, V. L.; Tokmenin, V. V.; Vertogradov, L. S.; Yatsunenko, Y. A.; Abbott, B.; Gutierrez, P.; Hossain, S.; Jain, S.; Rominsky, M.; Severini, H.; Skubic, P.; Strauss, M.; Abolins, M.; Benitez, J. A.; Brock, R.; Dyer, J.; Edmunds, D.
2009-06-01
We report on a study of the relative rates of B meson decays into {psi}(2S) and J/{psi} mesons using 1.3 fb{sup -1} of pp collisions at {radical}(s)=1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe the channels B{sub s}{sup 0}{yields}{psi}(2S){phi}, B{sub s}{sup 0}{yields}J/{psi}{phi}, B{sup {+-}}{yields}{psi}(2S)K{sup {+-}}, and B{sup {+-}}{yields}J/{psi}K{sup {+-}} and we measure the relative branching fractions for these channels to be (B(B{sub s}{sup 0}{yields}{psi}(2S){phi})/B(B{sub s}{sup 0}{yields}J/{psi}{phi}))=0.53{+-}0.10(stat){+-}0.07(syst){+-}0.06(B), (B(B{sup {+-}}{yields}{psi}(2S)K{sup {+-}})/B(B{sup {+-}}{yields}J/{psi}K{sup {+-}}))=0.63{+-}0.05(stat){+-}0.03(syst){+-}0.07(B),where the final error corresponds to the uncertainty in the J/{psi} and {psi}(2S) branching ratio into two muons.
Hyperfine meson splittings: chiral symmetry versus transverse gluon exchange
Felipe J. Llanes-Estrada; Stephen R. Cotanch; Adam P. Szczepaniak; Eric S. Swanson
2004-02-01
Meson spin splittings are examined within an effective Coulomb gauge QCD Hamiltonian incorporating chiral symmetry and a transverse hyperfine interaction necessary for heavy quarks. For light and heavy quarkonium systems the pseudoscalar-vector meson spectrum is generated by approximate BCS-RPA diagonalizations. This relativistic formulation includes both S and D waves for the vector mesons which generates a set of coupled integral equations. A smooth transition from the heavy to the light quark regime is found with chiral symmetry dominating the /pi-/rho mass difference. A good, consistent description of the observed meson spin splittings and chiral quantities, such as the quark condensate and the /pi mass, is obtained. Similar comparisons with TDA diagonalizations, which violate chiral symmetry, are deficient for light pseudoscalar mesons indicating the need to simultaneously include both chiral symmetry and a hyperfine interaction. The /eta{sub b} mass is predicted to be around 9400 MeV consistent with other theoretical expectations and above the unconfirmed 9300 MeV candidate. Finally, for comparison with lattice results, the J reliability parameter is also evaluated.
Magnetic monopole interactions: shell structure of meson and baryon states
Akers, D.
1986-12-01
It is suggested that a low-mass magnetic monopole of Dirac charge g = (137/2)e may be interacting with a c-quark's magnetic dipole moment to produce Zeeman splitting of meson states. The mass M/sub 0/ = 2397 MeV of the monopole is in contrast to the 10/sup 16/-GeV monopoles of grand unification theories (GUT). It is shown that shell structure of energy E/sub n/ = M/sub 0/ + 1/4nM/sub 0/... exists for meson states. The presence of symmetric meson states leads to the identification of the shell structure. The possible existence of the 2397-MeV magnetic monopole is shown to quantize quark masses in agreement with calculations of quantum chromodynamics (QCD). From the shell structure of meson states, the existence of two new mesons is predicted: eta(1814 +/- 50 MeV) with I/sup G/(J/sup PC/) = 0/sup +/(0/sup - +/) and eta/sub c/ (3907 +/- 100 MeV) with J/sup PC/ = 0/sup - +/. The presence of shell structure for baryon states is shown.
Method to study complex systems of mesons in lattice QCD
Detmold, William; Savage, Martin J.
2010-07-30
Correlation functions involving many hadrons allow finite density systems to be explored with Lattice QCD. Recently, systems with up to 12more » $$\\pi^+$$'s or $K^+$'s have been studied to determine the the $3$-$$\\pi^+$$ and $3$-$K^+$ interactions and the corresponding chemical potential has been determined as a function of density in each case. We derive recursion relations between correlation functions that allow us to extend this work to systems of arbitrary numbers of mesons and to systems containing arbitrary different types of mesons such as $$\\pi^+$$'s, $K^+$'s, $D^0$'s and $B^+$'s. These relations allow for the study of finite-density systems in arbitrary volumes, and the study of high-density systems. Systems comprised of up to N=12 m mesons can be explored with Lattice QCD calculations utilizing $m$ different sources for the quark propagators. As the recursion relations require only a small, N-independent, number of operations to derive the N+1 meson contractions from the N meson contractions, they are compuationally feasible.« less
Method to study complex systems of mesons in lattice QCD
Detmold, William; Savage, Martin J.
2010-07-30
Correlation functions involving many hadrons allow finite density systems to be explored with Lattice QCD. Recently, systems with up to 12 $\\pi^+$'s or $K^+$'s have been studied to determine the the $3$-$\\pi^+$ and $3$-$K^+$ interactions and the corresponding chemical potential has been determined as a function of density in each case. We derive recursion relations between correlation functions that allow us to extend this work to systems of arbitrary numbers of mesons and to systems containing arbitrary different types of mesons such as $\\pi^+$'s, $K^+$'s, $D^0$'s and $B^+$'s. These relations allow for the study of finite-density systems in arbitrary volumes, and the study of high-density systems. Systems comprised of up to N=12 m mesons can be explored with Lattice QCD calculations utilizing $m$ different sources for the quark propagators. As the recursion relations require only a small, N-independent, number of operations to derive the N+1 meson contractions from the N meson contractions, they are compuationally feasible.
Analysis of the meson-meson data in the framework of the dispersion D-matrix method
Anisovich, A. V.; Nikonov, V. A.; Sarantsev, A. V.; Anisovich, V. V.; Matveev, M. A.; Vulfs, T. O.; Nikonov, K. V.; Nyiri, J.
2011-10-01
We describe the meson-meson data for the (IJ{sup PC}=00{sup ++}) wave at 280{<=}{radical}(s){<=}1900 MeV in two approaches: (i) the K-matrix approach and (ii) the dispersion relation D-matrix method. With a good description of low-energy data (at 280{<=}{radical}(s){<=}900 MeV) as well as the data of two-meson transition amplitudes and antiproton-proton annihilation into three pseudoscalar meson states (at 450{<=}{radical}(s){<=}1950 MeV) we have found the positions of the resonance poles: (i) for the {sigma} meson pole: M{sub {sigma}=}(390{+-}35)-i(235{+-}50) MeV; (ii) two poles for the f{sub 0}(980), on the second sheet (under the {pi}{pi} cut): M{sub I}=(1011{+-}5)-i(35{+-}5) MeV, and on the third sheet (under the {pi}{pi} and KK cuts), M{sub II}=(1035{+-}50)-i(460{+-}50) MeV; for the f{sub 0}(1370) meson, M=(1285{+-}30)-i(160{+-}20) MeV; for the f{sub 0}(1500) meson, M=(1488{+-}4)-i(53{+-}5) MeV; for the f{sub 0}(1790) meson, M=(1775{+-}25)- i(140{+-}15) MeV; and for the broad state f{sub 0}(1200-1600) M=(1540{+-}120)-i(550{+-}70) MeV. Our estimation of the scalar-isoscalar scattering length obtained under different parameterizations and assumptions about the quality of low-energy {pi}{pi} scattering data is a{sub 0}{sup 0}=(0.215{+-}0.040)m{sub {pi}}{sup -1}. We also discuss the idea according to which the {sigma} meson could be a remnant of the confinement singularity, 1/s{sup 2}, in a white channel.
Nonresonant Background in Isobaric Models of Photoproduction of η-Mesons on Nucleons
NASA Astrophysics Data System (ADS)
Tryasuchev, V. A.; Alekseev, B. A.; Yakovleva, V. S.; Kondratyeva, A. G.
2016-07-01
Within the framework of isobaric models of pseudoscalar meson photoproduction, the nonresonant background of photoproduction of η-mesons on nucleons is investigated as a function of energy. A bound on the magnitude of the pseudoscalar coupling constant of the η-meson with a nucleon is obtained: g η NN 2 /4π ≤ 0.01, and a bound on vector meson exchange models is also obtained.
Color transparency in incoherent electroproduction of {rho} mesons off nuclei
Nemchik, J.; Kopeliovich, B. Z.; Potashnikova, I. K.
2013-04-15
Color transparency (CT) phenomena in elastic electroproduction of vector mesons off nuclei are usually infected by the onset of coherence length (CL) effects. However, at low energies corresponding to the CLAS experiment at Jefferson Lab (JLab), one can study practically the net CT effects, since CL is much shorter than the nuclear radius. We investigate various manifestations of CT effects using rigorous quantum mechanical approach based on the path integral technique. We include also the effects of {rho} meson decay inside the nucleus leading to a rise of the nuclear suppression towards small values of Q{sup 2}. Motivated by the last CLAS data we predict the A, Q{sup 2} and l{sub c} dependence of nuclear transparency for {rho}{sup 0} mesons produced incoherently off nuclei. We also perform predictions for expected signal of CT corresponding to the planned JLab upgrade to 12 GeV electron beam.
Properties of L=1 B(1) and B(2)* mesons.
Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguilo, E; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Ancu, L S; Andeen, T; Anderson, S; Andrieu, B; Anzelc, M S; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Asman, B; Assis Jesus, A C S; Atramentov, O; Autermann, C; Avila, C; Ay, C; Badaud, F; Baden, A; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Banerjee, P; Barberis, E; Barfuss, A-F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Berntzon, L; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Biscarat, C; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Borissov, G; Bos, K; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Buchanan, N J; Buchholz, D; Buehler, M; Buescher, V; Burdin, S; Burke, S; Burnett, T H; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Caron, S; Carvalho, W; Casey, B C K; Cason, N M; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chan, K; Chandra, A; Charles, F; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Clément, C; Clément, B; Coadou, Y; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Crépé-Renaudin, S; Cutts, D; Cwiok, M; da Motta, H; Das, A; Davies, G; De, K; de Jong, S J; de Jong, P; De La Cruz-Burelo, E; Martins, C De Oliveira; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dong, H; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Ford, M; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; Galyaev, E; Garcia, C; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Gelé, D; Gerber, C E; Gershtein, Y; Gillberg, D; Ginther, G; Gollub, N; Gómez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, J; Guo, F; Gutierrez, P; Gutierrez, G; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Hanagaki, K; Hansson, P; Harder, K; Harel, A; Harrington, R; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinmiller, J M; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hong, S J; Hooper, R; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Käfer, D; Kahn, S; Kajfasz, E; Kalinin, A M; Kalk, J R; Kalk, J M; Kappler, S; Karmanov, D; Kasper, J; Kasper, P; Katsanos, I; Kau, D; Kaur, R; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y M; Khatidze, D; Kim, H; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J-P; Kopal, M; Korablev, V M; Kothari, B; Kozelov, A V; Krop, D; Kryemadhi, A; Kuhl, T; Kumar, A; Kunori, S; Kupco, A; Kurca, T; Kvita, J; Lacroix, F; Lam, D; Lammers, S; Landsberg, G; Lazoflores, J; Lebrun, P; Lee, W M; Leflat, A; Lehner, F; Lellouch, J; Lesne, V; Leveque, J; Lewis, P; Li, J; Li, Q Z; Li, L; Lietti, S M; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobo, L; Lobodenko, A; Lokajicek, M; Lounis, A; Love, P; Lubatti, H J; Lyon, A L; Maciel, A K A; Mackin, D; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Makovec, N; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martin, B; McCarthy, R; Melnitchouk, A; Mendes, A; Mendoza, L; Mercadante, P G; Merkin, M; Merritt, K W; Meyer, J; Meyer, A; Michaut, M; Millet, T; Mitrevski, J; Molina, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulders, M; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nomerotski, A; Novaes, S F; Nunnemann, T; O'Dell, V; O'Neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Oshima, N; Osta, J; Otec, R; Y Garzón, G J Otero; Owen, M; Padley, P; Pangilinan, M; Parashar, N; Park, S-J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Penning, B; Perea, P M; Peters, K; Peters, Y; Pétroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M-E; Polozov, P; Pompos, A; Pope, B G; Popov, A V; Potter, C; da Silva, W L Prado; Prosper, H B; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Rani, K J; Ranjan, K; Ratoff, P N; Renkel, P; Reucroft, S; Rich, P; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rodrigues, R F; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santoro, A; Savage, G; Sawyer, L; Scanlon, T; Schaile, D; Schamberger, R D; Scheglov, Y; Schellman, H; Schieferdecker, P; Schliephake, T; Schmitt, C; Schwanenberger, C; Schwartzman, A; Schwienhorst, R; Sekaric, J; Sengupta, S; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Shpakov, D; Siccardi, V; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Smith, R P; Snow, J; Snow, G R; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Souza, M; Spurlock, B; Stark, J; Steele, J; Stolin, V; Stone, A; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, M; Strauss, E; Ströhmer, R; Strom, D; Strovink, M; Stutte, L; Sumowidagdo, S; Svoisky, P; Sznajder, A; Talby, M; Tamburello, P; Tanasijczuk, A; Taylor, W; Telford, P; Temple, J; Tiller, B; Tissandier, F; Titov, M; Tokmenin, V V; Tomoto, M; Toole, T; Torchiani, I; Trefzger, T; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, S; Uvarov, L; Uzunyan, S; Vachon, B; van den Berg, P J; van Eijk, B; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vartapetian, A; Vasilyev, I A; Vaupel, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Villeneuve-Seguier, F; Vint, P; Vokac, P; Von Toerne, E; Voutilainen, M; Vreeswijk, M; Wagner, R; Wahl, H D; Wang, L; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, M; Weber, G; Weerts, H; Wenger, A; Wermes, N; Wetstein, M; White, A; Wicke, D; Wilson, G W; Williams, M R J; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yacoob, S; Yamada, R; Yan, M; Yasuda, T; Yatsunenko, Y A; Yip, K; Yoo, H D; Youn, S W; Yu, J; Yu, C; Yurkewicz, A; Zatserklyaniy, A; Zeitnitz, C; Zhang, D; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zivkovic, L; Zutshi, V; Zverev, E G
2007-10-26
This Letter presents the first strong evidence for the resolution of the excited B mesons B(1) and B(2)* as two separate states in fully reconstructed decays to B(+)(*)pi(-). The mass of B(1) is measured to be 5720.6+/-2.4+/-1.4 MeV/c(2) and the mass difference DeltaM between B(2)* and B(1) is 26.2+/-3.1+/-0.9 MeV/c;{2}, giving the mass of the B(2)* as 5746.8+/-2.4+/-1.7 MeV/c(2). The production rate for B(1) and B(2)* mesons is determined to be a fraction (13.9+/-1.9+/-3.2)% of the production rate of the B+ meson. PMID:17995320
Hadronic molecules with a D ¯ meson in a medium
NASA Astrophysics Data System (ADS)
Caramés, T. F.; Fontoura, C. E.; Krein, G.; Tsushima, K.; Vijande, J.; Valcarce, A.
2016-08-01
We study the effect of a hot and dense medium on the binding energy of hadronic molecules with open-charm mesons. We focus on a recent chiral quark-model-based prediction of a molecular state in the N D ¯ system. We analyze how the two-body thresholds and the hadron-hadron interactions are modified when quark and meson masses and quark-meson couplings change in a function of the temperature and baryon density according to predictions of the Nambu-Jona-Lasinio model. We find that in some cases the molecular binding is enhanced in medium as compared to their free-space binding. We discuss the consequences of our findings for the search for exotic hadrons in high-energy heavy-ion collisions as well as in the forthcoming facilities FAIR or J-PARC.
Meson production in two-photon interactions at LHC energies
Da Silva, D. T.; Goncalves, V. P.; Sauter, W. K.
2013-03-25
The LHC opens a new kinematical regime at high energy, where several questions related to the description of the high-energy regime of the Quantum Chromodynamics (QCD) remain without satisfactory answers. Some open questions are the search for non-q-bar q resonances, the determination of the spectrum of q-bar q states and the identification of states with anomalous {gamma}{gamma} couplings. A possible way to study these problems is the study of meson production in two-photon interactions. In this contribution we calculate the meson production in two-photon interactions at LHC energies considering proton - proton collisions and estimate the total cross section for the production of the mesons {pi}, a, f, {eta} and {chi}.
Analyticity constraints on the in-medium spectrum of mesons
Cabrera, D.; Polls, A.; Ramos, A.; Tolos, L.
2011-05-23
Analyticity constraints in the form of energy weighted sum rules for the spectral function of mesons are derived, both in cold nuclear matter and at finite temperature, by matching the Dyson propagator with its spectral Lehmann representation at low and high energies. We illustrate our results by calculating the sum rules for specific models of the kaon and pion self-energy in a nuclear medium. We find satisfactory results from the lower energy weight sum rules, which reflect the contributions from the different quasi-particle and collective modes of the meson spectral function, and show examples of the sensitivity of the sum rules to model approximations. Finally, we discuss applications in asymmetric nuclear matter and in the study of the spectral properties of vector mesons.
Photoproduction of η and η' mesons off protons
NASA Astrophysics Data System (ADS)
Crede, V.; McVeigh, A.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, R.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Ehmanns, A.; Elsner, D.; Essig, K.; Ewald, R.; Fabry, I.; Fuchs, M.; Funke, Chr.; Gothe, R.; Gregor, R.; Gridnev, A.; Gutz, E.; Höffgen, St.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Langheinrich, J.; Löhner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Sparks, N.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Weinheimer, Ch.; Wendel, Ch.; Wilson, A.
2009-11-01
Total and differential cross sections for η and η'photoproduction off the proton have been determined with the CBELSA/TAPS detector for photon energies between 0.85 and 2.55 GeV. The η mesons are detected in their two neutral decay modes, η→γγ and η→3π0→6γ, and for the first time, cover the full angular range in cosθc.m. of the η meson. These new η photoproduction data are consistent with the earlier CB-ELSA results. The η' mesons are observed in their neutral decay to π0π0η→6γ and also extend the coverage in angular range.
Probing the Gluon Self-Interaction in Light Mesons
Fischer, Christian S.; Williams, Richard
2009-09-18
We investigate masses and decay constants of light mesons from a coupled system of Dyson-Schwinger and Bethe-Salpeter equations. We explicitly take into account dominant non-Abelian contributions to the dressed quark-gluon vertex stemming from the gluon self-interaction. We construct the corresponding Bethe-Salpeter kernel that satisfies the axial-vector Ward-Takahashi identity. Our numerical treatment fully includes all momentum dependencies with all equations solved completely in the complex plane. This approach goes well beyond the rainbow-ladder approximation and permits us to investigate the influence of the gluon self-interaction on the properties of mesons. As a first result we find indications of a nonperturbative cancellation of the gluon self-interaction contributions and pion cloud effects in the mass of the rho meson.
Mesonic Decay of Charm Hypernuclei Λc+
NASA Astrophysics Data System (ADS)
Ghosh, Sabyasachi; Fontoura, Carlos E.; Krein, Gastão
2016-03-01
Λc+ hypernuclei are expected to have binding energies and other properties similar to those of strange hypernuclei in view of the similarity between the quark structures of the strange and charmed hyperons, namely Λ(uds) and Λc+(udc). One striking difference however occurs in their mesonic decays, as there is almost no Pauli blocking in the nucleonic decay of a charm hypernucleus because the final-state nucleons leave the nucleus at high energies. The nuclear medium nevertheless affects the mesonic decays of charm hypernucleus because the nuclear mean fields modify the masses of the charm hyperon. In the present communication we present results of a first investigation of the effects of finite baryon density on different weak mesonic decay channels of the Λc+ baryon. We found a non-negligible reduction of the decay widths as compared to their vacuum values.
D meson-nucleon hadron and nuclear systems
Yasui, Shigehiro; Sudoh, Kazutaka
2010-12-28
We discuss the new exotic nuclei which contains charm and bottom flavors. We consider the possibility of exotic nuclei with D-bar and B mesons. As simplest systems, we consider the systems of D-bar and B bound with one nucleon and two nucleons. As an interaction between D-bar(B) meson and nucleon, we regard the heavy quark symmetry as important. The potential between D-bar(B) meson is supplied by one pion exchange potential as long range force based on heavy quark symmetry. We investigate possible D-barN(BN) bound state with several quantum numbers. We further discuss the possibility of the existence of D-barNN(BNN) as systems with baryon number two.
Proposal for the systematic naming of mesons and baryons
Porter, F.C.; Hernandez, J.J.; Montanet, L.; Roos, M.; Toernqvist, N.A.; Barnett, R.M.; Cahn, R.N.; Gidal, G.; Rittenberg, A.; Trippe, T.G.
1984-10-01
Twenty years ago, the Particle Data Group adopted a systematic naming convention for baryons: the symbols N, ..delta.., ..lambda.., ..sigma.., ..xi.., and ..cap omega.. were to identify the isospin and strangeness, The mesons, by contrast, have become an alphabet soup of uninformative names - theta, iota, xi, zeta, g/sub T/, g/sub s/, H, E, delta, h, g, r, kappa, etc. -, and in some cases identical names are used for mesons with different quantum numbers (A, B, and D). Furthermore, experimentalists are now discovering baryons that contain heavy quarks. It is therefore timely to consider systematic naming conventions both for mesons and for baryons with heavy quarks. The Particle Data Group is circulating this proposal in the hope of generating feedback, and we attach a sheet for responses. It should be emphasized that the Particle Tables would show both the old and new names for some time.
Charm Meson Spectroscopy at BaBar and CLEO-C
Zghiche, A.; /Annecy, LAPP
2007-10-16
In this mini-review we report on the most recent progress in charm meson spectroscopy. We discuss the precision measurements performed by the BABAR and CLEO-c experiments in the non strange charm meson part and we present the newly discovered strange charmed meson excited states.
Study of Heavy-Light Mesons Properties Via the Variational Method for Cornell Interaction
NASA Astrophysics Data System (ADS)
Hassanabadi, H.; Ghafourian, M.; Rahmani, S.
2016-04-01
Using the variational method we calculate mesonic wave function. We report masses and decay constants for heavy-light mesons. Leptonic decay widths of charmed and beauty mesons are also calculated. The obtained results are compared with the available experimental and theoretical data.
Exotic Meson Spectroscopy in Pion-Proton Collisions
NASA Astrophysics Data System (ADS)
Adams, Gary
2000-10-01
Although the form of the QCD Lagrangian is well established, the structure of the low lying hadrons is still an open question. The existence of gluonic states has emerged as one of the most promising avenues for further study. Lattice gauge calculations of hybrid meson masses lead one to believe that there should be numerous states below 2.5 GeV/c^2 in mass.[1] Flux-tube model predictions suggest that many of these states should have decay widths comparable to those of other mesons.[2] The predictions for exotic hybrids, for example those with J^pc= 1^-+, are particularly noteworthy since those states are excluded in the conventional quark-model picture for mesons. Previous attempts to locate these exotic states met with rather limited success. The present experiment, E852 at Brookhaven National Laboratory, has carried out a high-statistics search for exotic mesons by measuring multi-meson final-state decays. The measurements were made with 18 GeV negative pions incident on a proton target. Partial wave analyses of the exclusive final states allow one to extract resonance parameters even in the presence of many overlapping states. The results of these fits demonstrate the existence of isovector exotic mesons at 1.4 and 1.6 GeV/c^2. The latter state dominates the η 'π ^- decay spectrum. The data on η π ^+ π ^-π ^- decay show large strength in several exotic waves as well. 1. C. Bernard, et al., Phys.Rev. D56, 7039 (1997); P. Lacock, et al., Phys. Lett. B401, 308 (1997). 2. N. Isgur and J. Paton, Phys. Rev. D31, 2910 (1985); T. Barnes, F.E. Close and E.S. Swanson, Phys. Rev. D52, 5242 (1995).
The Search for a π1(1400) Exotic Meson in the γp->^amp;++η^amp;- System
NASA Astrophysics Data System (ADS)
Schott, Diane
2013-04-01
Over twenty years ago QCD-inspired models of hadronic states suggested the existence of mesons beyond the Naive Quark Model (NQM), which motivated a rigorous search for exotic mesons. The lightest of these states is the π1(1400) decaying to η^amp;- observed by experiment E852 at Brookhaven and the VES collaboration at IHEP. Photoproduction is predicted to favor production of a J^PC=1^-+ gluonic excitation resulting in the increase of the ratio of π1 to a2 mesons. A Partial Wave Analysis was conducted on the reaction γp->^amp;++X->p^amp;+^amp;-(η), using the ^amp;++ to select the pion exchange. The analysis has shown the final spectra of the resonance decaying to η^amp;- to be dominated by the quantum state of J^PC=2^++ corresponding to the presence of the a2(1320). The J^PC=1^-+ state, shows no structure in the intensity distribution. The phase difference between the J^PC=1^-+ and J^PC=2^++ amplitudes show the interference between the two states. This is the first spin-parity analysis of the ηπ final state in photoproduction.
Analysis of the scalar nonet mesons with QCD sum rules
NASA Astrophysics Data System (ADS)
Wang, Zhi-Gang
2016-08-01
In this article, we assume that the nonet scalar mesons below 1 GeV are the two-quark-tetraquark mixed states and study their masses and pole residues using the QCD sum rules. In the calculation, we take into account the vacuum condensates up to dimension 10 and the O(α _s) corrections to the perturbative terms in the operator product expansion. We determine the mixing angles, which indicate the two-quark components are much larger than 50~%, then we obtain the masses and pole residues of the nonet scalar mesons.
Light O{sup ++} Mesons: Scalargators in Florida
Pennington, M. R.
2010-08-05
Light scalar mesons abound in hadron processes, like the alligators in the Florida Everglades. Moreover, scalars are intimately tied to the vacuum structure of QCD. They are the product of many decays. Consequently, a rich source of recent information about them has come from experiments producing heavy flavour mesons. Indeed, scalars will continue to dominate many of the processes to be studied at forthcoming facilities like BESIII in Beijing, FAIR at GSI Darmstadt and the GlueX experiment at JLab, making an understanding (or at least an excellent and theoretically consistent description) essential for the physics missions of these facilities.
Lattice results for low moments of light meson distribution amplitudes
Arthur, R.; Boyle, P. A.; Broemmel, D.; Flynn, J. M.; Rae, T. D.; Sachrajda, C. T. C.; Donnellan, M. A.
2011-04-01
As part of the UKQCD and RBC collaborations'N{sub f}=2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons {pi} and K and the (longitudinally polarized) vector mesons {rho}, K{sup *}, and {phi}. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavor breaking effects. An important ingredient of the calculation is the nonperturbative renormalization of lattice operators using a regularization-independent momentum scheme.
Heavy-light mesons in a relativistic model
NASA Astrophysics Data System (ADS)
Liu, Jing-Bin; Yang, Mao-Zhi
2016-07-01
We study the heavy-light mesons in a relativistic model, which is derived from the Bethe-Salpeter equation by applying the Foldy-Wouthuysen transformation to the heavy quark. The kernel we choose is based on scalar confinement and vector Coulomb potentials. The transverse interaction of the gluon exchange is also taken into account in this model. The spectra and wave functions of D, Ds, B, Bs meson states are obtained. The spectra are calculated up to the order of 1/m Q, and wave functions are treated to leading order. Supported by National Natural Science Foundation of China (11375088, 10975077, 10735080, 11125525)
Charmed meson decay constants in three-flavor lattice QCD
Aubin, C.; Bernard, C.; DeTar, C.; Di Pierro, M.; Freeland, Elizabeth D.; Gottlieb, Steven; Heller, U.M.; Hetrick, J.E.; El-Khadra, Aida X.; Kronfeld, Andreas S.; Levkova, L.; Mackenzie, P.B.; Menscher, D.; Maresca, F.; Nobes, M.; Okamoto, M.; Renner, D.B.; Simone, J.; Sugar, R.; Toussaint, D.; Trottier, H.D.; /Art Inst. of Chicago /Columbia U. /Washington U., St. Louis /Utah U. /DePaul U. /Indiana U. /APS, New York /U. Pacific, Stockton /Illinois U., Urbana /Fermilab /Cornell U., LEPP /Arizona U. /UC, Santa Barbara /Simon Fraser U.
2005-06-01
The authors present the first lattice QCD calculation with realistic sea quark content of the D{sup +}-meson decay constant f{sub D+}. They use the MILC Collaboration's publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). They obtain f{sub D+} = 201 {+-} 3 {+-} 17 MeV, where the errors are statistical and a combination of systematic errors. They also obtain f{sub D{sub s}} = 249 {+-} 3 {+-} 16 MeV for the D{sub s} meson.
D meson hadronic decays at CLEO-c
Yang, Fan; /Fermilab
2011-01-01
The recent CLEO-c results on hadronic decays of D and D{sub s} mesons are presented. First the absolute branching fractions for D and D{sub s} mesons using a double tag technique are discussed, then are the Cabibbo suppressed decays and doubly Cabibbo suppressed decays. Finally, I present the inclusive and rare decay modes and other measurements from CLEO-c. These decays illuminate a wide range of physics. A brief theoretical introduction is given before the corresponding discussion on measurement.
A Precision Determination of the Φ Meson Mass
NASA Astrophysics Data System (ADS)
Pellinen, A.; Roos, M.
1982-05-01
From compilations of Kbar K mass histograms containing 25 080 phi mesons and bar pp mass histograms containing 33 260 ω mesons we determine the phi and the ω masses. In our fits the widths of the resonances are fixed and the mass and the resolution are free parameters. We then extrapolate to zero resolution with Orear's effective variance method which takes into account both mass and resolution errors. The results are mphi = (1019.67 ± 0.17) MeV and mω = (782.51 ± 0.82) MeV, where the errors are almost entirely systematic.
Probing new CP violating observables in D meson decays
NASA Astrophysics Data System (ADS)
Liu, Yong-Feng; Kang, Xian-Wei
2016-08-01
CP violation in the charm quark sector has not been examined very well as the case for strange and beauty ones. Some novel insights into the issue on the CP violation in D meson decay are discussed. Specifically, i) the T-violating observables in D → VV decays are constructed. Assuming CPT invariance T violation implies CP violation. This is a new idea and an alternative way for probing CP violation in D decays; ii) the decay of quantum correlated DD̅ pair to vector mesons (denoted by V) is explored, which offers the new CP violating observables that have not been noticed before;
Hybrid Meson Potentials and the Gluonic van der Waals Force
O. Lakhina; E.S. Swanson
2004-03-01
The chromoelectric polarizability of mesons governs the strength of the gluonic van der Waals force and therefore of non-quark-exchange processes in hadronic physics. We compute the polarizability of heavy mesons with the aid of lattice gauge theory and the Born--Oppenheimer adiabatic expansion. We find that the operator product expansion breaks down at surprisingly large quarks masses due to nonperturbative gluodynamics and that previous conclusions concerning J/{psi}--nuclear matter interactions and J/{psi} dissociation in the quark-gluon plasma must be substantially modified.
Rare Electroweak Decays of K and B Mesons
Swee-Ping, Chia
2009-07-07
A phenomenological model is employed to treat the rare decays of mesons with neutrino-antineutrino pair production or charged lepton-antilepton production. The model takes advantage of the fact that inside the hadrons, quarks and antiquarks are tightly bound, and they behave like free particles. As such, the rare decay process can be described in terms of the corresponding quark-level decay process, but with the quarks developing 'dressed' masses because of QCD effects. The 'dressed' quark masses are estimated from the weak decays of the hadrons. With this set of 'dressed' quark masses, a reasonable description of the rare decays of the K and B mesons is obtained.
Meson Structure in a Relativistic Many-Body Approach
Llanes-Estrada, Felipe J.; Cotanch, Stephen R.
2000-02-07
Results from an extensive relativistic many-body analysis utilizing a realistic effective QCD Hamiltonian are presented for the meson spectrum. A comparative numerical study of the BCS, Tamm-Dancoff (TDA), and RPA treatments provides new, significant insight into the condensate structure of the vacuum, the chiral symmetry governance of the pion, and the meson spin, orbital, and flavor mass splitting contributions. In contrast to a previous glueball application, substantial quantitative differences are computed between TDA and RPA for the light quark sector with the pion emerging as a Goldstone boson only in the RPA. (c) 2000 The American Physical Society.
Dynamical coupled-channels model for neutrino-induced meson productions in resonance region
NASA Astrophysics Data System (ADS)
Nakamura, S. X.; Kamano, H.; Sato, T.
2015-10-01
A dynamical coupled-channels (DCC) model for neutrino-nucleon reactions in the resonance region is developed. Starting from the DCC model that we have previously developed through an analysis of π N ,γ N →π N ,η N ,K Λ ,K Σ reaction data for W ≤2.1 GeV , we extend the model of the vector current to Q2≤3.0 (GeV /c )2 by analyzing electron-induced reaction data for both proton and neutron targets. We derive axial-current matrix elements that are related to the π N interactions of the DCC model through the partially conserved axial current (PCAC) relation. Consequently, the interference pattern between resonant and nonresonant amplitudes is uniquely determined. We calculate cross sections for neutrino-induced meson productions, and compare them with available data. Our result for the single-pion production reasonably agrees with the data. We also make a comparison with the double-pion production data. Our model is the first DCC model that can give the double-pion production cross sections in the resonance region. We also make comparison of our result with other existing models to reveal an importance of testing the models in the light of PCAC and electron reaction data. The DCC model developed here will be a useful input for constructing a neutrino-nucleus reaction model and a neutrino event generator for analyses of neutrino experiments.
Study of B meson decays with excited eta and eta' mesons.
Aubert, B; Bona, M; Boutigny, D; Karyotakis, Y; Lees, J P; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Tico, J Garra; Grauges, E; Lopez, L; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lopes Pegna, D; Lynch, G; Mir, L M; Orimoto, T J; Osipenkov, I L; Ronan, M T; Tackmann, K; Tanabe, T; Wenzel, W A; del Amo Sanchez, P; Hawkes, C M; Watson, A T; Held, T; Koch, H; Pelizaeus, M; Schroeder, T; Steinke, M; Walker, D; Asgeirsson, D J; Cuhadar-Donszelmann, T; Fulsom, B G; Hearty, C; Mattison, T S; McKenna, J A; Barrett, M; Khan, A; Saleem, M; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Martin, E C; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Liu, F; Long, O; Shen, B C; Zhang, L; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Schalk, T; Schumm, B A; Seiden, A; Wilson, M G; Winstrom, L O; Chen, E; Cheng, C H; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Andreassen, R; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Gabareen, A M; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Wacker, K; Klose, V; Kobel, M J; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Lombardo, V; Thiebaux, Ch; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Watson, J E; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cecchi, A; Cibinetto, G; Franchini, P; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Santoro, V; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Dauncey, P D; Flack, R L; Nash, J A; Panduro Vazquez, W; Tibbetts, M; Behera, P K; Chai, X; Charles, M J; Mallik, U; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gao, Y Y; Gritsan, A V; Guo, Z J; Lae, C K; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Béquilleux, J; D'Orazio, A; Davier, M; Grosdidier, G; Höcker, A; Lepeltier, V; Le Diberder, F; Lutz, A M; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Serrano, J; Sordini, V; Stocchi, A; Wang, W F; Wormser, G; Lange, D J; Wright, D M; Bingham, I; Burke, J P; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; George, K A; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flaecher, H U; Hopkins, D A; Paramesvaran, S; Salvatore, F; Wren, A C; Brown, D N; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; West, T J; Yi, J I; Anderson, J; Chen, C; Jawahery, A; Roberts, D A; Simi, G; Tuggle, J M; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Salvati, E; Saremi, S; Cowan, R; Dujmic, D; Fisher, P H; Koeneke, K; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Zhao, M; Zheng, Y; Mclachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; De Nardo, G; Fabozzi, F; Lista, L; Monorchio, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; Knoepfel, K J; LoSecco, J M; Benelli, G; Corwin, L A; Honscheid, K; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gagliardi, N; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Ben-Haim, E; Briand, H; Calderini, G; Chauveau, J; David, P; Del Buono, L; de la Vaissière, Ch; Hamon, O; Leruste, Ph; Malclès, J; Ocariz, J; Perez, A; Prendki, J; Gladney, L; Biasini, M; Covarelli, R; Manoni, E; Angelini, C; Batignani, G; Bettarini, S; Carpinelli, M; Cenci, R; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Haire, M; Biesiada, J; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Baracchini, E; Bellini, F; Cavoto, G; del Re, D; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Jackson, P D; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Renga, F; Voena, C; Ebert, M; Hartmann, T; Schröder, H; Waldi, R; Adye, T; Castelli, G; Franek, B; Olaiya, E O; Ricciardi, S; Roethel, W; Wilson, F F; Emery, S; Escalier, M; Gaidot, A; Ganzhur, S F; Hamel de Monchenault, G; Kozanecki, W; Vasseur, G; Yèche, Ch; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Grenier, P; Hast, C; Hryn'ova, T; Innes, W R; Kaminski, J; Kelsey, M H; Kim, H; Kim, P; Kocian, M L; Leith, D W G S; Li, S; Luitz, S; Luth, V; Lynch, H L; MacFarlane, D B; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ofte, I; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; van Bakel, N; Wagner, A P; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Ruland, A M; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Pelliccioni, M; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martinez-Vidal, F; Milanes, D A; Oyanguren, A; Albert, J; Banerjee, Sw; Bhuyan, B; Hamano, K; Kowalewski, R; Nugent, I M; Roney, J M; Sobie, R J; Harrison, P F; Ilic, J; Latham, T E; Mohanty, G B; Band, H R; Chen, X; Dasu, S; Flood, K T; Hollar, J J; Kutter, P E; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Neal, H
2008-08-29
Using 383 x 10(6) BBover pairs from the BABAR data sample, we report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to KKover* or etapipi final states with mass in the range (1.2-1.8) GeV/c2. We observe a significant enhancement at the low KKover* invariant mass which is interpreted as B+-->eta(1475)K+, find evidence for the decay B+-->eta(1295)K+, and place upper limits on the decays B+-->eta(1405)K+, B+-->f1(1285)K+, B+-->f1(1420)K+, and B+-->phi(1680)K+. PMID:18851601
Study of B Meson Decays with Excited eta and eta-prime Mesons
Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prudent, X.; Tisserand, V.; Zghiche, A.; Garra Tico, J.; Grauges, E.; Lopez, L.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Abrams, G.S.; Battaglia, M.; Brown, D.N.; Button-Shafer, J.; /Energy Sci. Network /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /Frascati /Genoa U. /Harvard U. /Heidelberg U. /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Karlsruhe U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /Padua U. /Paris U., VI-VII /Pennsylvania U. /Perugia U. /Pisa U. /Prairie View A-M /Princeton U. /INFN, Rome /Rostock U. /Rutherford /DSM, DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /INFN, Turin /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison /Yale U.
2008-04-18
Using 383 million B{bar B} pairs from the BABAR data sample, they report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to K{bar K}* or {eta}{pi}{pi} final states with mass in the range (1.2-1.8) GeV/c{sup 2}. They observe a significant enhancement at the low K{bar K}* invariant mass which is interpreted as B{sup +} {yields} {eta}(1475)K{sup +}, find evidence for the decay B{sup +} {yields} {eta}(1295)K{sup +}, and place upper limits on the decays B{sup +} {yields} {eta}(1405)K{sup +}, B{sup +} {yields} f{sub 1}(1285)K{sup +}, B{sup +} {yields} f{sub 1}(1420)K{sup +}, and B{sup +} {yields} {phi}(1680)K{sup +}.
Scalar meson f{sub 0}(980) in heavy-meson decays.
El-Bennich, B.; Leitner, O.; Dedonder, J.-P.; Loiseau, B.; Physics; Lab. de Physique Nucleaire et de Hautes Energies; Lab. Nazionali di Frascati
2009-04-01
A phenomenological analysis of the scalar meson f{sub 0}(980) is performed that relies on the quasi-two-body decays D and D{sub s} {yields} f{sub 0}(980)P, with P = {pi}, K. The two-body branching ratios are deduced from experimental data on D or D{sub s} {yields} {pi}{pi}{pi}, K{sup -} K{pi} and from the f{sub 0}(980) {yields} {pi}{sup +}{pi}{sup -} and f{sub 0}(980) {yields} K{sup +}K{sup -} branching fractions. Within a covariant quark model, the scalar form factors for the transitions D and D{sub s} {yields} f{sub 0}(980) are computed. The weak D decay amplitudes, in which these form factors enter, are obtained in the naive factorization approach assuming a q{bar q} state for the scalar and pseudoscalar mesons. They allow to extract information on the f{sub 0}(980) wave function in terms of u{bar u}, d{bar d}, and s{bar s} pairs as well as on the mixing angle between the strange and nonstrange components. The weak transition form factors are modeled by the one-loop triangular diagram using two different relativistic approaches: covariant light-front dynamics and dispersion relations. We use the information found on the f{sub 0}(980) structure to evaluate the scalar and vector form factors in the transitions D and D{sub s} {yields} f{sub 0}(980), as well as to make predictions for B and B{sub s} {yields} f{sub 0}(980), for the entire kinematically allowed momentum range of q{sup 2}.
Wu Xinggang; Huang Tao
2011-10-01
The meson-photon transition form factors {gamma}{gamma}*{yields}P (P stands for {pi}, {eta} and {eta}') provide strong constraints on the distribution amplitudes of the pseudoscalar mesons. In this paper, these transition form factors are calculated under the light-cone perturbative QCD approach, in which both the valence and nonvalence quarks' contributions have been taken into consideration. To be consistent, a unified wave function model is adopted to analyze these form factors. It is shown that with the proper charm component f{sub {eta}}'{sup c}{approx}-30 MeV and a moderate DA with B{approx}0.30, the experimental data on Q{sup 2}F{sub {eta}{gamma}}(Q{sup 2}) and Q{sup 2}F{sub {eta}'{gamma}}(Q{sup 2}) in the whole Q{sup 2} region can be explained simultaneously. Furthermore, a detailed discussion on the form factors' uncertainties caused by the constituent quark masses m{sub q} and m{sub s}, the parameter B, the mixing angle {phi}, and f{sub {eta}'}{sup c} are presented. It is found that, by adjusting these parameters within their reasonable regions, one can improve the form factor to a certain degree but cannot solve the puzzle for Q{sup 2}F{sub {pi}{gamma}}(Q{sup 2}), especially to explain the behavior of the {pi}-{gamma} form factor within the whole Q{sup 2} region consistently. We hope further experimental data on these form factors in the large Q{sup 2} region can clarify the present situation.
Scalar meson f{sub 0}(980) in heavy-meson decays
El-Bennich, B.; Leitner, O.; Dedonder, J.-P.; Loiseau, B.
2009-04-01
A phenomenological analysis of the scalar meson f{sub 0}(980) is performed that relies on the quasi-two-body decays D and D{sub s}{yields}f{sub 0}(980)P, with P={pi}, K. The two-body branching ratios are deduced from experimental data on D or D{sub s}{yields}{pi}{pi}{pi}, KK{pi} and from the f{sub 0}(980){yields}{pi}{sup +}{pi}{sup -} and f{sub 0}(980){yields}K{sup +}K{sup -} branching fractions. Within a covariant quark model, the scalar form factors for the transitions D and D{sub s}{yields}f{sub 0}(980) are computed. The weak D decay amplitudes, in which these form factors enter, are obtained in the naive factorization approach assuming a qq state for the scalar and pseudoscalar mesons. They allow to extract information on the f{sub 0}(980) wave function in terms of uu, dd, and ss pairs as well as on the mixing angle between the strange and nonstrange components. The weak transition form factors are modeled by the one-loop triangular diagram using two different relativistic approaches: covariant light-front dynamics and dispersion relations. We use the information found on the f{sub 0}(980) structure to evaluate the scalar and vector form factors in the transitions D and D{sub s}{yields}f{sub 0}(980), as well as to make predictions for B and B{sub s}{yields}f{sub 0}(980), for the entire kinematically allowed momentum range of q{sup 2}.
Observation and study of bottom-meson decays to a charm meson, a proton-antiproton pair, and pions
Hong, Tae Min
2010-04-27
Bottom-meson decays with baryons show two unusual features—the branching fractions are enhanced for multibody decays and the baryon-antibaryon subsystem recoils against the other decay products—and their reasons are not yet well understood. Moreover, measurements using explicit reconstruction techniques constitute only about 1% out of about 8% of such decays. This Dissertation reports the study of ten bottom-meson decays (labeled 0– 9) to a proton-antiproton pair, a charm meson, and a system of up to two pions, using the BABAR Experiment’s 455×10^{6} BB pairs produced with the PEP-II asymmetric-energy e^{+}e^{- }collider at the Stanford Linear Accelerator Center.
NASA Astrophysics Data System (ADS)
Maglich, Bogdan C.
2004-08-01
High resolution has been discouraged in meson spectrometry for 4 decades by the Doctrine of Experiments Incompatible with Theory (DEIT). DEIT a priori rejects narrow hadron resonances on the paradigm that only broad hadron peaks, Γ⩾ 100 MeV, can exist — in spite of the accumulated evidence to the contrary. The facts are: Mesons 2 orders of magnitude narrower than `allowed' for hadrons, have been confirmed; a new one was announced at this conference. Narrow meson structures have been repeatedly reported at high momentum transfer, |t| >0.2, while they are absent at the low transfer, |t| ˜0.01, where 99% of the experiments are performed. Modification of meson mass and width as a function of the density of nuclear matter in which they are produced, have been recently reported. We postulate for meson spectra: (1) Intrinsic (`true') width, Γ, is different from the observable (`apparent') width, Γ': Γ< Γ' (2) Γ of all meson states are narrow and can be observed only at or near the maximum |t| reachable in the reaction, and (3) Γ of all meson resonances are subject to broadening as |t| decreases. Since both Γ' and the production σ are inversely proportional to |t|, most of the observed spectra are produced at the lowest |t| <0.01 and thus the peaks appear broad. We have conceptually designed a novel type hadron spectrometer with an order of magnitude better resolution (0.1 MeV). It would operate at 2 orders of magnitude higher |t| (0.3< |t| <1 (GeV/c)2, than most experiments to date (|t| <0.01). Mesons in the mass region 0.5
Bottom quark mass from {Upsilon} mesons
Hoang, A.H.
1999-01-01
The bottom quark pole mass M{sub b} is determined using a sum rule which relates the masses and the electronic decay widths of the {Upsilon} mesons to large {ital n} moments of the vacuum polarization function calculated from nonrelativistic quantum chromodynamics. The complete set of next-to-next-to-leading order [i.e., O({alpha}{sub s}{sup 2},{alpha}{sub s}v,v{sup 2}) where v is the bottom quark c.m. velocity] corrections is calculated and leads to a considerable reduction of theoretical uncertainties compared to a pure next-to-leading order analysis. However, the theoretical uncertainties remain much larger than the experimental ones. For a two parameter fit for M{sub b}, and the strong
Insights into the pi- p --> eta n reaction mechanism
Durand, Johan; Julia Diaz, Bruno; Lee, Tsung-Shung; Sato, Toru
2009-01-01
A dynamical coupled-channels formalism is used to investigate the $\\eta-$meson production mechanism on the proton induced by pions, in the total center-of-mass energy region from threshold up to 2 GeV. We show how and why studying exclusively total cross section data might turn out to be misleading in pinning down the reaction mechanism.
Strong decays of hybrid mesons from the heavy quark expansion of QCD
Page, Philip R.
1998-05-29
We calculate the strong decays of hybrid mesons to conventional mesons for all the lowest lying J{sup PC} hybrids of flavour uu-bar, dd-bar, ss-bar, cc-bar and bb-bar. A decay operator developed from the heavy quark expansion of quantum chromodynamics is employed. We show that the selection rule that hybrid mesons do not decay to identical S-wave mesons, found in other models, is preserved. We predict decays of charmonium hybrids, discuss decays of J{sup PC}=1{sup -+} exotic isovector hybrids of various masses, and interpret the {pi}(1800) as a hybrid meson.
Binding of D, D-bar and J/Psi mesons in nuclei
Kazuo Tsushima
2009-12-01
We estimate the $D$, $\\overline{D}$ and $J/\\Psi$ meson potentials in nuclei. $J/\\Psi$-nuclear potential (self-energy) is calculated based on the color-singlet mechanism, by the $DD$ and $DD^*$ meson loops. This consistently includes the in-medium properties of $D$ and $D^*$ mesons. The potential obtained for the $J/\\Psi$ meson is attractive, and it is complementary to the attraction obtained from the color-octet gluon-based mechanism. We predict that the $D^-$ and $J/\\Psi$ mesons will be bound in nuclei under proper conditions.
The Modern description of semileptonic meson form factors
Hill, Richard J.
2006-06-01
I describe recent advances in our understanding of the hadronic form factors governing semileptonic meson transitions. The resulting framework provides a systematic approach to the experimental data, as a means of extracting precision observables, testing nonperturbative field theory methods, and probing a poorly understood limit of QCD.
Decay properties of charm and beauty open flavour mesons
Kumar Rai, Ajay; Vinodkumar, P. C.
2007-10-03
The masses of S and P states, pseudoscalar and vector decay constants, leptonic, semileptonic decay widths of charm (D) and beauty (B) open flavour mesons have been computed in the framework of Coulomb and power potential of the form V(r) = -({alpha}{sub c}/r)+Ar{sup v}. The results are compared with other theoretical as well as experimental results.
Evidence for the Production of Neutral Mesons by Photons
DOE R&D Accomplishments Database
Steinberger, J.; Panofsky, W. K. H.; Steller, J.
1950-04-01
Evidence in favor of the existence of a gamma unstable neutral meson; report on the detection of the coincidences between the two gamma rays produced by the bombardment of various nuclei in the x-ray beam of the Berkeley synchrotron.
Coulomb gauge approach for charmonium meson and hybrid radiative transitions
Gou, Peng; Yepez-Martínez, Tochtli; Szczepaniak, Adam P.
2015-01-22
We consider the lowest order interaction of the Foldy-Wouthuysen QED and QCD Hamiltonian in the Coulomb gauge approach, to describe radiative transitions between conventional and hybrids charmonium mesons. The results are compared to potential quark models and lattices calculations.
Systematic measurements of light vector mesons at RHIC-PHENIX
Nakamiya, Yoshihide; Awes, Terry C; Cianciolo, Vince; Efremenko, Yuri V; Enokizono, Akitomo; Hornback, Donald; Read Jr, Kenneth F; Silvermyr, David O; Sorensen, Soren P; Stankus, Paul W; Young, Glenn R; PHENIX, Collaboration
2008-01-01
Relativistic heavy-ion collisions offer a powerful tool to explore the phase transition between normal nuclear matter and strongly interacting matter governed by partonic degree of freedom. Measurement of light vector mesons such as {phi} and {omega} in heavy-ion collision provides important probes to investigate the property of the partonic matter. The Masses, lifetimes and branching ratios of these mesons are expected to change due to the partial restoration of chiral symmetry in extremely high temperature medium. The PHENIX experiment at RHIC is uniquely suitable for this study because PHENIX has a versatile detector with excellent capabilities to measure electrons and photons as well as hadrons in a wide dynamic range. Systematic studies of multiple decay channels for light vector mesons make it possible to extract important information from the complex physics environment of heavy-ion collision. We will report the latest results of light vector meson measurements for multiple decay channels ({phi} {yields} e{sup -}e{sup +}, K{sup +}K{sup -} and {omega} {yields} e{sup -}e{sup +}, {pi}{sup 0}{pi}{sup +}{pi}{sup -}) in various collision systems from proton+proton to Au+Au collisions over several collision energies up to {radical}s{sub NN} = 200 GeV.
Studies of the B(c) meson at CDF
Spezziga, Mario; /Texas Tech.
2005-11-01
The authors present the latest measurements of the B{sub c} meson properties using 360 pb{sup -1} of data collected by the CDF detector. The results include the B{sub c} mass and the ratio of branching fraction B{sub c} {yields} J/{psi} l with respect to B {yields} J/{psi}K.
Staggered chiral perturbation theory for heavy-light mesons
Aubin, C.; Bernard, C.
2006-01-01
We incorporate heavy-light mesons into staggered chiral perturbation theory (S{chi}PT), working to leading order in 1/m{sub Q}, where m{sub Q} is the heavy-quark mass. At first nontrivial order in the chiral expansion, staggered taste violations affect the chiral logarithms for heavy-light quantities only through the light-meson propagators in loops. There are also new analytic contributions coming from additional terms in the Lagrangian involving heavy-light and light mesons. Using this heavy-light S{chi}PT, we perform the one-loop calculation of the B (or D) meson leptonic decay constant in the partially quenched and full QCD cases. In our treatment, we assume the validity both of the 'fourth root trick' to reduce four staggered tastes to one, and of the S{chi}PT prescription to represent this trick by insertions of factors of 1/4 for each sea-quark loop.
Tetraquark mesons in large-N quantum chromodynamics.
Weinberg, Steven
2013-06-28
It is argued that exotic mesons consisting of two quarks and two antiquarks are not ruled out in quantum chromodynamics with a large number N of colors, as generally thought. Tetraquarks of one class are typically long-lived, with decay rates proportional to 1/N.
Inclusive /b decays to wrong sign charmed mesons
NASA Astrophysics Data System (ADS)
DELPHI Collaboration; Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alderweireld, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P. P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W.-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J. E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K.-H.; Begalli, M.; Behrmann, A.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P. S. L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T. J. V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J. M.; Bugge, L.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Chung, S. U.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M. J.; Crawley, B.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; da Silva, W.; della Ricca, G.; de Angelis, A.; de Boer, W.; de Clercq, C.; de Lotto, B.; de Maria, N.; de Min, A.; de Paula, L.; di Ciaccio, L.; di Simone, A.; Doroba, K.; Drees, J.; Dris, M.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M. C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Geralis, T.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Hansen, J.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S.-O.; Holt, P. J.; Houlden, M. A.; Hultqvist, K.; Jackson, J. N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E. K.; Johansson, P. D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B. P.; Kiiskinen, A.; King, B. T.; Kjaer, N. J.; Kluit, P.; Kokkinias, P.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J. H.; Lopez, J. M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Mc Nulty, R.; Meroni, C.; Meyer, W. T.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Moreno, S.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nicolaidou, R.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J. P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Peralta, L.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M. E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Rames, J.; Ramler, L.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Savoy-Navarro, A.; Schwickerath, U.; Schwanda, C.; Segar, A.; Sekulin, R.; Siebel, M.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A. C.; Tegenfeldt, F.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tomaradze, A.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M.-L.; Tyapkin, I. A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; van Dam, P.; van Eldik, J.; van Lysebetten, A.; van Remortel, N.; van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verbeure, F.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A. J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zimin, N. I.; Zintchenko, A.; Zupan, M.
2003-05-01
The production of wrong sign charmed mesons b-->D(s)X, D(s)=(D0,D+,Ds), is studied using the data collected by the DELPHI experiment in the years 1994 and 1995. Charmed mesons in /Z-->bb¯ events are exclusively reconstructed by searching for the decays D0-->K-π+, D+-->K-π+π+ and Ds+-->φπ+-->K+K-π+. The wrong sign contribution is extracted by using two discriminant variables: the charge of the /b-quark at decay time, estimated from the charges of identified particles, and the momentum of the charmed meson in the rest frame of the /b-hadron. The inclusive branching fractions of /b-hadrons into wrong sign charm mesons are measured to be: B(b-->D0X)+B(b-->D-X)=(9.3+/-1.7(stat)+/-1.3(syst)+/-0.4(B))%, B(b-->Ds-X)=(10.1+/-1.0(stat)+/-0.6(syst)+/-2.8(B))% where the first error is statistical, the second and third errors are systematic.
Inclusive b decays to wrong sign charmed mesons
NASA Astrophysics Data System (ADS)
Abdallah, J.; Abreu, P.; Adam, W.; Adzic, P.; Albrecht, T.; Alderweireld, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P. P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W.-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J. E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K.-H.; Begalli, M.; Behrmann, A.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P. S. L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T. J. V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J. M.; Bugge, L.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, N.; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Chung, S. U.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M. J.; Crawley, B.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; da Silva, W.; Della Ricca, G.; de Angelis, A.; de Boer, W.; de Clercq, C.; de Lotto, B.; de Maria, N.; de Min, A.; de Paula, L.; di Ciaccio, L.; di Simone, A.; Doroba, K.; Drees, J.; Dris, M.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M. C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, E.; Geralis, T.; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Hansen, J.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S.-O.; Holt, P. J.; Houlden, M. A.; Hultqvist, K.; Jackson, J. N.; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, E. K.; Johansson, P. D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B. P.; Kiiskinen, A.; King, B. T.; Kjaer, N. J.; Kluit, P.; Kokkinias, P.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, F.; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J. H.; Lopez, J. M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Mc Nulty, R.; Meroni, C.; Meyer, W. T.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Moenig, K.; Monge, R.; Montenegro, J.; Moraes, D.; Moreno, S.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nicolaidou, R.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J. P.; Palka, H.; Papadopoulou, Th. D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Peralta, L.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M. E.; Polok, G.; Poropat, P.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Rames, J.; Ramler, L.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Rosenberg, E.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Savoy-Navarro, A.; Schwickerath, U.; Schwanda, C.; Segar, A.; Sekulin, R.; Siebel, M.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A. C.; Tegenfeldt, F.; Timmermans, J.; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tomaradze, A.; Tome, B.; Tonazzo, A.; Tortosa, P.; Travnicek, P.; Treille, D.; Tristram, G.; Trochimczuk, M.; Troncon, C.; Turluer, M.-L.; Tyapkin, I. A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; van Dam, P.; van Eldik, J.; van Lysebetten, A.; van Remortel, N.; van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verbeure, F.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A. J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zimin, N. I.; Zintchenko, A.; Zupan, M.; Delphi Collaboration
2003-05-01
The production of wrong sign charmed mesons b→overlineD(s)X, D(s)=(D0,D+,Ds), is studied using the data collected by the DELPHI experiment in the years 1994 and 1995. Charmed mesons in Z→bb¯ events are exclusively reconstructed by searching for the decays D0→K-π+, D+→K-π+π+ and Ds+→φπ+→K+K-π+. The wrong sign contribution is extracted by using two discriminant variables: the charge of the b-quark at decay time, estimated from the charges of identified particles, and the momentum of the charmed meson in the rest frame of the b-hadron. The inclusive branching fractions of b-hadrons into wrong sign charm mesons are measured to be: B(b→overlineD0X)+B(b→D-X)=(9.3±1.7(stat)±1.3(syst)±0.4(B))%, B(b→Ds-X)=(10.1±1.0(stat)±0.6(syst)±2.8(B))% where the first error is statistical, the second and third errors are systematic.
Meson multiplicity versus energy in relativistic nucleus-nucleus collisions
NASA Technical Reports Server (NTRS)
Atwater, T. W.; Freier, P. S.
1986-01-01
A systematic study of meson multiplicity as a function of energy at energies up to 100 GeV/u in nucleus-nucleus collisions has been made, using cosmic-ray data in nuclear emulsion. The data are consistent with simple nucleon-nucleon superposition models. Multiplicity per interacting nucleon in AA collisions does not appear to differ significantly from pp collisions.
Probing the nuclear medium with the K{sup +} meson
Chrien, R.E.
1995-12-31
Elastic differential cross sections for K{sup +} mesons scattered from targets of carbon and {sup 6}Li have been measured at an incident momentum of 715 MeV/c. The ratios of scattering cross sections from these targets are not predicted by theory, and are consistent with earlier suggestions that the K{sup +}-nucleon interaction is modified in the nuclear medium.
Meson-production experiments at COSY-Jülich
NASA Astrophysics Data System (ADS)
Büscher, M.
2010-09-01
Selected results from experiments at COSY-Jülich are presented: an attempt to measure the mass of the η meson with high precision (ANKE facility), first steps towards the detection of rare η decays (WASA), and several measurements of Kbar K-pair production (ANKE, COSY-11, MOMO).
Lifetime of the η‧ meson at low temperature
NASA Astrophysics Data System (ADS)
Perotti, E.; Niblaeus, C.; Leupold, S.
2016-06-01
This work constitutes one part of an investigation of the low-temperature changes of the properties of the η‧ meson. In turn these properties are strongly tied to the U(1)A anomaly of Quantum Chromodynamics. The final aim is to explore the interplay of the chiral anomaly and in-medium effects. We determine the lifetime of an η‧ meson being at rest in a strongly interacting medium as a function of the temperature. To have a formally well-defined low-energy limit we use in a first step Chiral Perturbation Theory for a large number of colors. We determine the pertinent scattering amplitudes in leading and next-to-leading order. In a second step we include resonances that appear in the same mass range as the η‧ meson. The resonances are introduced such that the low-energy limit remains unchanged and that they saturate the corresponding low-energy constants. This requirement fixes all coupling constants. We find that the width of the η‧ meson is significantly increased from about 200 keV in vacuum to about 10 MeV at a temperature of 120 MeV.
New Heavy-Light Mesons Q bar{q}
NASA Astrophysics Data System (ADS)
Matsuki, T.; Morii, T.; Sudoh, K.
2007-06-01
We succeed in reproducing the ℓ = 1 B mesons B1(5720), B2*(5745), and Bs2*(5839) that were recently reported by D0 and CDF, using our semi-relativistic quark potential model, which also succeeds in predicting the mass spectra of the narrow DsJ, as well as broad D0*(0+) and D1'(1+) particles observed a couple of years ago. par The mass of higher excited states (ell = 1, 2) of B and Bs mesons, which have not yet been observed, is also predicted to first order in p/mb with the internal quark momentum p and the b quark mass mb. We find that the corresponding BsJ are below the BK/B*K threshold and should have narrow decay widths, contrary to most other predictions. Also, already established states (ℓ = 0 and ell = 1) of D, Ds, B, and Bs heavy mesons are simultaneously reproduced in good agreement with experimental data, within one percent accuracy. To calculate these D/Ds and B/Bs heavy mesons, we use different values of the strong coupling, αsc and αsc, respectively.
Heavy Meson Production at COSY - 11
Moskal, P.; Adam, H.H.; Balewski, J.T.; Budzanowski, A.; Goodman, C.; Grzonka, D.; Jarczyk, L.; Jochmann, M.; Khoukaz, A.; Kilian, K.; Kowina, P.; Koehler, M.; Lister, T.; Oelert, W.; Quentmeier, C.; Santo, R.; Schepers, G.; Seddik, U.; Sefzick, T.; Sewerin, S.; Smyrski, J.; Strzalkowski, A.; Wolke, M.; Wuestner, P.
2000-12-31
The COSY-11 collaboration has measured the total cross section for the pp {yields} pp{eta}{prime} and pp {yields} pp{eta} reactions in the excess energy range from Q = 1.5 MeV to Q = 23.6 MeV and from Q = 0.5 MeV to Q= 5.4 MeV, respectively. Measurements have been performed with the total luminosity of 73 nb{sup {minus}1} for the pp {yields} pp{eta} reaction and 1360 nb{sup {minus}1} for the pp {yields} pp{eta}{prime} one. Recent results are presented and discussed.
Dalitz Decay of Pseudoscalar Mesons from Photoproduction on Hydrogen Target with CLAS
NASA Astrophysics Data System (ADS)
Kunkel, Michael; Amaryan, Moskov; Paolone, Michael; Weygand, Dennis; CLAS Collaboration
2013-10-01
Experimental results on the Dalitz decay of pseudoscalar mesons P(π0 , η ,η') -->e+e- γ produced in the photoproduction reaction γ + p --> P(π0 , η , η ') + p on a Hydrogen target, with CLAS setup at Thomas Jefferson National Accelerator Facility (TJNAF), are presented. The total statistics collected for π0 , η Dalitz decay exceeds the world's published statistics by an order of magnitude, while the Dalitz decay of η' -->e+e- γ is observed and measured for the first time. The data obtained will allow for measurements of transition form factors that are encoded in the mass spectrum of the e+e- system. The current status of analysis of the π0 , η transition form factors and the search for the heavy photon from the e+e- mass system will be discussed.
Measurement of the transverse target and beam-target asymmetries in η meson photoproduction at MAMI.
Akondi, C S; Annand, J R M; Arends, H J; Beck, R; Bernstein, A; Borisov, N; Braghieri, A; Briscoe, W J; Cherepnya, S; Collicott, C; Costanza, S; Downie, E J; Dieterle, M; Fix, A; Fil'kov, L V; Garni, S; Glazier, D I; Gradl, W; Gurevich, G; Hall Barrientos, P; Hamilton, D; Hornidge, D; Howdle, D; Huber, G M; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lazarev, A; Lisin, V; Livingston, K; MacGregor, I J D; Mancel, J; Manley, D M; Martel, P; McNicoll, E F; Meyer, W; Middleton, D; Miskimen, R; Mushkarenkov, A; Nefkens, B M K; Neganov, A; Nikolaev, A; Oberle, M; Ostrick, M; Ortega, H; Ott, P; Otte, P B; Oussena, B; Pedroni, P; Polonski, A; Polyanski, V V; Prakhov, S; Reicherz, G; Rostomyan, T; Sarty, A; Schumann, S; Steffen, O; Strakovsky, I I; Strub, Th; Supek, I; Tiator, L; Thomas, A; Unverzagt, M; Usov, Yu A; Watts, D P; Werthmüller, D; Witthauer, L; Wolfes, M
2014-09-01
We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the γ[over →]p[over →]→ηp reaction up to a center-of-mass energy of W=1.9 GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. All existing model predictions fail to reproduce the new data indicating a significant impact on our understanding of the underlying dynamics of η meson photoproduction. The peculiar nodal structure observed in existing T data close to threshold is not confirmed. PMID:25238349
The octet meson and octet baryon interaction with strangeness and the Λ(1405)
NASA Astrophysics Data System (ADS)
He, Jun; Lü, Pei-Liang
2015-10-01
The octet meson and baryon interaction with strangeness S = -1 is studied fully relativistically with chiral Lagrangian. In this paper, a Bethe-Salpeter equation (BSE) approach with spectator quasipotential approximation is applied to study the reactions K-p → MB with MB = K-p,K¯0n,π-Σ+,π0Σ0,π+Σ- and ηΛ with all possible partial waves and theoretical results are comparable with experimental data. It is found that the Weinberg-Tomozawa potential derived from the lowest order chiral Lagrangian only provides the contributions from partial waves with spin-parities JP = 1/2+ and 1/2-. Two-pole structure of the Λ(1405) is confirmed with poles at 1383 + 99i and 1423 + 14i MeV. The lower and higher poles originate from Σπ interaction as a resonance and K¯N interaction as a bound state, respectively.
Importance of the meson cloud to hadron structure
NASA Astrophysics Data System (ADS)
Pearce, B. C.; Speth, J.; Szczurek, A.
1994-07-01
We present a review of our recent results on the role of the mesonic cloud in the structure of hadrons in both soft and hard kinematical regimes. We compute the pion and nucleon form factors of the scalar operator overlineuu + overlinedd within a meson exchange model. Our results agree with recent dispersion relation analyses near the Cheng-Dashen point but show some deviation at higher energies. In particular, we confirm the observation that the strong ππ interaction gives rise to a scalar square radius of the nucleon of 1.5 fm 2 and a 15 MeV contribution to the pion nucleon sigma term. Some aspects of the meson cloud around the nucleon for deep-inelastic lepton scattering are studied in the framework of the Sullivan formalism. We present a simple two-phase model of the nucleon. Renormalization of the valence quark distribution due to the mesonic cloud is taken into account explicitly. We study the dependence of different quantities on the cut-off parameter of the form factor, the role of different mesons in deep-inelastic scattering, and SU(2) F symmetry breaking in the nucleon sea in connection to the Gottfried Sum Rule. It is possible to obtain agreement with the CCFR data using relatively hard meson-N-N form factors. The E615 data on ( overlineu + overlined)/2 - overlines restrict the cut-off parameter in the dipole form factor to about 1.2 GeV. For this value the cut-off parameter we get the largest violation of the Gottfried Sum Rule, about half of that observed by NMC. Mesonic models predict violation of the SU (2) symmetry in the nucleon sea which seems to be necessary to explain the violation of the Gottfried Sum Rule. Since up to now there is no consensus concerning the explanation of the NMC effect, one has to study the role the overlined/ overlineu asymmetry may play in other processes. Here we study the effect of the asymmetry for the Drell-Yan processes. We find that careful analysis of the dilepton production in the p-p and p-n collisions should
Search for Popcorn Mesons in Events with Two Charmed Baryons
Hartfiel, Brandon; /SLAC
2006-07-07
The physics of this note is divided into two parts. The first part measures the {Lambda}{sub c} {yields} {pi}kp continuum momentum spectrum at a center of mass energy of 10.54 GeV/c. The data sample consists of 15,400 {Lambda}{sub c} baryons from 9.46 fb{sup -1} of integrated luminosity. With more than 13 times more data than the best previous measurement, we are able to exclude some of the simpler, one parameter fragmentation functions. In the second part, we add the {Lambda}{sub c} {yields} K{sup 0}p mode, and look for events with a {Lambda}{sub c}{sup +} and a {bar {Lambda}}{sub c}{sup -} in order to look for ''popcorn'' mesons formed between the baryon and antibaryon. We add on-resonance data, with a kinematic cut to eliminate background from B decays, as well as BaBar run 3 and 4 data to increase the total data size to 219.70 fb{sup -1}. We find 619 events after background subtraction. After a subtraction of 1.06 {+-} .09 charged pions coming from decays of known resonances to {Lambda}{sub c} + {eta}{pi}, we are left with 2.63 {+-} .21 additional charged pions in each of these events. This is significantly higher than the .5 popcorn mesons per baryon pair used in the current tuning of Pythia 6.2, the most widely used Monte Carlo generator. The extra mesons we find appear to be the first direct evidence of popcorn mesons, although some of them could be arising from hypothetical unresolved, unobserved charmed baryon resonances contributing decay mesons to our data. To contribute a significant fraction, this hypothesis requires a large number of such broad unresolved states and seems unlikely, but can not be completely excluded.
Search for popcorn mesons in events with two charmed baryons
NASA Astrophysics Data System (ADS)
Hartfiel, Brandon
The physics of this dissertation is divided into two parts. The first part measures the Λc → pi kp continuum momentum spectrum at a center of mass energy of 10.54 GeV/c, which is just below the Υ(4s) resonance. The data sample consists of 15,400 Λc baryons from 9.46 fb-1 of integrated luminosity collected with the BaBar detector at the PEP-II asymmetric B factory at the Stanford Linear Accelerator Center. With more than 13 times more data than the best previous measurement, we are able to exclude some of the simpler, one parameter fragmentation functions. In the second part, we add the Λc → K0p mode, and look for events with a Λc+ and a Λ c- in order to look for "popcorn" mesons formed between the baryon and antibaryon. We add on-resonance data, with a kinematic cut to eliminate background from B decays, as well as BaBar run 3 and 4 data to increase the total data size to 219.70 fb-1. We find 619 events after background subtraction. After a subtraction of 1.06+/-.09 charged pions coming from decays of known resonances to Λc + npi, we are left with 2.63+/-.21 additional charged pious in each of these events. This is significantly higher than the .5 popcorn mesons per bayon pair used in the current tuning of Pythia 6.2, the most widely used Monte Carlo generator. The extra mesons we find appear to be the first direct evidence of popcorn mesons, although some of them could be arising from hypothetical unresolved, unobserved charmed baryon resonances contributing decay mesons to our data. To contribute a significant fraction, this hypothesis requires a large number of such broad unresolved states and seems unlikely, but can not be completely excluded.
NASA Astrophysics Data System (ADS)
Lee, Dean
1992-01-01
An attempt is made to understand charmed meson decays in a simple yet quantitative language. The {1}/{N} expansion of QCD is chosen for the analysis of these decays. With the {1}/{N} expansion, significant SU(3)-flavor breaking effects are isolated and evaluated.
Meson interferometry in relativistic heavy ion collisions
Not Available
1993-05-01
This report contains discussions on the following topics: Recent HBT results form CERN experiment NA44; interferometry results from E802/E859/E866; recent results on two particle correlations from E814; source sizes from CERN data; intermittency and interferometry; Bose-Einstein correlations in 200A GeV S+Au collisions; HBT correlations at STAR; HBT interferometry with PHENIX; HBT calculations from ARC; three pion correlations; and pion correlations in proton-induced reactions.
Azimuthal anisotropy of D-meson production in Pb-Pb collisions at √sNN =2.76 TeV
NASA Astrophysics Data System (ADS)
Abelev, B.; Adam, J.; Adamová, D.; Aggarwal, M. M.; Agnello, M.; Agostinelli, A.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahmed, I.; Ahn, S. U.; Ahn, S. A.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Baumann, C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Belmont, R.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Berger, M. E.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Böhmer, F. V.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Casula, E. A. R.; Catanescu, V.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortese, P.; Cortés Maldonado, I.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dang, R.; Danu, A.; Das, D.; Das, I.; Das, K.; Das, S.; Dash, A.; Dash, S.; de, S.; Delagrange, H.; Deloff, A.; Dénes, E.; D'Erasmo, G.; de Caro, A.; de Cataldo, G.; de Cuveland, J.; de Falco, A.; de Gruttola, D.; De Marco, N.; de Pasquale, S.; de Rooij, R.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; di Bari, D.; di Liberto, S.; di Mauro, A.; di Nezza, P.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dørheim, S.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Hilden, T. E.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erdal, H. A.; Eschweiler, D.; Espagnon, B.; Esposito, M.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floratos, E.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Garishvili, I.; Gerhard, J.; Germain, M.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Graczykowski, L. K.; Grajcarek, R.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Guilbaud, M.; Gulbrandsen, K.; Gulkanyan, H.; Gumbo, M.; Gunji, T.; Gupta, A.; Gupta, R.; Khan, K. H.; Haake, R.; Haaland, Ø.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hippolyte, B.; Hladky, J.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Innocenti, G. M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Jachołkowski, A.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kadyshevskiy, V.; Kalcher, S.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskikh, A.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kramer, F.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; La Pointe, S. L.; La Rocca, P.; Lea, R.; Leardini, L.; Lee, G. R.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; Leoncino, M.; León Monzón, I.; Lévai, P.; Li, S.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohner, D.; Loizides, C.; Lopez, X.; López Torres, E.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Ma, R.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martin Blanco, J.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mlynarz, J.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moretto, S.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nicassio, M.; Niculescu, M.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Okatan, A.; Olah, L.; Oleniacz, J.; Oliveira da Silva, A. C.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Ortona, G.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Sahoo, P.; Pachmayer, Y.; Pachr, M.; Pagano, P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S. K.; Palmeri, A.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Patalakha, D. I.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Pereira da Costa, H.; Pereira de Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Pesci, A.; Peskov, V.; Pestov, Y.; Petráček, V.; Petran, M.; Petris, M.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Pohjoisaho, E. H. O.; Polichtchouk, B.; Poljak, N.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Rauf, A. W.; Razazi, V.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohni, S.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, R.; Sahu, P. K.; Saini, J.; Sakai, S.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Sánchez Rodríguez, F. J.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Segato, G.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabetai, A.; Shabratova, G.; Shahoyan, R.; Shangaraev, A.; Sharma, N.; Sharma, S.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Sicking, E.; Siddhanta, S.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Susa, T.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tarazona Martinez, A.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Vande Vyvre, P.; van der Maarel, J.; van Hoorne, J. W.; van Leeuwen, M.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wagner, V.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yang, S.; Yano, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yoo, I.-K.; Yushmanov, I.; Zaccolo, V.; Zach, C.; Zaman, A.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, F.; Zhou, Y.; Zhou, Zhuo; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zoccarato, Y.; Zyzak, M.; Alice Collaboration
2014-09-01
The production of the prompt charmed mesons D0, D+, and D*+ relative to the reaction plane was measured in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision of √sNN =2.76TeV with the ALICE detector at the CERN Large Hadron Collider. D mesons were reconstructed via their hadronic decays at central rapidity in the transverse-momentum (pT) interval 2-16 GeV /c. The azimuthal anisotropy is quantified in terms of the second coefficient v2 in a Fourier expansion of the D-meson azimuthal distribution and in terms of the nuclear modification factor RAA, measured in the direction of the reaction plane and orthogonal to it. The v2 coefficient was measured with three different methods and in three centrality classes in the interval 0%-50%. A positive v2 is observed in midcentral collisions (30%-50% centrality class), with a mean value of 0.204-0.036+0.099 (tot. unc.) in the interval 2
Hughes, R.E.
1992-01-01
The author reports on the full reconstruction of B meson decays using data obtained at the Collider Detector at Fermilab in [bar p]p collisions at [radical]s = 1.8 TeV. The author has reconstructed B meson decays in the mode B[sup [minus
Philip L. Cole
2004-09-01
The set of experiments forming the g8a run took place in the summer of 2001 in Hall B of Jefferson Lab. The g8a run was the commissioning experiment for the linearly-polarized photon beam at CLAS. The aim of these experiments is to improve the understanding of the underlying symmetry of the quark degrees of freedom in the nucleon, the nature of the parity exchange between the incident photon and the target nucleon, and the mechanism of associated strangeness production in electromagnetic reactions. A beam of tagged and collimated linearly polarized photons (energy range 1.8-2.2 GeV) in conjunction with the large solid angle coverage of CLAS make possible the extraction of the differential cross-sections and polarization observables for the photoproduction of vector mesons and kaons. The reaction channels are under investigation to search for possibly missing nucleon resonances. An overview of the experiment and preliminary results on the measurement of the photon asymmetries of the aforementioned reactions will be presented in this paper.
Properties of magnetized neutral mesons within a full RPA evaluation
NASA Astrophysics Data System (ADS)
Avancini, Sidney S.; Tavares, William R.; Pinto, Marcus B.
2016-01-01
We consider the two-flavor Nambu-Jona-Lasinio model within the random phase approximation (RPA) framework to evaluate the masses of the σ and π0 mesons and the π0 decay constant in the presence of a magnetic field at vanishing temperatures and baryonic densities. The present work extends other RPA applications by fully considering the external momenta which enter the integrals representing the magnetized polarization tensor. We employ a a field-independent regularization scheme so that more accurate results can be obtained in the evaluation of physical quantities containing pionic contributions. As we show, this technical improvement generates results which agree well with those produced by lattice simulations and chiral perturbation theory. Our method may also prove to be useful in future evaluations of quantities, such as the shear viscosity and the equation of state of magnetized quark matter with mesonic contributions.
Further Results on the Production of Neutral Mesons by Photons
DOE R&D Accomplishments Database
Panofsky, W. K. H.; Steinberger, J.; Steller, J.
1951-10-01
Further measurements have been made on the photoproduction of neutral mesons using the gamma-gamma coincidence technique. New data have been obtained on the gamma-gamma correlation curves in beryllium. The angular distribution of the photo mesons in Be has been determined and found to be strongly peaked forward. The dependence on the atomic number A of production has been found to obey an A{sup 2/3} law. Some data obtained for production in hydrogen show that the pi-zero and pi-plus production cross sections are comparable and that the pi-zero excitation curve starts more slowly from threshold than does the pi-plus photo excitation curve.
Dynamical instabilities of warm npe matter: {delta} meson effects
Pais, Helena; Santos, Alexandre; Providencia, Constanca
2009-10-15
The effects of {delta} mesons on the dynamical instabilities of cold and warm nuclear and stellar matter at subsaturation densities are studied in the framework of relativistic mean-field hadron models (NL3, NL{rho}, and NL{rho}{delta}) with the inclusion of the electromagnetic field. The distillation effect and the spinodals for all the models considered are discussed. The crust-core transition density and pressure are obtained as a function of temperature for {beta}-equilibrium matter with and without neutrino trapping. An estimation of the size of the clusters formed in the nonhomogeneous phase and the corresponding growth rates are made. It is shown that cluster sizes increase with temperature. The effects of the {delta} meson on the instability region are larger for low temperatures, very asymmetric matter, and densities close to the spinodal surface. It increases the distillation effect above {approx}0.4{rho}{sub 0} and has the opposite effect below that density.
Near-threshold photoproduction of Φ mesons from deuterium
Qian, X.; Chen, W.; Gao, H.; Hicks, K.; Kramer, K.; Laget, J. M.; Mibe, T.; Qiang, Y.; Stepanyan, S.; Tedeschi, D. J.; et al
2011-01-05
In this report, we measure the differential cross section onmore » $$\\phi$$-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, $K^+$ and $K^-$ near the theoretical production threshold of 1.57 GeV. Moreover, the extracted differential cross sections $$\\frac{d\\sigma}{dt}$$ for the initial photon energy from 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Ultimately, this experiment establishes a baseline for a future experimental search for an exotic $$\\phi$$-N bound state from heavier nuclear targets utilizing subthreshold/near-threshold production of $$\\phi$$ mesons.« less
Finite volume effects for nucleon and heavy meson masses
Colangelo, Gilberto; Fuhrer, Andreas; Lanz, Stefan
2010-08-01
We apply the resummed version of the Luescher formula to analyze finite volume corrections to the mass of the nucleon and of heavy mesons. We show that by applying the subthreshold expansion of the scattering amplitudes one can express the finite volume corrections in terms of only a few physical observables and the size of the box. In the case of the nucleon, the available information about the quark mass dependence of these physical quantities is discussed and used to assess the finite volume corrections to the nucleon mass as a function of the quark mass including a detailed analysis of the remaining uncertainties. For heavy mesons, the Luescher formula is derived both fully relativistically and in a nonrelativistic approximation and a first attempt at a numerical analysis is made.
Toward the excited meson spectrum of dynamical QCD
Dudek, Jozef J.; Edwards, Robert G.; Peardon, Michael J.; Richards, David G.; Thomas, Christopher E.
2010-08-01
We present a detailed description of the extraction of the highly excited isovector meson spectrum on dynamical anisotropic lattices using a new quark-field construction algorithm and a large variational basis of operators. With careful operator construction, the combination of these techniques is used to identify the continuum spin of extracted states reliably, overcoming the reduced rotational symmetry of the cubic lattice. Excited states, states with exotic quantum numbers (0+-, 1-+ and 2+-) and states of high spin are resolved, including, for the first time in a lattice QCD calculation, spin-four states. The determinations of the spectrum of isovector mesons and kaons are performed on dynamical lattices with two volumes and with pion masses down to ~ 400 MeV, with statistical precision typically at or below 1% even for highly excited states.
Near-threshold photoproduction of Φ mesons from deuterium
Qian, X.; Chen, W.; Gao, H.; Hicks, K.; Kramer, K.; Laget, J. M.; Mibe, T.; Qiang, Y.; Stepanyan, S.; Tedeschi, D. J.; Xu, W.; Adhikari, K. P.; Amaryan, M.; Anghinolfi, M.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bellis, M.; Biselli, A. S.; Bookwalter, C.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Cole, P. L.; Collins, P.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Dey, B.; Dhamija, S.; Djalali, C.; Doughty, D.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Eugenio, P.; Fegan, S.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Jawalkar, S. S.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Konczykowski, P.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Martinez, D.; Mayer, M.; McAndrew, J.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mikhailov, K.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, I.; Niroula, M. R.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Park, S.; Pereira, S. Anefalos; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, C. E.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vineyard, M. F.; Voutier, E.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.
2011-01-05
In this report, we measure the differential cross section on $\\phi$-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, $K^+$ and $K^-$ near the theoretical production threshold of 1.57 GeV. Moreover, the extracted differential cross sections $\\frac{d\\sigma}{dt}$ for the initial photon energy from 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Ultimately, this experiment establishes a baseline for a future experimental search for an exotic $\\phi$-N bound state from heavier nuclear targets utilizing subthreshold/near-threshold production of $\\phi$ mesons.
Introduction to heavy meson decays and CP asymmetries
Ligeti, Zoltan
2003-02-05
These lectures are intended to provide an introduction to heavy meson decays and CP violation. The first lecture contains a brief review of the standard model and how the CKM matrix and CP violation arise, mixing and CP violation in neutral meson systems, and explanation of the cleanliness of the sin 2{beta} measurement. The second lecture deals with the heavy quark limit, some applications of heavy quark symmetry and the operator product expansion for exclusive and inclusive semileptonic B decays. The third lecture concerns with theoretically clean CP violation measurements that may become possible in the future, and some developments toward a better understanding of nonleptonic B decays. The conclusions include a subjective best buy list for the near future.
Ideal quarks and mesons in the relativistic quark model
Kaneko, K. )
1994-05-01
We propose a microscopic theory for interacting mesons and ideal quarks in the relativistic quark model using the time-dependent mean-field theory technique. For simplicity we examined the Nambu--Jona-Lasinio model. The dynamical chiral-symmetry breaking leads to a zero-frequency mode (pion) due to the restoration of chiral symmetry. The ideal quarks are represented as dressed particles independent of mean fields, and do not have the conventional properties of fermions. This is due to the constraints of eliminating the double counting of degrees of freedom between the mean fields and quarks. The small fluctuation around the static solution is then investigated. The pseudoscalar and scalar mesons are represented as the collective modes of the mean fields.
Observation of orbitally excited B(s) mesons.
Aaltonen, T; Abulencia, A; Adelman, J; Akimoto, T; Albrow, M G; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Bednar, P; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'orso, M; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; 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Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zheng, Y; Zucchelli, S
2008-02-29
We report the observation of two narrow resonances consistent with states of orbitally excited (L=1) B_(s) mesons using 1 fb;(-1) of pp[over ] collisions at sqrt[s]=1.96 TeV collected with the Collider Detector at Fermilab II detector at the Fermilab Tevatron. We use two-body decays into K- and B+ mesons reconstructed as B(+)-->J/psiK(+), J/psi-->mu(+)mu(-) or B(+)-->D[over ](0)pi(+), D[over ](0)-->K(+)pi(-). We deduce the masses of the two states to be m(B_(s1))=5829.4+/-0.7 MeV/c(2) and m(B_(s2);(*))=5839.6+/-0.7 MeV/c;(2).
Evidence for new nucleon resonances from electromagnetic meson production
Volker Burkert
2012-12-01
The study of nucleon resonances in electromagnetic meson production with the CLAS detector is discussed. The electromagnetic interaction is complementary to pion scattering in the exploration of the nucleon excitation spectrum. Higher mass states often decouple from the N{pi} channel and are not seen in {pi} N --> {pi} N. Photoproduction of mesons, such as K {Lambda}, {omega} p and {eta}' p may be more sensitive to many of these states. The CLAS detector, combined with the use of energy-tagged polarized photons and polarized electrons, as well as po- larized targets and the measurement of recoil polarization, are the tools needed for a comprehensive nucleon resonance program. Some of the recently published high statistics data sets had significant impact on further clarifying the nucleon excitation spectrum.
A precise measurement of the B^0 meson oscillation frequency
NASA Astrophysics Data System (ADS)
Aaij, R.; Abellán Beteta, C.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A., Jr.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Anderson, J.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belloli, N.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Buchanan, E.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chiapolini, N.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Demmer, M.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Färber, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fohl, K.; Fol, P.; Fontana, M.; Fontanelli, F.; C. Forshaw, D.; Forty, R.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianì, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; K. Kuonen, A.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Liu, X.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusardi, N.; Lusiani, A.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Melnychuk, D.; Merk, M.; Michielin, E.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Pappenheimer, C.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; W. Ronayne, J.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefkova, S.; Steinkamp, O.; Stenyakin, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Teklishyn, M.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yu, J.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.; Zhukov, V.; Zucchelli, S.
2016-07-01
The oscillation frequency, Δ m_d, of B^0 mesons is measured using semileptonic decays with a D^- or D^{*-} meson in the final state. The data sample corresponds to 3.0fb^{-1} of pp collisions, collected by the LHCb experiment at centre-of-mass energies √{s} = 7 and 8 TeV. A combination of the two decay modes gives Δ m_d = (505.0 ± 2.1 ± 1.0) ns^{-1}, where the first uncertainty is statistical and the second is systematic. This is the most precise single measurement of this parameter. It is consistent with the current world average and has similar precision.
Quantum correlations in B and K meson systems
NASA Astrophysics Data System (ADS)
Banerjee, Subhashish; Alok, Ashutosh Kumar; MacKenzie, Richard
2016-05-01
The interplay between the various measures of quantum correlations is well known in stable optical and electronic systems. Here we study such foundational issues in unstable quantum systems. Specifically we study meson-antimeson systems ( Kbar{K}, Bd bar{B}d and Bsbar{B}s, which are produced copiously in meson factories. In particular, the nonclassicality of quantum correlations which can be characterized in terms of nonlocality (which is the strongest condition), entanglement, teleportation fidelity or weaker nonclassicality measures like quantum discord are analyzed. We also study the impact of decoherence on these measures of quantum correlations, using the semigroup formalism. A comparison of these measures brings out the fact that the relations between them can be nontrivially different from those of their stable counterparts such as neutrinos.
Exploring pseudoscalar meson scattering in linear sigma models
NASA Astrophysics Data System (ADS)
Black (Speaker), Deirdre; Fariborz, Amir H.; Moussa, Sherif; Nasri, Salah; Schechter, Joseph
2001-11-01
The three flavor linear sigma model is studied as a toy model for understanding the role of possible light scalar mesons in the ππ, πK and πɛ elastic scattering channels. We unitarize tree level amplitudes using the K-matrix prescription and, with a sufficiently general model, obtain reasonable fits to the experimental data. The effect of unitarization is very important and leads to the emergence of a nonet of light scalars, with masses below 1 GeV. We compare with a scattering treatment using a more general non-linear sigma model approach and also comment briefly upon how our results fit in with the scalar meson puzzle. .
Chiral Extrapolation of Lattice Data for Heavy Meson Hyperfine Splittings
X.-H. Guo; P.C. Tandy; A.W. Thomas
2006-03-01
We investigate the chiral extrapolation of the lattice data for the light-heavy meson hyperfine splittings D*-D and B*-B to the physical region for the light quark mass. The chiral loop corrections providing non-analytic behavior in m{sub {pi}} are consistent with chiral perturbation theory for heavy mesons. Since chiral loop corrections tend to decrease the already too low splittings obtained from linear extrapolation, we investigate two models to guide the form of the analytic background behavior: the constituent quark potential model, and the covariant model of QCD based on the ladder-rainbow truncation of the Dyson-Schwinger equations. The extrapolated hyperfine splittings remain clearly below the experimental values even allowing for the model dependence in the description of the analytic background.
Light-Meson Two-Photon Decays in Full QCD
Cohen, Saul; Lin, Huey-Wen; Dudek, Jozef; Edwards, Robert
2008-12-01
We present a study of two-photon decays of light mesons, focusing on the neutral pion decay. This important process highlights the effects of the axial anomaly in QCD but has been little studied on the lattice. By applying the Lehmann-Symanzik-Zimmermann (LSZ) reduction formula, we reconstruct the electromagnetic matrix elements from three-point vector-vector Green functions calculated on 2+1-flavor isotropic clover lattices.
Decay constants of pseudoscalar mesons containing heavy quarks
Mathur, V. S.; Yamawaki, M. T.
1981-01-01
The QCD sum-rules of Shifman et al. for n-th order moments are applied to the determination of the decay constants of pseudoscalar mesons containing a heavy quark (c or b). The general case when Q/sup 2/, the squared momentum transfer, is non-zero is considered. The stability of the sum-rules against variations in both Q/sup 2/ and n is discussed.
Instantaneous Bethe-Salpeter kernel for the lightest pseudoscalar mesons
NASA Astrophysics Data System (ADS)
Lucha, Wolfgang; Schöberl, Franz F.
2016-05-01
Starting from a phenomenologically successful, numerical solution of the Dyson-Schwinger equation that governs the quark propagator, we reconstruct in detail the interaction kernel that has to enter the instantaneous approximation to the Bethe-Salpeter equation to allow us to describe the lightest pseudoscalar mesons as quark-antiquark bound states exhibiting the (almost) masslessness necessary for them to be interpretable as the (pseudo) Goldstone bosons related to the spontaneous chiral symmetry breaking of quantum chromodynamics.
Heavy Meson Production at a Low-Energy Photon Collider
Asztalos, S
2004-04-15
A low-energy {gamma}{gamma} collider has been discussed in the context of a testbed for a {gamma}{gamma} interaction region at the Next Linear Collider(NLC). We consider the production of heavy mesons at such a testbed using Compton-backscattered photons and demonstrate that their production rivals or exceeds those by BELLE, BABAR or LEP where they are produced indirectly via virtual {gamma}{gamma} luminosities.
Strong and electromagnetic mass splittings in heavy mesons
Jose L. Goity; Chandana P. Jayalath
2007-01-26
The contributions to heavy meson mass differences by the strong hyperfine interaction, the light quark masses and the electromagnetic interaction are obtained from the empirical values of the D, D*, B and B* masses by means of a mass formula based on the heavy quark mass expansion. The three different types of contributions are determined with significant accuracy to next to leading order in that expansion.
B meson decays in leptons: powerful probes of new physics
NASA Astrophysics Data System (ADS)
Rotondo, Marcello
2014-11-01
We review some recent measurements of B meson decays that involve leptons in the final states and that are sensitive to physics beyond the Standard Model, such as the electroweak penguin decays B → Xsℓ+ℓ-, the Lepton Number Violating process B → Xℓ±ℓ'± and the tree-level dominated decay with τ leptons: B → τντ and B → D(∗)τντ.
Correlations between D and Dbar mesons in high energy photoproduction
Erik E Gottschalk
2002-11-13
Over 7000 events containing a fully reconstructed D{bar D} pair have been extracted from data recorded by the FOCUS photoproduction experiment at Fermilab. Preliminary results from a study of correlations between D and {bar D} mesons are presented. Correlations are used to study perturbative QCD predictions and investigate non-perturbative effects. We also present a preliminary result on the production of {psi}(3770).
CP Violation in B Meson Decays: Experimental Results
Lanceri, Livio; /Trieste U. /INFN, Trieste
2005-08-30
CP violation is intimately connected with the puzzle of matter-antimatter asymmetry and baryogenesis. In the Standard Model of particle physics, the observed CP violation phenomena are accounted for by the Cabibbo-Kobayashi-Maskawa mechanism involving a phase in the quark mixing matrix. This paper is devoted to a review of the experimental status of CP violation in the decays of B mesons.
S=0 pseudoscalar meson photoproduction from the proton
M. Dugger for the CLAS Collaboration
2005-10-10
Many measurements of pseudoscalar mesons with S = 0 photoproduced on the proton have been made recently. These new data are particularly useful in theoretical investigations of nucleon resonances. How the new data from various labs complement each other and help fill in the gaps in the world data set is disscussed, with a glance at measurements to be made in the near future. Some theoretical techniques used to explain the data are briefly described.
Physics of B0(s) Mesons and Bottom Baryons
Paulini, Manfred; /Carnegie Mellon U.
2009-06-01
We discuss the physics of B{sub s}{sup 0} mesons focusing on CP violation in B{sub s}{sup 0} {yields} J/{Psi}{phi} decays at the Tevatron. We summarize measurements of the properties of bottom baryons at the Tevatron including the {Sigma}{sub b} states and the {Xi}{sub b}{sup -} baryon. We also discuss the discovery of the {Omega}{sub b}{sup -} baryon.
Heavy-meson decay constants from QCD sum rules
Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano
2010-12-22
We sketch a recent sum-rule extraction of the decay constants of the heavy pseudoscalar mesons D, D{sub s}, B, and B{sub s} from the two-point correlator of heavy-light pseudoscalar currents. Our main emphasis lies on the control over all the uncertainties in the decay constants, related both to the input QCD parameters and to the limited accuracy of the method of sum rules. Gaining this control has become possible by application of our new procedure of extracting hadron observables based on a dual threshold depending on the Borel parameter. For the charmed-meson decay constants, we find fD = (206.2{+-}7.3{sub (OPE)}{+-}5.1{sub (syst)}) MeV, fD{sub s} = (245.3{+-}15.7{sub (OPE)}{+-}4.5{sub (syst)}) MeV. For the beauty mesons, the decay constants turn out to be extremely sensitive to the precise value of the {ovr MS} mass of the b-quark, {bar m}{sub b}({bar m}{sub b}). By requiring our sum-rule estimate to match the average of the lattice determinations of f{sub B}, we extract the rather accurate value {bar m}{sub b}({bar m}{sub b}) = (4.245{+-}0.025) GeV. Feeding this parameter value into our sum-rule formalism leads to the beauty-meson decay constants fB = (193.4{+-}12.3{sub (OPE)}{+-}4.3{sub (syst)}) MeV, fB{sub s} = (232.5{+-}18.6{sub (OPE)}{+-}2.4{sub (syst)}) MeV.
Highly excited and exotic meson spectrum from dynamical lattice QCD
Jozef Dudek, Robert Edwards, David Richards, Christopher Thomas
2009-12-01
Using a new quark-field construction algorithm and a large variational basis of operators, we extract a highly excited isovector meson spectrum on dynamical anisotropic lattices. We show how carefully constructed operators can be used to identify the continuum spin of extracted states. This method allows us to extract, with confidence, excited states, states of high spin and states with exotic quantum numbers, including, for the first time, spin-four states.
B meson decays to charmless meson pairs containing eta or eta'
Aubert, : B.
2009-12-14
The authors present updated measurements of the branching fractions for B{sup 0} meson decays to {eta}K{sup 0}, {eta}{eta}, {eta}{phi}, {eta}{omega}, {eta}{prime}K{sup 0}, {eta}{prime}{eta}{prime}, {eta}{prime}, {phi}, and {eta}{prime}{omega} and branching fractions and CP-violating charge asymmetries for B{sup +} decays to {eta}{pi}{sup +}, {eta}K{sup +}, {eta}{prime}{pi}{sup +}, and {eta}{prime} K{sup +}. The data represent the full dataset of 467 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. Besides large signals for the four charged B decays modes and for B{sup 0} {yields} {eta}{prime}K{sup 0}, they find evidence for three B{sup 0} decays modes at greater than 3.0{sigma} significance. They find {Beta}(B{sup 0} {yields} {eta}K{sup 0}) = (1.15{sub -0.38}{sup +0.43} {+-} 0.09) x 10{sup -6}, {Beta}(B{sup 0} {yields} {eta}{omega}) = (0.94{sub -0.30}{sup +0.35} {+-} 0.09) x 10{sup -6}, and {Beta}(B{sup 0} {yields} {eta}{prime}{omega}) = (1.01{sub -0.38}{sup +0.46} {+-} 0.09) x 10{sup -6}, where the first (second) uncertainty is statistical (systematic). For the B{sup +} {yields} {eta}K{sup +} decay mode, they measure the charge asymmetry {Alpha}{sub ch} (B{sup +} {yields} {eta}K{sup +}) = -0.36 {+-} 0.11 {+-} 0.03.
Exotic Baryons from a Heavy Meson and a Nucleon
NASA Astrophysics Data System (ADS)
Yamaguchi, Yasuhiro
2016-08-01
Hadronic molecules have been considered to be one of the candidate of exotic hadron structures near the threshold. In the heavy quark sector, new symmetry, called the heavy quark symmetry, plays an important role to form the molecules. This symmetry has an essential role which is to enhance the one pion exchange potential arising through the mixing of heavy pseudoscalar and heavy vector mesons. In this study, we investigate new hadronic molecule formed by the heavy meson P^{(*)}=bar{D}^{(*)},B^{(*)} and a nucleon N, being P^{(*)}N and P^{(*)}NN few-body states. As the interaction between P and N, the π exchange and vector meson (ρ and ω ) exchanges are considered. By solving the coupled-channel schrödinger equations for PN(N) and P^{(*)}N(N) , we predict the bound and resonant states in the charm and bottom sectors. In the bound and resonant states, the PN-P^*N mixing effect is important, where the tensor force of the one pion exchange potential generates the strong attraction.
Decay Constants of Beauty Mesons from QCD Sum Rules
NASA Astrophysics Data System (ADS)
Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano
2014-11-01
Our recently completed analysis of the decay constants of both pseudoscalar and vector beauty mesons reveals that in the bottom-quark sector two specific features of the sum-rule predictions show up: (i) For the input value of the bottom-quark mass in the M̅S̅ scheme m̅b(m̅b) ≈ 4:18 GeV; the sum-rule result fB ≈ 210-220 MeV for the B meson decay constant is substantially larger than the recent lattice-QCD finding fB ≈ 190 MeV: Requiring QCD sum rules to reproduce the lattice-QCD value of fB yields a significantly larger b-quark mass: m̅b(m̅b) = 4:247 GeV: (ii) Whereas QCD sum-rule predictions for the charmed-meson decay constants fD; fDs, fD* and fDs* are practically independent of the choice of renormalization scale, in the beauty sector the results for the decay constants—and especially for the ratio fB* / fB—prove to be very sensitive to the specific scale setting.
Can strong correlations be experimentally revealed for Ҡ -mesons?
NASA Astrophysics Data System (ADS)
Hiesmayr, Beatrix C.
2014-11-01
In 1964 the physicists John St. Bell working at CERN took the 1935-idea of Einstein-Podolsky-Rosen seriously and found that all theories based on local realism have to satisfy a certain inequality, nowadays dubbed Bell's inequality. Experiments with ordinary matter systems or light show violations of Bell's inequality favouring the quantum theory though a loophole free experiment has not yet been performed. This contribution presents an experimentally feasible Bell inequality for systems at higher energy scales, i.e. entangled neutral Ҡ -meson pairs that are typically produced in Φ -mesons decays or proton-antiproton annihilation processes. Strong requirements have to be overcome in order to achieve a conclusive tests, such a proposal was recently published. Surprisingly, this new Bell inequality reveals new features for weakly decaying particles, in particular, a strong sensitivity to the combined charge-conjugation-parity (CP) symmetry. Here-with, a puzzling relation between a symmetry breaking for mesons and Bell's inequality—which is a necessary and sufficient condition for the security of quantum cryptography protocols— is established. This becomes the more important since CP symmetry is related to the cosmological question why the antimatter disappeared after the Big Bang.
Phi meson spectral moments and QCD condensates in nuclear matter
NASA Astrophysics Data System (ADS)
Gubler, Philipp; Weise, Wolfram
2016-10-01
A detailed analysis of the lowest two moments of the ϕ meson spectral function in vacuum and nuclear matter is performed. The consistency is examined between the constraints derived from finite energy QCD sum rules and the spectra computed within an improved vector dominance model, incorporating the coupling of kaonic degrees of freedom with the bare ϕ meson. In the vacuum, recent accurate measurements of the e+e- →K+K- cross section allow us to determine the spectral function with high precision. In nuclear matter, the modification of the spectral function can be described by the interactions of the kaons from ϕ → K K ‾ with the surrounding nuclear medium. This leads primarily to a strong broadening and an asymmetric deformation of the ϕ meson peak structure. We confirm that, both in vacuum and nuclear matter, the zeroth and first moments of the corresponding spectral functions satisfy the requirements of the finite energy sum rules to a remarkable degree of accuracy. Limits on the strangeness sigma term of the nucleon are examined in this context. Applying our results to the second moment of the spectrum, we furthermore discuss constraints on four-quark condensates and the validity of the commonly used ground state saturation approximation.
The η ' g* g(*) vertex including the η '-meson mass
NASA Astrophysics Data System (ADS)
Ali, A.; Parkhomenko, A. Ya
2003-10-01
The η^' g^* g^{(*)} effective vertex function is calculated in the QCD hard-scattering approach, taking into account the η^'-meson mass. We work in the approximation in which only one non-leading Gegenbauer moment for both the quark-antiquark and the gluonic light-cone distribution amplitudes for the η^'-meson is kept. The vertex function with one off-shell gluon is shown to have the form (valid for \\vert q_1^2 \\vert > m_{η^'^2) F_{η^' g^* g} (q_1^2, 0, m_{η^'^2) = m_{η^'^2 H(q_1^2)/(q_1^2 - m_{η^'^2), where H( q 1 2) is a slowly varying function, derived analytically in this paper. The resulting vertex function is in agreement with the phenomenologically inferred form of this vertex obtained from an analysis of the CLEO data on the η^'-meson energy spectrum in the decay Upsilon(1S) to η^' X. We also present an interpolating formula for the vertex function F_{η^' g^* g} (q_1^2, 0, m_{η^'^2) for the space-like region of the virtuality q 1 2, which satisfies the QCD anomaly normalization for on-shell gluons and the perturbative QCD result for the gluon virtuality \\vert q_1^2\\vert gtrsim 2 GeV2.
Measurement of Leptonic and Hadronic Decays of omega- and phi-Mesons at RHIC by PHENIX
Riabov, Yu; Awes, Terry C; Batsouli, Sotiria; Cianciolo, Vince; Efremenko, Yuri; Read Jr, Kenneth F; Silvermyr, David O; Sorensen, Soren P; Stankus, Paul W; Young, Glenn R; Zhang, Chun; PHENIX, Collaboration
2007-01-01
The PHENIX experiment at RHIC has measured production of {omega}- and {phi}-mesons in p + p, d + Au and Au+Au collisions at {radical}s{sub NN}=62.4 and 200 GeV. Transverse momentum (mass) spectra measured in hadronic and di-electron decay channels are found to be in agreement with each other within the errors. Nuclear modification factors R{sub AA} measured for both mesons are consistent with results obtained for other neutral mesons. The position of the meson mass peaks and their widths reconstructed in hadronic decay channels are in agreement with their properties measured in vacuum.
Mass spectra of heavy-light mesons in heavy hadron chiral perturbation theory
NASA Astrophysics Data System (ADS)
Alhakami, Mohammad H.
2016-05-01
We study the masses of the low-lying charm and bottom mesons within the framework of heavy hadron chiral perturbation theory (HHChPT). We work to third order in the chiral expansion, where meson loops contribute. In contrast to previous approaches, we use physical meson masses in evaluating these loops. This ensures that their imaginary parts are consistent with the observed widths of the D mesons. The lowest odd- and even-parity, strange and nonstrange charm mesons provide enough constraints to determine only certain linear combinations of the low-energy constants in the effective Lagrangian. We comment on how lattice QCD could provide further information to disentangle these constants. Then, we use the results from the charm sector to predict the spectrum of odd and even parity of the bottom mesons. The predicted masses from our theory are in good agreement with experimentally measured masses for the case of the odd-parity sector. For the even-parity sector, the B -meson states have not yet been observed; thus, our results provide useful information for experimentalists investigating such states. The near degeneracy of nonstrange and strange scalar B mesons is confirmed in our predictions using HHChPT. We show why previous approaches of using HHChPT in studying the mass degeneracy in the scalar states of charm and bottom meson sectors gave unsatisfactory results.
Vector meson production in ultra-peripheral collisions
NASA Astrophysics Data System (ADS)
Thomas, James O.
Charged ions moving at relativistic speeds generate strong electromagnetic fields (E/M) that, at regions outside the source (important when the E/M sources are nuclei), behave like the fields from a beam of real photons. These equivalent, or virtual photons, can induce an excitation in another nucleus as the source flies by. Existing theories attempt to explain such processes and predict their outcome. One way to study such Ultra-Peripheral Collisions (UPCs) is to simulate them using a Monte-Carlo Multi-Collisional (MCMC) model based on nucleon degrees of freedom. The CRISP (acronym for Collaboration Rio-Illheus-Sao Paulo) model is one such theory. It is basically at the stage of a well-documented software package that implements the MCMC. This model has successfully predicted observables, such as neutron multiplicity, from central collisions and also in UPCs with relativistic heavy ions. However, the photoproduction of vector mesons has only recently been added to the CRISP model. A completely different approach to study UPCs focuses on the role of Parton Distribution Functions (PDFs) in the excitation process. Here, instead of nucleons, the degrees of freedom are quarks and gluons (generically known as partons). Several distinct PDFs exist in the literature and are continually being updated. This work used experimental results released from the ALICE collaboration at the Large Hadron Collider (LHC) facility located at the international particle physics laboratory CERN in Switzerland. Our outputs from the CRISP model, and from the sub-nucleon degrees of freedom model, were photonuclear cross sections for vector meson production. A comparison of our results with the experimental data allowed us to constrain different PDFs, as well as the effect of multiple collisions on the production of mesons with nucleons in the final channel. Upon completion of the calculations, it was seen that the hadronic models could accurately predict the production of the J/psi meson, but
NASA Astrophysics Data System (ADS)
Ji, Shi-Tao; Shen, Zhen-Yu; Xu, Xiao-Ming
2015-09-01
We study kaon-charmonium and η-charmonium dissociation reactions. The K-charmonium dissociation and the η-charmonium dissociation include the following 27 reactions: {KJ}/\\psi \\to {\\bar{D}}*{D}s+, \\bar{D}{D}s*+ and {\\bar{D}}*{D}s*+; K\\psi \\prime \\to {\\bar{D}}*{D}s+, \\bar{D}{D}s*+ and {\\bar{D}}*{D}s*+; K{χ }c\\to {\\bar{D}}*{D}s+, \\bar{D}{D}s*+ and {\\bar{D}}*{D}s*+; η J/\\psi \\to {\\bar{D}}*D, \\bar{D}{D}*, {\\bar{D}}*{D}*, {D}s*-{D}s+, {D}s-{D}s*+ and {D}s*-{D}s*+; η \\psi \\prime \\to {\\bar{D}}*D, \\bar{D}{D}*, {\\bar{D}}*{D}*, {D}s*-{D}s+, {D}s-{D}s*+ and {D}s*-{D}s*+; η {χ }c\\to {\\bar{D}}*D, \\bar{D}{D}*, {\\bar{D}}*{D}*, {D}s*-{D}s+, {D}s-{D}s*+ and {D}s*-{D}s*+. Cross sections for the reactions are calculated in the Born approximation, in the quark-interchange mechanism and with a temperature-dependent quark potential. The temperature dependence of peak cross sections of endothermic reactions is linked to the temperature dependence of quark-antiquark relative-motion wave functions, meson masses and the quark potential. Although the η meson and kaon have similar masses, the energy and temperature dependence of the η-charmonium dissociation cross sections are quite different from those of the K-charmonium dissociation cross sections. Using the η-charmonium and π-charmonium dissociation cross sections, we calculate the ratio of the corresponding dissociation rates in hadronic matter and we find that such rates are comparable at low J/\\psi momenta.
New thermal model with distinct freeze-out temperatures for baryons and mesons
De Assis, Leonardo P. G.; Duarte, Sergio B.; Chiapparini, Marcelo; Hirsch, Luciana R.; Delfino, Antonio Jr.
2013-05-06
A significant amount of experimental data for particle production in high-energy heavy ion collisions (10 - 200 GeV/A at center of mass) has been accumulated during last years. Many different theoretical attempts have tried to describe these data using thermal models in the approximation of global thermal equilibrium considering only one freeze-out temperature. However the thermal models often are not able to describe adequately the whole multiplicities of hadrons. For instance, the abundance of strange particles is overestimate and the pion yields are underestimated. In this work is presented a thermal hadronic model with two different temperatures in order to describe the baryonic and mesonic chemical freeze-out in ultra-relativistic heavy ion collisions. The model is used to fit the particle population ratios of the hadrons produced in the reaction. The proposal is not merely to incorporate one additional degree of freedom in the adjustment procedure of data, but to present and alternative scenario for the freeze out stage in the collisional proces s. This new reformulated version of thermal model was applied to a set of data, offering a rather good improvement in the fitting of the calculated particle ratios to the data. The results suggest that the introduced model makes the thermal approach more robust to handle with a larger number of colliding systems and a more comprehensive set of reaction observables.
Photoproduction of π0 mesons off neutrons in the nucleon resonance region.
Dieterle, M; Keshelashvili, I; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Bekrenev, V; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Demissie, B; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Glazier, D I; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jaegle, I; Jahn, O; Jude, T C; Käser, A; Kashevarov, V L; Kondratiev, R; Korolija, M; Kruglov, S P; Krusche, B; Kulbardis, A; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; Martinez, M; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Nikolaev, A; Novotny, R; Oberle, M; Ostrick, M; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S N; Robinson, J; Rosner, G; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D; Starostin, A; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P; Werthmüller, D; Witthauer, L
2014-04-11
Precise angular distributions have been measured for the first time for the photoproduction of π0 mesons off neutrons bound in the deuteron. The effects from nuclear Fermi motion have been eliminated by a complete kinematic reconstruction of the final state. The influence of final-state-interaction effects has been estimated by a comparison of the reaction cross section for quasifree protons bound in the deuteron to the results for free protons and then applied as a correction to the quasifree neutron data. The experiment was performed at the tagged photon facility of the Mainz Microtron MAMI with the Crystal Ball and TAPS detector setup for incident photon energies between 0.45 and 1.4 GeV. The results are compared to the predictions from reaction models and partial-wave analyses based on data from other isospin channels. The model predictions show large discrepancies among each other and the present data will provide much tighter constraints. This is demonstrated by the results of a new analysis in the framework of the Bonn-Gatchina coupled-channel analysis which included the present data.
NN-->NNπ reaction near threshold in a covariant one-boson-exchange model
NASA Astrophysics Data System (ADS)
Shyam, R.; Mosel, U.
1998-04-01
We calculate the cross sections for the p(p,nπ+)p and p(p,pπ0)p reactions for proton beam energies near threshold in a covariant one-boson-exchange model, which incorporates the exchange of π, ρ, σ and ω mesons, treats both nucleon and delta isobar as intermediate states. The final state interaction effects are included within the Watson's theory. Within this model the ω and σ meson exchange terms contribute significantly at these energies, which, along with other meson exchanges, make it possible to reproduce the available experimental data for the total as well as differential cross sections for both the reactions. The cross sections at beam energies <=300 MeV are found to be almost free from the contributions of the Δ isobar excitation.
Composition of the pseudoscalar η and η' mesons
NASA Astrophysics Data System (ADS)
Thomas, Christopher E.
2007-10-01
The composition of the η and η' mesons has long been a source of discussion and is of current interest with new experimental results appearing. We investigate what can be learnt from a number of different processes: V→Pγ and P→Vγ (V and P are light vector and pseudoscalar mesons respectively), P→γγ, J/ψ,ψ'→Pγ, J/ψ,ψ'→PV, and χc0,2→PP. These constrain the η-η' mixing angle to a consistent value, phi approx 42° we find that the cbar c components are lesssim5% in amplitude. We also find that, while the data hint at a small gluonic component in the η', the conclusions depend sensitively on unknown form factors associated with exclusive dynamics. In addition, we predict BR(ψ'→η'γ) approx 1 × 10-5 and BR(χc0→ηη') approx 2 × 10-5-1 × 10-4. We provide a method to test the mixing using χc2→ηη, η'η' and ηη' modes and make some general observations on χc0,2 decays. We also survey the semileptonic and hadronic decays of bottom and charmed mesons and find some modes where the mixing angle can be extracted cleanly with the current experimental data, some where more data will allow this, and some where a more detailed knowledge of the different amplitudes is required.
Flavour and spin of the proton and the meson cloud
NASA Astrophysics Data System (ADS)
Holtmann, H.; Szczurek, A.; Speth, J.
1996-02-01
We present a complete set of formulas for longitudinal momentum distribution functions (splitting functions) of mesons in the nucleon. It can be applied in the framework of the convolution formalism to the deep-inelastic structure functions (quark distributions) of the nucleon viewed as a system composed of virtual "mesons" and "baryons". Pseudoscalar and vector mesons as well as octet and decuplet baryons are included. In contrast to many approaches in the literature the present approach ensures charge and momentum conservation by the construction. We present not only spin averaged splitting functions but also helicity-dependent ones, which can be used to study the spin content of the nucleon. The cut-off parameters of the underlying form factors for different vertices are determined from high-energy particle production data. We find a universal cut-off parameter for processes involving octet baryons. This information allows one to calculate the flavour and spin content of the nucleon. The value of the Gottfried Sum Rule obtained from our model ( SG = 0.224) nicely agrees with that obtained by the NMC. In addition, we calculate the x-dependence of the overlined - overlineu asymmetry and get an impressive agreement with a recent fit of Martin-Stirling-Roberts. The calculated axial coupling constants for semileptonic decays of the octet baryons agree with the experimental data already with the SU(6) wave function for the bare nucleon. As a consequence the Bjorken Sum Rule is nicely reproduced. Although we get improvements for the Ellis-Jaffe Sum Rules for the proton and neutron in comparison to the naive quark model, the MCM is not sufficient to reproduce the experimental data.
Meson Transition Form Factors in Light-Front Holographic QCD
Brodsky, Stanley J.; Cao, Fu-Guang; de Teramond, Guy F.; /Costa Rica U.
2011-06-22
We study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The Chern-Simons action, which is a natural form in 5-dimensional anti-de Sitter (AdS) space, leads directly to an expression for the photon-to-pion TFF for a class of confining models. Remarkably, the predicted pion TFF is identical to the leading order QCD result where the distribution amplitude has asymptotic form. The Chern-Simons form is local in AdS space and is thus somewhat limited in its predictability. It only retains the q{bar q} component of the pion wavefunction, and further, it projects out only the asymptotic form of the meson distribution amplitude. It is found that in order to describe simultaneously the decay process {pi}{sup 0} {yields} {gamma}{gamma} and the pion TFF at the asymptotic limit, a probability for the q{bar q} component of the pion wavefunction P{sub q{bar q}} = 0.5 is required; thus giving indication that the contributions from higher Fock states in the pion light-front wavefunction need to be included in the analysis. The probability for the Fock state containing four quarks (anti-quarks) which follows from analyzing the hadron matrix elements, P{sub q{bar q}q{bar q}} {approx} 10%, agrees with the analysis of the pion elastic form factor using light-front holography including higher Fock components in the pion wavefunction. The results for the TFFs for the {eta} and {eta}{prime} mesons are also presented. The rapid growth of the pion TFF exhibited by the BABAR data at high Q{sup 2} is not compatible with the models discussed in this article, whereas the theoretical calculations are in agreement with the experimental data for the {eta} and {eta}{prime} TFFs.
PQChPT with Staggered Sea and Valence Ginsparg-Wilson Quarks: Vector Meson Masses
Hovhannes R. Grigoryan; Anthony W. Thomas
2005-09-16
We consider partially quenched, mixed chiral perturbation theory with staggered sea and Ginsparg-Wilson valence quarks in order to extract a chiral-continuum extrapolation expression for the vector meson mass up to order O(a{sup 2}), at one-loop level. Based on general principles, we accomplish the task without explicitly constructing a sophisticated, heavy vector meson chiral Lagrangian.
Yukawa and the Birth of Meson Theory: Fiftieth Anniversary for Nuclear Forces.
ERIC Educational Resources Information Center
Spradley, Joseph L.
1985-01-01
In 1935 physicist Hideki Yukawa proposed the meson theory of nuclear forces. Background, influences, and chronology of Yukawa's work are presented and discussed. Yukawa was supported in his meson idea by Japan's strong emphasis on intuitive and creative approaches which are also evident in subsequent developments in that country. (DH)
Mixing parameters of neutral beauty mesons from the Coulomb plus power potential (CPPν)
NASA Astrophysics Data System (ADS)
Patel, Bhavin; Vinodkumar, P. C.
2009-11-01
The investigation of mixing parameters in neutral B meson systems provides an important testing ground for standard model flavour dynamics. The spectroscopic parameters deduced from the potential model are used to calculate the pseudoscalar decay constant and mixing parameters of the B and Bs mesons.
The nucleon-delta splitting in the chiral quark-meson model
NASA Astrophysics Data System (ADS)
Cohen, Thomas D.; Banerjee, Manoj K.
1986-01-01
Cranking techniques are employed to calculate the N - Δ splitting in the chiral quark-meson model. A splitting of 322 MeV is obtained. It is determined that about 80% of the angular momentum and isospin in the model are carried by the mesons.
Exclusive Vector Meson Production and Deep Virtual Compton Scattering in Electron-Ion Collisions
Cazaroto, E. R.; Navarra, F. S.; Carvalho, F.; Kugeratski, M. S.; Goncalves, V. P.
2010-11-12
We calculate the nuclear cross section for coherent and incoherent deep virtual Compton scattering as well as for coherent and incoherent vector meson production for the mesons J/{Psi}, {phi} and {rho} within the QCD color dipole picture, including saturation effects. Theoretical estimates for scattering on both light and heavy nuclei are given over a wide range of energy.
The charge form factor of pseudoscalar mesons in a relativistic constituent quark model
Cardarelli, F.; Pace, E.; Grach, I.L.
1994-04-01
The charge form factor of pseudoscalar mesons has been investigated in the light-cone formalism, up to Q{sup 2} relevant to CEBAF energies. The consequences of adopting the meson wave functions generated through the Godfrey-Isgur q{bar q} potential, which reproduces the mass spectra, are discussed.
Quark condensate and deviations from string-like behaviour of meson spectra
NASA Astrophysics Data System (ADS)
Afonin, S. S.
2003-12-01
I analyze the hypothesis that deviations from the linear meson mass spectra appear due to the dynamical chiral symmetry breaking in QCD. It is shown that the linear mass spectrum for the light, non-strange vector and axial-vector mesons is then parametrized by the constant fπ, being successful phenomenologically. The toy model for deviations from linearity is proposed.
Diffusion of hidden charm mesons in hadronic medium
NASA Astrophysics Data System (ADS)
Mitra, Sukanya; Ghosh, Sabyasachi; Das, Santosh K.; Sarkar, Sourav; Alam, Jan-e.
2016-07-01
The drag and diffusion coefficients of a hot hadronic medium have been evaluated by using hidden charm mesons as probes. The scattering amplitudes required for the evaluation of these coefficients are calculated using an effective theory and scattering lengths obtained from lattice QCD calculations. It is found that although the magnitude of the transport coefficients are small their temperature variation is strong. The insignificant momentum diffusion of J / ψ in the hadronic medium keeps their momentum distribution largely unaltered. Therefore, the task of characterization of quark gluon plasma by using the observed suppression of J / ψ at high momentum will be comparatively easier.
Vector mesons at finite temperature and QCD sum rules
Kwon, Youngshin; Weise, Wolfram; Sasaki, Chihiro
2010-06-15
Finite energy sum rules for vector and axial-vector currents are derived in a thermal medium to provide constraints for the spectral behavior of rho and a{sub 1} mesons at nonvanishing temperature and hence to study the tendency toward chiral symmetry restoration. The parity-mixing ansatz for the rho and a{sub 1} spectra, including finite widths, is investigated as a function of temperature. Characteristic differences between vector and axial-vector channels are discussed with regard to the implementation of the chiral-symmetry-breaking scale, 4pi times the pion decay constant, in the sum-rule approach.
Properties of low-lying heavy-light mesons
NASA Astrophysics Data System (ADS)
Duncan, Anthony; Eichten, Estia; El-Khadra, Aida X.; Flynn, Jonathan M.; Hill, Brian R.; Thacker, Hank
1993-03-01
We present preliminary results for fB and masses of low-lying heavy-light mesons in the static limit. Calculations were performed in the quenched approximation using multistate smearing functions generated from a Hamiltonian for a spinless relativistic quark. The 2 S-1 S and 1 P-1 S mass splitting are measured. Using the 1 P-1 S charmonium splitting to set the overall scale, the ground state decay constant fB, is 319 ± 11 (stat) MeV.
Meson photoproduction and baryon resonances at MAMBO experiment
NASA Astrophysics Data System (ADS)
Romaniuk, Mariia
2013-03-01
Photoproduction of mesons within the framework of the MAMBO experiment (BGO-OD at Bonn plus MAMI at Mainz) was studied. The results on the operative work of the cryogenic H2/D2 target system during the last commissioning beam times at the March and June 2012 are shown. Investigation of the single charged pion photoproduction was provided using a polarized 3He target at the tagged photon facility of the MAMI accelerator. Unpolarized and helicity dependent cross sections are presented for channels γN → π±X in the Δ(1232) baryon resonance region.
Studies of N* Structure from the CLAS Meson Electroproduction Data
Mokeev, Viktor I.; Aznauryan, Inna G.
2014-01-01
The transition {gamma}{sub v}pN amplitudes (electrocouplings) for prominent excited nucleon states obtained in a wide area of photon virtualities offer valuable information for the exploration of the N structure at different distances and allow us to access the complex dynamics of non-perturbative strong interaction. The current status in the studies of {gamma}{sub v}pN electrocouplings from the data on exclusive meson electroproduction off protons measured with the CLAS detector at Jefferson Lab is presented. The impact of these results on exploration of the N structure is discussed.
Measurement of charmless semileptonic decays of [ital B] mesons
Bartelt, J.; Csorna, S.E.; Egyed, Z.; Jain, V.; Akerib, D.S.; Barish, B.; Chadha, M.; Chan, S.; Cowen, D.F.; Eigen, G.; Miller, J.S.; O'Grady, C.; Urheim, J.; Weinstein, A.J.; Acosta, D.; Athanas, M.; Masek, G.; Paar, H.; Sivertz, M.; Bean, A.; Gronberg, J.; Kutschke, R.; Menary, S.; Morrison, R.J.; Nakanishi, S.; Nelson, H.N.; Nelson, T.K.; Richman, J.D.; Ryd, A.; Tajima, H.; Schmidt, D.; Sperka, D.; Witherell, M.S.; Procario, M.; Yang, S.; Cho, K.; Daoudi, M.; Ford, W.T.; Johnson, D.R.; Lingel, K.; Lohner, M.; Rankin, P.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berkelman, K.; Besson, D.; Browder, T.E.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Drell, P.S.; Ehrlich, R.; Garcia-Sciveres, M.; Geiser, B.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Jones, C.D.; Jones, S.L.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Ogg, M.; Patterson, J.R.; Peterson, D.; Riley, D.; Salman, S.; Sapper,
1993-12-20
Using the CLEO II detector and a sample of 955 000 [Upsilon](4S) decays we have confirmed charmless semileptonic decays of [ital B] mesons. In the momentum interval 2.3--2.6 GeV/[ital c] we observe an excess of 107[plus minus]15[plus minus]11 leptons, which we attribute to [ital b][r arrow][ital ul][nu]. This result yields a model-dependent range of values for [vert bar][ital V][sub [ital u][ital b
Non-perturbative QCD Modeling and Meson Physics
Nguyen, T.; Souchlas, N. A.; Tandy, P. C.
2009-04-20
Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.
Meson exchange currents in neutron-proton bremsstrahlung
Li Yi; Liou, M. K.; Schreiber, W. M.; Gibson, B. F.; Timmermans, R. G. E.
2008-04-15
Background: The meson exchange current (MEC) contribution is important in the neutron-proton bremsstrahlung process (np{gamma}) when the two nucleon-scattering angles are small. However, our understanding of such effects is limited, and the reason why meson exchange current effects dominate the np{gamma} cross section has not been thoroughly investigated. Purpose: The primary focus of this investigation is to understand the origin of the MEC contribution, to identify the leading MEC amplitudes, and to comprehend why these MEC amplitudes dominate the np{gamma} cross sections. Method: We used a new method that combines the one-boson-exchange (OBE) approach with the soft-photon approach to define 10 different np{gamma} amplitudes. These amplitudes are used to calculate np{gamma} cross sections at 225 MeV for nucleon laboratory scattering angles lying between 12 deg. and 43 deg. The results of these calculations are then compared to investigate the meson exchange current effect in np{gamma}. Results: (i) The OBE amplitude M{sub np{gamma}}{sub ,{mu}}{sup PS} and the two-u-two-t special (TuTts) soft-photon amplitude M{sub np{gamma}}{sub ,{mu}}{sup TuTts} predict quantitatively similar np{gamma} cross sections. (ii) The MEC effect is found to be significant when the two nucleon-scattering angles are far from the elastic limit (45 deg.), but the effect is insignificant when the nucleon angles approach the elastic limit. (iii) The origin of the MEC effect and the leading MEC amplitudes have been identified in this investigation. Furthermore, the reason is now clear why the leading MEC amplitudes dominate the np{gamma} cross section when the nucleon-scattering angles are small. (iv) The contribution from the anomalous magnetic moments of the proton and the neutron is confirmed to be negligibly small. (v) In general, the theoretical cross sections using the amplitude M{sub np{gamma}}{sub ,{mu}}{sup PS}, or the amplitude M{sub np{gamma}}{sub ,{mu}}{sup TuTts}, are consistent
Determination of the X(3872) meson quantum numbers.
Aaij, R; Abellan Beteta, C; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; Anderlini, L; Anderson, J; Andreassen, R; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Baesso, C; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bauer, Th; Bay, A; Beddow, J; Bedeschi, F; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Benayoun, M; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M -O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bowen, E; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Burducea, I; Bursche, A; Busetto, G; Buytaert, J; Cadeddu, S; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carranza-Mejia, H; Carson, L; Carvalho Akiba, K; Casse, G; Cattaneo, M; Cauet, Ch; Charles, M; Charpentier, Ph; Chen, P; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coca, C; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Couturier, B; Cowan, G A; Craik, D; Cunliffe, S; Currie, R; D'Ambrosio, C; David, P; David, P N Y; De Bonis, I; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Oyanguren Campos, M; De Paula, L; De Silva, W; De Simone, P; Decamp, D; Deckenhoff, M; Del Buono, L; Derkach, D; Deschamps, O; Dettori, F; Di Canto, A; Dijkstra, H; Dogaru, M; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Elsby, D; Falabella, A; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Ferguson, D; Fernandez Albor, V; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Furcas, S; Furfaro, E; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garofoli, J; Garosi, P; Garra Tico, J; Garrido, L; Gaspar, C; Gauld, R; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hampson, T; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hartmann, T; He, J; Heijne, V; Hennessy, K; Henrard, P; Hernando Morata, J A; van Herwijnen, E; Hicks, E; Hill, D; Hoballah, M; Hombach, C; Hopchev, P; Hulsbergen, W; Hunt, P; Huse, T; Hussain, N; Hutchcroft, D; Hynds, D; Iakovenko, V; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jans, E; Jaton, P; Jing, F; John, M; Johnson, D; Jones, C R; Jost, B; Kaballo, M; Kandybei, S; Karacson, M; Karbach, T M; Kenyon, I R; Kerzel, U; Ketel, T; Keune, A; Khanji, B; Kochebina, O; Komarov, I; Koopman, R F; Koppenburg, P; Korolev, M; Kozlinskiy, A; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Kucharczyk, M; Kudryavtsev, V; Kvaratskheliya, T; La Thi, V N; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lambert, R W; Lanciotti, E; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J -P; Lefèvre, R; Leflat, A; Lefrançois, J; Leo, S; Leroy, O; Leverington, B; Li, Y; Li Gioi, L; Liles, M; Lindner, R; Linn, C; Liu, B; Liu, G; von Loeben, J; Lohn, S; Lopes, J H; Lopez Asamar, E; Lopez-March, N; Lu, H; Lucchesi, D; Luisier, J; Luo, H; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Malde, S; Manca, G; Mancinelli, G; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martin, L; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Maurice, E; Mazurov, A; McCarthy, J; McNulty, R; Mcnab, A; Meadows, B; Meier, F; Meissner, M; Merk, M; Milanes, D A; Minard, M -N; Molina Rodriguez, J; Monteil, S; Moran, D; Morawski, P; Morello, M J; Mountain, R; Mous, I; Muheim, F; Müller, K; Muresan, R; Muryn, B; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neufeld, N; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nicol, M; Niess, V; Niet, R; Nikitin, N; Nikodem, T; Nomerotski, A; Novoselov, A; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Otalora Goicochea, J M; Owen, P; Pal, B K; Palano, A; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrick, G N; Patrignani, C; Pavel-Nicorescu, C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Perez Trigo, E; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pessina, G; Petridis, K; Petrolini, A; Phan, A; Picatoste Olloqui, E; Pietrzyk, B; Pilař, T; Pinci, D; Playfer, S; Plo Casasus, M; Polci, F; Polok, G; Poluektov, A; Polycarpo, E; Popov, D; Popovici, B; Potterat, C; Powell, A; Prisciandaro, J; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Ricciardi, S; Richards, A; Rinnert, K; Rives Molina, V; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodriguez Perez, P; Roiser, S; Romanovsky, V; Romero Vidal, A; Rouvinet, J; Ruf, T; Ruffini, F; Ruiz, H; Ruiz Valls, P; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salzmann, C; Sanmartin Sedes, B; Sannino, M; Santacesaria, R; Santamarina Rios, C; Santovetti, E; Sapunov, M; Sarti, A; Satriano, C; Satta, A; Savrie, M; Savrina, D; Schaack, P; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M -H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Senderowska, K; Sepp, I; Serra, N; Serrano, J; Seyfert, P; Shapkin, M; Shapoval, I; Shatalov, P; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, O; Shevchenko, V; Shires, A; Silva Coutinho, R; Skwarnicki, T; Smith, N A; Smith, E; Smith, M; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Stagni, F; Stahl, S; Steinkamp, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Subbiah, V K; Swientek, S; Syropoulos, V; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teklishyn, M; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tresch, M; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Urner, D; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vilasis-Cardona, X; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; Waldi, R; Wallace, R; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Webber, A D; Websdale, D; Whitehead, M; Wicht, J; Wiechczynski, J; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, F; Xing, Z; Yang, Z; Young, R; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L; Zvyagin, A
2013-05-31
The quantum numbers of the X(3872) meson are determined to be J(PC)=1(++) based on angular correlations in B(+)→X(3872)K(+) decays, where X(3872)→π(+)π(-)J/ψ and J/ψ→μ(+)μ(-). The data correspond to 1.0 fb(-1) of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements J(PC)=2(-+) is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) state. PMID:23767712
Evidence for Simultaneous Production of J /ψ and ϒ Mesons
NASA Astrophysics Data System (ADS)
Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; Atkins, S.; Augsten, K.; Aushev, V.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Borysova, M.; Brandt, A.; Brandt, O.; Brock, R.; Bross, A.; Brown, D.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Pérez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Cuth, J.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Fauré, A.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Franc, J.; Fuess, S.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Gogota, O.; Golovanov, G.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jayasinghe, A.; Jeong, M. S.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kajfasz, E.; Karmanov, D.; Katsanos, I.; Kaur, M.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kumar, A.; Kupco, A.; Kurča, T.; Kuzmin, V. A.; Lammers, S.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaña-Villalba, R.; Malik, S.; Malyshev, V. L.; Mansour, J.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nguyen, H. T.; Nunnemann, T.; Orduna, J.; Osman, N.; Osta, J.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Pleier, M.-A.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Ratoff, P. N.; Razumov, I.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santos, A. S.; Savage, G.; Savitskyi, M.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schott, M.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Simak, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stoyanova, D. A.; Strauss, M.; Suter, L.; Svoisky, P.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verkheev, A. Y.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yang, S.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yin, H.; Yip, K.; Youn, S. W.; Yu, J. M.; Zennamo, J.; Zhao, T. G.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.; D0 Collaboration
2016-02-01
We report evidence for the simultaneous production of J /ψ and ϒ mesons in 8.1 fb-1 of data collected at √{s }=1.96 TeV by the D0 experiment at the Fermilab p p ¯ Tevatron Collider. Events with these characteristics are expected to be produced predominantly by gluon-gluon interactions. In this analysis, we extract the effective cross section characterizing the initial parton spatial distribution, σeff=2.2 ±0.7 (stat ) ±0.9 (syst ) mb .
Search for narrow resonances lighter than Upsilon mesons
Aaltonen, T.; Adelman, Jahred A.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, Dante E.; Anastassov, A.; Annovi, Alberto; Antos, Jaroslav; Apollinari, G.; Apresyan, A.; /Purdue U. /Waseda U.
2009-03-01
We report a search for narrow resonances, produced in p{bar p} collisions at {radical}s = 1.96 TeV, that decay into muon pairs with invariant mass between 6.3 and 9.0 GeV/c{sup 2}. The data, collected with the CDF II detector at the Fermilab Tevatron collider, correspond to an integrated luminosity of 630 pb{sup -1}. We use the dimuon invariant mass distribution to set 90% upper credible limits of about 1% to the ratio of the production cross section times muonic branching fraction of possible narrow resonances to that of the {Upsilon}(1S) meson.
Warm stellar matter within the quark-meson-coupling model
Panda, P. K.; Providencia, C.; Menezes, D. P.
2010-10-15
In the present article, we investigate stellar matter obtained within the quark-meson-coupling (QMC) model for fixed temperature and with the entropy of the order of 1 or 2 Boltzmann units per baryon for neutrino-free matter and matter with trapped neutrinos. A new prescription for the calculation of the baryon effective masses in terms of the free energy is used. Comparing the results of the present work with those obtained from the nonlinear Walecka model, smaller strangeness and neutrino fractions are predicted within QMC. As a consequence, QMC has a smaller window of metastability for conversion into a low-mass blackhole during cooling.
Measurement of orbitally excited D-mesons at CDF II
Gorelov, Igor V.; /New Mexico U.
2004-12-01
Results of the first measurement of {sup 3}P orbitally excited neutral D-meson states, D*{sub 2}{sup 0} and D{sub 1}{sup 0}, produced in hadron collisions at the Tevatron are presented. Using data from the displaced track trigger, CDF II collects a large sample of these states in decay modes D*{sup +} {pi}{sup -}, D{sup +} {pi}{sup -}. Masses and widths of both states have been measured with precision better than or comparable to that of the world average.
Analytic Bethe-Salpeter description of the lightest pseudoscalar mesons
NASA Astrophysics Data System (ADS)
Lucha, Wolfgang; Schöberl, Franz F.
2016-03-01
Within the Bethe-Salpeter formalism for instantaneous interactions, we describe, along a totally analytic route, the lightest pseudoscalar mesons by quark-antiquark bound states which show at least three indispensable general features—namely, the (almost) masslessness required for pions and kaons to be interpretable as (pseudo-)Goldstone bosons, the suitable asymptotic behavior in the limit of large spacelike relative momenta as determined by the relationship between quark mass function and Bethe-Salpeter amplitudes, and a pointwise behavior for finite spacelike relative momenta suited for guaranteeing color confinement.
Meson transition form factors in light-front holographic QCD
Brodsky, Stanley J.; Cao Fuguang; de Teramond, Guy F.
2011-10-01
We study the photon-to-meson transition form factors (TFFs) F{sub M}{gamma}(Q{sup 2}) for {gamma}{gamma}{sup *}{yields}M using light-front holographic methods. The Chern-Simons action, which is a natural form in five-dimensional anti-de Sitter (AdS) space, is required to describe the anomalous coupling of mesons to photons using holographic methods and leads directly to an expression for the photon-to-pion TFF for a class of confining models. Remarkably, the predicted pion TFF is identical to the leading order QCD result where the distribution amplitude has asymptotic form. The Chern-Simons form is local in AdS space and is thus somewhat limited in its predictability. It only retains the qq component of the pion wave function, and further, it projects out only the asymptotic form of the meson distribution amplitude. It is found that in order to describe simultaneously the decay process {pi}{sup 0}{yields}{gamma}{gamma} and the pion TFF at the asymptotic limit, a probability for the qq component of the pion wave function P{sub qq}=0.5 is required, thus giving indication that the contributions from higher Fock states in the pion light-front wave function need to be included in the analysis. The probability for the Fock state containing four quarks P{sub qqqq}{approx}10%, which follows from analyzing the hadron matrix elements for a dressed current model, agrees with the analysis of the pion elastic form factor using light-front holography including higher Fock components in the pion wave function. The results for the TFFs for the {eta} and {eta}{sup '} mesons are also presented. The rapid growth of the pion TFF exhibited by the BABAR data at high Q{sup 2} is not compatible with the models discussed in this article, whereas the theoretical calculations are in agreement with the experimental data for the {eta} and {eta}{sup '} TFFs.
Search for B Meson Decays to eta' eta' K
Aubert, B.
2006-05-05
The authors describe searches for decays of B mesons to the charmless final states {eta}'{eta}'K. The data consist of 228 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation, collected with the BABAR detector at the Stanford Linear Accelerator Center. The 90% confidence level upper limits for the branching fractions are {Beta}(B{sup 0} {yields} {eta}'{eta}'K{sup 0}) < 31 x 10{sup -6} and {Beta}(B{sup +} {yields} {eta}'{eta}'K{sup +}) < 25 x 10{sup -6}.
Determination of the X(3872) meson quantum numbers.
Aaij, R; Abellan Beteta, C; Adeva, B; Adinolfi, M; Adrover, C; Affolder, A; Ajaltouni, Z; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; Anderlini, L; Anderson, J; Andreassen, R; Appleby, R B; Aquines Gutierrez, O; Archilli, F; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Bachmann, S; Back, J J; Baesso, C; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Bauer, Th; Bay, A; Beddow, J; Bedeschi, F; Bediaga, I; Belogurov, S; Belous, K; Belyaev, I; Ben-Haim, E; Benayoun, M; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bettler, M -O; van Beuzekom, M; Bien, A; Bifani, S; Bird, T; Bizzeti, A; Bjørnstad, P M; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borgia, A; Bowcock, T J V; Bowen, E; Bozzi, C; Brambach, T; van den Brand, J; Bressieux, J; Brett, D; Britsch, M; Britton, T; Brook, N H; Brown, H; Burducea, I; Bursche, A; Busetto, G; Buytaert, J; Cadeddu, S; Callot, O; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carranza-Mejia, H; Carson, L; Carvalho Akiba, K; Casse, G; Cattaneo, M; Cauet, Ch; Charles, M; Charpentier, Ph; Chen, P; Chiapolini, N; Chrzaszcz, M; Ciba, K; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coca, C; Coco, V; Cogan, J; Cogneras, E; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Couturier, B; Cowan, G A; Craik, D; Cunliffe, S; Currie, R; D'Ambrosio, C; David, P; David, P N Y; De Bonis, I; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Oyanguren Campos, M; De Paula, L; De Silva, W; De Simone, P; Decamp, D; Deckenhoff, M; Del Buono, L; Derkach, D; Deschamps, O; Dettori, F; Di Canto, A; Dijkstra, H; Dogaru, M; Donleavy, S; Dordei, F; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dupertuis, F; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; van Eijk, D; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Elsby, D; Falabella, A; Färber, C; Fardell, G; Farinelli, C; Farry, S; Fave, V; Ferguson, D; Fernandez Albor, V; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fitzpatrick, C; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Furcas, S; Furfaro, E; Gallas Torreira, A; Galli, D; Gandelman, M; Gandini, P; Gao, Y; Garofoli, J; Garosi, P; Garra Tico, J; Garrido, L; Gaspar, C; Gauld, R; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gibson, V; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gordon, H; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hampson, T; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hartmann, T; He, J; Heijne, V; Hennessy, K; 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Lu, H; Lucchesi, D; Luisier, J; Luo, H; Machefert, F; Machikhiliyan, I V; Maciuc, F; Maev, O; Malde, S; Manca, G; Mancinelli, G; Marconi, U; Märki, R; Marks, J; Martellotti, G; Martens, A; Martin, L; Martín Sánchez, A; Martinelli, M; Martinez Santos, D; Martins Tostes, D; Massafferri, A; Matev, R; Mathe, Z; Matteuzzi, C; Maurice, E; Mazurov, A; McCarthy, J; McNulty, R; Mcnab, A; Meadows, B; Meier, F; Meissner, M; Merk, M; Milanes, D A; Minard, M -N; Molina Rodriguez, J; Monteil, S; Moran, D; Morawski, P; Morello, M J; Mountain, R; Mous, I; Muheim, F; Müller, K; Muresan, R; Muryn, B; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nasteva, I; Needham, M; Neufeld, N; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Nicol, M; Niess, V; Niet, R; Nikitin, N; Nikodem, T; Nomerotski, A; Novoselov, A; Oblakowska-Mucha, A; Obraztsov, V; Oggero, S; Ogilvy, S; Okhrimenko, O; Oldeman, R; Orlandea, M; Otalora Goicochea, J M; Owen, P; Pal, B K; Palano, A; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Parkes, C; Parkinson, C J; Passaleva, G; Patel, G D; Patel, M; Patrick, G N; Patrignani, C; Pavel-Nicorescu, C; Pazos Alvarez, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perego, D L; Perez Trigo, E; Pérez-Calero Yzquierdo, A; Perret, P; Perrin-Terrin, M; Pessina, G; Petridis, K; Petrolini, A; Phan, A; Picatoste Olloqui, E; Pietrzyk, B; Pilař, T; Pinci, D; Playfer, S; Plo Casasus, M; Polci, F; Polok, G; Poluektov, A; Polycarpo, E; Popov, D; Popovici, B; Potterat, C; Powell, A; Prisciandaro, J; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Rademacker, J H; Rakotomiaramanana, B; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Redford, S; Reid, M M; dos Reis, A C; Ricciardi, S; Richards, A; Rinnert, K; Rives Molina, V; Roa Romero, D A; Robbe, P; Rodrigues, E; Rodriguez Perez, P; Roiser, S; Romanovsky, V; Romero Vidal, A; Rouvinet, J; Ruf, T; Ruffini, F; Ruiz, H; Ruiz Valls, P; Sabatino, G; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salzmann, C; Sanmartin Sedes, B; Sannino, M; Santacesaria, R; Santamarina Rios, C; Santovetti, E; Sapunov, M; Sarti, A; Satriano, C; Satta, A; Savrie, M; Savrina, D; Schaack, P; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmidt, B; Schneider, O; Schopper, A; Schune, M -H; Schwemmer, R; Sciascia, B; Sciubba, A; Seco, M; Semennikov, A; Senderowska, K; Sepp, I; Serra, N; Serrano, J; Seyfert, P; Shapkin, M; Shapoval, I; Shatalov, P; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, O; Shevchenko, V; Shires, A; Silva Coutinho, R; Skwarnicki, T; Smith, N A; Smith, E; Smith, M; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Sparkes, A; Spradlin, P; Stagni, F; Stahl, S; Steinkamp, O; Stoica, S; Stone, S; Storaci, B; Straticiuc, M; Straumann, U; Subbiah, V K; Swientek, S; Syropoulos, V; Szczekowski, M; Szczypka, P; Szumlak, T; T'Jampens, S; Teklishyn, M; Teodorescu, E; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Tolk, S; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Tran, M T; Tresch, M; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ubeda Garcia, M; Ukleja, A; Urner, D; Uwer, U; Vagnoni, V; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vilasis-Cardona, X; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; Voss, H; Waldi, R; Wallace, R; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Webber, A D; Websdale, D; Whitehead, M; Wicht, J; Wiechczynski, J; Wiedner, D; Wiggers, L; Wilkinson, G; Williams, M P; Williams, M; Wilson, F F; Wishahi, J; Witek, M; Wotton, S A; Wright, S; Wu, S; Wyllie, K; Xie, Y; Xing, F; Xing, Z; Yang, Z; Young, R; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, F; Zhang, L; Zhang, W C; Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L; Zvyagin, A
2013-05-31
The quantum numbers of the X(3872) meson are determined to be J(PC)=1(++) based on angular correlations in B(+)→X(3872)K(+) decays, where X(3872)→π(+)π(-)J/ψ and J/ψ→μ(+)μ(-). The data correspond to 1.0 fb(-1) of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements J(PC)=2(-+) is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) state.
Exclusive vector meson production at HERA from QCD with saturation
Marquet, C.; Peschanski, R.; Soyez, G.
2007-08-01
Following recent predictions that the geometric scaling properties of deep inelastic scattering data in inclusive {gamma}*p collisions are expected also in exclusive diffractive processes, we investigate the diffractive production of vector mesons. Using analytic results in the framework of the Balitsky-Kovchegov (BK) equation at nonzero momentum transfer, we extend to the nonforward amplitude a QCD-inspired forward saturation model including charm, following the theoretical predictions for the momentum transfer dependence of the saturation scale. We obtain a good fit to the available HERA data and make predictions for deeply virtual Compton scattering measurements.
Beam Spin Asymmetry Measurements from Deeply Virtual Meson Production
Joo, K.; Ungaro, M.; Zhao, B.; De Masi, R.; Garcon, M.; Kubarovsky, V.; Stoler, P.
2007-06-13
Study of deeply virtual exclusive meson production (DVMP), is being conducted in the E1-DVCS experiment with the CLAS detector at Jefferson Lab. The main motivation of the experiment is to characterize the partonic properties of the nucleon in the framework of generalized parton distributions (GPDs). The data were taken in the spring of 2005 using a 5.7 GeV longitudinally polarized electron beam and an unpolarized hydrogen target. We report on the on-going beam spin asymmetry analysis for pseudo-scalar channels and future experiments.
Beam Spin Asymmetry Measurements from Deeply Virtual Meson Production
K. Joo; R. De Masi; M. Garcon; V. Kubarovsky; P. Stoler; M. Ungaro; B. Zhao
2007-06-01
Study of deeply virtual exclusive meson production (DVMP), is being conducted in the E1-DVCS experiment with the CLAS detector at Jefferson Lab. The main motivation of the experiment is to characterize the partonic properties of the nucleon in the framework of generalized parton distributions (GPDs). The data were taken in the spring of 2005 using a 5.7 GeV longitudinally polarized electron beam and an unpolarized hydrogen target. We report on the on-going beam spin asymmetry analysis for pseudo-scalar channels and future experiments.
Warm stellar matter within the quark-meson-coupling model
NASA Astrophysics Data System (ADS)
Panda, P. K.; Providência, C.; Menezes, D. P.
2010-10-01
In the present article, we investigate stellar matter obtained within the quark-meson-coupling (QMC) model for fixed temperature and with the entropy of the order of 1 or 2 Boltzmann units per baryon for neutrino-free matter and matter with trapped neutrinos. A new prescription for the calculation of the baryon effective masses in terms of the free energy is used. Comparing the results of the present work with those obtained from the nonlinear Walecka model, smaller strangeness and neutrino fractions are predicted within QMC. As a consequence, QMC has a smaller window of metastability for conversion into a low-mass blackhole during cooling.
Soft and Hard Scale QCD Dynamics in Mesons
NASA Astrophysics Data System (ADS)
Nguyen, T.; Souchlas, N. A.; Tandy, P. C.
2011-09-01
Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.
Non-perturbative QCD Modeling and Meson Physics
NASA Astrophysics Data System (ADS)
Nguyen, T.; Souchlas, N. A.; Tandy, P. C.
2009-04-01
Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a heavy quark dressed propagator for such states. The difference between vector and axial vector current correlators is explored within the same model to provide an estimate of the four quark chiral condensate and the leading distance scale for the onset of non-perturbative phenomena in QCD.
Tensor meson production in proton-proton collisions from the color glass condensate
Fillion-Gourdeau, Francois; Jeon, Sangyong
2008-05-15
We compute the inclusive cross section of f{sub 2} tensor-meson production in proton-proton collisions at high energy. We use an effective theory inspired from the tensor-meson dominance hypothesis that couples gluons to f{sub 2} mesons. We compute the differential cross section in the k{sub perpendicular} factorization and in the color glass condensate formalism in the low density regime. We show that the two formalisms are equivalent for this specific observable. Finally, we study the phenomenology of f{sub 2} mesons by comparing theoretical predictions of different parametrizations of the unintegrated gluon distribution function. We find that f{sub 2}-meson production is another observable that can be used to put constraints on these distributions.
A Measurement of the Semileptonic Branching Fraction of the B_s Meson
Lees, J.P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D.A.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Koch, H.; Schroeder, T.; Asgeirsson, D.J.; Hearty, C.; Mattison, T.S.; McKenna, J.A.; /more authors..
2012-06-12
We report a measurement of the inclusive semileptonic branching fraction of the B{sub s} meson using data collected with the BABAR detector in the center-of-mass energy region above the {gamma}(4S) resonance. We use the inclusive yield of {phi} mesons and the {phi} yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of B{sub s} mesons relative to all B mesons as a function of center-of-mass energy. The inclusive semileptonic branching fraction of the B{sub s} meson is determined to be {Beta}(B{sub s} {yields} {ell}{nu}X) = 9.5{sub -2.0}{sup +2.5}(stat){sub -1.9}{sup +1.1}(syst)%, where {ell} indicates the average of e and {mu}.
Counting of oscillatory modes of valence quarks forming q-q¯ mesons
NASA Astrophysics Data System (ADS)
Kabana, Sonia; Minkowski, Peter
2016-03-01
We present the unique properties of oscillatory modes of valence quarks (u,d,s) and antiquarks in mesons and the mass spectrum of associated mesons. The mesonic multiplets are shown to emerge from the picture of oscillating quarks and antiquarks in three space dimensions in the center of mass system of the mesons. All oscillatory modes are fully relativistic with a finite number of oscillators and this is forming the unique harmonic oscillator with these properties. The density of states as a function of masssquare is calculated. Since it is known that there are missing states of unobserved hadrons this estimate is of relevance for the accounting of the latter, as the here estimated mesonic multiplets include both the observed and the unobserved (or “missing”) hadrons. The estimate is conceptually different from Hagedorn’s model and is based on field theory of QCD.
The effect of meson wave function on heavy-quark fragmentation function
NASA Astrophysics Data System (ADS)
Moosavi Nejad, S. Mohammad
2016-05-01
We calculate the process-independent fragmentation functions (FFs) for a heavy quark to fragment into heavy mesons considering the effects of meson wave function. In all previous works, where the FFs of heavy mesons or heavy baryons were calculated, a delta function form was approximated for the wave function of hadrons. Here, for the first time, we consider a typical mesonic wave function which is different from the delta function and is the nonrelativistic limit of the solution of Bethe-Salpeter equation with the QCD kernel. We shall present our numerical results for the heavy FFs and show how the proposed wave function improves the previous results. As an example, we focus on the fragmentation function for c -quark to split into S -wave D^0 -meson and compare our results with experimental data from BELLE and CLEO.
Production of the φ mesons at intermediate rapidity in Au+Au collisions at √sNN = 200 GeV
NASA Astrophysics Data System (ADS)
Pal, Dipali
2007-10-01
Study of the φ mesons produced in relativistic heavy-ion collisions can unfold properties of the hot and dense quark gluon matter produced in these reactions. Since the φ is a bound state of s and s quarks it is not subject to the canonical suppression of strangeness in p+p interactions and thus serves as a clean probe of strangeness enhancement in Au+Au collisions. The measurement of the φ-meson spectra, yield, and temperature parameter gives information on strangeness enhancement and the bulk properties of the partonic matter. The BRAHMS experiment at RHIC has measured particles produced in high luminosity Au+Au collisions at √sNN = 200 GeV over a broad range of rapidity and pT. Using the efficient tracking system and high resolution time of flight wall of the mid-rapidity spectrometer (MRS), we have measured the φ mesons in the K^+K^- decay channel at y ˜ 1. The first results of the φ -> K^+K^- measurements with focus on spectra and yield analysis will be presented.
Hyperon stars in a modified quark meson coupling model
NASA Astrophysics Data System (ADS)
Mishra, R. N.; Sahoo, H. S.; Panda, P. K.; Barik, N.; Frederico, T.
2016-09-01
We determine the equation of state (EOS) of nuclear matter with the inclusion of hyperons in a self-consistent manner by using a modified quark meson coupling model where the confining interaction for quarks inside a baryon is represented by a phenomenological average potential in an equally mixed scalar-vector harmonic form. The hadron-hadron interaction in nuclear matter is then realized by introducing additional quark couplings to σ ,ω , and ρ mesons through mean-field approximations. The effect of a nonlinear ω -ρ term on the EOS is studied. The hyperon couplings are fixed from the optical potential values and the mass-radius curve is determined satisfying the maximum mass constraint of 2 M⊙ for neutron stars, as determined in recent measurements of the pulsar PSR J0348+0432. We also observe that there is no significant advantage of introducing the nonlinear ω -ρ term in the context of obtaining the star mass constraint in the present set of parametrizations.
Realizing vector meson dominance with transverse charge densities
Gerald Miller, Mark Strikman, Christian Weiss
2011-10-01
The transverse charge density in a fast-moving nucleon is represented as a dispersion integral of the imaginary part of the Dirac form factor in the timelike region (spectral function). At a given transverse distance b the integration effectively extends over energies in a range {radical}t {approx}< 1/b, with exponential suppression of larger values. The transverse charge density at peripheral distances thus acts as a low-pass filter for the spectral function and allows one to select energy regions dominated by specific t-channel states, corresponding to definite exchange mechanisms in the spacelike form factor. We show that distances b {approx} 0.5 - 1.5 fm in the isovector density are maximally sensitive to the {rho} meson region, with only a {approx}10% contribution from higher-mass states. Soft-pion exchange governed by chiral dynamics becomes relevant only at larger distances. In the isoscalar density higher-mass states beyond the {omega} are comparatively more important. The dispersion approach suggests that the positive transverse charge density in the neutron at b {approx} 1 fm, found previously in a Fourier analysis of spacelike form factor data, could serve as a sensitive test of the isoscalar strength in the {approx}1 GeV mass region. In terms of partonic structure, the transverse densities in the vector meson region b {approx} 1 fm support an approximate mean-field picture of the motion of valence quarks in the nucleon.
Hadronic decays of the D/sub s/ meson
Wasserbaech, S.R.
1989-06-01
The D/sub s//sup +/ is the lowest-lying pseudoscalar meson containing charm and anti-strange quarks. Evidence for this state was first reported in 1977, although more recent observations disagree with some of the early results. Since 1983 the weakly decaying D/sub s//sup +/ has been observed in many experiments. Relative branching fractions have been measured for many non-leptonic decay modes, including D/sub s//sup +/ /yields/ /phi//pi//sup +/, /phi//pi//sup +//pi//sup +//pi//sup /minus//, /bar K/*/sup 0/K/sup +/, and f/sub 0/(975)/pi//sup +/. The absolute branching fractions are estimated in high energy e/sup +/e/sup /minus// annihilation from the observed numbers of reconstructed D/sub s//sup +/ decays and the expected D/sub s//sup +/ production cross section. The lowest-lying vector c/bar s/ meson, the D/sub s/*/sup +/, has also been seen in its decay to /gamma/D/sub s//sup +/. Weak decays of the heavy quark and lepton flavors are relevant to the development of the Standard Model of both the electroweak and the strong interactions. Measurements of charmed particle weak decay are useful for determining the parameter of the Standard Model and for testing phenomenological models which include strong effects. 83 refs., 56 figs., 12 tabs.
Multisolitons with vector mesons on the two-sphere
NASA Astrophysics Data System (ADS)
Carrasco, F. L.; Reula, Oscar A.
2014-08-01
Recent studies have suggested a strong connection between the static solutions of the 3D Skyrme model and those corresponding to its low-dimensional analog (baby-Skyrme model) on a two-sphere. We have found almost identical solutions considering an alternative two-dimensional model in which a vector meson field is introduced and coupled to the system, instead of the usual Skyrme term. It has been known that including this vector meson field in three dimensions stabilizes the nonlinear sigma model without the need for a term that is quartic on derivatives of the pion fields (Skyrme term). The resulting model has proven to share many of the features that the usual Skyrme theory has, but with a better mathematical formulation in terms of the well posedness of its evolution equations. In the present work, we have numerically searched for static multisolitonic solutions of this alternative stabilization, for the case in which the base space is a two-sphere. Moreover, we analyze the stability of these solutions under small perturbations in a fully dynamical setting. We have also considered the inclusion of a particular potential term in the Lagrangian and explored the low- and high-density phases of solitons for different ranges of the parameter space, achieving solitons localized enough, which allows for a comparison with planar (two-dimensional) studies.
Improved Measurement of Inclusive Radiative B-meson decays
Schuemann, J.; Limosani, A.
2008-11-23
We report a fully inclusive measurement of the flavor changing neutral current decay B{yields}X{sub s{gamma}} in the energy range 1.7 GeV{<=}E{sub {gamma}}{sup c.m.s}{<=}2.8 GeV, covering 97% of the total spectrum, where c.m.s is the center of mass system. Using 605 fb{sup -1} of data, we obtain in the rest frame of the B-meson B(B{yields}X{sub s{gamma}}:E{sub {gamma}}{sup B}>1.7 GeV) = (3.31{+-}0.19{+-}0.37{+-}0.01)x10{sup -4}, where the errors are statistical, systematic and from the boost correction needed to transform from the rest frame of the {upsilon}(4S)(c.m.s) to that of the B-meson, respectively. We also measure the first and second moments of the photon energy spectrum as functions of various energy thresholds, which extend down to 1.7 GeV. The results are preliminary.
Spin-orbit inversion of excited heavy quark mesons
Nathan Isgur
1997-06-01
The mesonic heavy quark spin multiplets with s{sub l}{sup {pi}{sub l}}=(1/2){sup +} and (3/2){sup +} are expected to be the lowest-lying excitations about the pseudoscalar and vector ground states with s{sub l}{sup {pi}{sub l}}=(1/2){sup {minus}}. The author shows that for charm and bottom these multiplets are probably inverted, with the 2{sup +} and 1{sup +} states with s{sub l}{sup {pi}{sup l}}=(3/2){sup +} about 150 MeV below the 1{sup +} and 0{sup +} states with s{sub l}{sup {pi}{sub l}}=(1/2){sup +}. If verified, such an inversion would both support the expectation that confinement has no dynamical spin-dependence and indicate that heavy and light quark systems may be characterized by the same effective low-energy degrees of freedom. As an important byproduct, this work establishes the dynamics of the strange quark as a critical link between heavy- and light-quark hadrons, justifying efforts toward a much more complete experimental and theoretical understanding of strange mesons and baryons and of strangeonia.
Lepton flavor violating B meson decays via a scalar leptoquark
NASA Astrophysics Data System (ADS)
Sahoo, Suchismita; Mohanta, Rukmani
2016-06-01
We study the effect of scalar leptoquarks in the lepton flavor violating B meson decays induced by the flavor-changing transitions b →q li+lj- with q =s , d . In the standard model, these transitions are extremely rare as they are either two-loop suppressed or proceed via box diagrams with tiny neutrino masses in the loop. However, in the leptoquark model, they can occur at tree level and are expected to have significantly large branching ratios. The leptoquark parameter space is constrained using the experimental limits on the branching ratios of Bq→l+l- processes. Using such constrained parameter space, we predict the branching ratios of LFV semileptonic B meson decays, such as B+→K+(π+)li+lj-, B+→(K*+,ρ+)li+lj-, and Bs→ϕ li+lj-, which are found to be within the experimental reach of LHCb and the upcoming Belle II experiments. We also investigate the rare leptonic KL ,S→μ+μ-(e+e-) and KL→μ∓e± decays in the leptoquark model.
Exploring a new S U (4 ) symmetry of meson interpolators
NASA Astrophysics Data System (ADS)
Glozman, L. Ya.; Pak, M.
2015-07-01
In recent lattice calculations it has been discovered that mesons upon truncation of the quasizero modes of the Dirac operator obey a symmetry larger than the S U (2 )L×S U (2 )R×U (1 )A symmetry of the QCD Lagrangian. This symmetry has been suggested to be S U (4 )⊃S U (2 )L×S U (2 )R×U (1 )A that mixes not only the u- and d-quarks of a given chirality, but also the left- and right-handed components. Here it is demonstrated that bilinear q ¯q interpolating fields of a given spin J ≥1 transform into each other according to irreducible representations of S U (4 ) or, in general, S U (2 NF). This fact together with the coincidence of the correlation functions establishes S U (4 ) as a symmetry of the J ≥1 mesons upon quasizero mode reduction. It is shown that this symmetry is a symmetry of the confining instantaneous charge-charge interaction in QCD. Different subgroups of S U (4 ) as well as the S U (4 ) algebra are explored.
Charmless three-body decays of B mesons
Cheng, H.-Y.; Chua, C.-K.; Soni, Amarjit
2007-11-01
An exploratory study of charmless 3-body decays of B mesons is presented using a simple model based on the framework of the factorization approach. The nonresonant contributions arising from B{yields}P{sub 1}P{sub 2} transitions are evaluated using heavy meson chiral perturbation theory (HMChPT). The momentum dependence of nonresonant amplitudes is assumed to be in the exponential form e{sup -{alpha}{sub N}{sub R}}{sup p{sub B}{center_dot}}{sup (p{sub i}+p{sub j})} so that the HMChPT results are recovered in the soft meson limit p{sub i},p{sub j}{yields}0. In addition, we have identified another large source of the nonresonant signal in the matrix elements of scalar densities, e.g.
Charmless three-body decays of B mesons
NASA Astrophysics Data System (ADS)
Cheng, Hai-Yang; Chua, Chun-Khiang; Soni, Amarjit
2007-11-01
An exploratory study of charmless 3-body decays of B mesons is presented using a simple model based on the framework of the factorization approach. The nonresonant contributions arising from B→P1P2 transitions are evaluated using heavy meson chiral perturbation theory (HMChPT). The momentum dependence of nonresonant amplitudes is assumed to be in the exponential form e-αNRpB·(pi+pj) so that the HMChPT results are recovered in the soft meson limit pi,pj→0. In addition, we have identified another large source of the nonresonant signal in the matrix elements of scalar densities, e.g. ⟨KK¯|s¯s|0⟩, which can be constrained from the decay B¯0→KSKSKS or B-→K-KSKS. The intermediate vector-meson contributions to 3-body decays are identified through the vector current, while the scalar meson resonances are mainly associated with the scalar density. Their effects are described in terms of the Breit-Wigner formalism. Our main results are: (i) All KKK modes are dominated by the nonresonant background. The predicted branching ratios of K+K-KS(L), K+K-K- and K-KSKS modes are consistent with the data within errors. (ii) Although the penguin-dominated B0→K+K-KS decay is subject to a potentially significant tree pollution, its effective sin2β is very similar to that of the KSKSKS mode. However, direct CP asymmetry of the former, being of order -4%, is more prominent than the latter. (iii) For B→Kππ decays, we found sizable nonresonant contributions in K-π+π- and K¯0π+π- modes, in agreement with the Belle measurements but larger than the BABAR result. (iv) Time-dependent CP asymmetries in KSπ0π0, a purely CP-even state, and KSπ+π-, an admixture of CP-even and CP-odd components, are studied. (v) The π+π-π0 mode is found to have a rate larger than π+π-π- even though the former involves a π0 in the final state. They are both dominated by resonant ρ contributions. (vi) We have computed the resonant contributions to 3-body decays and determined
Charmless hadronic B decays into a tensor meson
Cheng, Hai-Yang; Yang, Kwei-Chou
2011-02-01
Two-body charmless hadronic B decays involving a tensor meson in the final state are studied within the framework of QCD factorization (QCDF). Because of the G-parity of the tensor meson, both the chiral-even and chiral-odd two-parton light-cone distribution amplitudes of the tensor meson are antisymmetric under the interchange of momentum fractions of the quark and antiquark in the SU(3) limit. Our main results are: (i) In the naieve factorization approach, the decays such as B{sup -}{yields}K{sub 2}*{sup 0}{pi}{sup -} and B{sup 0}{yields}K{sub 2}*{sup -}{pi}{sup +} with a tensor meson emitted are prohibited because a tensor meson cannot be created from the local V-A or tensor current. Nevertheless, the decays receive nonfactorizable contributions in QCDF from vertex, penguin and hard spectator corrections. The experimental observation of B{sup -}{yields}K{sub 2}*{sup 0}{pi}{sup -} indicates the importance of nonfactorizable effects. (ii) For penguin-dominated B{yields}TP and TV decays, the predicted rates in naieve factorization are usually too small by 1 to 2 orders of magnitude. In QCDF, they are enhanced by power corrections from penguin annihilation and nonfactorizable contributions. (iii) The dominant penguin contributions to B{yields}K{sub 2}*{eta}{sup (')} arise from the processes: (a) b{yields}sss{yields}s{eta}{sub s} and (b) b{yields}sqq{yields}qK{sub 2}* with {eta}{sub q}=(uu+dd)/{radical}(2) and {eta}{sub s}=ss. The interference, constructive for K{sub 2}*{eta}{sup '} and destructive for K{sub 2}*{eta}, explains why {Gamma}(B{yields}K{sub 2}*{eta}{sup '})>>{Gamma}(B{yields}K{sub 2}*{eta}). (iv) We use the measured rates of B{yields}K{sub 2}*({omega},{phi}) to extract the penguin-annihilation parameters {rho}{sub A}{sup TV} and {rho}{sub A}{sup VT} and the observed longitudinal polarization fractions f{sub L}(K{sub 2}*{omega}) and f{sub L}(K{sub 2}*{phi}) to fix the phases {phi}{sub A}{sup VT} and {phi}{sub A}{sup TV}. (v) The experimental observation
Theory of photon and electron induced reactions
Onley, D.S.; Wright, L.E.
1992-01-01
During the first year and half of the current grant from the Department of Energy we have made considerable progress on the following aspects of the general investigation of electron and photon induced reactions: (1) photo- and electro-production of mesons; (2) Coulomb distortion effects on (e,e{prime}{gamma}) and (e,e{prime}) and (e,e{prime}p) in the quasi-elastic region, (3) studies involving the relativistic shell model, and (4) quark models. We will report on each of these developments in this paper.
Search for eta '(958)-nucleus Bound States by (p,d) Reaction at GSI and FAIR
NASA Astrophysics Data System (ADS)
Fujioka, H.; Ayyad, Y.; Benlliure, J.; Brinkmann, K.-T.; Friedrich, S.; Geissel, H.; Gellanki, J.; Guo, C.; Gutz, E.; Haettner, E.; Harakeh, M. N.; Hayano, R. S.; Higashi, Y.; Hirenzaki, S.; Hornung, C.; Igarashi, Y.; Ikeno, N.; Itahashi, K.; Iwasaki, M.; Jido, D.; Kalantar-Nayestanaki, N.; Kanungo, R.; Knoebel, R.; Kurz, N.; Metag, V.; Mukha, I.; Nagae, T.; Nagahiro, H.; Nanova, M.; Nishi, T.; Ong, H. J.; Pietri, S.; Prochazka, A.; Rappold, C.; Reiter, M. P.; Rodríguez-Sánchez, J. L.; Scheidenberger, C.; Simon, H.; Sitar, B.; Strmen, P.; Sun, B.; Suzuki, K.; Szarka, I.; Takechi, M.; Tanaka, Y. K.; Tanihata, I.; Terashima, S.; Watanabe, Y. N.; Weick, H.; Widmann, E.; Winfield, J. S.; Xu, X.; Yamakami, H.; Zhao, J.
The mass of the {\\eta}' meson is theoretically expected to be reduced at finite density, which indicates the existence of {\\eta}'-nucleus bound states. To investigate these states, we perform missing-mass spectroscopy for the (p, d) reaction near the {\\eta}' production threshold. The overview of the experimental situation is given and the current status is discussed.
Meson self-energies calculated by the relativistic particle-hole-antiparticle representation
Nakano, M.; Noda, N.; Mitsumori, T.; Koide, K.; Kouno, H.; Hasegawa, A.; Liu, L.
1997-12-01
A new formulation of meson self-energies is introduced for {sigma},{omega},{pi},{rho},{delta}, and {eta} mesons on the basis of the particle-hole-antiparticle representation. We have studied the difference between the meson self-energy (MSE) of this representation and the MSE of the traditional density-Feynman (DF) representation. It is shown that the new formulation describes exactly the physical processes such as particle-hole excitations or particle-antiparticle excitations, and that, on the other hand, the meson self-energy based on the DF representation includes unphysical components. By numerical calculations, the meson self-energies describing the particle-hole excitations are shown to be close to each other for most of the meson self-energy in low momentum (R{lt}500 MeV) and low energy (R{sub 0}{lt}200 MeV). This fact implies that former calculations using the low momentum and low-energy part do not change greatly. The density part of the density-Feynman representation has been shown to have a resonant structure around the energy of particle-antiparticle excitation, which causes a large difference between the two representations in the meson spectrum calculations. Our investigation concludes that the former calculations based on the density-Feynman representation are not invalidated in many cases, but the particle-hole-antiparticle representation is more appropriate to treat exactly the physical processes. {copyright} {ital 1997} {ital The American Physical Society}
Electromagnetic production of mesons and nucleon resonances at GeV energies
Lee, T.S.H.; Pichowsky, M.; Sato, T.
1995-08-01
A coupled-channels model for investigating the electromagnetic excitation of nucleon resonances (N*) at energies accessible to CEBAF, was developed. Motivated by the existing QCD-based hadron models, we assume that the basic resonant interaction mechanisms of the model Hamiltonian are the absorption and emission of photons and mesons by a bare quark core. The matrix elements of nonresonant interactions are deduced from low-order Feynman diagrams of an effective Lagrangian with chiral symmetry. The standard projection operator technique was applied to obtain a set of unitary scattering equations for describing {pi}N and {gamma}N reactions up to the GeV energy region. By assuming that the nonresonant two-pion continuum can be approximated as a fictitious {sigma}N state, the scattering equations can then be cast into a set of coupled-channels equations involving only two-particle {gamma}N, {pi}N, {eta}N, {rho}N, {pi}{Delta}, {omega}N and {sigma}N channels, which can be solved by well-developed numerical methods. The bare coupling constants and the range parameters of the hadronic form factors are adjusted to reproduce {pi}N scattering phase shifts up to 2-GeV incident pion energy. We then explore the dependence of the {gamma}N {yields} {pi}N and N(e,e{prime}{pi}) observables on the {gamma}N {yields} N* excitation strengths predicted by various QCD-based models of hadrons.
Antistrange meson-baryon interaction in hot and dense nuclear matter
NASA Astrophysics Data System (ADS)
Cabrera, D.; Tolós, L.; Aichelin, J.; Bratkovskaya, E.
2014-11-01
We present a study of in-medium cross sections and (off-shell) transition rates for the most relevant binary reactions for strange pseudoscalar meson production close to threshold in heavy-ion collisions at energies available at the Facility for Antiproton and Ion Research. Our results rely on a chiral unitary approach in coupled channels which incorporates the s and p waves of the kaon-nucleon interaction. The formalism, which is modified in the hot and dense medium to account for Pauli blocking effects, mean-field binding on baryons, and pion and kaon self-energies, has been improved to implement unitarization and self-consistency for both the s - and the p -wave interactions at finite temperature and density. This gives access to in-medium amplitudes in several elastic and inelastic coupled channels with strangeness content S =-1 . The obtained total cross sections mostly reflect the fate of the Λ (1405 ) resonance, which melts in the nuclear environment, whereas the off-shell transition probabilities are also sensitive to the in-medium properties of the hyperons excited in the p -wave amplitudes [Λ ,Σ , and Σ*(1385 ) ]. The single-particle potentials of these hyperons at finite momentum, density, and temperature are also discussed in connection with the pertinent scattering amplitudes. Our results are the basis for future implementations in microscopic transport approaches accounting for off-shell dynamics of strangeness production in nucleus-nucleus collisions.
Inclusive electron scattering within the SuSAv2 meson-exchange current approach
NASA Astrophysics Data System (ADS)
Megias, G. D.; Amaro, J. E.; Barbaro, M. B.; Caballero, J. A.; Donnelly, T. W.
2016-07-01
We present our recent progress on the relativistic modeling of electron-nucleus reactions and compare our predictions with inclusive 12C (e , e' ) experimental data in a wide kinematical region. The model, originally based on the superscaling phenomenon shown by electron-nucleus scattering data, has recently been improved through the inclusion of relativistic mean field theory effects that take into account the enhancement of the quasielastic transverse scaling function compared with its longitudinal counterpart. In this work, we extend the model to include the complete inelastic spectrum—resonant, nonresonant and deep inelastic scattering. We also discuss the impact of meson-exchange currents through the analysis of two-particle two-hole contributions to electromagnetic response functions evaluated within the framework of the relativistic Fermi gas, considering for the first time not only the transverse but also the longitudinal channel. The results show quite good agreement with data over the whole range of energy transfer, including the dip region between the quasielastic peak and the Δ resonance.
Deeply Virtual Pseudoscalar Meson Production at Jefferson Lab and Transversity GPDs
NASA Astrophysics Data System (ADS)
Kubarovsky, Valery
2016-02-01
The cross section of the exclusive π0 and η electroproduction reaction ep → e‧p‧π0/η was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections d4σ/dtdQ2dx Bdϕπ and structure functions σT + ɛσL,σTT and σLT as functions of t were obtained over a wide range of Q2 and xB. The data are compared with the GPD based theoretical models. Analyses find that a large dominance of transverse processes is necessary to explain the experimental results. Generalized form factors of the transversity GPDs
Off-shell effects for the reaction pp{yields}{pi}d at high energies
Lee, T.S.H.; Locher, M.P.; Lu, Y.
1995-08-01
The reaction pp {yields} {pi}d is studied in a relativistic meson rescattering model. For 1.3 < T{sub p} < 2.4 GeV, the differential cross section and the asymmetry are calculated and compared to experiment. The model introduces simple form factors for the leading {pi}N partial waves, which depend on the virtuality of the exchanged {pi} and {rho} mesons. All remaining input is derived from experimental constraints. The data can be described by energy-independent form factors. The asymmetries are sensitive to pp distortion factors and further details of the model. A paper describing our results was published.
Charmless hadronic two-body decays of Bs mesons
NASA Astrophysics Data System (ADS)
Chen, Yaw-Hwang; Cheng, Hai-Yang; Tseng, B.
1999-04-01
Two-body charmless nonleptonic decays of the Bs meson are studied within the framework of generalized factorization in which factorization is applied to the tree level matrix elements while the effective Wilson coefficients are μ and renormalization scheme independent, and nonfactorizable effects are parametrized in terms of Neffc(LL) and Neffc(LR), the effective numbers of colors arising from (V-A)(V-A) and (V-A)(V+A) four-quark operators, respectively. Branching ratios of Bs-->PP,PV,VV decays (P: pseudoscalar meson, V: vector meson) are calculated as a function of Neffc(LR) with two different considerations for Neffc(LL): (a) Neffc(LL) being fixed at the value of 2 and (b) Neffc(LL)=Neffc(LR). Tree and penguin transitions are classified into six different classes. We find the following. (i) The electroweak penguin contributions account for about 85% [for Neffc(LL)=2] of the decay rates of Bs-->ηπ, η'π, ηρ, η'ρ, φπ, φρ, which receive contributions only from tree and electroweak penguin diagrams; a measurement of them will provide a clean determination of the electroweak penguin coefficient a9. (ii) Electroweak penguin corrections to Bs-->ωη('),φη,ωφ,K(*)φ,φφ are in general as significant as QCD penguin effects and even play a dominant role; their decay rates depend strongly on Neffc(LR). (iii) The branching ratio of Bs-->ηη', the analogue of Bd-->η'K, is of order 2×10-5, which is only slightly larger than that of η'η',K*+ρ-,K+K-,K0K¯0 decay modes. (iv) The contribution from the η' charm content is important for Bs-->η'η', but less significant for Bs-->ηη'. (v) The decay rates for the final states K+(*)K-(*) follow the pattern Γ(B¯s-->K+K-)>Γ(B¯s-->K+K*-)>~Γ(B¯s-->K*+K*-)>Γ(B¯s-->K+*K-) and likewise for K0(*)K¯0(*), as a consequence of various interference effects between the penguin amplitudes governed by the effective QCD penguin coefficients a4 and a6.
Determination of the X(3872) meson quantum numbers
NASA Astrophysics Data System (ADS)
Gui, Bin
The Large Hadron Collider beauty (LHCb) is one of the several experiments located at the ring of the Large Hadron Collider (LHC) in Geneva. The LHCb detector is a single arm forward spectrometer and is designed to perform high precision measurements of Charge Parity (CP) violation parameters and rare decays of the beauty and charm hadrons. The detector was successfully operated at a center-of-mass energy of 7 TeV in 2010 and 2011 and at 8 TeV in 2012. Over 3 fb-1 of data has been collected by the LHCb. The LHCb experiment is also well suited for studies on hadron spectroscopy. Besides the well established mesons consisting of quark-antiquark pairs (qq), it has been proposed that "exotic" qqqq mesons could exist. One of the candidates for a four-quark state is the charmonium-like state X(3872) which was first observed by the Belle experiment in 2003. This narrow state has a mass of about 3872 MeV which is located in a region of excited charmonium states (cc). However its mass does not match to any theoretically predicted charmonium state. In order to investigate the nature of this anomalous state, we analyze its quantum number which is the key for its interpretation. The X(3872) events are reconstructed from B+ → X(3872)K+, where X(3872) → pi + pi J/psi, J/psi → mu+mu -; based on 1 fb-1 of 2011 data collected by LHCb detector. We implement a method which is guaranteed by statistics to be the most powerful way to discriminate between spin hypotheses; namely unbinned likelihood ratio test using full angular phase-space. The 5-dimensional analysis shows that 1++ hypothesis is preferred with overwhelming significance. The only alternative assignment allowed by the previous measurements, JPC = 2 -+, is rejected with a confidence level equivalent to more than eight Gaussian standard deviations. This result favors exotic explanations of the X(3872) state, such as a mesonic molecule or a tetraquark.
Pion and η -meson mass splitting at the two-flavor chiral crossover
NASA Astrophysics Data System (ADS)
Heller, Markus; Mitter, Mario
2016-10-01
We study the splitting in the screening mass of pions and the η -meson across the chiral crossover. This splitting is determined by the 't Hooft determinant. We use results for the renormalization group scale dependence of the 't Hooft determinant obtained within the functional renormalization group in quenched QCD with two flavors. The scale dependence of the 't Hooft determinant is mapped to its temperature dependence with the help of a Polyakov-quark-meson model. As a result we obtain the temperature dependence of the splitting in the screening mass of pions and the η -meson.
Search for B-meson decays to b1rho and b1K___
Aubert, Bernard; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G. /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt State U. /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /INFN, Naples /Naples U. /INFN, Naples /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /Pennsylvania U. /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison
2010-06-11
We present a search for decays of B mesons to final states with a b{sub 1} meson and a {rho} or K*(892) meson. The search is based on a data sample consisting of 465 million B{bar B} pairs collected by the BABAR detector at the SLAC National Accelerator Laboratory. We do not observe any statistically significant signal. The upper limits we set on the branching fractions range from 1.4 to 8.0 x 10{sup -6} at the 90% confidence level (C.L.), including systematic uncertainties.
Search for B-meson decays to b1ρ and b1K*
NASA Astrophysics Data System (ADS)
Aubert, B.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D. N.; Hooberman, B.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Osipenkov, I. L.; Tackmann, K.; Tanabe, T.; Hawkes, C. M.; Soni, N.; Watson, A. T.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Barrett, M.; Khan, A.; Randle-Conde, A.; Blinov, V. E.; Bukin, A. D.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Bondioli, M.; Curry, S.; Eschrich, I.; Kirkby, D.; Lankford, A. J.; Lund, P.; Mandelkern, M.; Martin, E. C.; Stoker, D. P.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Yasin, Z.; Sharma, V.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Mazur, M. A.; Richman, J. D.; Beck, T. W.; Eisner, A. M.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schalk, T.; Schumm, B. A.; Seiden, A.; Wang, L.; Winstrom, L. O.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Fang, F.; Hitlin, D. G.; Narsky, I.; Ongmongkolkul, P.; Piatenko, T.; Porter, F. C.; Andreassen, R.; Mancinelli, G.; Meadows, B. T.; Mishra, K.; Sokoloff, M. D.; Bloom, P. C.; Chavez, A.; Ford, W. T.; Gaz, A.; Hirschauer, J. F.; Nagel, M.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Wilson, R. J.; Feltresi, E.; Hauke, A.; Jasper, H.; Karbach, T. M.; Merkel, J.; Petzold, A.; Spaan, B.; Wacker, K.; Kobel, M. J.; Nogowski, R.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Latour, E.; Verderi, M.; Clark, P. J.; Playfer, S.; Watson, J. E.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cecchi, A.; Cibinetto, G.; Fioravanti, E.; Franchini, P.; Luppi, E.; Munerato, M.; Negrini, M.; Petrella, A.; Piemontese, L.; Santoro, V.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Pacetti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Tosi, S.; Chaisanguanthum, K. S.; Morii, M.; Adametz, A.; Marks, J.; Schenk, S.; Uwer, U.; Bernlochner, F. U.; Klose, V.; Lacker, H. M.; Lueck, T.; Volk, A.; Bard, D. J.; Dauncey, P. D.; Tibbetts, M.; Behera, P. K.; Charles, M. J.; Mallik, U.; Cochran, J.; Crawley, H. B.; Dong, L.; Eyges, V.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gao, Y. Y.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Béquilleux, J.; D'Orazio, A.; Davier, M.; Derkach, D.; Firmino da Costa, J.; Grosdidier, G.; Le Diberder, F.; Lepeltier, V.; Lutz, A. M.; Malaescu, B.; Pruvot, S.; Roudeau, P.; Schune, M. H.; Serrano, J.; Sordini, V.; Stocchi, A.; Wormser, G.; Lange, D. J.; Wright, D. M.; Bingham, I.; Burke, J. P.; Chavez, C. A.; Fry, J. R.; Gabathuler, E.; Gamet, R.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Clarke, C. K.; di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Paramesvaran, S.; Wren, A. C.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Hafner, A.; Alwyn, K. E.; Bailey, D.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; West, T. J.; Yi, J. I.; Anderson, J.; Chen, C.; Jawahery, A.; Roberts, D. A.; Simi, G.; Tuggle, J. M.; Dallapiccola, C.; Salvati, E.; Cowan, R.; Dujmic, D.; Fisher, P. H.; Henderson, S. W.; Sciolla, G.; Spitznagel, M.; Yamamoto, R. K.; Zhao, M.; Patel, P. M.; Robertson, S. H.; Schram, M.; Biassoni, P.; Lazzaro, A.; Lombardo, V.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Zhao, H. W.; Simard, M.; Taras, P.; Nicholson, H.; de Nardo, G.; Lista, L.; Monorchio, D.; Onorato, G.; Sciacca, C.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Knoepfel, K. J.; Losecco, J. M.; Wang, W. F.; Corwin, L. A.; Honscheid, K.; Kagan, H.; Kass, R.; Morris, J. P.; Rahimi, A. M.; Sekula, S. J.; Wong, Q. K.; Blount, N. L.; Brau, J.; Frey, R.; Igonkina, O.; Kolb, J. A.; Lu, M.; Rahmat, R.; Sinev, N. B.; Strom, D.; Strube, J.; Torrence, E.; Castelli, G.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Voci, C.; Del Amo Sanchez, P.; Ben-Haim, E.; Bonneaud, G. R.; Briand, H.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Perez, A.; Prendki, J.; Sitt, S.; Gladney, L.; Biasini, M.; Manoni, E.; Angelini, C.; Batignani, G.; Bettarini, S.; Calderini, G.; Carpinelli, M.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Morganti, M.; Neri, N.; Paoloni, E.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Baracchini, E.; Cavoto, G.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Jackson, P. D.; Li Gioi, L.; Mazzoni, M. A.; Morganti, S.; Piredda, G.; Renga, F.; Voena, C.; Ebert, M.; Hartmann, T.; Schröder, H.; Waldi, R.; Adye, T.; Franek, B.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Esteve, L.; Hamel de Monchenault, G.; Kozanecki, W.; Vasseur, G.; Yèche, Ch.; Zito, M.; Allen, M. T.; Aston, D.; Bartoldus, R.; Benitez, J. F.; Cenci, R.; Coleman, J. P.; Convery, M. R.; Dingfelder, J. C.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Field, R. C.; Franco Sevilla, M.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.; Kaminski, J.; Kelsey, M. H.; Kim, H.; Kim, P.; Kocian, M. L.; Leith, D. W. G. S.; Li, S.; Lindquist, B.; Luitz, S.; Luth, V.; Lynch, H. L.; Macfarlane, D. B.; Marsiske, H.; Messner, R.; Muller, D. R.; Neal, H.; Nelson, S.; O'Grady, C. P.; Ofte, I.; Perl, M.; Ratcliff, B. N.; Roodman, A.; Salnikov, A. A.; Schindler, R. H.; Schwiening, J.; Snyder, A.; Su, D.; Sullivan, M. K.; Suzuki, K.; Swain, S. K.; Thompson, J. M.; Va'Vra, J.; Wagner, A. P.; Weaver, M.; West, C. A.; Wisniewski, W. J.; Wittgen, M.; Wright, D. H.; Wulsin, H. W.; Yarritu, A. K.; Young, C. C.; Ziegler, V.; Chen, X. R.; Liu, H.; Park, W.; Purohit, M. V.; White, R. M.; Wilson, J. R.; Bellis, M.; Burchat, P. R.; Edwards, A. J.; Miyashita, T. S.; Ahmed, S.; Alam, M. S.; Ernst, J. A.; Pan, B.; Saeed, M. A.; Zain, S. B.; Soffer, A.; Spanier, S. M.; Wogsland, B. J.; Eckmann, R.; Ritchie, J. L.; Ruland, A. M.; Schilling, C. J.; Schwitters, R. F.; Wray, B. C.; Drummond, B. W.; Izen, J. M.; Lou, X. C.; Bianchi, F.; Gamba, D.; Pelliccioni, M.; Bomben, M.; Bosisio, L.; Cartaro, C.; Della Ricca, G.; Lanceri, L.; Vitale, L.; Azzolini, V.; Lopez-March, N.; Martinez-Vidal, F.; Milanes, D. A.; Oyanguren, A.; Albert, J.; Banerjee, Sw.; Bhuyan, B.; Choi, H. H. F.; Hamano, K.; King, G. J.; Kowalewski, R.; Lewczuk, M. J.; Nugent, I. M.; Roney, J. M.; Sobie, R. J.; Gershon, T. J.; Harrison, P. F.; Ilic, J.; Latham, T. E.; Mohanty, G. B.; Puccio, E. M. T.; Band, H. R.; Chen, X.; Dasu, S.; Flood, K. T.; Pan, Y.; Prepost, R.; Vuosalo, C. O.; Wu, S. L.
2009-09-01
We present a search for decays of B mesons to final states with a b1 meson and a ρ or K*(892) meson. The search is based on a data sample consisting of 465 million B Bmacr pairs collected by the BABAR detector at the SLAC National Accelerator Laboratory. We do not observe any statistically significant signal. The upper limits we set on the branching fractions range from 1.4 to 8.0×10-6 at the 90% confidence level, including systematic uncertainties.
Sigma meson and lowest possible glueball candidate in an extended linear {sigma} model
Mukherjee, Tamal K.; Huang Mei; Yan Qishu
2012-10-23
We formulate an extended linear {sigma} model of a quarkonia nonet and a tetraquark nonet as well as a complex iso-singlet (glueball) field to study the low-lying scalar meson. Chiral symmetry and U{sub A}(1) symmetry and their breaking play important role to shape the scalar meson spectrum in our work. Based on our study we will comment on what may be the mass of the lowest possible scalar and pseudoscalar glueball states. We will also discuss on what may be the nature of the sigma or f{sub 0}(600) meson.
The Inclusive Production of the Meson Resonances in Neutrino Charged Current (cc) Interactions
NASA Astrophysics Data System (ADS)
Polyarush, A. Yu.
2015-03-01
The inclusive production of the meson resonances ρ0(770), f0(980), f2(1270), K*+(892) in neutrino-nucleon interactions has been studied with the NOMAD detector. For the first time the f0(980) meson is observed in neutrino interactions. The presence of f2(1270) in the neutrino interactions is reliably established. The average multiplicity of these three resonances is measured as a function of several kinematic variables. The experimental results are compared to the multiplicities obtained from a simulation based on the Lund model. Matrix element of spin density matrix for K*+(892) meson have been measured.
Exclusive and Semi-Exclusive Reactions at a Higher Energy CEBAF
Carl Carlson
1998-06-01
More energy at CEBAF provides more opportunity for studies of hadron and nuclear properties. Many of the experiments that could be done are extensions of things already done at lower energies. Others represent new initiatives that could not work or could not theoretically be interpreted at lower energies. The author concentrates on the new initiatives, but do not wish our thinking to neglect what can be learned from continuations of lower energy work. The author begins with a list of some things that should be continued into a new energy regime. (1) Baryon and meson spectroscopy of higher mass states. With 4 GeV incoming electron energy, strange mesons are limited to 1.8 GeV in mass and charm is not producible. (2) Exclusive reactions, including meson and baryon form factors and reactions on few nucleon systems. The latter includes deuteron photodisintegration, the A and B form factors of the deuteron, and the deuteron tensor polarization T{sub 20}. (And we should not forget T{sub 20} in inclusive scattering.) (3) Hadrons in the nuclear medium, with such topics as color transparency, electroproduction of {rho} mesons, virtual Compton scattering off nuclei, and backward hadrons from e-d reactions. The very last must be especially important, since it gives the logo used in the advertizing for this conference. In addition, there are new initiatives that this talk will call attention to, in particular: (1) semi-exclusive meson production; (2) duality in semi-exclusive reactions; and (3) new views of exclusive reactions and perturbative QCD (leading to ''off-forward parton distributions'').
... or diabetes. But medicines can also cause unwanted reactions. One problem is interactions, which may occur between ... more serious. Drug allergies are another type of reaction. They can be mild or life-threatening. Skin ...
B Meson Decays With Tau Leptons in the Final State
Mazur, Michael; /Freiburg U.
2009-08-05
We present measurements of B meson decays with {tau} leptons in the final state. These decays, while experimentally more challenging than those involving light leptons, provide enhanced sensitivity to physics beyond the Standard Model due to the large {tau} mass. We present measurements of the branching fractions of B{sup -} {yields} {tau}{sup -} {bar {nu}}{sub {tau}} and B {yields} D{sup (*)}{tau}{sup -}{bar {nu}}{sub {tau}}, as well as searches for the forbidden decays B{sup 0} {yields} {ell}{sup {+-}}{tau}{sup {-+}} and B{sup -} {yields} K{sup -} {tau}{sup {+-}}{mu}{sup {-+}}. These measurements are based on several hundred million e{sup +}e{sup -} {yields} {Upsilon}(4S) {yields} B{bar B} events recorded with the BaBar detector at the PEP-II asymmetric-energy collider.
Measurements of the properties of D-meson decays
Schindler, R. H.; Alam, M. S.; Boyarski, A. M.; Breidenbach, M.; Burke, D. L.; Dorenbosch, J.; Dorfan, J. M.; Feldmann, G. J.; Feldman, M. E.B.; Hanson, G.; Hayes, K. G.; Himel, T.; Hitlin, D. G.; Hollebeek, R. J.; Innes, W. R.; Jaros, J. A.; Jenni, P.; Larsen, R. R.; Luth, V.; Peri, M. L.; Richter, B.; Roussarie, A.; Scharre, D. L.; Schwitters, R. F.; Siegrist, J. L.; Taureg, H.; Tonutti, M.; Vidal, R. A.; Wiess, J. M.; Zaccone, H.; Abrams, G.; Blocker, C. A.; Blondel, A.; Carithers, W. C.; Chinowsky, W.; Coles, M. W.; Cooper, S.; Dieterle, W. E.; Dillon, J. B.; Eaton, M. W.; Gidal, G.; Goldhaber, G.; Johnson, A. D.; Kadyk, J. A.; Lankford, A. J.; Millikan, R. E.; Nelson, M. E.; Pang, C. Y.; Patrick, J. F.; Strait, J.; Trilling, G. H.; Vella, E. N.; Videau, I.
1981-07-01
We present a study of the decay properties of charmed D mesons produced near the peak of the {psi}" (3770) resonance in e⁺e⁻ annihilation. Branching fractions for nine Cabibbo-favored and three Cabibbo-suppressed decay modes are presented along with upper limits on one additional Cabibbo-favored and four additional Cabibbo-suppressed decay modes. A study of Kππ decay mode Dalitz plots reveals a large quasi-two-body pseudoscalar-vector component for the D{sup 0} decays and an apparent nonuniform population an the Dalitz plot for the D⁺ decay into K⁻π⁺π⁺. Using tagged events, we measure the charged particle multiplicity and strange particle content of D decays. A measurement of the D⁺ and D⁰ semileptonic decay fractions indicates that the D{sup +} has a significantly longer lifetime than the D⁰.
The FOREST detector for meson photoproduction experiments at ELPH
NASA Astrophysics Data System (ADS)
Ishikawa, T.; Fujimura, H.; Fukasawa, H.; Hashimoto, R.; Ishida, T.; Kaida, S.; Kasagi, J.; Kawano, A.; Kuwasaki, S.; Maeda, K.; Miyahara, F.; Mochizuki, K.; Nakabayashi, T.; Nakamura, A.; Nawa, K.; Ogushi, S.; Okada, Y.; Okamura, K.; Onodera, Y.; Saito, Y.; Sakamoto, Y.; Sato, M.; Shimizu, H.; Sugai, H.; Suzuki, K.; Takahashi, S.; Tsuchikawa, Y.; Yamazaki, H.; Yonemura, H.
2016-10-01
An electromagnetic calorimeter complex, FOREST, has been constructed for meson photoproduction experiments at the Research Center for Electron Photon Science, Tohoku University. It consists of three types of calorimeters, which are made of pure cesium-iodide crystals, lead scintillating-fiber modules, and lead glass Cherenkov counters. Each calorimeter is equipped with a plastic scintillator hodoscope to identify charged particles. The design and performance of FOREST are described. The energy responses of test calorimeters have been investigated by using 100-800 MeV positron beams. The energy resolutions of the three calorimeters are found to be approximately 3%, 7%, and 5% for 1-GeV photons, respectively. A cryogenic hydrogen/deuterium target system fitted to the FOREST experiments and a newly developed data acquisition system are also presented.
Moments of pseudoscalar meson distribution amplitudes from the lattice
Braun, V. M.; Goeckeler, M.; Horsley, R.; Zanotti, J. M.; Perlt, H.; Schiller, A.; Pleiter, D.; Schroers, W.; Schierholz, G.; Stueben, H.
2006-10-01
Based on lattice simulations with two flavors of dynamical, O(a)-improved Wilson fermions we present results for the first two moments of the distribution amplitudes of pseudoscalar mesons at several values of the valence quark masses. By extrapolating our results to the physical masses of up/down and strange quarks, we find the first two moments of the K{sup +} distribution amplitude and the second moment of the {pi}{sup +} distribution amplitude. We use nonperturbatively determined renormalization coefficients to obtain results in the MS scheme. At a scale of 4 GeV{sup 2} we find a{sub 2}{sup {pi}}=0.201(114) for the second Gegenbauer moment of the pion's distribution amplitude, while for the kaon, a{sub 1}{sup K}=0.0453(9)(29) and a{sub 2}{sup K}=0.175(18)(47)
Scalar mesons and the search for the 0{sup ++} Glueball
Ulrike Thoma
2002-10-01
The possibility that gluonic excitations of hadronic matter or of the QCD vacuum may exist is perhaps one of the most fascinating topics in hadron spectroscopy. Glueballs are predicted by many models; in particular present-day lattice gauge calculations require their existence. All these models agree that the lightest glueball should have scalar quantum numbers and a mass around 1.6 GeV, which corresponds to the mass region where the scalar qq[bar]-mesons are expected. Therefore mixing effects can complicate the search for the glueball. Experiments indeed show an overpopulation of states, for which many different interpretations exist. This reflects the complexity of the situation. New data from various experiments on scalar states give hints toward an interpretation of the scalar states. But, still many questions remain.
Impressions of the Meson Spectrum: Hybrids & Exotics, present and future
NASA Astrophysics Data System (ADS)
Pennington, M. R.
2016-03-01
It has long been expected that the spectrum of hadrons in QCD would be far richer and extensive than experiment has so far revealed. While there have been experimental hints of this richness for some time, it is really only in the last few years that dramatic progress has been seen in the exploration both experimentally and in calculations on the lattice. Precision studies enabled by new technology both with detectors and high performance computations are converging on an understanding of the spectrum in strong coupling QCD. These methodologies are laying the foundation for a decade of potential discovery that electro and photoproduction experiments at Jefferson Lab, which when combined with key results on B and charmonium decays from both e+e- and pp colliders, should turn mere impressions of the light meson spectrum into a high definition picture.
{eta} and {eta}{sup '} Mesons from Lattice QCD
Christ, N. H.; Liu, Q.; Mawhinney, R. D.; Dawson, C.; Izubuchi, T.; Jung, C.; Soni, A.; Sachrajda, C. T.; Zhou, R.
2010-12-10
The large mass of the ninth pseudoscalar meson, the {eta}{sup '}, is believed to arise from the combined effects of the axial anomaly and the gauge field topology present in QCD. We report a realistic, 2+1-flavor, lattice QCD calculation of the {eta} and {eta}{sup '} masses and mixing which confirms this picture. The physical eigenstates show small octet-singlet mixing with a mixing angle of {theta}=-14.1(2.8) deg. Extrapolation to the physical light quark mass gives, with statistical errors only, m{sub {eta}}=573(6) MeV and m{sub {eta}{sup '}}=947(142) MeV, consistent with the experimental values of 548 and 958 MeV.
Staggered fermions, zero modes, and flavor-singlet mesons
Donald, Gordon C; Davies, Christine T.H.; Follana, Eduardo; Kronfeld, Andreas S.
2011-09-12
We examine the taste structure of eigenvectors of the staggered-fermion Dirac operator. We derive a set of conditions on the eigenvectors of modes with small eigenvalues (near-zero modes), such that staggered fermions reproduce the 't Hooft vertex in the continuum limit. We also show that, assuming these conditions, the correlators of flavor-singlet mesons are free of contributions singular in 1/m, where m is the quark mass. This conclusion holds also when a single flavor of sea quark is represented by the fourth root of the staggered-fermion determinant. We then test numerically, using the HISQ action, whether these conditions hold on realistic lattice gauge fields. We find that the needed structure does indeed emerge.
Staggered fermions, zero modes, and flavor-singlet mesons
Donald, Gordon C; Davies, Christine T.H.; Follana, Eduardo; Kronfeld, Andreas S.
2011-09-12
We examine the taste structure of eigenvectors of the staggered-fermion Dirac operator. We derive a set of conditions on the eigenvectors of modes with small eigenvalues (near-zero modes), such that staggered fermions reproduce the 't Hooft vertex in the continuum limit. We also show that, assuming these conditions, the correlators of flavor-singlet mesons are free of contributions singular in 1/m, where m is the quark mass. This conclusion holds also when a single flavor of sea quark is represented by the fourth root of the staggered-fermion determinant. We then test numerically, using the HISQ action, whether these conditions hold onmore » realistic lattice gauge fields. We find that the needed structure does indeed emerge.« less
Rare radiative decays of the B c meson
NASA Astrophysics Data System (ADS)
Ju, Wan-Li; Wang, Tianhong; Jiang, Yue; Yuan, Han; Wang, Guo-Li
2016-08-01
In this paper, we study the rare radiative processes {B}c\\to {D}{sJ}(*)γ within the Standard Model, where {D}{sJ}(*) stands for the meson {D}s*, {D}s1(2460,2536) or {D}s2*(2573). During the investigations, we consider the contributions from the penguin, annihilation, color-suppressed and color-favored cascade diagrams. Our results show that: (1) the penguin and annihilation contributions are dominant in the branching fractions; (2) for the processes {B}c\\to {D}s*γ and {B}c\\to {D}s1(2460,2536)γ , the effects from the color-suppressed and color-favored cascade diagrams are un-negligible.
Electro- and Photoproduction of Vector Mesons at Jefferson Lab
Marco Battaglieri
2002-09-01
The total and differential cross section for exclusive electro- and photoproduction of vector mesons in the resonance region and above (1.6 < W < 2.9 GeV) was measured at Jefferson Laboratory in a wide kinematic range (0 < Q2 < 4 GeV2 and 0< -t < 5 GeV2). The measurement of the total and differential cross section down to 100 pb/GeV2 with the full kinematic coverage, was possible for the first time thanks to the combination of the 100% duty cycle of CEBAF and the large acceptance of the CLAS detector. The main results from the CLAS Collaboration activity in this field will be presented and discussed.
Search for rare charm meson decays at FNAL E791
D. J. Summers
2003-08-14
We report the results of a blind search for flavor-changing neutral current (FCNC), lepton-flavor violating, and lepton-number violating decays of D{sup +}, D{sub s}{sup +}, and D{sup 0} mesons (and their antiparticles) into 2-, 3-, and 4-body states including a lepton pair. Such decays may involve Flavor-Changing Neutral Currents, Leptoquarks, Horizontal Gauge Bosons, or Majorana Neutrinos. No evidence for any of these decays is found. Therefore, we present 90% confidence level branching-fraction upper limits, typically at the 10{sup -4} level. A total of 51 decay channels have been examined; 26 have not been previously reported and 18 are significant improvements over previous results.
Finite-mass effects on inclusive B-meson hadroproduction
Kniehl, Bernd A.; Kramer, Gustav; Schienbein, Ingo; Spiesberger, Hubert
2008-01-01
We calculate the transverse-momentum (p{sub T}) distribution for the inclusive hadroproduction of B mesons at intermediate values of p{sub T} at next-to-leading order (NLO) in a dedicated finite-mass scheme using realistic nonperturbative fragmentation functions that are obtained through a global fit to e{sup +}e{sup -} data from CERN LEP1 and SLAC SLC exploiting their universality and scaling violations. We find that finite-mass effects moderately enhance the cross section, by about 20% at p{sub T}=2m{sub b}, and rapidly fade out with increasing value of p{sub T}, so that the zero-mass prediction is reached. We also perform comparisons with recent pp data taken by the CDF Collaboration in run II at the Fermilab Tevatron and comment on the usefulness of the fixed-flavor-number scheme.
Meson exchange current (MEC) models in neutrino interaction generators
Katori, Teppei
2015-05-15
Understanding of the so-called 2 particle-2 hole (2p-2h) effect is an urgent program in neutrino interaction physics for current and future oscillation experiments. Such processes are believed to be responsible for the event excesses observed by recent neutrino experiments. The 2p-2h effect is dominated by the meson exchange current (MEC), and is accompanied by a 2-nucleon emission from the primary vertex, instead of a single nucleon emission from the charged-current quasi-elastic (CCQE) interaction. Current and future high resolution experiments can potentially nail down this effect. For this reason, there are world wide efforts to model and implement this process in neutrino interaction simulations. In these proceedings, I would like to describe how this channel is modeled in neutrino interaction generators.
Determining pseudoscalar meson photoproduction amplitudes from complete experiments
A. M. Sandorfi, S. Hoblit, H. Kamano, T.-S. H. Lee
2011-05-01
In preparation for a new generation of complete experiments with the goal of performing a high precision extraction of pseudoscalar meson photo-production amplitudes, we present expressions that allow the direct numerical calculation of matrix elements with arbitrary spin projections from Chew-Goldberger-Low-Nambu (CGLN) amplitudes. We use this numerical tool to verify the most general analytic form of the cross section, dependent upon the three polarization vectors of the beam, target and recoil baryon, including all single, double and triple-polarization terms involving 16 spin-dependent observables. Analytic expressions that determine the recoil baryon polarization are presented, together with examples of their potential use with quasi-4? detectors to deduce observables. We assemble the analytic equations relating the 16 experimental observables and the CGLN amplitudes and use our independent method of numerical evaluation to resolve sign differences that exist in the literature.
Early LHC phenomenology of Yukawa-bound heavy QQ mesons
Enkhbat, Tsedenbaljir; Hou, Wei-Shu; Yokoya, Hiroshi
2011-11-01
Current limits from the LHC on fourth generation quarks are already at the unitarity bound of 500 GeV or so. If they exist, the strong Yukawa couplings are turning nonperturbative, and may form bound states. We study the domain of m{sub b'} and m{sub t'} in the range of 500 to 700 GeV, where we expect binding energies are mainly of Yukawa origin, with QCD subdominant. To be consistent with electroweak precision tests, the t' and b' quarks have to be nearly degenerate, exhibiting a new 'isospin'. Comparing relativistic expansion with a relativistic bound state approach, we find the most interesting is the production of a color octet, isosinglet vector meson (a 'gluon-prime') via qq-bar{yields}{omega}{sub 8}. Leading decay modes are {pi}{sub 8}{sup {+-}}W{sup {+-}}, {pi}{sub 8}{sup 0}Z{sup 0}, and constituent quark decay, with qq and tt-bar' and bb' subdominant. The color octet, isovector pseudoscalar {pi}{sub 8} meson decays via constituent quark decay, or to Wg. These decay rates are parameterized by the decay constant, the binding energy and mass differences, and V{sub tb'}. For small V{sub t'b}, one could have a spectacular signal of WWg, where a soft W accompanies a very massive Wg pair. In general, however, one has high multiplicity signals with b, W, and t jet substructures that are not so different from the t't-bar' and b'b-bar' search.
Direct CP Violation in Charmless Hadronic B-Meson Decays at the PEP-II Asymmetric B-Meson Factory
Telnov, Alexandre Valerievich; /UC, Berkeley
2005-05-06
The study of the quark transition b {yields} s{bar s}s, which is a pure loop-level (''penguin'') process leading to several B-meson-decay final states, most notably {phi}K, is arguably the hottest topic in B-meson physics today. The reason is the sensitivity of the amplitudes and the CP-violating asymmetries in such processes to physics beyond the Standard Model. By performing these measurements, we improve our understanding of the phenomenon of combined-parity (CP) violation, which is believed to be responsible for the dominance of matter over antimatter in our Universe. Here, we present measurements of branching fractions and charge asymmetries in the decays B{sup +} {yields} {phi}K{sup +} and B{sup 0} {yields} {phi}K{sup 0} in a sample of approximately 89 million B{bar B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy B-meson Factory at SLAC. We determine {Beta}(B{sup +} {yields} {phi}K{sup +}) = (10.0{sub -0.8}{sup +0.9} {+-} 0.5) x 10{sup -6} and {Beta}(B{sup 0} {yields} {phi}K{sup 0}) = (8.4{sub -1.3}{sup +1.5} {+-} 0.5) x 10{sup -6}, where the first error is statistical and the second is systematic. Additionally, we measure the CP-violating charge asymmetry {Alpha}{sub CP}(B{sup {+-}} {yields} {phi}K{sup {+-}}) = 0.04 {+-} 0.09 {+-} 0.01, with a 90% confidence-level interval of [-0.10, 0.18], and set an upper limit on the CKM- and color-suppressed decay B{sup +} {yields} {phi}{pi}{sup +}, {Beta}(B{sup +} {yields} {phi}{pi}{sup +}) < 0.41 x 10{sup -6} (at the 90% confidence level). Our results are consistent with the Standard Model, which predicts {Alpha}{sub CP}(B{sup {+-}} {yields} {phi}K{sup {+-}}) {approx}< 1% and {Beta}(B {yields} {phi}{tau}) << 10{sup -7}. Since many models of physics beyond the Standard Model introduce additional loop diagrams with new heavy particles and new CP-violating phases that would contribute to these decays, potentially making {Alpha}{sub CP} (B{sup {+-}} {yields} {phi}K{sup {+-}}) and {Beta}(B {yields
New Resonances and Meson Spectroscopy at BaBar and Belle
Poireau, Vincent; /Annecy, LAPP
2007-06-06
We present a short review on the recent progresses that have been made in meson spectroscopy. We discuss the experimental discoveries made at the BaBar and Belle experiments, as well as the possible interpretations of the new resonances.
Poincaré covariant pseudoscalar and scalar meson spectroscopy in Wigner-Weyl phase
NASA Astrophysics Data System (ADS)
Hilger, T.
2016-03-01
The coupled quark Dyson-Schwinger and meson Bethe-Salpeter equations in rainbow-ladder truncation for spin-0 mesons are solved in the Wigner-Weyl phase in the chiral limit and beyond, retaining only the ultraviolet finite terms of the phenomenologically most successful Maris-Tandy interaction. This allows one to reveal and discuss the scalar and pseudoscalar meson masses in a chirally symmetric setting without additional medium effects. Independent of the current-quark mass, the found solutions are spacelike, i.e., have negative squared masses. The current-quark mass dependence of meson masses, leptonic decay constants and chiral condensate are illustrated in the Wigner-Weyl phase.
Exotic Hybrid Meson Spectroscopy with the GlueX detector at Jlab
Lawrence, David W.
2014-03-01
The GlueX experiment is scheduled to begin taking data in 2015. The goal is to discover evidence for the existence of exotic hybrid mesons and to map out their spectrum in the light quark sector. Recent theoretical developments using Lattice QCD predict exotic hybrid states in a mass range accessible using the newly upgraded 12GeV electron accelerator at Jefferson Lab. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. The experiment will use 9 GeV linearly polarized photons produced via coherent bremsstrahlung to produce the exotic hybrids. The decay products will be detected in the solenoid-based GlueX detector currently under construction at Jefferson Lab. The status of the GlueX experiment including detector parameters will be presented along with theoretical motivation for the experiment.
Hypertriton calculation with meson-theoretical nucleon-nucleon and hyperon-nucleon interactions
Miyagawa, K.; Gloeckle, W. Faculty of Liberal Arts and Science, Okayama University of Science, Ridai-cho, Okayama 700 )
1993-12-01
Faddeev equations for the coupled [Lambda][ital NN] and [Sigma][ital NN] systems are solved precisely for meson-theoretical nucleon-nucleon and hyperon-nucleon interactions. In this force model the hypertriton is not bound.
Nucleon-meson transport capability for accelerator-breeder target design. [CALOR
Gabriel, T.A.; Alsmiller, R.G. Jr.
1982-01-01
A state-of-the-art code system for nucleon-meson-lepton transport which has direct applicability to accelerator breeders is presented. Some pertinent data that have been obtained using this system are discussed and compared with experimental data.
Production of χc- and χb-mesons in high energy hadronic collisions
NASA Astrophysics Data System (ADS)
Likhoded, A. K.; Luchinsky, A. V.; Poslavsky, S. V.
2014-10-01
This paper is devoted to a phenomenological study of χc ,b-meson production in high energy hadronic collisions in the framework of nonrelativistic QCD (NRQCD). We analyze all available experimental data on χc-meson production and extract nonperturbative NRQCD matrix elements by data fitting. It is shown that measured pT spectra of χc-mesons is mainly formed by color singlet components, while the σ(χc2)/σ(χc1) ratio depends strongly on color octet matrix elements; this ratio becomes a highly sensitive tool to study contributions of the different NRQCD expansion terms. Predictions for χb-meson production cross sections, which are obtained using NRQCD scaling rules, are also given.
Exotic JPC = 1-+ Mesons at the Present Time (discussion of some problems)
NASA Astrophysics Data System (ADS)
Sarycheva, L. I.; Korotkikh, V. L.
2002-06-01
Some problems and questions on Exotic meson physics are presented. The particular attention is given to the discrepancy between theory and experiment and to the interpretation of experimental results.
Semileptonic B and B{sub s} decays into orbitally excited charmed mesons
Segovia, J.; Albertus, C.; Entem, D. R.; Fernandez, F.; Hernandez, E.; Perez-Garcia, M. A.
2011-11-01
The BABAR Collaboration has recently reported products of branching fractions that include B meson semileptonic decays into final states with charged and neutral D{sub 1}(2420) and D{sub 2}*(2460), two narrow orbitally excited charmed mesons. We evaluate these branching fractions, together with those concerning D{sub 0}*(2400) and D{sub 1}{sup '}(2430) mesons, within the framework of a constituent quark model. The calculation is performed in two steps, one of which involves a semileptonic decay and the other is mediated by a strong process. Our results are in agreement with the experimental data. We also extend the study to semileptonic decays of B{sub s} into orbitally excited charmed-strange mesons, providing predictions to the possible measurements to be carried out at LHC.
Heavy quark fragmentation functions for D-wave quarkonium and charmed beauty mesons
Cheung, K.; Yuan, T.C.
1995-09-01
At the large transverse momentum region, the production of heavy-heavy bound-states such as charmonium, bottomonium, and {anti b}c mesons in high energy e{sup +}e{sup {minus}} and hadronic collisions is dominated by parton fragmentation. The authors calculate the heavy quark fragmentation functions into the D-wave quarkonium and {anti b}c mesons to leading order in the strong coupling constant and in the non-relativistic expansion. In the {anti b}c meson case, one set of its D-wave states is expected to lie below the open flavor threshold. The total fragmentation probability for a {anti b} antiquark to split into the D-wave {anti b}c mesons is about 2 {times} 10{sup {minus}5}, which implies that only 2% of the total pseudo-scalar ground state B{sub c} comes from the cascades of these orbitally excited states.
Evidence for a new S U (4 ) symmetry with J =2 mesons
NASA Astrophysics Data System (ADS)
Denissenya, M.; Glozman, L. Ya.; Pak, M.
2015-06-01
Recently, a new symmetry of mesons has been found upon truncation of the quasizero modes of the overlap Dirac operator in lattice simulations. Namely, the ρ , ρ', ω , ω', a1, b1, h1, and possibly f1 J =1 mesons get degenerate after removal of the quasizero modes. This emergent symmetry has been established to be S U (4 )⊃S U (2 )L×S U (2 )R×U (1 )A . It is higher than the symmetry of the QCD Lagrangian and provides not only a mixing of quarks of given chirality in the isospin space, but also the mixing of left-handed and right-handed components. Here we study, with the overlap Dirac operator, the isovector J =2 mesons upon the quasizero mode reduction and observe a similar degeneracy. This result further supports the S U (4 ) symmetry in mesons of given spin J ≥1 .
Observation and properties of the orbitally excited B_(s2)(*) meson.
Abazov, V M; Abbott, B; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguilo, E; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Ancu, L S; Andeen, T; Anderson, S; Andrieu, B; Anzelc, M S; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; Asman, B; Assis Jesus, A C S; Atramentov, O; Autermann, C; Avila, C; Ay, C; Badaud, F; Baden, A; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Banerjee, P; Barberis, E; Barfuss, A-F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benitez, J A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Biscarat, C; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Bloom, K; Boehnlein, A; Boline, D; Bolton, T A; Borissov, G; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Buchanan, N J; Buchholz, D; Buehler, M; Buescher, V; Bunichev, S; Burdin, S; Burke, S; Burnett, T H; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Carvalho, W; Casey, B C K; Cason, N M; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K M; Chan, K; Chandra, A; Charles, F; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Coadou, Y; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M-C; Crépé-Renaudin, S; Cutts, D; Cwiok, M; da Motta, H; Das, A; Davies, G; De, K; de Jong, S J; De La Cruz-Burelo, E; De Oliveira Martins, C; Degenhardt, J D; Déliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dong, H; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Ford, M; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; Galyaev, E; Garcia, C; Garcia-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Gelé, D; Gerber, C E; Gershtein, Y; Gillberg, D; Ginther, G; Gollub, N; Gómez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, Ph; Grivaz, J-F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, J; Guo, F; Gutierrez, P; Gutierrez, G; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Hanagaki, K; Hansson, P; Harder, K; Harel, A; Harrington, R; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinmiller, J M; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hong, S J; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Käfer, D; Kajfasz, E; Kalinin, A M; Kalk, J R; Kalk, J M; Kappler, S; Karmanov, D; Kasper, P; Katsanos, I; Kau, D; Kaur, R; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y M; Khatidze, D; Kim, H; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J-P; Kopal, M; Korablev, V M; Kozelov, A V; Krop, D; Kuhl, T; Kumar, A; Kunori, S; Kupco, A; Kurca, T; Kvita, J; Lacroix, F; Lam, D; Lammers, S; Landsberg, G; Lebrun, P; Lee, W M; Leflat, A; Lehner, F; Lellouch, J; Leveque, J; Lewis, P; Li, J; Li, Q Z; Li, L; Lietti, S M; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobo, L; Lobodenko, A; Lokajicek, M; Love, P; Lubatti, H J; Lyon, A L; Maciel, A K A; Mackin, D; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martin, B; McCarthy, R; Melnitchouk, A; Mendes, A; Mendoza, L; Mercadante, P G; Merkin, M; Merritt, K W; Meyer, J; Meyer, A; Millet, T; Mitrevski, J; Molina, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulders, M; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nogima, H; Nomerotski, A; Novaes, S F; Nunnemann, T; O'Dell, V; O'Neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Oshima, N; Osta, J; Otec, R; Otero Y Garzón, G J; Owen, M; Padley, P; Pangilinan, M; Parashar, N; Park, S-J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Penning, B; Perfilov, M; Peters, K; Peters, Y; Pétroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M-A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M-E; Polozov, P; Pope, B G; Popov, A V; Potter, C; Prado da Silva, W L; Prosper, H B; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Ranjan, K; Ratoff, P N; Renkel, P; Reucroft, S; Rich, P; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rodrigues, R F; Rominsky, M; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Sánchez-Hernández, A; Sanders, M P; Santoro, A; Savage, G; Sawyer, L; Scanlon, T; Schaile, D; Schamberger, R D; Scheglov, Y; Schellman, H; Schieferdecker, P; Schliephake, T; Schwanenberger, C; Schwartzman, A; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Siccardi, V; Simak, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Snow, J; Snow, G R; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Souza, M; Spurlock, B; Stark, J; Steele, J; Stolin, V; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, M; Strauss, E; Ströhmer, R; Strom, D; Stutte, L; Sumowidagdo, S; Svoisky, P; Sznajder, A; Talby, M; Tamburello, P; Tanasijczuk, A; Taylor, W; Temple, J; Tiller, B; Tissandier, F; Titov, M; Tokmenin, V V; Toole, T; Torchiani, I; Trefzger, T; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, S; Uvarov, L; Uzunyan, S; Vachon, B; van den Berg, P J; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Vaupel, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Villeneuve-Seguier, F; Vint, P; Vokac, P; Von Toerne, E; Voutilainen, M; Wagner, R; Wahl, H D; Wang, L; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, M; Weber, G; Wenger, A; Wermes, N; Wetstein, M; White, A; Wicke, D; Williams, M R J; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yacoob, S; Yamada, R; Yan, M; Yasuda, T; Yatsunenko, Y A; Yip, K; Yoo, H D; Youn, S W; Yu, J; Zatserklyaniy, A; Zeitnitz, C; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zivkovic, L; Zutshi, V; Zverev, E G
2008-02-29
We report the direct observation of the excited L=1 state B_(s2)(*) in fully reconstructed decays to B+K-. The mass of the B_(s2)(*) meson is measured to be 5839.6+/-1.1(stat)+/-0.7(syst) MeV/c(2), and its production rate relative to the B+ meson is measured to be [1.15+/-0.23(stat)+/-0.13(syst)]%. PMID:18352617
Vector and axial vector mesons in a nonlocal chiral quark model
NASA Astrophysics Data System (ADS)
Izzo Villafañe, M. F.; Gómez Dumm, D.; Scoccola, N. N.
2016-09-01
Basic features of nonstrange vector and axial vector mesons are analyzed in the framework of a chiral quark model that includes nonlocal four-fermion couplings. Unknown model parameters are determined from some input values of masses and decay constants, while nonlocal form factors are taken from a fit to lattice QCD results for effective quark propagators. Numerical results show a good agreement with the observed meson phenomenology.
Production of D*+ (2010) mesons by high-energy neutrinos from the Tevatron
Asratian, A.E.; Aderholz, M.; Ammosov, V.V.; Barth, M.; Bingham, H.H.; Brucker, E.B.; Burnstein, R.A.; Chatterjee, T.K.; Clayton, E.C.; Ermolov, P.F.; Erofeeva, I.N.; Faulkner, P.J.W.; Gapienko, G.S.; Guy, J.; Hanlon, J.; Harigel, G.; Ivanilov, A.A.; Jain, V.; Jones, G.T.; Jones, M.D.; Kafka, T.; /UC, Berkeley /Birmingham U. /Brussels U., IIHE /CERN /Panjab U. /Fermilab /Hawaii U. /Serpukhov, IHEP /IIT, Chicago /Imperial Coll., London /Moscow, ITEP /Jammu U. /Munich, Max Planck Inst. /Moscow State U. /Oxford U. /Rutgers U., Piscataway /Rutherford /DAPNIA, Saclay /Stevens Tech. /Tufts U.
1997-08-01
Charged vector D*{sup +}(2010) meson production is studied in a high energy neutrino bubble chamber experiment with mean neutrino energy of 141 GeV. The D*{sup +} are produced in (5.6 {+-} 1.8)% of the neutrino charged current interactions, indicating a steep increase of cross section with energy. The mean fractional hadronic energy of the D*{sup +} meson is 0.55 {+-} 0.06.
Decay Constants of B and D Mesons from Non-pertubatively Improved Lattice QCD
K.C. Bowler; L. Del Debbio; J.M. Flynn; G.N, Lacagnina; V.I. Lesk; C.M. Maynard; D.G. Richards
2000-07-01
The decay constants of B and D mesons are computed in quenched lattice QCD at two different values of the coupling. The action and operators are ? (a) improved with non-perturbative coefficients where available. The results and systematic errors are discussed in detail. Results for vector decay constants, flavour symmetry breaking ratios of decay constants, the pseudoscalar-vector mass splitting and D meson masses are also presented.
Meson emission model of Ψ→NN¯m charmonium strong decays
NASA Astrophysics Data System (ADS)
Barnes, T.; Li, Xiaoguang; Roberts, W.
2010-02-01
In this paper we consider a sequential “meson emission” mechanism for charmonium decays of the type Ψ→NN¯m, where Ψ is a generic charmonium state, N is a nucleon, and m is a light meson. This decay mechanism, which may not be dominant in general, assumes that an NN¯ pair is created during charmonium annihilation, and the light meson m is emitted from the outgoing nucleon or antinucleon line. A straightforward generalization of this model can incorporate intermediate N* resonances. We derive Dalitz plot event densities for the cases Ψ=ηc, J/ψ, χc0, χc1, and ψ'; and m=π0, f0, and ω (and implicitly, any 0-+, 0++, or 1- final light meson). It may be possible to separate the contribution of this decay mechanism to the full decay amplitude through characteristic event densities. For the decay subset Ψ→pp¯π0 the two model parameters are known, so we are able to predict absolute numerical partial widths for Γ(Ψ→pp¯π0). In the specific case J/ψ→pp¯π0 the predicted partial width and Mpπ event distribution are intriguingly close to experiment. We also consider the possibility of scalar meson and glueball searches in Ψ→pp¯f0. If the meson emission contributions to Ψ→NN¯m decays can be isolated and quantified, they can be used to estimate meson-nucleon strong couplings {gNNm}, which are typically poorly known, and are a crucial input in meson exchange models of the NN interaction. The determination of gNNπ from J/ψ→pp¯π0 and the (poorly known) gNNω and the anomalous “strong magnetic” coupling κNNω from J/ψ→pp¯ω are considered as examples.
Observation of a 1750 MeV narrow meson decaying into ηη
NASA Astrophysics Data System (ADS)
Alde, D.; Binon, F.; Bricman, C.; Donskov, S. V.; Gouanère, M.; Inyakin, A. V.; Kachanov, V. A.; Kakauridze, D. B.; Khaustov, G. V.; Knapp, E. A.; Kulik, A. V.; Lagnaux, J. P.; Lednev, A. A.; Mikhailov, Yu. V.; Mouthuy, Th.; Peigneux, J. P.; Prokoshkin, Yu. D.; Rodnov, Yu. V.; Sadovsky, S. A.; Samoilenko, V. D.; Shagin, P. M.; Shtannikov, A. V.; Singovsky, A. V.; Stroot, J. P.; Sugonyaev, V. P.
1986-12-01
A narrow meson which decays into ηη is observed in 38 GeV/c π-p collisions at large momentum transfer. The experiment has been performed at the Serpukhov accelerator with the GAMS-2000 spectrometer. The mass of this new meson is (1755 +/- 8) MeV, its width is less than 50 MeV. Its spin-parity is JPC=0++ or less probably 2++.
Regarding the Charmed-Strange Member of the 23S1 Meson State
Feng, Xue-Chao; Chen, Jing
2013-01-01
By employing the mass relations derived from the mass matrix and Regge trajectory, we investigate the masses of charmed and charmed-strange members of the 23S1 meson. The masses are compared with the values predicted by other theoretical approaches and experimental data. The results may be useful for the discovery of the unobserved meson and the determination of the quantum number of the newly discovered states. PMID:24250272
NASA Astrophysics Data System (ADS)
Zöllner, R.; Kämpfer, B.
2016-10-01
Minor extensions of the soft-wall model are used to accommodate two variants of Regge trajectories of vector meson excitations. At nonzero temperatures, various options for either sequential or instantaneous disappearance of vector mesons as normalizable modes are found, thus emulating deconfinement at a certain temperature in the order of the (pseudo)critical temperature of QCD. The crucial role of the blackness function, which steers the thermodynamic properties of the considered system, is highlighted.
Quark matter and meson properties in a Nonlocal SU(3) chiral quark model at finite temperature
Gomez Dumm, D.; Contrera, G. A.
2012-06-15
We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with a background color field. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles, and decay constants.
Isospin violating decays of positive parity B_s mesons in HMχ PT
NASA Astrophysics Data System (ADS)
Fajfer, Svjetlana; Prapotnik Brdnik, Anita
2016-10-01
Recent lattice QCD results suggest that the masses of the first two positive parity B_s mesons lie below the BK threshold, similar to the case of D^*_{s0}(2317)^+ and D_{s1}(2460)^+ mesons. The mass spectrum of B_s mesons seems to follow the pattern of a D_s mass spectrum. As in the case of charmed mesons, the structure of positive parity B_s mesons is very intriguing. To shed more light on this issue, we investigate the strong isospin violating decays B_{s0}^{*0} → B_s^0 π ^0, B_{s1}0 → B_s^{*0} π ^0, and B_{s1}0 → B_s^0 π π within heavy meson chiral perturbation theory. The two-body decay amplitude arises at tree level and we show that the loop corrections give significant contributions. On the other hand, in the case of three-body decay B_{s1}0 → B_s^0 π π the amplitude occurs only at loop level. We find that the decay widths for these decays are Γ (B_{s1}0 → B_s^0 π π )˜ 10^{-3} keV, and Γ (B_{s0}^{*0} → B_s^0 π ^0) ≤ 55 keV, Γ (B_{s1}0 → B_s^{*0} π ^0) ≤ 50 keV. More precise knowledge of the coupling constant describing the interaction of positive and negative parity heavy mesons with light pseudo-scalar mesons would help to increase the accuracy of our calculation.
Measurement of D-meson production in Pb—Pb collisions at the LHC with ALICE
NASA Astrophysics Data System (ADS)
Festanti, Andrea
2016-01-01
The measurement of D-meson production in heavy-ion collisions at LHC energy provides insights into the mechanisms of interaction of charm quarks in the hot and dense medium formed in these collisions. ALICE results on the D-meson nuclear modification factor and azimuthal anisotropy in Pb-Pb collisions at √sNN = 2.76 TeV are presented.
Effect of three-pion unitarity on resonance poles from heavy meson decays
Satoshi X. Nakamura
2011-10-01
We study the final state interaction in 3-pion decay of meson resonances at the Excited Baryon Analysis Center (EBAC) of JLab. We apply the dynamical coupled-channels formulation which has been extensively used by EBAC to extract N* information. The formulation satisfies the 3-pion unitarity condition which has been missed in the existing works with the isobar models. We report the effect of the 3-pion unitarity on the meson resonance pole positions and Dalitz plot.
Meson Emission Model of Psi -> N Nbar m Charmonium Strong Decays
Barnes, Ted {F E }; Li, Xiaoguang; Roberts, Prof. Winston
2010-01-01
In this paper we consider a sequential "meson emission" mechanism for charmonium decays of the type $\\Psi \\to \\NNm$, where $\\Psi$ is a generic charmonium state, $N$ is a nucleon and $m$ is a light meson. This decay mechanism, which may not be dominant in general, assumes that an $\\NN$ pair is created during charmonium annihilation, and the light meson $m$ is emitted from the outgoing nucleon or antinucleon line. A straightforward generalization of this model can incorporate intermediate $N^*$ resonances. We derive Dalitz plot event densities for the cases $\\Psi = \\eta_c$, $J/\\psi$, $\\chi_{c0}$, $\\chi_{c1}$ and $\\psi'$ and $m = \\pi^0, f_0$ and $\\omega$ (and implicitly, any $0^{-+}$, $0^{++}$ or $1^{--}$ final light meson). It may be possible to separate the contribution of this decay mechanism to the full decay amplitude through characteristic event densities. For the decay subset $\\Psi \\to \\pppi$ the two model parameters are known, so we are able to predict absolute numerical partial widths for $\\Gamma(\\Psi\\to \\pppi)$. In the specific case $J/\\psi \\to \\pppi$ the predicted partial width and $M_{p\\pi}$ event distribution are intriguingly close to experiment. We also consider the possibility of scalar meson and glueball searches in $\\Psi \\to \\ppf0$. If the meson emission contributions to $\\Psi \\to \\NNm$ decays can be isolated and quantified, they can be used to estimate meson-nucleon strong couplings $\\{g_{NNm}\\}$, which are typically poorly known, and are a crucial input in meson exchange models of the $NN$ interaction. The determination of $g_{NN\\pi}$ from $J/\\psi \\to \\pppi$ and the (poorly known) $g_{NN\\omega}$ and the anomalous ``strong magnetic" coupling $\\kappa_{NN\\omega}$ from $J/\\psi \\to \\ppw$ are considered as examples.
Fragmentation functions of neutral mesons π0 and k0 with Laplace transform approach
NASA Astrophysics Data System (ADS)
Taghavi-Shahri, F.; Tehrani, S. Atashbar; Zarei, M.
2016-06-01
With an analytical solutions of DGLAP evolution equations based on the Laplace transform method, we find the fragmentation functions (FFs) of neutral mesons, π0 and k0 at NLO approximation. We also calculated the total fragmentation functions of these mesons and compared them with experimental data and those from global fits. The results show a good agreement between our solutions and other models and they are compatible with experimental data.
Rare decays of B mesons via on-shell sterile neutrinos
NASA Astrophysics Data System (ADS)
Cvetič, Gorazd; Kim, C. S.
2016-09-01
In view of the projected high number of produced B mesons in the Belle II experiment (˜1 010 per year), in addition to the ongoing LHC-b, we calculate the rate of decay for the rare decays of B mesons via a sterile on-shell neutrino N , which subsequently may decay leptonically or semileptonically within the detector: B →(D(*))ℓ1±N , then N →ℓ1±ℓ2∓ν or N →ℓ±π∓. Here, ℓ1≠ℓ2 in order to avoid serious QED background. We account for the possible effects of the neutrino lifetime on the observability of the rare decays. If no charmed mesons [D(*)] are produced at the first vertex of the sterile neutrino, a strong Cabibbo-Kobayashi-Maskawa (CKM) suppression becomes effective; this is not true if we consider instead the decays of Bc mesons, which can be produced copiously in LHC-b. The production of charmed mesons D(*) at the first vertex offers an attractive possibility because it avoids strong CKM suppression. Such rare decays of B mesons could be detected at the Belle II experiment, with the N neutrino either decaying within the detector or manifesting itself as a massive missing momentum.
Ablakulov, Kh. Narzikulov, Z.
2015-01-15
A phenomenological model is developed in terms of bilocal meson fields in order to describe a vector meson and its leptonic decays. A new Salpeter equation for this particle and the Schwinger-Dyson equation allowing for the presence of an arbitrary potential and for a modification associated with the renormalization of the quark (antiquark ) wave function within the meson are given. An expression for the constant of the leptonic decay of the charged rho meson is obtained from an analysis of the decay process τ → ρν via parametrizing in it the hadronization of intermediate charged weak W bosons into a bilocal vector meson. The potential is chosen in the form of the sum of harmonic-oscillator and Coulomb potentials, and the respective boundary-value problem is formulated. It is shown that the solutions to this problem describe both the mass spectrum of vector mesons and their leptonic-decay constants.
Study of B Meson Decays to ppbarh Final States
Hryn'ova, Tetiana B.; /SLAC
2006-03-22
B mesons are unique among well-established non-quarkonium mesons in their ability to decay into baryons. Baryonic B decays offer a wide range of interesting areas of study: they can be used to test our theoretical understanding of rare decay processes involving baryons, search for direct CP violation and study low-energy QCD. This thesis presents measurements of branching fractions and a study of the decay dynamics of the charmless three-body decays of B meson into p{bar p}h final states, where h = {pi}{sup +}, K{sup +}, K{sub S}{sup 0}, K*{sup 0} or K*{sup +}. With a sample of 232 million {Upsilon}(4S) {yields} B{bar B} events collected with the BaBar detector, we report the first observation of the B {yields} p{bar p}K*{sup 0} decay, and provide improved measurements of branching fractions of the other modes. The distribution of the three final-state particles is of particular interest since it provides dynamical information on the possible presence of exotic intermediate states such as the hypothetical pentaquark states {Theta}*{sup ++} and {Theta}{sup +}in the m{sub pK{sup +}} and m{sub pK{sub S}{sup 0}} spectra, respectively, or glueball states (such as the tensor glueball f{sub J}(2220)) in the m{sub p{bar p}} spectrum. No evidence for exotic states is found and upper limits on the branching fractions are set. An enhancement at low p{bar p} mass is observed in all the B {yields} p{bar p}h modes, and its shape is compared between the decay modes and with the shape of the time-like proton form factor. A Dalitz plot asymmetry in B {yields} p{bar p}K{sup +} mode suggests dominance of the penguin amplitude in this decay and disfavors the possibility that the low mass p{bar p} enhancement originates from the presence of a resonance below threshold (such as the recently seen baryonium candidate at 1835 MeV/c{sup 2}). We also identify decays of the type B {yields} X{sub c{bar c}}h {yields} p{bar p}h, where h = K{sup +}, K{sub S}{sup 0}, K*{sup 0} or K*{sup +}, and X
Probing the simplest mesons to study the transverse spatial structure of hadrons
NASA Astrophysics Data System (ADS)
Carmignotto, Marco; Horn, Tanja
2014-09-01
According to the constituent quark model, mesons are the hadrons with the simplest structures since they are built of two valence quarks only. This relative simple structure gives the mesons one of the best place in our quest to understand the structure and interaction of hadrons on the basis of QCD. The pion, the lightest meson, has been studied in details over the last decades. Measurements of the pion form factor are bringing important information about the pion structure and the meson electroproduction mechanism. Pion form factor data also allow one to extract the pion transverse charge density, an important quantity related to the GPDs that can also provide interesting information on the spatial structure of the nucleon's meson cloud. In this talk, I will present the transverse pion charge density extracted from world data of the pion form factor and their comparison to proton transverse charge densities. The kaon, the next simplest system available for studies, is relatively unexploited to date due to the lack of the necessary experimental facilities. I will also discuss the current status and opportunities for kaon studies in the 12 GeV era at Jefferson Laboratory and future facilities like the Electron-Ion Collider, as well as instrumentation required for such studies. According to the constituent quark model, mesons are the hadrons with the simplest structures since they are built of two valence quarks only. This relative simple structure gives the mesons one of the best place in our quest to understand the structure and interaction of hadrons on the basis of QCD. The pion, the lightest meson, has been studied in details over the last decades. Measurements of the pion form factor are bringing important information about the pion structure and the meson electroproduction mechanism. Pion form factor data also allow one to extract the pion transverse charge density, an important quantity related to the GPDs that can also provide interesting information on the
Weak decays of the B c meson to B s and B mesonsin the relativistic quark model
NASA Astrophysics Data System (ADS)
Ebert, D.; Faustov, R. N.; Galkin, V. O.
2003-12-01
Semileptonic and non-leptonic decays of the B c meson to B s and B mesons, caused by the cto s,d quark transitions, are studied in the framework of the relativistic quark model. The heavy quark expansion in inverse powers of the active c and spectator bar b quark is used to simplify calculations while the final s and d quarks in the B s and B mesons are treated relativistically. The decay form factors are explicitly expressed through the overlap integrals of the meson wave functions in the whole accessible kinematical range. The obtained results are compared with the predictions of other approaches.
Study of reactions disclosing hidden charm pentaquarks with or without strangeness
NASA Astrophysics Data System (ADS)
Oset, Eulogio; Chen, Hua-Xing; Feijoo, Albert; Geng, Li-Sheng; Liang, Wei-Hong; Li, De-Min; Lu, Jun-Xu; Magas, Vladymir K.; Nieves, Juan; Ramos, Angels; Roca, Luis; Wang, En; Xie, Ju-Jun
2016-10-01
We present results for five reactions, Λb → J / ψK- p, Λb → J / ψηΛ, Λb → J / ψπ- p, Λb → J / ψK0 Λ and Ξb- → J / ψK- Λ, where combining information from the meson baryon interaction, using the chiral unitary approach, and predictions made for molecular states of hidden charm, with or without strangeness, we can evaluate invariant mass distributions for the light meson baryon states, and for those of J / ψp or J / ψΛ. We show that with the present available information, in all of these reactions one finds peaks where the pentaquark states show up. In the Λb → J / ψK- p and Λb → J / ψπ- p reactions we show that the results obtained from our study are compatible with present experimental observations.
Bogolyubsky, M. Yu.; Evdokimov, S. V.; Izucheev, V. I.; Patalakha, D. I.; Polishchuk, B. V.; Sadovsky, S. A.; Soloviev, A. S.; Stolpovsky, M. V.; Kharlov, Yu. V. Kuzmin, N. A.; Obudovsky, V. P.; Petukhov, Yu. P.; Sychkov, S. Ya.
2013-11-15
The {pi}{sup 0}, {eta}, K{sup 0}, {omega}, and f{sub 2}(1270) masses were measured at the HYPERON-Msetup in meson-nucleus interactions at a momentum of 7 GeV/c by using six nuclear targets: Be, C, Al, Cu, Sn, and Pb. The experiment in question proved to be insensitive to the expected effects of a modification to the omega-meson mass in nuclear matter. As for the f{sub 2}(1270) meson, its mass and width values averaged over all experimental data, m{sub f{sub 2}} = 1275.8 {+-} 1.0(stat.) {+-} 0.4(syst.) MeV/c{sup 2} and {Gamma}{sub f{sub 2}} = 190.3 {+-} 1.9(stat.) {+-} 1.8(syst.) MeV/c{sup 2}, agree well with the world-average values. At the same time, our experimental data do not rule out the possible effect of an in-medium modification to the f{sub 2}(1270)-meson mass for heavy nuclei at a level better than 0.4%.
Finite Nuclei in the Quark-Meson Coupling Model.
Stone, J R; Guichon, P A M; Reinhard, P G; Thomas, A W
2016-03-01
We report the first use of the effective quark-meson coupling (QMC) energy density functional (EDF), derived from a quark model of hadron structure, to study a broad range of ground state properties of even-even nuclei across the periodic table in the nonrelativistic Hartree-Fock+BCS framework. The novelty of the QMC model is that the nuclear medium effects are treated through modification of the internal structure of the nucleon. The density dependence is microscopically derived and the spin-orbit term arises naturally. The QMC EDF depends on a single set of four adjustable parameters having a clear physics basis. When applied to diverse ground state data the QMC EDF already produces, in its present simple form, overall agreement with experiment of a quality comparable to a representative Skyrme EDF. There exist, however, multiple Skyrme parameter sets, frequently tailored to describe selected nuclear phenomena. The QMC EDF set of fewer parameters, derived in this work, is not open to such variation, chosen set being applied, without adjustment, to both the properties of finite nuclei and nuclear matter.
Finite Nuclei in the Quark-Meson Coupling Model.
Stone, J R; Guichon, P A M; Reinhard, P G; Thomas, A W
2016-03-01
We report the first use of the effective quark-meson coupling (QMC) energy density functional (EDF), derived from a quark model of hadron structure, to study a broad range of ground state properties of even-even nuclei across the periodic table in the nonrelativistic Hartree-Fock+BCS framework. The novelty of the QMC model is that the nuclear medium effects are treated through modification of the internal structure of the nucleon. The density dependence is microscopically derived and the spin-orbit term arises naturally. The QMC EDF depends on a single set of four adjustable parameters having a clear physics basis. When applied to diverse ground state data the QMC EDF already produces, in its present simple form, overall agreement with experiment of a quality comparable to a representative Skyrme EDF. There exist, however, multiple Skyrme parameter sets, frequently tailored to describe selected nuclear phenomena. The QMC EDF set of fewer parameters, derived in this work, is not open to such variation, chosen set being applied, without adjustment, to both the properties of finite nuclei and nuclear matter. PMID:26991171
Measurements of the properties of D-meson decays
Schindler, R.H.; Alam, M.S.; Boyarski, A.M.; Breidenbach, M.; Burke, D.L.; Dorenbosch, J.; Dorfan, J.M.; Feldman, G.J.; Franklin, M.E.B.; Hanson, G.; Hayes, K.G.; Himel, T.; Hitlin, D.G.; Hollebeek, R.J.; Innes, W.R.; Jaros, J.A.; Jenni, P.; Larsen, R.R.; Lueth, V.; Perl, M.L.; Richter, B.; Roussarie, A.; Scharre, D.L.; Schwitters, R.F.; Siegrist, J.L.; Taureg, H.; Tonutti, M.; Vidal, R.A.; Weiss, J.M.; Zaccone, H.; Abrams, G.; Blocker, C.A.; Blondel, A.; Carithers, W.C.; Chinowsky, W.; Coles, M.W.; Cooper, S.; Dieterle, W.E.; Dillion, J.B.; Eaton, M.W.; Gidal, G.; Goldhaber, G.; Johnson, A.D.; Kadyk, J.A.; Lankford, A.J.; Millikan, R.E.; Nelson, M.E.; Pang, C.Y.; Patrick, J.F.; Strait, J.; Trilling, G.H.; Vella, E.N.; Videau, I.
1981-07-01
We present a study of the decay properties of charmed D mesons produced near the peak of the psi''(3770) resonance in e/sup +/e/sup -/ annihilation. Branching fractions for nine Cabibbo-favored and three Cabibbo-suppressed decay modes are presented along with upper limits on one additional Cabibbo-favored and four additional Cabibbo-suppressed decay modes. A study of K..pi pi..-decay-mode Dalitz plots reveals a large quasi-two-body pseudoscalar-vector component for the D/sup 0/ decays and an apparent nonuniform population on the Dalitz plot for the D/sup +/ decay into K/sup -/..pi../sup +/..pi../sup +/. Using tagged events, we measure the charged-particle multiplicity and strange-particle content of D decays. A measurement of the D/sup +/ and D/sup 0/ semileptonic decay fractions indicates that the D/sup +/ has a significantly longer lifetime than the D/sup 0/.
{rho} meson decay in 2+1 flavor lattice QCD
Aoki, S.; Ishizuka, N.; Taniguchi, Y.; Ukawa, A.; Yoshie, T.; Ishikawa, K-I.; Okawa, M.; Kanaya, K.; Kuramashi, Y.; Namekawa, Y.; Ukita, N.; Yamazaki, T.
2011-11-01
We perform a lattice QCD study of the {rho} meson decay from the N{sub f}=2+1 full QCD configurations generated with a renormalization group improved gauge action and a nonperturbatively O(a)-improved Wilson fermion action. The resonance parameters, the effective {rho}{yields}{pi}{pi} coupling constant and the resonance mass, are estimated from the P-wave scattering phase shift for the isospin I=1 two-pion system. The finite size formulas are employed to calculate the phase shift from the energy on the lattice. Our calculations are carried out at two quark masses, m{sub {pi}=}410 MeV (m{sub {pi}/}m{sub {rho}=}0.46) and m{sub {pi}=}300 MeV (m{sub {pi}/}m{sub {rho}=}0.35), on a 32{sup 3}x64 (La=2.9 fm) lattice at the lattice spacing a=0.091 fm. We compare our results at these two quark masses with those given in the previous works using N{sub f}=2 full QCD configurations and the experiment.
High-energy photoproduction of rho and phi vector mesons
Callahan, P.H.
1983-01-01
We have studied the photoproduction of rho and phi vector mesons from hydrogen in the Fermilab broad band neutral beam. Forward going two particle final states were detected in a multiparticle spectrometer consisting of two analyzing magnets, a multiwire-proportional-chamber tracking system and a particle identification system. Recoil protons and target fragments were observed in a recoil detector which surrounded the target. The total elastic cross-sections were measured to be independent of energy at the 10% level from 35 to 225 GeV at 10.6 ..mu..b for the rho and from 35 to 165 GeV at 0.64 ..mu..b for the phi. The elastic differential cross-sections were also measured. Approximately 20% of the diffractive rho and phi events were found to be inelastic from an analysis of the recoil detector. The t-dependence of the fraction of diffractive events which are inelastic for both the phi and the psi are consistent with a universal function determined from the rho data.
New mechanisms for double charmed meson production at the LHCb
NASA Astrophysics Data System (ADS)
Maciuła, Rafał; Saleev, Vladimir A.; Shipilova, Alexandra V.; Szczurek, Antoni
2016-07-01
We discuss production of D0D0 (and Dbar0Dbar0) pairs related to the LHCb Collaboration results for √{ s} = 7 TeV in proton-proton scattering. We consider double-parton scattering (DPS) mechanisms of double c c bar production and subsequent cc →D0D0 hadronization as well as double g and mixed gc c bar production with gg →D0D0 and gc →D0D0 hadronization calculated with the help of the scale-dependent hadronization functions of Kniehl et al. Single-parton scattering (SPS) mechanism of digluon production is also taken into account. We compare our results with several correlation observables in azimuthal angle φD0D0 between D0 mesons or in dimeson invariant mass MD0D0. The inclusion of new mechanisms with g →D0 fragmentation leads to larger cross sections, than when including only DPS mechanism cc →D0D0 with standard scale-independent fragmentation functions. Some consequences of the presence of the new mechanisms are discussed. In particular a larger σeff is needed to describe the LHCb data. There is a signature that σeff may depend on transverse momentum of c quarks and/or c bar antiquarks.
Role of 'intrinsic charm' in semileptonic B-meson decays
Breidenbach, C.; Feldmann, T.; Turczyk, S.; Mannel, T.
2008-07-01
We discuss the role of so-called 'intrinsic-charm' operators in semileptonic B-meson decays, which appear first at order 1/m{sub b}{sup 3} in the heavy quark expansion. We show by explicit calculation that - at scales {mu}{<=}m{sub c} - the contributions from 'intrinsic-charm' effects can be absorbed into short-distance coefficient functions multiplying, for instance, the Darwin term. Then, the only remnant of 'intrinsic charm' are logarithms of the form ln(m{sub c}{sup 2}/m{sub b}{sup 2}), which can be resummed by using renormalization-group techniques. As long as the dynamics at the charm-quark scale is perturbative, {alpha}{sub s}(m{sub c})<<1, this implies that no additional nonperturbative matrix elements aside from the Darwin and the spin-orbit term have to be introduced at order 1/m{sub b}{sup 3}. Hence, no sources for additional hadronic uncertainties have to be taken into account. Similar arguments may be made for higher orders in the 1/m{sub b} expansion.
Seismic vulnerability study Los Alamos Meson Physics Facility (LAMPF)
Salmon, M.; Goen, L.K.
1995-12-01
The Los Alamos Meson Physics Facility (LAMPF), located at TA-53 of Los Alamos National Laboratory (LANL), features an 800 MeV proton accelerator used for nuclear physics and materials science research. As part of the implementation of DOE Order 5480.25 and in preparation for DOE Order 5480.28, a seismic vulnerability study of the structures, systems, and components (SSCs) supporting the beam line from the accelerator building through to the ends of die various beam stops at LAMPF has been performed. The study was accomplished using the SQUG GIP methodology to assess the capability of the various SSCs to resist an evaluation basis earthquake. The evaluation basis earthquake was selected from site specific seismic hazard studies. The goals for the study were as follows: (1) identify SSCs which are vulnerable to seismic loads; and (2) ensure that those SSCs screened during die evaluation met the performance goals required for DOE Order 5480.28. The first goal was obtained by applying the SQUG GIP methodology to those SSCS represented in the experience data base. For those SSCs not represented in the data base, information was gathered and a significant amount of engineering judgment applied to determine whether to screen the SSC or to classify it as an outlier. To assure the performance goals required by DOE Order 5480.28 are met, modifications to the SQUG GIP methodology proposed by Salmon and Kennedy were used. The results of this study ire presented in this paper.
Search for T violation in charm meson decays
Link, J.M.; Yager, P.M.; Anjos, J.C.; Bediaga, I.; Castromonte, C.; Machado, A.A.; Magnin, J.; Massafferri, A.; de Miranda, J.M.; Pepe, I.M.; Polycarpo, E.; dos Reis, A.C.; Carrillo, S.; Casimiro, E.; Cuautle, E.; Sanchez-Hernandez, A.; Uribe, C.; Vazquez, F.; Agostino, L.; Cinquini, L.; Cumalat, J.P.; /Colorado U. /Fermilab /Frascati /Guanajuato U. /Illinois U., Urbana /Indiana U. /Korea U. /Kyungpook Natl. U. /INFN, Milan /Milan U. /North Carolina U. /Pavia U. /INFN, Pavia /Rio de Janeiro, Pont. U. Catol. /Puerto Rico U., Mayaguez /South Carolina U. /Tennessee U. /Vanderbilt U. /Wisconsin U., Madison
2005-06-01
Using data from the FOCUS (E831) experiment, they have searched for T violation in charm meson decays using the four-body decay channels D{sup 0} {yields} K{sup -}K{sup +} {pi}{sup -}{pi}{sup +}, D{sup +} {yields} K{sub S}{sup 0}K{sup +}{pi}{sup -}{pi}{sup +}, and D{sub s}{sup +} {yields} K{sub S}{sup 0}K{sup +}{pi}{sup -}{pi}{sup +}. The T violation asymmetry is obtained using triple-product correlations and assuming the validity of the CPT theorem. They find the asymmetry values to be A{sub T{sub viol}}(D{sup 0}) = 0.010 {+-} 0.057(stat.) {+-} 0.037(syst.), A{sub T{sub viol}}(D{sup +}) = 0.023 {+-} 0.062(stat.) {+-} 0.022(syst.), and A{sub T{sub viol}}(D{sub s}{sup +}) = -0.036 {+-} 0.067(stat.) {+-} 0.023(syst.). Each measurement is consistent with no T violation. New measurements of the CP asymmetries for some of these decay modes are also presented.
Search for rare b-meson decays at CDF
Mack, Philipp; /Karlsruhe U., EKP
2007-10-01
We report on the search for B{sup 0}{sub s}{yields}{mu}{sup +}{mu}{sup -}, B{sup 0}{sub d}{yields}{mu}{sup +}{mu}{sup -} decays and b{yields} s{mu}{sup +}{mu}{sup -} transitions in exclusive decays of B mesons using the CDF II detector at the Fermilab Tevatron Collider. Using 2 fb{sup -1} of Run II data we find upper limits on the branching fractions {beta}(B{sup 0}{sub s}{yields}{mu}{sup +}{mu}{sup -})<5.8 x 10{sup -8} and {beta}(B{sup 0}{sub d}{yields}{mu}{sup +}{mu}{sup -})<1.8 x 10{sup -8} at 95% confidence level. The results for the branching fractions of the b{yields} s{mu}{sup +}{mu}{sup -} transitions using 924 pb{sup -1} of Run II data are {beta}(B{sup +}{yields}{mu}{sup +}{mu}{sup -}K{sup +})=(0.60{+-}0.15{+-}0.04) x 10{sup -6}, {beta}(B{sup 0}{sub d}{yields}{mu}{sup +}{mu}{sup -}K{sup *0})=(0.82{+-}0.31{+-}0.10) x 10{sup -6} and {beta}(B{sup 0}{sub s}{yields} {mu}{sup +}{mu}{sup -}{phi})/{beta}(B{sup 0}{sub s}{yields}J/{psi}{phi}) < 2.61 x 10{sup -3} at 95% confidence level.
Line shapes of the exotic charm-anticharm mesons X(3872) and Z(4430)
NASA Astrophysics Data System (ADS)
Lu, Meng
The B-factory experiments have recently discovered a series of new cc mesons, including the X(3872) and the first manifestly exotic meson Z +/-(4430). The proximity of the mass of the X to the D*0D 0 threshold has motivated its identification as a loosely-bound hadronic molecule whose constituents are a superposition of the charm mesons pairs D*0D 0 and D0D* 0. Factorization formulas for its line shapes are derived by taking advantage of the universality of S-wave resonances near a 2-particle threshold and by including the effects from the nonzero width of D* meson and the inelastic scattering channels of the charm mesons. The best fit to the line shapes of X in the J/psipi +pi- and D0 D0pi0 channels measured by the Belle Collaboration corresponds to the X being a bound state whose mass is just below the D*0 D0 threshold. The differences between the line shapes of X produced in B+ decays and B0 decays as well as in decay channels J/psipi+pi-, J /psipi+pi-pi0 , and D0D 0pi0 are further derived by taking into account the effects from the closeby channel composed of charged charm mesons. A more speculative application of the universality of S-wave resonances near a 2-particle threshold is to the Z+/-(4430), which is interpreted as a charm meson molecule composed of a superposition of D+1D*0 and D*+D01 . The small ratio of the binding energy of the Z + to the width of its constituent D1 is exploited to obtained simple predictions for its line shapes in the channels psi(2S)pi + and D*D*pi.
Diagrammatic Approach to Meson Production in Proton-Proton Collisions near Threshold
Kaiser, Norbert
2000-12-31
We evaluate the threshold T-matrices for the reactions pp {yields} pp{pi}{sup 0}, pn{pi}{sup +}, pp{eta}, pp{omega},p{Lambda}K{sup +}, and pn {yields} pn{eta} in a relativistic Feynman diagram approach. We employ an effective range approximation to take care of the strong S-wave pN and p{Lambda} final-state interaction. We stress that the heavy baryon formalism is not applicable in the NN-system above {pi}-production threshold due to the large external momentum, {vert_bar}{rvec p}{vert_bar} {approx_equal} {radical}(Mm{sub {pi}}). The magnitudes of the experimental threshold amplitudes extracted from total cross section data, script-A = (2.7{minus}0.3i)fm{sup 4}, script-B = (2.8{minus}1.5i)fm{sup 4}, {vert_bar}script-C{vert_bar} = 1.32 fm{sup 4}, {vert_bar}{Omega}{vert_bar} = 0.53 fm{sup 4}, script-K = {radical}(2{vert_bar}K{sub s}{vert_bar}{sup 2} + {vert_bar}K{sub t}{vert_bar}{sup 2}) = 0.38 fm{sup 4} and {vert_bar}script-D{vert_bar} = 2.3 fm{sup 4} can be reproduced by (long-range) o ne-pion exchange and short-range vector meson exchanges, with the latter giving the largest contributions. Pion loop effects in pp {yields} pp{pi}{sup 0} appear to be small. The presented diagrammatic approach requires further tests via studies of angular distributions and polarization observables.
Photoproduction of Scalar Mesons Using the CEBAF Large Acceptance Spectrometer (CLAS)
NASA Astrophysics Data System (ADS)
Chandavar, Shloka K.
The search for glueballs has been ongoing for several decades. The lightest glueball has been predicted by quenched lattice QCD to have mass in the range of 1.0--1.7 GeV and JPC = 0++ . The mixing of glueball states with neighbouring meson states complicates their identification and hence several experiments have been carried out over the years to study the glueball candidates. By analyzing the decay channels and production mechanisms of these candidates, their glueball content can theoretically be determined. In reality, a lot of confusion still exists about the status of these glueball candidates. The f0(1500) is one of several contenders for the lightest glueball, which has been extensively studied in several different kinds of experiments. However, there exists no photoproduction data on this particle. In the analysis presented in this dissertation, the presence of the f0(1500) in the KS 0KS0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility, also called Jefferson Lab (JLab). This is done by studying the reaction, gammap → fJp → KS0 KS0p → 2(pi +pi-)p using data from the g12 experiment. A clear peak is seen at 1500 MeV in the background subtracted data. This is enhanced if the momentum transfer is restricted to be less than 1 GeV2. Comparing with simulations, it is seen that this peak is associated with t channel production mechanism. The f 2'(1525) has a mass of 1525 MeV and a width of 73 MeV, and hence there is a possibility of it contributing to the peak observed in our data. A moments analysis seems to suggest some presence of a D wave, however, the low acceptance at forward and backward angles prohibits a definitive conclusion.
Mixed Meson Mass for Domain-Wall Valence and Staggered Sea Fermions
Konstantinos Orginos; Andre Walker-Loud
2007-05-01
Mixed action lattice calculations allow for an additive lattice spacing dependent mass renormalization of mesons composed of one sea and one valence quark, regardless of the type of fermion discretization methods used in the valence and sea sectors. The value of the mass renormalization depends upon the lattice actions used. This mixed meson mass shift is the most important lattice artifact to determine for mixed action calculations: because it modifies the pion mass, it plays a central role in the low energy dynamics of all hadronic correlation functions. We determine the leading order and next to leading order additive mass renormalization of valence-sea mesons for a mixed lattice action with domain-wall valence fermions and staggered sea fermions. We find that on the asqtad improved coarse MILC lattices, the leading order additive mass renormalization for the mixed mesons is Δ(am)^2 LO = 0.0409(11) which corresponds to a^2 Δ_Mix = (319 MeV)^2± (53 MeV)^2 for a = 0.125 fm. We also find significant next to leading order contributions which reduce the mass renormalization by a significant amount, such that for 0 < am_π ≤ 0.22 the mixed meson mass renormalization is well approximated by Δ(am)^2 = 0.0340 (23) or a^2δ_Mix = (290 MeV)^2 ± (76 MeV)^2. The full next-to-leading order analysis is presented in the text.
Central exclusive production as a probe of the gluonic component of the η' and η mesons
NASA Astrophysics Data System (ADS)
Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.; Stirling, W. J.
2013-05-01
Currently, the long-standing issue concerning the size of the gluonic content of the η' and η mesons remains unsettled. With this in mind we consider the central exclusive production (CEP) of η', η meson pairs in the perturbative regime, applying the Durham pQCD-based model of CEP and the `hard exclusive' formalism to evaluate the meson production subprocess. We calculate for the first time the relevant leading order parton-level processes gg to qoverline{q}gg and gg→ gggg, where the final-state gg and qoverline{q} pairs form a pseudoscalar flavour-singlet state. We observe that these amplitudes display some non-trivial and interesting theoretical properties, and we comment on their origin. Finally, we present a phenomenological study, and show that the cross sections for the CEP of η', η meson pairs are strongly sensitive to the size of the gluon content of these mesons. The observation of these processes could therefore provide important and novel insight into this problem.
New results on the b^-+c meson at the Tevatron
Rahaman, M.A.; /Pittsburgh U.
2006-09-01
The authors present recent results on B{sub c}{sup -} meson from the Tevatron. The B{sub c}{sup -} meson has been observed in semileptonic decays, B{sub c}{sup -} {yields} J/{psi}{ell}{sup -} {nu}X, both by CDF and D0 experiments at a significance larger than 5{sigma}. The D0 experiment has used the candidates in B{sub c}{sup -} {yields} J/{psi}{mu}{sup -} {nu}X decay to extract the mass and lifetime of B{sub c}{sup -} meson. The CDF experiment has used both electron and muon channel candidates in B{sub c}{sup -} {yields} J/{psi}{ell}{sup -} {nu}X decays to measure the relative production times branching ratio with respect to B{sup -} {yields} J/{psi}K{sup -} decay and also measured the lifetime of B{sub c}{sup -} meson in electron channel as {tau}(B{sub c}{sup -}) = 0.463{sub -0.055}{sup +0.073} {+-} 0.036 ps. The CDF experiment has also observed B{sub c}{sup -} {yields} J/{psi}{pi}{sup -} decay with a significance exceeding 6.5{sigma} and has measured the mass of B{sub c}{sup -} meson as M(B{sub c}{sup -}) = 6276.5 {+-} 4.0 {+-} 2.7 MeV/c{sup 2}.
{pi}- and {rho}-mesons, and their diquark partners, from a contact interaction.
Roberts, H. L. L.; Bashir, A.; Gutierrez-Guerrero, L. X.; Roberts, C. D.; Wilson, D. J.
2011-06-22
We present a unified Dyson-Schwinger equation treatment of static and electromagnetic properties of pseudoscalar and vector mesons, and scalar and axial-vector diquark correlations, based upon a vector-vector contact interaction. A basic motivation for this paper is the need to document a comparison between the electromagnetic form factors of mesons and those diquarks that play a material role in nucleon structure. A notable result, therefore, is the large degree of similarity between related meson and diquark form factors. The simplicity of the interaction enables computation of the form factors at arbitrarily large spacelike Q{sup 2}, which enables us to expose a zero in the {rho}-meson electric form factor at z{sub Q}{sup {rho}} {approx} {radical}6m{sub {rho}}. Notably, r{sub {rho}}z{sub Q}{sup {rho}} {approx} r{sub D}z{sub Q}{sup D}, where r{sub {rho}} and r{sub D} are, respectively, the electric radii of the {rho}-meson and deuteron.
Effective meson masses in nuclear matter based on a cutoff field theory
Nakano, M.; Noda, N.; Mitsumori, T.; Koide, K.; Kouno, H.; Hasegawa, A.
1997-02-01
Effective masses of {sigma}, {omega}, {pi}, and {rho} mesons in nuclear matter are calculated based on a cutoff field theory. Instead of the traditional density-Feynman representation, we adopt the particle-hole-antiparticle representation for nuclear propagators so that unphysical components are not included in the meson self-energies. For an estimation of the contribution from the divergent particle-antiparticle excitations, i.e., vacuum polarization in nuclear matter, the idea of the renormalization group method is adopted. In this cutoff field theory, all the counterterms are finite and calculated numerically. It is shown that the predicted meson masses converge even if the cutoff {Lambda} is changed as long as {Lambda} is sufficiently large and that the prescription works well also for so-called nonrenormalized mesons such as {pi} and {rho}. According to this method, it is concluded that meson masses in nuclear matter have a weak dependence on the baryon density. {copyright} {ital 1997} {ital The American Physical Society}
Excited meson radiative transitions from lattice QCD using variationally optimized operators
Shultz, Christian J.; Dudek, Jozef J.; Edwards, Robert G.
2015-06-02
We explore the use of 'optimized' operators, designed to interpolate only a single meson eigenstate, in three-point correlation functions with a vector-current insertion. These operators are constructed as linear combinations in a large basis of meson interpolating fields using a variational analysis of matrices of two-point correlation functions. After performing such a determination at both zero and non-zero momentum, we compute three-point functions and are able to study radiative transition matrix elements featuring excited state mesons. The required two- and three-point correlation functions are efficiently computed using the distillation framework in which there is a factorization between quark propagation and operator construction, allowing for a large number of meson operators of definite momentum to be considered. We illustrate the method with a calculation using anisotopic lattices having three flavors of dynamical quark all tuned to the physical strange quark mass, considering form-factors and transitions of pseudoscalar and vector meson excitations. In conclusion, the dependence on photon virtuality for a number of form-factors and transitions is extracted and some discussion of excited-state phenomenology is presented.
Charmed Meson Production in 800 GEV Proton-Proton Interactions.
NASA Astrophysics Data System (ADS)
Senko, Mark Frederick
The purpose of this dissertation is to present the results of a study concerning the energy dependence of charmed meson production properties as a test of Quantum Chromodynamics (QCD). This experiment was performed at Fermi National Accelerator Laboratory, using a rapid cycling bubble chamber (LEBC) as a hydrogen target and high resolution vertex detector, in combination with the Fermilab Multiparticle Spectrometer (FMPS). The multiplicity trigger was unbiased, and spectrometer acceptance was good at x_ {F} >=q 0. A comparison of the results from previous experiments at center of mass energies sqrt{s} <=q 27 GeV and sqrt {s} >=q 53 GeV implies a total charm particle production cross section which rises rapidly as a function of sqrt{s} . The result of our experiment, sigma (D/| D) = 42.7 +/- 7.8 mub at sqrt{s} = 38 GeV, indicates a slower rise, in agreement with QCD predictions. A maximum likelihood fit to the parameterization of the differential cross section as d^2sigma/dx_{F}dp _sp{|}{2} ~ (1 - | x_{F }|)^{n}e^{-bp _sp{|}{2}} gives the results n = 8.4_sp {-1.9}{+2.2}, b = 0.78_sp{-0.16}{+0.19} (GeV/c)^{-2}, and < pbot > = 1.1_sp{-0.1}{+0.2} GeV/c. When compared with results from the lower energy experiments, these values indicate charm production becoming more central and < pbot > being consistent with the charmed quark mass. These results are once again consistent with QCD predictions. Lastly, analysis has shown that sigma(D ^*^+/-)/sigma(D^0) is governed primarily by spin statistics, displaying no energy dependence. The resulting cross section for D^*^+/- production is sigma(D^*^+/-) = 13.31 +/- 5.74 mub.
Simulations for an experiment to probe the in-medium properties of photoproduced vector mesons
Clarisse Tur
2003-04-01
The g7 experiment has been devised to measure the modifications of the vector meson properties, such as mass or width, inside nuclear medium, based on the ideas presented in the numerous papers published during the fifteen years that preceded its run. It consisted in sending a bremstrahlung photon beam on a target that contained elements with different densities, a liquid deuterium cell, and seven solid foils: carbon, iron, carbon, lead, carbon, titanium, carbon. The goal of the experiment is to examine the inclusive e{sup +}e{sup -} photoproduction in the incoherent region. The reaction of interest to g7 is {gamma}A {yields} VA{prime} {yields} e{sup +}e{sup -}A{prime} where V could be a {rho} an {omega} or a {phi} meson. The goal of the present thesis was to present the simulation work done prior to the g7 run in the fall of 2002 at Jlab, essential for the choice of the ideal experimental setup and conditions, as well as the test run of June 2002. The simulations needed a particular attention, given the many experimental challenges that awaited the g7 team. First, one had to prove that the resolution of the CLAS detector was sufficient to properly locate the vertices of the events given the multi-segmented target, and the simulations proved that fact. They also provided a rough idea of the systematic errors that one had to expect. Using nuclei bigger than carbon was a first time for CLAS. Given the very small branching ratio for {rho} {yields} e{sup +}e{sup -}, a very intense beam had to be sent on the target containing high-Z material. Thus, a huge background, formed of low energy e{sup +}e{sup -} pairs, was expected around the target and the region I of the drift chambers and which one had to reduce in an efficient way. The simulations showed that using the mini torus with its current set to 75% of its maximum value would give a reduction of about a factor of 3 in the number of hits in the region I of the drift chambers, compared to the case with no mini torus
Superconformal Baryon-Meson Symmetry and Light-Front Holographic QCD
Dosch, Hans Guenter; de Teramond, Guy F.; Brodsky, Stanley J.
2015-04-10
We construct an effective QCD light-front Hamiltonian for both mesons and baryons in the chiral limit based on the generalized supercharges of a superconformal graded algebra. The superconformal construction is shown to be equivalent to a semi-classical approximation to light-front QCD and its embedding in AdS space. The specific breaking of conformal invariance inside the graded algebra uniquely determines the effective confinement potential. The generalized supercharges connect the baryon and meson spectra to each other in a remarkable manner. In particular, the π/b_{1} Regge trajectory is identified as the superpartner of the nucleon trajectory. However, the lowest-lying state on this trajectory, the π-meson is massless in the chiral limit and has no supersymmetric partner.
Superconformal Baryon-Meson Symmetry and Light-Front Holographic QCD
Dosch, Hans Guenter; de Teramond, Guy F.; Brodsky, Stanley J.
2015-04-10
We construct an effective QCD light-front Hamiltonian for both mesons and baryons in the chiral limit based on the generalized supercharges of a superconformal graded algebra. The superconformal construction is shown to be equivalent to a semi-classical approximation to light-front QCD and its embedding in AdS space. The specific breaking of conformal invariance inside the graded algebra uniquely determines the effective confinement potential. The generalized supercharges connect the baryon and meson spectra to each other in a remarkable manner. In particular, the π/b1 Regge trajectory is identified as the superpartner of the nucleon trajectory. However, the lowest-lying state on thismore » trajectory, the π-meson is massless in the chiral limit and has no supersymmetric partner.« less
D* and B* mesons in strange hadronic medium at finite temperature
NASA Astrophysics Data System (ADS)
Chhabra, Rahul; Kumar, Arvind
2016-03-01
We calculate the effect of density and temperature of isospin symmetric strange medium on the shift in masses and decay constants of vector D and B mesons using chiral SU(3) model and QCD sum rule approach. In the present investigation the values of quark and gluon condensates are calculated from the chiral SU(3) model and these condensatesare further used as input in the QCD Sum rule framework to calculate the in-medium masses and decay constants of vector D and B mesons. These in medium properties of vector D and B mesons may be helpful to understand the experimental observables of the experiments like CBM and PANDA under FAIR project at GSI, Germany. The results which are observed in present work are also compared with the previous predictions.
Vector D and B mesons in asymmetric and hot dense medium
NASA Astrophysics Data System (ADS)
Chhabra, Rahul; Kumar, Arvind
2016-03-01
We calculate the effect of density and temperature of isospin asymmetric non-strange medium on the shift in masses and decay constants of vector D and B mesons using chiral SU(3) model and QCD sum rule approach. In the present investigation the values of quark and gluon condensates are calculated from the chiral SU(3) model and these condensates are further used as input in the QCD Sum rule framework. These condensates are further used to calculate the in medium masses and decay constants of vector D and B mesons. These in medium properties of vector D and B mesons are helpful to understand the experimental observables of the experiments like CBM and PANDA under FAIR project at GSI, Germany. The results which are observed in present work are also compared with the previous predictions.
Approximate degeneracy of heavy-light mesons with the same L
NASA Astrophysics Data System (ADS)
Matsuki, Takayuki; Lü, Qi-Fang; Dong, Yubing; Morii, Toshiyuki
2016-07-01
Careful observation of the experimental spectra of heavy-light mesons tells us that heavy-light mesons with the same angular momentum L are almost degenerate. The estimate is given how much this degeneracy is broken in our relativistic potential model, and it is analytically shown that expectation values of a commutator between the lowest order Hamiltonian and L→2 are of the order of 1 /mQ with a heavy quark mass mQ. It turns out that nonrelativistic approximation of heavy quark system has a rotational symmetry and hence degeneracy among states with the same L. This feature can be tested by measuring higher orbitally and radially excited heavy-light meson spectra for D /Ds / B /Bs in LHCb and forthcoming BelleII.