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Sample records for nn-2170 dibaryons

  1. Inevitable'' dibaryons

    SciTech Connect

    Goldman, T.

    1991-01-01

    Two dibaryons, one with high strangeness, the other with the quantum numbers of a spin excitation of the deuteron, are found in essentially all models of QCD. Experimental proof that they are not produced at levels well below the predicted cross sections would require major revisions of our understanding of QCD. 14 refs., 4 tabs.

  2. Dibaryons in neutron stars

    NASA Technical Reports Server (NTRS)

    Olinto, Angela V.; Haensel, Pawel; Frieman, Joshua A.

    1991-01-01

    The effects are studied of H-dibaryons on the structure of neutron stars. It was found that H particles could be present in neutron stars for a wide range of dibaryon masses. The appearance of dibaryons softens the equations of state, lowers the maximum neutron star mass, and affects the transport properties of dense matter. The parameter space is constrained for dibaryons by requiring that a 1.44 solar mass neutron star be gravitationally stable.

  3. H dibaryons and primordial nucleosynthesis

    NASA Astrophysics Data System (ADS)

    de Freitas Pacheco, J. A.; Stoica, S.; Thévenin, F.; Horvath, J. E.

    1999-01-01

    The apparent discrepancy between abundances of light nuclides predicted by the standard big bang and observational data is explained by assuming the presence of metastable H dibaryons at the nucleosynthesis era. These dibaryons could be formed out of a small fraction of strange quarks at the moment of the confinement transition. For a primordial deuterium abundance of the order of 3×10-5, the measured differences in the 4He abundances requires a relative abundance of H dibaryons of the order of nH/nB~0.07, decaying in a time scale of the order of 105 s.

  4. Future dibaryon research at BNL

    SciTech Connect

    Pile, P.H.

    1986-01-01

    An experiment designed to search for a strangeness -1 dibaryon is discussed. The experiment will use the /sup 3/He(K/sup -/, ..pi../sup +/)nD/sub s/ reaction and is expected to begin near the end of the year at the BNL AGS using the existing LESB-I beamline and hypernuclear spectrometer system. Planned searches for a strangeness -2 dibaryon are also discussed. The strangeness -2 dibaryon searches will however require the construction of a new 1.8 GeV/c kaon beam line at the AGS.

  5. Summary of S = 0 dibaryon resonances and candidates

    SciTech Connect

    Yokosawa, A.

    1985-04-18

    Experimental data concerning S = O dibaryon resonances are reviewed, with an emphasis on the nucleon-nucelon system. Structures observed in the ..gamma..d channel, the ..pi..d elastic scattering, pp ..-->.. ..pi..d channel, and other channels are discussed. Experimental data are compared with various theories. The short-range forces can be represented by dibaryon resonances. Further measurements to clarify the understanding of dibaryons are also discussed. 53 refs., 24 figs.

  6. Search for a T =2 dibaryon

    SciTech Connect

    Parker, B.; Seth, K.K.; Ginsburg, C.M.; O'Reilly, B.; Sarmiento, M.; Soundranayagam, R.; Trokenheim, S. )

    1989-10-09

    We have made a good-resolution, high-sensitivity search for a {ital T}=2 dibaryon in the missing-mass spectra for the reaction {ital d}({pi}{sup {minus}},{pi}{sup +}){pi}{sup {minus}}nn at 292 MeV. Our results are consistent with there being no resonance peak due to such a state in the mass region 2001--2070 MeV. 95%-confidence upper limits for the integrated cross sections for such a state are presented. It is found that a quasifree model calculation, without final-state interactions, considerably underpredicts the continuum yield in the vicinity of the threshold.

  7. Evidence for a bound H-dibaryon using lattice QCD

    SciTech Connect

    Will Detmold

    2012-04-01

    The H-dibaryon, a J = 0 state with the valence quark content udsuds, has long been hypothesized to exist because of the attractive nature of color magnetic gluon exchange in the flavor- singlet channel. Using lattice QCD the NPLQCD collaboration have investigated this system and evidence is presented for the existence of a stable H-dibaryon, albeit at a quark mass somewhat larger than that in nature. This calculation is reviewed and combined with subsequent calculations by the HALQCD collaboration at the SU(3) flavor symmetric point to identify bounds on the H-dibaryon mass at the physical quark masses.

  8. Amplitude tests of direct channel resonances: The dibaryon

    NASA Astrophysics Data System (ADS)

    Goldstein, G. R.; Moravosik, M. J.; Arash, F.

    1985-02-01

    A recently formulated polarization amplitude test for the existence of one-particle-exchange mechanisms is modified to deal with direct-channel resonances. The results are applied to proton-proton elastic scattering at and around 800 MeV to test the suggested existence of a dibaryon resonance. This test is sensitive to somewhat different circumstances and parameters than the methods used in the past to find dibaryon resonances. The evidence, on the basis of the SAID data set, is negative for a resonance in any singlet partial wave, but is tantalizingly subliminal for a 3F3 resonance.

  9. Amplitude tests of direct channel resonances: the dibaryon

    SciTech Connect

    Goldstein, G.R.; Moravcsik, M.J.; Arash, F.

    1984-02-01

    A recently formulated polarization amplitude test for the existence of one-particle-exchange mechanisms is modified to deal with direct-channel resonances. The results are applied to proton-proton elastic scattering at and around 800 MeV to test the suggested existence of a dibaryon resonance. This test is sensitive to somewhat different circumstances and parameters than the methods used in the past to find dibaryon resonances. The evidence, on the basis of the SAID data set, is negative for a resonance in any singlet partial wave, but is tantalizingly subliminal for a /sup 3/F/sub 3/ resonance. 7 refs., 4 figs.

  10. Hidden dibaryons in one- and two-pion production in NN collisions

    NASA Astrophysics Data System (ADS)

    Platonova, M. N.; Kukulin, V. I.

    2016-02-01

    Processes of one- and two-pion production in NN collisions are considered in connection with excitation of intermediate dibaryon resonances. In particular, relative contributions of the conventional meson-exchange and dibaryon excitation mechanisms in the reaction pp → dπ+ are investigated in detail. Inclusion of the intermediate isovector dibaryon resonances is shown to essentially improve the description of experimental data for this reaction, provided the soft meson-baryon form factors consistent with πN elastic scattering are used. Manifestation of the intermediate isoscalar and isovector dibaryons in the two-pion production processes is also studied. The role of the isovector dibaryon resonances in the reaction pp → ppππ is discussed for the first time. An explanation of the observed strong differences between two-pion production cross sections in pn and pp collisions based in part on the analysis of dibaryon structure is suggested.

  11. Evidence for a bound H-dibaryon from lattice QCD

    SciTech Connect

    Beane, S R; Detmold, W; Lin, H W; Luu, T C; Orginos, K; Parreno, A; Savage, M J; Torok, A; Walker-Loud, A

    2011-04-01

    We present evidence for the existence of a bound H-dibaryon, an I = 0, J = 0, s = -2 state with valence quark structure uuddss, at a pion mass of m_\\pi < 389 MeV. Extrapolating the results of lattice QCD calculations performed on four ensembles of anisotropic clover gauge-field configurations, with spatial extents of L < 2.0, 2.5, 3.0 and 3.9 fm at a spatial lattice spacing of b_s < 0.123 fm, we find an H-dibaryon bound by B_ ^H = 16.6±2.1±4.6 MeV at a pion mass of m_\\pi < 389 MeV.

  12. Experimental and theoretical backgrounds for generation of dibaryons in NN and 3N interactions

    NASA Astrophysics Data System (ADS)

    Kukulin, V. I.; Pomerantsev, V. N.

    2010-04-01

    Numerous experimental and theoretical arguments in favor of the intermediate dibaryon generation in NN and 3N interactions are presented. Using some specific mechanism for the scalar field production when the 2ħω-excited multi-quark system deexcites to the ground state one formulates a concept for σ-dressed dibaryon as a carrier of intermediate-range attraction and a reason for short-range repulsion in NN-interaction. It is argued that the basic mechanisms responsible for large lowering of the Roper-resonance and the dressed dibaryon masses should be very similar. The modern experimental data of a few groups seem to confirm strongly the dibaryon picture in NN and 3N-interactions. Some important common features of the dibaryon and pomeron in highenergy NN scattering are discussed.

  13. On the resonance energy of the strange dibaryon

    SciTech Connect

    Yoichi Ikeda, Hiroyuki Kamano, Toru Sato

    2010-03-01

    The three-body resonance energies of the strange dibaryon are studied with the View the MathML source coupled-channels Faddeev equations. Our resonance energies are compared with those of an effective potential approach (EPA), where a coupling to the πYN channel is simulated by an effective View the MathML source potential, and the spectator momentum in the πYN Green function is neglected. About a 30% reduction of the binding energies due to neglecting the spectator momentum in the πYN Green's function is observed.

  14. Pion-assisted N Δ and Δ Δ dibaryons, and beyond

    NASA Astrophysics Data System (ADS)

    Gal, Avraham

    2015-08-01

    Experimental evidence for I( J P )=0(3+) Δ Δ dibaryon has been presented recently by the WASA-at-COSY Collaboration. Here I review new hadronic-basis Faddeev calculations of L=0 nonstrange pion-assisted N Δ and Δ Δ dibaryon candidates. These calculations are so far the only ones to reproduce the relatively small width of 70-80 MeV. Predictions are also given for the location and width of , the I( J P )=3(0+) exotic partner of . Extensions to strangeness dibaryons are briefly discussed.

  15. Search for the H-dibaryon. A proposal to E871

    SciTech Connect

    Fitch, V.; Klein, J.; May, M.

    1998-10-01

    This report consists of vugraphs for a lecture on the search for the H-dibaryon. The physics importance of this search are: (1) low energy test of QCD; (2) new form of matter; (3) missing link between normal hadronic matter and strange matter; (4) astrophysical explanations; and (5) cosmology and dark matter. The author reviews past experiments searching for H-dibaryon. Finally he discusses search methods at E871.

  16. Dibaryons with two strange quarks and total spin zero in a constituent quark model

    NASA Astrophysics Data System (ADS)

    Park, Woosung; Park, Aaron; Lee, Su Houng

    2016-04-01

    We investigate the symmetry property and construct the wave function of the dibaryon states containing two strange quarks with S =0 in both the flavor SU(3) symmetric and breaking cases. We discuss how the color ⊗ isospin ⊗ spin states of dibaryon in the symmetry broken case of flavor SU(3) can be extracted from the fully antisymmetric states in flavor SU(3). The stability of the dibaryon against the strong decay into two baryons is then discussed, by using the variational method within a constituent quark model with confining and color-spin interactions. To compare our results with those from lattice QCD in the flavor SU(3) limit, we search for the stable H-dibaryon in a wide range of π meson masses. We find that with the given potential, there is no compact six-quark dibaryon state in the SU(3) flavor symmetry broken case with realistic quark masses as well as in the flavor SU(3) symmetric case in a wide range of quark masses.

  17. Present constraints on the H-dibaryon at the physical point from Lattice QCD

    SciTech Connect

    Beane, S. R.; Chang, E.; Detmold, W.; Joo, B.; Lin, H. -W.; Luu, T. C.; Orginos, K.; Parreno, A.; Savage, M. J.; Torok, A.; Walker-Loud, A.

    2011-11-10

    The current constraints from Lattice QCD on the existence of the H-dibaryon are discussed. With only two significant Lattice QCD calculations of the H-dibaryon binding energy at approximately the same lattice spacing, the form of the chiral and continuum extrapolations to the physical point are not determined. In this brief report, an extrapolation that is quadratic in the pion mass, motivated by low-energy effective field theory, is considered. An extrapolation that is linear in the pion mass is also considered, a form that has no basis in the effective field theory, but is found to describe the light-quark mass dependence observed in Lattice QCD calculations of the octet baryon masses. In both cases, the extrapolation to the physical pion mass allows for a bound H-dibaryon or a near-threshold scattering state.

  18. Present constraints on the H-dibaryon at the physical point from Lattice QCD

    DOE PAGESBeta

    Beane, S. R.; Chang, E.; Detmold, W.; Joo, B.; Lin, H. -W.; Luu, T. C.; Orginos, K.; Parreno, A.; Savage, M. J.; Torok, A.; et al

    2011-11-10

    The current constraints from Lattice QCD on the existence of the H-dibaryon are discussed. With only two significant Lattice QCD calculations of the H-dibaryon binding energy at approximately the same lattice spacing, the form of the chiral and continuum extrapolations to the physical point are not determined. In this brief report, an extrapolation that is quadratic in the pion mass, motivated by low-energy effective field theory, is considered. An extrapolation that is linear in the pion mass is also considered, a form that has no basis in the effective field theory, but is found to describe the light-quark mass dependencemore » observed in Lattice QCD calculations of the octet baryon masses. In both cases, the extrapolation to the physical pion mass allows for a bound H-dibaryon or a near-threshold scattering state.« less

  19. Searches for a possible strangeness S = -2 dibaryon

    SciTech Connect

    Barnes, P. D.

    1982-01-01

    Since the advent of QCD there has been a strong interest in manifestations of quark degrees of freedom in medium energy nuclear and particle physics. Within the framework of multiquark states the emphasis has centered on states with more than three quarks bound by colour forces rather than by the conventional mesonic forces. Dibaryon systems have played an important role within that framework. One of the most spectacular and exciting predictions is the possible existence, according to the MIT bag model, of a stable, flavor-singlet, strangeness = /sup -/2,J/sup P/ = 0/sup +/ dihyperon, called by R. Jaffe the H particle. It is a six-quark object (2u, 2d, 2s quarks) with a predicted mass around 2150 MeV, i.e., below the ..lambda lambda.. mass with a binding energy around 80 MeV. Its decay channels would be restricted to ..sigma..N and ..lambda..N, via the weak interaction. The relevant two body states are shown. A similar prediction was obtained on the basis of the same model by Mulders et al., with a mass of 2164 MeV for this state. For completeness it should be mentioned that in a recent estimate of the center-of-mass correction to the static MIT bag model, the authors suggest that the dilambda mass moves up to just above the ..lambda lambda.. threshold. These calculations are undergoing further tets. Although all these results come from a specific model, Lipkin has argued that the general features of QCD and the known baryon mass splittings imply that the six-quark state with charge zero, spin zero, and strangeness = /sup -/2 would have the greatest binding potential.

  20. Two-nucleon production of hyperons in an S = {minus}1 dibaryon search

    SciTech Connect

    Chrien, R.E.; E820 Collaboration

    1992-09-01

    The double-charge-exchange reaction {sup 3}He(K{sup {minus}}, {pi}{sup +})Xn was studied at p{sub K}- = 870 MeV/c. In the missing mass range below the sigma-nucleon production threshold (3075 MeV/c{sup 2}) events were detected and attributed to the two-nucleon reaction pp(K{sup {minus}}, {pi}{sup +}){Lambda}n. This reaction and mass range is supposed to be a fertile field for a search for the I = 1/2, L = 1 ({sup 1}P{sub 1}) spin-singlet dibaryon suggested as the lowest mass S = {minus}1 dibaryon of bag model predictions. We find no need to invoke such an object to account for the observed events below {Sigma} production threshold.

  1. Two-nucleon production of hyperons in an S = minus 1 dibaryon search

    SciTech Connect

    Chrien, R.E.

    1992-01-01

    The double-charge-exchange reaction {sup 3}He(K{sup {minus}}, {pi}{sup +})Xn was studied at p{sub K}- = 870 MeV/c. In the missing mass range below the sigma-nucleon production threshold (3075 MeV/c{sup 2}) events were detected and attributed to the two-nucleon reaction pp(K{sup {minus}}, {pi}{sup +}){Lambda}n. This reaction and mass range is supposed to be a fertile field for a search for the I = 1/2, L = 1 ({sup 1}P{sub 1}) spin-singlet dibaryon suggested as the lowest mass S = {minus}1 dibaryon of bag model predictions. We find no need to invoke such an object to account for the observed events below {Sigma} production threshold.

  2. Energy Dependence of $\\bar{K}N$ Interactions and Resonance Pole of Strange Dibaryons

    SciTech Connect

    Ikeda, Y.; Kamano, H.; Sato, T.

    2010-09-01

    We study the resonance energy of the strange dibaryons using two models with the energy-independent and energy-dependent potentials for the s-wave $\\bar{K}N$ interaction, both of which are derived by certain reductions from the leading order term of the effective chiral Lagrangian. These potential models produce rather different off-shell behaviors of the two-body $\\bar{K}N$ - $\\pi\\Sigma$ amplitudes in $I=0$ channel, i.e., the model with energy-independent (energy-dependent) potential predicts one (two) resonance pole in the $\\Lambda(1405)$ region, while they describe the available data equally well. We find that the energy-independent potential model predicts one resonance pole of the strange dibaryons, whereas the energy-dependent potential model predicts two resonance poles: one is the shallow quasi-bound state of the $\\bar{K}NN$, and another is the resonance of the $\\pi Y N$ with large width. An investigation of the binding energy of the strange dibaryons will make a significant contribution to clarify resonance structure of s-wave $\\bar{K}N$ -$\\pi\\Sigma$ around the $\\Lambda(1405)$ region.

  3. Further measurements of iT/sub 11/ in. pi. -d pol scattering as an investigation of dibaryon resonance effects

    SciTech Connect

    Bolger, J.; Boschitz, E.; Mathie, E.L.; Smith, G.R.; Meyer, M.; Vogler, F.; Mango, S.; Konter, J.A.; Mutchler, G.S.; Arvieux, J.

    1982-06-14

    The vector analyzing power (iT/sub 11/) in elastic ..pi..-d scattering has been measured for several angles at T/sub ..pi../ = 219, 256, 275, and 294 MeV. Strong oscillations are confirmed at 256 MeV. The data are compared with Faddeev calculations; Faddeev amplitudes plus the /sup 3/F/sub 3/(2220) dibaryon resonance only; and Faddeev amplitudes plus the /sup 1/G/sub 4/(2430) dibaryon resonance only. At 219 MeV the Faddeev calculations are consistant with the data, while at the higher energies the general trend of the data favors the admixing of the /sup 1/G/sub 4/ dibaryon resonance. The forward angle data at 294 MeV are not well described by an existing calculation.

  4. H-dibaryon search via the (K-,K+) reaction using a diamond target (BNL-E885)

    NASA Astrophysics Data System (ADS)

    Yamamoto, K.; Alburger, D.; Bassalleck, B.; Berdoz, A. R.; Bürger, T.; Burger, M.; Carman, D.; Chrien, R. E.; Davis, C. A.; Fischer, H.; Franklin, G. B.; Franz, J.; Gan, L.; Ichikawa, A.; Iijima, T.; Imai, K.; Khaustov, P.; Koran, P.; Kondo, Y.; Landry, M.; Lee, L.; Lowe, J.; Magahiz, R.; May, M.; McCrady, R.; Merrill, F.; Meyer, C. A.; Page, S. A.; Paschke, K.; Pile, P. H.; Quinn, B. P.; Ramsay, W. D.; Rusek, A.; Sawafta, R.; Schumacher, R. A.; Schumit, H.; Stotzer, R. W.; Sutter, R.; Takeuchi, F.; van Oers, W. T. H.; Yosoi, M.; Zeps, V.

    1998-08-01

    An experiment to study double-strangeness systems was performed at the BNL-AGS via the (K-,K+) reaction using a diamond target and scintillating fiber (SCIFI) blocks (E885). A search for the H dibaryon through the stopped Ξ- process is one of the objectives. The number of stopped Ξ-'s is about 9000, and the expected sensitivity of the H dibaryon search is more than one order of magnitude higher than that of the previous experiment at KEK-PS (E224).

  5. From CELSIUS to COSY: on the observation of a dibaryon resonance

    NASA Astrophysics Data System (ADS)

    Clement, H.; Bashkanov, M.; Skorodko, T.

    2015-11-01

    Using a high-quality beam of storage rings in combination with a pellet target and a hermetic WASA detector covering practically the full solid angle, two-pion production in nucleon-nucleon collisions has been systematically studied by exclusive and kinematically complete measurements—first at CELSIUS and subsequently at COSY. These measurements resulted in a detailed understanding of the two-pion production mechanism by t-channel meson exchange. The investigation of the ABC effect, which denotes an unusual low-mass enhancement in the ππ-invariant mass spectrum, in double-pionic fusion reactions led the trace to the observation of a narrow dibaryon resonance with I({J}P)=0({3}+) about 80 MeV below the nominal mass of the conventional Δ Δ system. New neutron-proton scattering data, taken with a polarized beam at COSY, produced a pole in the coupled {}3{D}3-3{G}3 partial waves at (2380+/- 10\\-\\i\\40+/- 5) MeV, establishing thus the first observation of a genuine s-channel dibaryon resonance.

  6. All strange and terrible events: A search for the H dibaryon

    SciTech Connect

    Ware, B.

    1995-12-01

    No six-quark bound hadron, (other than the loosely bound deuteron) has been observed, despite several experimental searches. Some models of quark dynamics predict the existence of such a state, the doubly-strange six-quark H dibaryon (uuddss) being the most likely. The mass of the H would be between that of the deuteron and the 2m{sub {Lambda}} strong interaction decay threshold. In 1992, Experiment E888 at Brookhaven National Lab`s Alternating Gradient Synchrotron collected data to search for this particle. The detector consisted of a two-arm spectrometer with drift chamber tracking and two magnets for momentum analysis, scintillator hodoscope triggering, Cerenkov particle identification, an electromagnetic calorimeter, and a muon hodoscope and rangefinder. The experiment searched for the decay {Lambda} {yields} p{pi}{sup -} from the weak decays of H {yields} {Lambda}n and H {yields} {Sigma}{sup 0}n (followed by {Sigma}{sup 0} {yields} {Lambda}{gamma}). This search was sensitive to weakly decaying H dibaryons with lifetimes from 6-230 us with production cross-sections greater than {approximately}2 {mu}b/steradian.

  7. Azimuthal correlations and dibaryon states in the reaction /sup 4/Hep. -->. dppn

    SciTech Connect

    Not Available

    1984-08-01

    We have analyzed the behavior of correlations of pairs of nucleons in their relative azimuthal angles in the reaction /sup 4/Hep..-->..dppn. The experiment was performed in the synchrophasotron at the High Energy Laboratory of the Joint Institute for Nuclear Research by means of the 100-cm hydrogen bubble chamber. It is shown that the reaction studied occurs mainly through a double interaction. The difference obtained in the behavior of the correlations in the direct channel of this reaction and in the channel with charge exchange is in good agreement with the assumption of an important role of the ..delta../sub 3,3/N interaction. The enhancement of the correlation in the region of the peaks in the effective mass of the two-proton system at M = 2035 and 2137 MeV/c/sup 2/ argues in favor of dibaryon states.

  8. Polarization phenomena in nucleon-nucleon scattering at intermediate and high energies including the present status of dibaryons

    SciTech Connect

    Yokosawa, A.

    1985-01-01

    We review experimental results concerning polarization phenomena in nucleon-nucleon scattering in which both the elastic scattering and hadron-production reaction are included. We also present summary of S = 0 dibaryon resonances and candidates by reviewing experimental data in the nucleon-nucleon system, ..gamma..d channel, ..pi..d elastic scattering, pp ..-->.. ..pi..d channel, deuteron break-up reactions, and narrow structures in missing-mass spectra. 93 refs., 26 figs.

  9. Evidence for a dibaryon signal in the measurement of elastic. pi. /sup +/-d/sub pol/ scattering

    SciTech Connect

    Bolger, J.; Boschitz, E.; Proebstle, G.; Smith, G.R.; Mango, S.; Vogler, F.; Johnson, R.R.; Arvieux, J.

    1981-01-19

    The vector analyzing power (iT/sub 11/) in elastic ..pi..-d/sub pol/ scattering has been measured for several angles at T/sub ..pi../=142 and 256 MeV. The results are compared with calculations reported in the literature. At the lower energies, Faddeev calculations agree fairly well with the data. At the higher energies, the experimental results differ markedly from any conventional calculation, but agree surprisingly well with predictions in which effects of dibaryon resonances are explicitly included.

  10. Hexaquark states as possible candidates for di-baryonic molecular states with Yukawa potential in a semi-relativistic scheme

    NASA Astrophysics Data System (ADS)

    Patel, Smruti J.; Vinodkumar, P. C.

    2016-05-01

    We study the mass spectra of hexaquark states as di-hadronic molecules with Yukawa potential in a semi-relativistic scheme. We have solved numerically the relevant equation using mathematica notebook of Range-Kutta method including effective Yukawa like potential between two baryons to model the two-body interaction and have calculated their masses and binding energy. We have been able to assign the JP values for many of the exotic states according to their compositions. We have predicted some of the di-baryonic exotic states for which experimental as well as theoretical data are not available and we look forward to see the experimental support in favour of our predictions. So in the absence of such results our predictions can be used as guidelines for future experimental and theoretical analysis of exotic states.

  11. Development of a prototype GEM TPC with a gating grid for an H-dibaryon search experiment at J-PARC

    NASA Astrophysics Data System (ADS)

    Sako, H.; Sugimura, H.; Ahn, J. K.; Han, Y.; Hasegawa, S.; Hwang, S. H.; Ichikawa, Y.; Imai, K.; Kiuchi, R.; Ozawa, K.; Sato, S.; Shirotori, K.

    2014-11-01

    We have developed a prototype TPC (Time Projection Chamber) based on GEMs (Gas Electron Multipliers) with a gating grid for an H-dibaryon search experiment at J-PARC. To investigate its performance, we conducted laboratory tests and a beam test with two kinds of gases, Ar-CH4 (90:10) and Ar-CF4 (95:5), where the former is mainly used for the tests. The hit detection efficiency per pad row was measured to be 98% at the beam rate up to 5×105 cps cm2 (counts per second), and 90% at the rate of 3×106 cps/cm2. Based on the measured horizontal resolution of 0.19-0.46 mm at the drift length of 5-20 cm, the horizontal position resolution of better than 0.3 mm is estimated in 1 T magnetic field for the final experiment. The ion backflow fraction was measured to be 5% and reduced up to 3% by tuning the GEM voltage configuration, at the gain of 1.6 ×104. The horizontal position distortion due to ion backflow in the gate operation was suppressed within 0.2 mm at the beam rates up to 5 ×105 cps /cm2, corresponding to the ion backflow up to 2.7 ×108s-1cm-1. On the other hand, the distortion with the gate open was measured to be 1.3 mm, corresponding to the backflow of 1.3 ×109s-1cm-1. The distortion in the final experiment is estimated to be 0.3 ± 0.2 mm, within the requirement of 1 mm. The GEMs have been operated continuously for a comparable period of the final experiment, with average energy deposit rates per unit GEM area of 30 times as high as that expected for the experiment.

  12. New way to produce dense double-antikaonic dibaryon system, 𝐾̄𝐾̄NN, through Λ(1405)-doorway sticking in p + p collisions

    PubMed Central

    YAMAZAKI, Toshimitsu; AKAISHI, Yoshinori; HASSANVAND, Maryam

    2011-01-01

    A recent successful observation of a dense and deeply bound 𝐾̄ nuclear system, K−pp, in the p + p → K+ + K−pp reaction in a DISTO experiment indicates that the double-𝐾̄ dibaryon, K−K−pp, which was predicted to be a dense nuclear system, can also be formed in p + p collisions. We find theoretically that the K−-K− repulsion plays no significant role in reducing the density and binding energy of K−K−pp and that, when two Λ(1405) resonances are produced simultaneously in a short-range p + p collision, they act as doorways to copious formation of K−K−pp, if and only if K−K−pp is a dense object, as predicted. PMID:21670568

  13. Evidence for dibaryon resonances in nucleon-nucleon scattering

    SciTech Connect

    Roberts, J.B.

    1980-01-01

    There has been a revival of interest in the subject of nucleon-nucleon resonances in the past 3 to 4 years, largely generated by experimental results from the polarized beam program at the Argonne ZGS. Evidence from experimental results and phase shift and phenomenological analyses incorporating these results regarding the existence of these resonances is summarized. 20 figures.

  14. Search for dibaryons in measurements of the. pi. d(pol) system

    SciTech Connect

    Smith, G.R.; Mathie, E.L.; Boschitz, E.T.; Ottermann, C.R.; Gyles, W.; List, W.; Mango, S.; Konter, J.A.; Van der Brandt, B.; Olszewski, R.

    1984-11-15

    Comprehensive measurements of the vector analyzing power iT/sub 11/ have recently been completed in the elastic, absorption, and breakup channels of the ..pi..d system using a polarized deuteron target and a TOF detection system at SIN. Discrepancies between the experimental data and the predictions of Faddeev calculations appear with varying severity in all three channels.

  15. Effects of Heavy-Meson Exchange on the 1D2 and 3F3 N-N Partial Waves and the Question of Dibaryon Resonance

    NASA Astrophysics Data System (ADS)

    Kloet, W. M.; Silbar, Richard R.

    1980-09-01

    The 1D2 and 3F3 N-N amplitudes are studied in a unitary dynamical model. Parameterfree long- and medium-range forces are given by multiple pion exchange, allowing coupling to the NNπ channel. Short-range forces are mainly given by ρ and ω exchange, parametrized to fit known low-energy phase shifts for J>=2. Resulting Argand diagrams at medium energies show counter-clockwise loops, but far less dramatic than in the Hoshizaki phase-shift analysis. However, the results are similar to recent Arndt phase shifts.

  16. Case for exotic baryon-baryon states

    SciTech Connect

    Thomas, G.H.

    1980-01-01

    Three main points are presented. (1) Current theoretical prejudices are presented for why dibaryon states are interesting, and why they should be expected. (2) A review is given of some of the unsettled experimental issues which have emerged during this conference concerning dibaryons. (3) Phenomenological issues are raised which are critical to understanding whether dibaryon states are observable in the medium energy NN system.

  17. Summary of low-energy aspects of QCD and medium-energy hadron parallel sessions

    SciTech Connect

    McClelland, J.B.

    1991-01-01

    Two sessions were organized dealing with low energy aspects of QCD. The first dealt with the issue of QCD dibaryons. The second session centered on mostly low-energy tests of QCD. This report discusses experiments dealing with these sessions.

  18. K meson-nucleus interactions: strangeness and nuclear matter

    SciTech Connect

    Kahana, S.

    1985-01-01

    A brief review is provided of some straightforward K-nuclear and ..lambda..-hypernuclear systems. A discussion of less straightforward speculations on H-dibaryons and strange quark matter by many authors, is also given. 28 refs., 6 figs.

  19. Search for weakly decaying Λn ‾ and ΛΛ exotic bound states in central Pb-Pb collisions at √{sNN} = 2.76 TeV

    NASA Astrophysics Data System (ADS)

    Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmed, I.; Ahn, S. U.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alfaro Molina, R.; 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.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Ball, M.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bello Martinez, H.; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; 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.; Biswas, S.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Castro, A. J.; Casula, E. A. R.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Choi, K.; 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.; Cortés Maldonado, I.; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; De Caro, A.; de Cataldo, G.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; Deisting, A.; Deloff, A.; Dénes, E.; D'Erasmo, G.; Di Bari, D.; Di Mauro, A.; Di Nezza, P.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erhardt, F.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; 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.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; 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.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; 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.

    2016-01-01

    We present results of a search for two hypothetical strange dibaryon states, i.e. the H-dibaryon and the possible Λn ‾ bound state. The search is performed with the ALICE detector in central (0-10%) Pb-Pb collisions at √{sNN} = 2.76 TeV, by invariant mass analysis in the decay modes Λn ‾ → d ‾π+ and H-dibaryon → Λpπ-. No evidence for these bound states is observed. Upper limits are determined at 99% confidence level for a wide range of lifetimes and for the full range of branching ratios. The results are compared to thermal, coalescence and hybrid UrQMD model expectations, which describe correctly the production of other loosely bound states, like the deuteron and the hypertriton.

  20. Hadron interactions and exotic hadrons from lattice QCD

    NASA Astrophysics Data System (ADS)

    Ikeda, Yoichi

    2014-09-01

    One of the interesting subjects in hadron physics is to look for the multiquark configurations. One of candidates is the H-dibaryon (udsuds), and the possibility of the bound H-dibaryon has been recently studied from lattice QCD. We also extend the HAL QCD method to define potentials on the lattice between baryons to meson-meson systems including charm quarks to search for the bound tetraquark Tcc (ud c c) and Tcs (ud c s). In the presentation, after reviewing the HAL QCD method, we report the results on the H-dibaryon, the tetraquark Tcc (ud c c) and Tcs (ud c s), where we have employed the relativistic heavy quark action to treat the charm quark dynamics with pion masses, mπ = 410, 570, 700 MeV.

  1. Strange experiments at the AGS

    SciTech Connect

    Chrien, R.

    1990-01-01

    The purpose of this review is to report recent progress in nuclear experiments involving strangeness which have been carried out at the Brookhaven Alternating Gradient Synchrotron over the past three years. These recent developments are noted in three areas: few body systems and dibaryons; strange probes of the nucleus; and associated production of hypernuclei. 9 refs., 3 figs.

  2. Experimental medium energy physics

    SciTech Connect

    Barnes, P.D.

    1990-01-01

    This report discusses the following topics: search for the H-dibaryon at the AGS; weak interaction studies with hypernuclear decays at the AGS; search for the {xi}(2230) at LEAR; relativistic proton-nucleus and heavy ion-nucleus collisions at the SPS; hyperon-antihyperon production studies at LEAR; photoproduction of strange CEBAF; and experiment design development.

  3. Recent results for the (anti-)(hyper-)nuclei production and searches for exotica by ALICE at the LHC

    NASA Astrophysics Data System (ADS)

    Barile, Francesco

    2016-01-01

    The excellent tracking and particle identification capabilities of the ALICE apparatus combined with the high particle production rates reached at the LHC in pp, p-Pb and in particular in Pb-Pb collisions allow for detailed study of the production of (anti-)(hyper-)nuclei and searches for exotica, like dibaryons. In this report, we present recent results on the production of the (anti-)deuteron and (anti-)helium. Further, we discuss recent results on the production and the lifetime of the (anti-)hypertriton. In addition, results from the searches for the weakly-decaying exotic nuclear bound states H-dibaryon and An are shown. The results are compared with the expectations from statistical (thermal) particle production and coalescence models.

  4. Nuclear and particle physics aspects of hyperon and antinucleon interactions

    SciTech Connect

    Dover, C.B.

    1984-01-01

    A discussion is given of hyperon (Y) and antinucleon (anti N) interactions with nucleons and nuclei, emphasizing some of the future prospects for nuclear structure and elementary particle physics studies at LEAR or a future kaon factory. The topics addressed include: (1) production and decay of strange dibaryons; (2) spectroscopy of strangeness S = -2 many body systems; (3) N anti N annihilation mechanisms; and (4) inelastic anti N-nucleus scattering and spin-flip excitations in nuclei. 36 references.

  5. Measurements of the vector analyzing power iT/sub 11/ in the. pi. d elastic scattering reaction between 117 and 325 MeV

    SciTech Connect

    Smith, G.R.; Mathie, E.L.; Boschitz, E.T.; Ottermann, C.R.; Mango, S.; Konter, J.A.; Daum, M.; Meyer, M.; Olszewski, R.; Vogler, F.

    1984-06-01

    The vector analyzing power iT/sub 11/ has been measured for the ..pi..d elastic scattering reaction at 12 incident pion energies between 117 and 325 MeV, using a vector polarized deuteron target. The results cover an average of 14 angles per incident pion energy. A detailed comparison with existing Faddeev calculations is made. The effect of including dibaryon resonances with one of these predictions is investigated.

  6. Experimental Medium Energy Physics

    SciTech Connect

    Not Available

    1992-01-01

    This report discusses the following topics: Search for the H Dibaryon at the AGS; hypernuclear weak decay studies at the LAGS; search for strangelets using the 2 GeV/c beam line; experiment to detect double lambda hypernuclei; hyperon photoproduction at CEBAF; the region 1 drift chambers for the CLAS spectrometer; parity violating electron scattering from the proton: the G{sup 0}experiment at CEBAF; and relativistic heavy ion - nucleus collisions at the SPS.

  7. Experimental Medium Energy Physics. Annual progress report, June 1991--May 1992

    SciTech Connect

    Not Available

    1992-09-01

    This report discusses the following topics: Search for the H Dibaryon at the AGS; hypernuclear weak decay studies at the LAGS; search for strangelets using the 2 GeV/c beam line; experiment to detect double lambda hypernuclei; hyperon photoproduction at CEBAF; the region 1 drift chambers for the CLAS spectrometer; parity violating electron scattering from the proton: the G{sup 0}experiment at CEBAF; and relativistic heavy ion - nucleus collisions at the SPS.

  8. Studies in Medium Energy Physics. Progress report, April 1, 1992--March 31, 1993

    SciTech Connect

    Hoffmann, G.W.; McDonough, J.; Purcell, M.J.; Ray, R.L.; Read, D.M.; Worm, S.D.

    1992-12-01

    Progress is briefly reported in the following areas: p + A precision elastic forward-angle cross sections for 500- to 800-MeV p on {sup 40}Ca; precision measurement of D{sub NN} for {sup 13}C({rvec p}, {rvec p}) at 500 MeV; design of a polarized nuclear target; search for very rare K{sub L} decays; search for the H dibaryon; experimental search for quark -- gluon plasma; and theoretical work on proton -- nucleus scattering.

  9. Studies in Medium Energy Physics. [Dept. of Physics, Univ. of Texas at Austin, Austin, Texas

    SciTech Connect

    Hoffmann, G.W.; McDonough, J.; Purcell, M.J.; Ray, R.L.; Read, D.M.; Worm, S.D.

    1992-12-01

    Progress is briefly reported in the following areas: p + A precision elastic forward-angle cross sections for 500- to 800-MeV p on [sup 40]Ca; precision measurement of D[sub NN] for [sup 13]C([rvec p], [rvec p]) at 500 MeV; design of a polarized nuclear target; search for very rare K[sub L] decays; search for the H dibaryon; experimental search for quark -- gluon plasma; and theoretical work on proton -- nucleus scattering.

  10. Review of N-N scattering

    SciTech Connect

    Yokosawa, A.

    1980-01-01

    Structures appearing in various experimental data (particularly those with polarized beams) in nucleon-nucleon systems are reviewed. A number of candidates are presented for dibaryon resonances which can couple to nucleon-nucleon systems. The present status of experimental data in the nucleon-nucleon system is discussed. Details of N-N scattering are written elsewhere, and here relatively new aspects are presented.

  11. Spin analysis of 0+1-->0+1 and its application to π+d-->π+d data

    NASA Astrophysics Data System (ADS)

    Arash, Firooz; Moravcsik, Michael J.; Goldstein, Gary R.

    1985-11-01

    The polarization structure of the reaction 0+1-->0+1 is discussed in the optimal transversity frame. First, the relationship between the observables and the bilinear products of amplitudes (``bicoms'') is given when only Lorentz invariance is imposed. Then parity conservation and time-reversal invariance are also imposed, resulting in modified relationships. The measurements of spin correlations between initial- and final-state spins needed to determine the amplitudes completely are enumerated. The results are applied to the existing π-d data, and the consequences of any possible dibaryon resonances are examined.

  12. Theoretical nuclear physics. Progress report, July 1, 1991--June 30, 1992

    SciTech Connect

    French, J.B.; Koltun, D.S.

    1992-06-01

    This report summarizes progress during the past year in the following areas of research: Pion double charge exchange and the role of meson exchange currents, including vector mesons, deltas, and nuclear correlations. K{sup +}-nucleus scattering and the role of meson exchange currents in supplying ``missing cross section.`` Pion excess distributions in nuclei, and the role of nuclear correlations. Interactions of two hyperons and the possibility of an H dibaryon. Shell model spectra and the NN tensor interaction. Statistical nuclear spectroscopy, including state densities and expectation values evaluated in terms of one-point and two-point (correlation) functions.

  13. Theoretical nuclear physics

    SciTech Connect

    French, J.B.; Koltun, D.S.

    1992-06-01

    This report summarizes progress during the past year in the following areas of research: Pion double charge exchange and the role of meson exchange currents, including vector mesons, deltas, and nuclear correlations. K{sup +}-nucleus scattering and the role of meson exchange currents in supplying missing cross section.'' Pion excess distributions in nuclei, and the role of nuclear correlations. Interactions of two hyperons and the possibility of an H dibaryon. Shell model spectra and the NN tensor interaction. Statistical nuclear spectroscopy, including state densities and expectation values evaluated in terms of one-point and two-point (correlation) functions.

  14. ({lambda}, p) Spectrum Analysis in p+A Interactions at 10 GeV/c

    SciTech Connect

    Aslanyan, P. Zh.; Emelyanenko, V. N.

    2007-06-13

    Experimental data from the 2m propane bubble chamber have been analyzed for exotic baryon states search. A number of peculiarities were found in the effective mass spectra of: {lambda}{pi}+({sigma}*+(1382),PDG), {lambda}p and {lambda}pp subsystems. A few events detected on the photographs of the propane bubble chamber exposed to a 10 GeV/c proton beam, were interpreted as S=-2 H0 light(dibaryon by two weak decay channels of K-pp or {sigma}+p{pi}-.

  15. Multiquark interactions

    SciTech Connect

    Goldman, T.; Maltman, K.R.; Schmidt, K.E.; Stephenson, G.J. Jr.

    1988-01-01

    The conflict between the description of a field theory by its asymptotic states and the confinement of quarks in QCD is discussed. It is argued that a correct hadronic description of QCD (in terms of color singlets) may require very unusual vertex functions, despite the overlap of parts of the path integral with natural hadronic degrees-of-freedom. A formalism, which incorporates many of the advantages of an hadronic description into a quark picture, is described. Dibaryons are presented which show how well this approach illuminates the physics relevant to the multiquark problem. 14 refs., 1 fig., 5 tabs.

  16. On the Resonance-Like Behavior in the pp Scattering Amplitudes

    NASA Astrophysics Data System (ADS)

    Otofuji, T.; Sakai, K.; Kanada, H.; Saito, S.; Yasuno, M.

    1985-03-01

    The series of ``dibaryons'' is investigated in detail by means of a coupled-channel model of the NN, N Delta and Delta Delta channels. The π and rho meson exchange potential is employed with cutoff form factors and inner hard core. It is shown that the model reproduces the series of the ``dibaryons'' of the natural-parity states; that is the resonance-like behavior (RLB) in the 1D2, 3F3, 1G4, (3H5) and 1I6 states. The masses and widths of these ``resonances'' agree well with those given by Auer et al. A detailed study shows that the RLB is mainly due to the coupling with the N Delta aligned states (NDAS) (L=J-2 and S=2), and that the NDAS give rise to a spectrum of rotational-like structure. It is suggested that aligned states (SAS) of L=J and S=2 bring about resonance-like behavior for the even-parity states in the higher energy region.

  17. A new hadron spectroscopy

    NASA Astrophysics Data System (ADS)

    Olsen, Stephen Lars

    2015-04-01

    QCD-motivated models for hadrons predict an assortment of "exotic" hadrons that have structures that are more complex than the quark-antiquark mesons and three-quark baryons of the original quark-parton model. These include pentaquark baryons, the six-quark H-dibaryon, and tetraquark, hybrid and glueball mesons. Despite extensive experimental searches, no unambiguous candidates for any of these exotic configurations have been identified. On the other hand, a number of meson states, one that seems to be a proton-antiproton bound state, and others that contain either charmed-anticharmed quark pairs or bottom-antibottom quark pairs, have been recently discovered that neither fit into the quark-antiquark meson picture nor match the expected properties of the QCD-inspired exotics. Here I briefly review results from a recent search for the H-dibaryon, and discuss some properties of the newly discovered states -the proton-antiproton state and the so-called XY Z mesons- and compare them with expectations for conventional quark-antiquark mesons and the predicted QCD-exotic states.

  18. Amplitude description of elastic pp scattering at 800 MeV

    NASA Astrophysics Data System (ADS)

    Moravcsik, Michael J.; Arash, Firooz; Goldstein, Gary R.

    1985-04-01

    Recent polarization data on proton-proton elastic scattering at 800 MeV taken at LAMPF are used for an amplitude analysis using the optimal formalism. The direct analysis of data is done in the transversity frame, which is best suited to parity-conserving reactions. From the results, amplitudes are also obtained in the helicity frame and the ``magic'' frame. Agreement with previous amplitudes obtained from an energy-dependent phase-shift analysis is good. The comparison of the helicity amplitudes c and e strengthens previous suggestions for a possible triplet-state dibaryon resonance. The comparison of the amplitudes am and cm in the magic frame indicates a possible domination of the process near 90° scattering angle by one-particle-exchange mechanism involving exchanged particles with natural parity.

  19. Investigation of rare particle production in high energy nuclear collisions. Progress report, December 15, 1997--December 14, 1998

    SciTech Connect

    Crawford, H.J.; Engelage, J.

    1998-11-01

    The program is an investigation of the hadronization process through experimental measurement of rare particle production in high energy nuclear interactions. These interactions provide an environment similar in energy density to the conditions in the Big Bang. The authors are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. They have completed the first physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. They have prototyped the STAR trigger and are in the process of fabricating its components and installing them in the STAR detector.

  20. Investigation of Rare Particle Production in High Energy Nuclear Collisions

    SciTech Connect

    1999-09-02

    Our program is an investigation of the hadronization process through measurement of rare particle production in high energy nuclear interactions. Such collisions of heavy nuclei provide an environment similar in energy density to the conditions in the Big Bang. We are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. We have completed our physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. We have produced the electronics and software for the STAR trigger and will begin to use these tools to search for anti-nuclei and strange hadrons when RHIC turns on later this year.

  1. Nuclear structure studies at intermediate energies. Summary progress report, 1987--1990

    SciTech Connect

    Hintz, N.M.

    1990-07-01

    This report discusses the following topics: Search for dibaryon resonances; analysis of {sup 208}Pb({pi}{sup {plus_minus}},{pi}{sup {plus_minus}}) data; analysis of {sup 206,207,208}Pb(p,p{prime}) data; study of transition nuclei by (p,p{prime}); search for recoil free {delta}-production; search for low lying magnetic states; proton nucleus scattering and swelling of nucleons; measurement of spin observables in {sup 28}Si(p,p{prime}); strength of tensor force in nuclei; global analysis of (p,p{prime}) reactions to high spin states in {sup 28}Si and {sup 58}Ni and density dependent modifications; MRS Setup and development; and development of coincidence studies with the MRS.

  2. Nuclear structure studies at intermediate energies

    SciTech Connect

    Hintz, N.M.

    1990-07-01

    This report discusses the following topics: Search for dibaryon resonances; analysis of {sup 208}Pb({pi}{sup {plus minus}},{pi}{sup {plus minus}}) data; analysis of {sup 206,207,208}Pb(p,p{prime}) data; study of transition nuclei by (p,p{prime}); search for recoil free {delta}-production; search for low lying magnetic states; proton nucleus scattering and swelling of nucleons; measurement of spin observables in {sup 28}Si(p,p{prime}); strength of tensor force in nuclei; global analysis of (p,p{prime}) reactions to high spin states in {sup 28}Si and {sup 58}Ni and density dependent modifications; MRS Setup and development; and development of coincidence studies with the MRS.

  3. Observation of B^0 -> p anti lamda D^(*)-

    SciTech Connect

    Chang, Y. Y.; Wang, M. Z.; Abdesselam, A.; Adachi, I.; Adamczyk, K.; Aihara, H.; Al Said, S.; Asner, David M.; Atmacan, H.; Aushev, T.; Babu, V.; Badhrees, I.; Bakich, A. M.; Barberio, E.; Bhuyan, B.; Biswal, J.; Bobrov, A.; Bozek, A.; Bracko, Marko; Browder, Thomas E.; Cervenkov, D.; Chekelian, V.; Chen, A.; Cheon, B. G.; Chilikin, K.; Chistov, R.; Chobanova, V.; Choi, S-K.; Choi, Y.; Cinabro, David A.; Dalseno, J.; Danilov, M.; Dingfelder, J.; Dolezal, Z.; Drasal, Z.; Dutta, D.; Eidelman, S.; Farhat, H.; Fast, James E.; Ferber, T.; Fulsom, Bryan G.; Gaur, Vipin; Gabyshev, N.; Ganguly, Sudeshna; Garmash, A.; Gillard, R.; Glattaur, R.; Goh, Y. M.; Goldenzweig, P.; Greenwald, D.; Grzymkowska, O.; Haba, J.; Hayasaka, K.; Hayashii, H.; He, X. H.; Hou, W. S.; Hsu, C. L.; Iijima, T.; Inami, K.; Ishikawa, A.; Itoh, R.; Iwasaki, Y.; Jacobs, W. W.; Jaegle, Igal; Joffe, D.; Joo, K. K.; Kawasaki, T.; Kim, D. Y.; Kim, H. J.; Kim, J. B.; Kim, J. H.; Kim, K. T.; Kim, M. J.; Kim, S. H.; Kim, Y. J.; Kinoshita, Kay; Korpar, S.; Krizan, P.; Krokovny, Pavel; Kuhr, T.; Kumita, T.; Kuzmin, A.; Kwon, Y. J.; Lai, Yun-Tsung; Lee, I. S.; Li, L.; Li, Y.; Libby, J.; Liventsev, D.; Lukin, P.; Masuda, M.; Matvienko, D.; Miyabayashi, K.; Miyake, Hideki; Miyata, H.; Mizuk, R.; Mohanty, G. B.; Mohanty, Subhashree; Moll, A.; Moon, H K.; Mori, T.; Nakano, E.; Nakao, M.; Nanut, T.; Nayak, Minakshi; Nishida, S.; Ogawa, S.; Ozaki, H.; Pakhlov, P.; Pakhlova, G.; Pal, Bilas K.; Park, C. W.; Pedlar, Todd; Pestotnik, R.; Petric, M.; Piilonen, Leo E.; Rauch, J.; Ribezl, Eva; Ritter, M.; Rostomyan, A.; Ryu, S.; Sahoo, Himansu B.; Sakai, Y.; Sandilya, Saurabh; Santelj, L.; Sanuki, T.; Savinov, Vladimir; Schneider, O.; Schnell, G.; Schwanda, C.; Seino, Y.; Senyo, K.; Seong, Ilsoo; Sevior, ME; Shebalin, V.; Shen, CP; Shibata, TA; Shiu, Jing-Ge; Simon, F.; Sohn, Y. S.; Staric, M.; Stypula, J.; Sumihama, M.; Sumisawa, K.; Sumiyoshi, T.; Tamponi, Umberto; Tanida, K.; Teramoto, Y.; Uglov, T.; Unno, Y.; Uno, S.; Usov, Y.; Van Hulse, C.; Vanhoefer, P.; Varner, G.; Vorobyev, V.; Vossen, Anslem G.; Wagner, M. N.; Wang, C. H.; Wang, P.; Watanabe, M.; Watanabe, Y.; Williams, K. M.; Won, E.; Yamaoka, Jared AK; Yashchenko, S.; Yelton, John M.; Yusa, Y.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.

    2015-09-11

    We report the first observation of the decays B^0 -> p anti lamda D^(*)-. the data sample of 711 fb^-1 used in this analysis corresponds to 772 million B B bar pairs, collected at the Y(4S) resonance by the Belle detector at the KEKB asymmetric-energy e+e- collider. We observe 19.8σ and 10.8σ excesses of events for the two decay modes and measure the branching fractions ofB^0 -> p anti lamda D^- and B^0 -> p anti lamda D^*- to be (25.1 +/- 2.6 +/- 3.5) x 10^-6 and (33.6 +/- 6.3 +/- 4.4) x 10^-6, respectively, where the first predictions based on the generalized factorization approach. In addition, a threshold enhancement in the di-baryon (p anti lamda) consistent with that observed in similar B decays.

  4. Light Nuclei and HyperNuclei from Quantum Chromodynamics in the Limit of SU(3) Flavor Symmetry

    SciTech Connect

    Beane, S R; Cohen, S D; Detmold, W; Lin, H W; Luu, T C; Orginos, K; Parreno, A; Savage, M J; Walker-Loud, A

    2013-02-01

    The binding energies of a range of nuclei and hypernuclei with atomic number A <= 4 and strangeness |s| <= 2, including the deuteron, di-neutron, H-dibaryon, {sup 3}He, {sub {Lambda}}{sup 3}He, {sub {Lambda}}{sup 4}He, and {sub {Lambda}{Lambda}}{sup 4}He, are calculated in the limit of flavor-SU(3) symmetry at the physical strange quark mass with quantum chromodynamics (without electromagnetic interactions). The nuclear states are extracted from Lattice QCD calculations performed with n{sub f}=3 dynamical light quarks using an isotropic clover discretization of the quark-action in three lattice volumes of spatial extent L ~ 3.4 fm, 4.5 fm and 6.7 fm, and with a single lattice spacing b ~ 0.145 fm.

  5. On a Missed Mechanism of Dielectron Production in Nucleon-Nucleon Collisions

    SciTech Connect

    Khrykin, Anatoliy S.

    2011-10-24

    We examine a new mechanism of e{sup +}e{sup -} pair production in NN collisions associated with the NN-decoupled dibaryon d{sub 1}*(1956) formation in the process NN{yields}{gamma}*d{sub 1}*, where {gamma}{sup *} is the virtual photon which converts into a e{sup +}e{sup -} pair. It is shown that a substantial excess of dielectron yields from Ca+Ca and C+C collisions at 1 GeV/A in the dielectron mass spectra in the region from 0.2 to 0.5 GeV/c{sup 2} measured by the DLS Collaboration as compared with calculated ones can be attributed to the contribution of this mechanism. A simple means for verification of the existence of such a mechanism is proposed.

  6. Measurement of the B0 -> Lambda-bar p pi Branching Fraction andStudy of the Decay Dynamics

    SciTech Connect

    Bondioli, M

    2006-08-16

    We present a measurement of the B{sup 0} {center_dot} {bar {Lambda}}p{pi}{sup -} branching fraction performed using the BABAR detector at the PEP-II asymmetric energy e{sup +}e{sup -} collider. Based on a 232 million B{bar B} pairs data sample we measure: {center_dot} (B{sup 0} {center_dot} {bar {Lambda}}p{pi}{sup -}) = [3.30 {center_dot} 0.53(stat.) {center_dot} 0.31 (syst.)] {center_dot} 10{sup -6}. A measurement of the differential spectrum as a function of the di-baryon invariant mass m({Lambda}p) is also presented; this shows a near-threshold enhancement similar to that observed in other baryonic B decays.

  7. Measurement of the Branching Fraction and Lambda-bar Polarization in B0 -> Lambda-par p pi-

    SciTech Connect

    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.; /LBL, Berkeley /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 U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /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, LNS /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 /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., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison

    2009-08-03

    We present a measurement of the B{sup 0} {yields} {bar {Lambda}}p{pi}{sup -} branching fraction performed using the BABAR detector at the PEP-II asymmetric e{sup +}e{sup -} collider. Based on a sample of 467 x 10{sup 6} B{bar B} pairs we measure {Beta}(B{sup 0} {yields} {bar {Lambda}}p{pi}{sup -}) [3.07 {+-} 0.31(stat.) {+-} 0.23(syst.)] x 10{sup -6}. The measured differential spectrum as a function of the dibaryon invariant mass m({bar {Lambda}}p) shows a near-threshold enhancement similar to that observed in other baryonic B decays. We study the {bar {Lambda}} polarization as a function of {bar {Lambda}} energy in the B{sup 0} rest frame (E*{sub {bar {Lambda}}}) and compare it with theoretical expectations of fully longitudinally right-polarized {bar {Lambda}} at large E*{sub {bar {Lambda}}}.

  8. Nuclear structure studies with medium energy probes. [Northwestern Univ

    SciTech Connect

    Seth, Kamal K.

    1980-01-01

    Progress in the continuing program of experimental research in nuclear structure with medium-energy probes during the year 1979-1980 is reviewed, and the research activities planned for the year 1980-1981 are discussed. In the study of pion-induced reactions emphasis is placed on investigation of isovector characteristics of nuclear excitations and on double charge exchange reactions. Pion production studies form the major part of the program of experiments with proton beams of 400 to 800 MeV at LAMPF. Current emphasis is on the bearing of these investigations on di-baryon existence. The study of high-spin states and magnetic scattering constitute the main goals of the electron scattering program at Bates. Representative results are presented; completed work is reported in the usual publications. (RWR)

  9. Rearranging Pionless Effective Field Theory

    SciTech Connect

    Martin Savage; Silas Beane

    2001-11-19

    We point out a redundancy in the operator structure of the pionless effective field theory which dramatically simplifies computations. This redundancy is best exploited by using dibaryon fields as fundamental degrees of freedom. In turn, this suggests a new power counting scheme which sums range corrections to all orders. We explore this method with a few simple observables: the deuteron charge form factor, n p -> d gamma, and Compton scattering from the deuteron. Higher dimension operators involving electroweak gauge fields are not renormalized by the s-wave strong interactions, and therefore do not scale with inverse powers of the renormalization scale. Thus, naive dimensional analysis of these operators is sufficient to estimate their contribution to a given process.

  10. 1 to 2 GeV/c beam line for hypernuclear and kaon research

    SciTech Connect

    Chrien, R.E.

    1985-02-15

    A kaon beam line operating in the range from 1.0 to 2.0 GeV/c is proposed. The line is meant for kaon and pion research in a region hitherto inaccessible to experimenters. Topics in hypernuclear and kaon physics of high current interest include the investigation of doubly strange nuclear systems with the K/sup -/,K/sup +/ reaction, searching for dibaryon resonances, hyperon-nucleon interactions, hypernuclear ..gamma.. rays, and associated production of excited hypernuclei. The beam line would provide separated beams of momentum analyzed kaons at intensities greater than 10/sup 6/ particles per spill with a momentum determined to one part in a thousand. This intensity is an order of magnitude greater than that currently available. 63 references.

  11. Study of Omega-proton correlations in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Han, Yifei; STAR Collaboration

    2015-10-01

    Recently the STAR experiment at RHIC measured Lambda-Lambda correlations from Au+Au collisions at √{sNN} = 200 GeV to search for the H particle (uuddss). The correlation strength indicated that the Lambda-Lambda interaction is weak and is unlikely to be attractive enough to form a bound state. A recent lattice QCD calculation predicted a possible di-baryon bound state with Omega-nucleon. Thus, we will extend the correlation measurements to Omega-proton, which could potentially be a sensitive approach to search for such a state. We will present the Omega-proton correlations based on data collected by STAR in Au+Au collisions at √{sNN} =200 GeV, and discuss the physics implications. for the STAR collaboration.

  12. Production of multistrange hadrons, light nuclei and hypertriton in central Au+Au collisions at √{sNN} = 11.5 and 200 GeV

    NASA Astrophysics Data System (ADS)

    Shah, N.; Ma, Y. G.; Chen, J. H.; Zhang, S.

    2016-03-01

    The production of dibaryons, light nuclei and hypertriton in the most central Au+Au collisions at √{sNN} = 11.5 and 200 GeV is investigated by using a naive coalescence model. The production of light nuclei is studied and found that the production rate reduces by a factor of 330 (1200) for each extra nucleon added to nuclei at √{sNN} = 11.5 (200) GeV. The pT integrated yield of multistrange hadrons falls exponentially as strangeness quantum number increases. We further investigate strangeness population factors S3 ,S2 as a function of transverse momentum as well as √{sNN}. The calculations for √{sNN} = 11.5 GeV presented here will stimulate interest to carry out these measurements during the phase-II of beam energy scan program at STAR experiment.

  13. pp{yields}p{Lambda}K{sup +} reaction in search for the K{sup -}pp state - quest for a kaonic nuclei

    SciTech Connect

    Suzuki, Ken; Kienle, Paul; Maggiora, Marco; Yamazaki, Toshimitsu

    2011-10-21

    The dibaryonic kaonic nuclear bound state, K{sup -}pp is searched by studying an exclusive p+p{yields}p+{Lambda}+K{sup +} process at several beam energies. A signature of the K{sup -}pp is explored in a p+p{yields}X({identical_to}K{sup -}pp)+K{sup +} reaction that follows a decay of the X into p+{Lambda}. We found in a missing-mass {Delta}M(K{sup +}) spectrum and a {Lambda}p invariant-mass M({Lambda}p) spectrum of DISTO data at 2.85 GeV a resonance with M = 2267 MeV/c{sup 2} and {Gamma} = 118 MeV. Those events are found to be associated with a mono energetic kaon. We investigate this resonance as a candidate of the K{sup -}pp further also with a different beam energies.

  14. Thomas-Fermi Quark Model and Techniques to Improve Lattice QCD Calculation

    NASA Astrophysics Data System (ADS)

    Liu, Quan

    Two topics are discussed separately in this thesis. In the first part a semiclassical quark model, called the Thomas-Fermi quark model, is reviewed. After a modified approach to spin in the model is introduced, I present the calculation of the spectra of octet and decuplet baryons. The six-quark doubly strange H-dibaryon state is also investigated. In the second part, two numerical techniques which improve latice QCD calculations are covered. The first one, which we call Polynomial-Preconditioned GMRES-DR(PP-GMRESDR), is used to speed up the calculation of large systems of linear equations in LQCD. The second one, called the Polynomial-Subtraction method, is used to help reduce the noise variance of the calculations for disconnected loops in LQCD.

  15. Application of polarization in particle reactions

    SciTech Connect

    Arash, F.

    1986-01-01

    In this dissertation polarization phenomena in particle reactions have been used to study the revealing features of the reactions. First, it is shown that it is impossible to design a non-dynamical null-experimental to test the time-reversal invariant. Second, the optimal formalism representation is used to determine proton-proton elastic scattering amplitudes at 579 MeV and 800 MeV. Thirdly, the polarization structure of two-body reaction in a collinear configuration is investigated, and it is demonstrated that the structure becomes much simpler than it was for the general configuration. Fourthly, an amplitude test is conducted to search for dibaryon resonances in p-p elastic scattering and it is found that at the energies around 800 MeV there is no evidence for any singlet partial wave state resonances. There exist, however, some tantalizing subliminal evidence for /sup 3/F/sub 3/ resonance. This method is also applied for pion-deutron elastic scattering to pin point the effect of a dibaryon resonance. Fifthly, evidence for the preeminence of one-particle-exchange mechanism is p-p elastic scattering is also examined in the 300 MeV-6 GeV/c range. Finally, a phenomenological model is developed to explain a striking feature of p-p scattering amplitudes pertaining to the amplitudes being either purely real or purely imaginary, and having three amplitudes almost equal in magnitudes and three times smaller than one amplitude in magnitude. This feature is extended to ..pi../sup +/p and k/sup +/p elastic scattering where spin flip and spin non-flip amplitudes appear to be equal in magnitude.

  16. The Thomas–Fermi quark model: Non-relativistic aspects

    SciTech Connect

    Liu, Quan Wilcox, Walter

    2014-02-15

    The first numerical investigation of non-relativistic aspects of the Thomas–Fermi (TF) statistical multi-quark model is given. We begin with a review of the traditional TF model without an explicit spin interaction and find that the spin splittings are too small in this approach. An explicit spin interaction is then introduced which entails the definition of a generalized spin “flavor”. We investigate baryonic states in this approach which can be described with two inequivalent wave functions; such states can however apply to multiple degenerate flavors. We find that the model requires a spatial separation of quark flavors, even if completely degenerate. Although the TF model is designed to investigate the possibility of many-quark states, we find surprisingly that it may be used to fit the low energy spectrum of almost all ground state octet and decuplet baryons. The charge radii of such states are determined and compared with lattice calculations and other models. The low energy fit obtained allows us to extrapolate to the six-quark doubly strange H-dibaryon state, flavor symmetric strange states of higher quark content and possible six quark nucleon–nucleon resonances. The emphasis here is on the systematics revealed in this approach. We view our model as a versatile and convenient tool for quickly assessing the characteristics of new, possibly bound, particle states of higher quark number content. -- Highlights: • First application of the statistical Thomas–Fermi quark model to baryonic systems. • Novel aspects: spin as generalized flavor; spatial separation of quark flavor phases. • The model is statistical, but the low energy baryonic spectrum is successfully fit. • Numerical applications include the H-dibaryon, strange states and nucleon resonances. • The statistical point of view does not encourage the idea of bound many-quark baryons.

  17. Application of Polarization in Particle Reactions.

    NASA Astrophysics Data System (ADS)

    Arash, Firooz

    In this dissertation we have utilized polarization phenomena in particle reactions to study the revealing features of the reaction. First, it is shown that it is impossible to design a non-dynamical null-experiment to test the time-reversal invariant. Second, the optimal formalism representation is used to determine proton-proton elastic scattering amplitudes at 579 MeV and 800 MeV. It is shown that, despite an extensive set of data at 579 MeV, the resulting amplitudes have a four-fold ambiguity. At 800 MeV, however, we managed to obtain a unique solution. Thirdly, the polarization structure of two-body reaction in a collinear configuration is investigated, and it is demonstrated that the structure becomes much simpler than it was for the general configuration. It is shown that in a collinear reaction all observables in which only one particle is polarized vanish. The results of this study are also applicable to all models in which helicity conservation holds, since they are formally identical with collinear reactions. Fourthly, an amplitude test is conducted to search for dibaryon resonances in p-p elastic scattering and it is found that at the energies around 800 MeV there is no evidence for any singlet partial wave state resonances. There exist, however, some tantalizing subliminal evidence for ('3)F(,3) resonance. This method is also applied for pion-deutron elastic scattering to pin point the effect of a dibaryon resonance. We have also given a practical guideline to carry out a complete set of experiments toward the reconstruction of pion-deutron scattering amplitudes. Fifthly, evidence for the preeminence of one-particle-exchange mechanism is p-p elastic scattering is also examined in the 300 MeV - 6 GeV/c range. Finally, a phenomenological model is developed to explain a striking feature of p-p scattering amplitudes pertaining to the amplitudes being either purely real or purely imaginary, and having three amplitudes almost equal in magnitudes and three

  18. Radiative neutron capture on a proton at big-bang nucleosynthesis energies

    SciTech Connect

    Ando, S.; Cyburt, R. H.; Hong, S. W.; Hyun, C. H.

    2006-08-15

    The total cross section for radiative neutron capture on a proton, np{yields}d{gamma}, is evaluated at big-bang nucleosynthesis (BBN) energies. The electromagnetic transition amplitudes are calculated up to next-to-leading-order within the framework of pionless effective field theory with dibaryon fields. We also calculate the d{gamma}{yields}np cross section and the photon analyzing power for the d{gamma}(vector sign){yields}np process from the amplitudes. The values of low-energy constants that appear in the amplitudes are estimated by a Markov Chain Monte Carlo analysis using the relevant low-energy experimental data. Our result agrees well with those of other theoretical calculations except for the np{yields}d{gamma} cross section at some energies estimated by an R-matrix analysis. We also study the uncertainties in our estimation of the np{yields}d{gamma} cross section at relevant BBN energies and find that the estimated cross section is reliable to within {approx}1% error.

  19. Observation of B0→p Λ ¯ D(*)-

    NASA Astrophysics Data System (ADS)

    Chang, Y.-Y.; Wang, M.-Z.; Abdesselam, A.; Adachi, I.; Adamczyk, K.; Aihara, H.; Al Said, S.; Asner, D. M.; Atmacan, H.; Aushev, T.; Babu, V.; Badhrees, I.; Bakich, A. M.; Barberio, E.; Bhuyan, B.; Biswal, J.; Bobrov, A.; Bozek, A.; Bračko, M.; Browder, T. E.; Červenkov, D.; Chekelian, V.; Chen, A.; Cheon, B. G.; Chilikin, K.; Chistov, R.; Chobanova, V.; Choi, S.-K.; Choi, Y.; Cinabro, D.; Dalseno, J.; Danilov, M.; Dingfelder, J.; Doležal, Z.; Drásal, Z.; Dutta, D.; Eidelman, S.; Farhat, H.; Fast, J. E.; Ferber, T.; Fulsom, B. G.; Gaur, V.; Gabyshev, N.; Ganguly, S.; Garmash, A.; Gillard, R.; Glattauer, R.; Goh, Y. M.; Goldenzweig, P.; Greenwald, D.; Grzymkowska, O.; Haba, J.; Hayasaka, K.; Hayashii, H.; He, X. H.; Hou, W.-S.; Hsu, C.-L.; Iijima, T.; Inami, K.; Ishikawa, A.; Itoh, R.; Iwasaki, Y.; Jacobs, W. W.; Jaegle, I.; Joffe, D.; Joo, K. K.; Kawasaki, T.; Kim, D. Y.; Kim, H. J.; Kim, J. B.; Kim, J. H.; Kim, K. T.; Kim, M. J.; Kim, S. H.; Kim, Y. J.; Kinoshita, K.; Korpar, S.; Križan, P.; Krokovny, P.; Kuhr, T.; Kumita, T.; Kuzmin, A.; Kwon, Y.-J.; Lai, Y.-T.; Lee, I. S.; Li, L.; Li, Y.; Libby, J.; Liventsev, D.; Lukin, P.; Masuda, M.; Matvienko, D.; Miyabayashi, K.; Miyake, H.; Miyata, H.; Mizuk, R.; Mohanty, G. B.; Mohanty, S.; Moll, A.; Moon, H. K.; Mori, T.; Nakano, E.; Nakao, M.; Nanut, T.; Nayak, M.; Nishida, S.; Ogawa, S.; Ozaki, H.; Pakhlov, P.; Pakhlova, G.; Pal, B.; Park, C. W.; Pedlar, T. K.; Pestotnik, R.; Petrič, M.; Piilonen, L. E.; Rauch, J.; Ribežl, E.; Ritter, M.; Rostomyan, A.; Ryu, S.; Sahoo, H.; Sakai, Y.; Sandilya, S.; Santelj, L.; Sanuki, T.; Savinov, V.; Schneider, O.; Schnell, G.; Schwanda, C.; Seino, Y.; Senyo, K.; Seong, I. S.; Sevior, M. E.; Shebalin, V.; Shen, C. P.; Shibata, T.-A.; Shiu, J.-G.; Simon, F.; Sohn, Y.-S.; Starič, M.; Stypula, J.; Sumihama, M.; Sumisawa, K.; Sumiyoshi, T.; Tamponi, U.; Tanida, K.; Teramoto, Y.; Uglov, T.; Unno, Y.; Uno, S.; Usov, Y.; Van Hulse, C.; Vanhoefer, P.; Varner, G.; Vorobyev, V.; Vossen, A.; Wagner, M. N.; Wang, C. H.; Wang, P.; Watanabe, M.; Watanabe, Y.; Williams, K. M.; Won, E.; Yamaoka, J.; Yashchenko, S.; Yelton, J.; Yusa, Y.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.; Belle Collaboration

    2015-11-01

    We report the first observation of the decays B0→p Λ ¯ D(*)- . The data sample of 711 fb-1 used in this analysis corresponds to 772 ×106 B B ¯ pairs, collected at the ϒ (4 S ) resonance by the Belle detector at the KEKB asymmetric-energy e+e- collider. We observe 19.8 σ and 10.8 σ excesses of events for the two decay modes and measure the branching fractions of B0→p Λ ¯D- and B0→p Λ ¯D*- to be (25.1 ±2.6 ±3.5 )×1 0-6 and (33.6 ±6.3 ±4.4 )×1 0-6, respectively, where the first uncertainties are statistical and the second are systematic. These results are not compatible with the predictions based on the generalized factorization approach. In addition, a threshold enhancement in the dibaryon (p Λ ¯) system is observed, consistent with that observed in similar B decays.

  20. Coherent ω-Meson Photoproduction off Deuteron

    NASA Astrophysics Data System (ADS)

    Chetry, Taya; Hicks, Kenneth; CLAS Collaboration

    2016-03-01

    Coherent ω photoproduction from the deuteron has been studied using CLAS at Jefferson Lab, Virginia, as a function of the photon energy and the 4-momentum transfer. Tagged photons with beam energies between 0.8 and 3.6 GeV were produced using the bremsstrahlung process incident on a deuterium target, during the run period g10. The final state particles detected are an energetic deuteron and a pair of charged pions. These events were constrained to have neutral pion missing mass, to ensure an exclusive reaction where an ω-meson decays into a π+, a π- and a π0. This study allows to test models of hadronic scattering of ω-mesons from the nucleon, as it is not possible to produce beams of ω-mesons. A preliminary differential cross section of the ω-meson in the coherent process is presented. In addition, this final state is useful to investigate a possible d* dibaryon resonance that has been seen in other reaction channels at CLAS, as well as being seen earlier in partial-wave analysis of pion-deuteron scattering at a mass of about 2145 MeV.

  1. lambda lambda. hypernuclei and the. lambda lambda. interaction

    SciTech Connect

    Bodmer, A.R.; Usmani, Q.N.

    1986-01-01

    Variational calculations of ..cap alpha..-cluster models for /sup 6//sub ..lambda lambda../He, /sup 9//sub ..lambda lambda../Be have been made. These calculations require a knowledge of the ..cap alpha lambda.. potential which is obtained in several ways including the use of five-body Monte Carlo (MC) calculations of /sup 5//sub ..lambda../He. We discuss the ..lambda lambda.. interaction strengths and the relation between the /sup 6//sub ..lambda lambda../He and /sup 10//sub ..lambda lambda../Be binding energies and, in particular, the dependence of these on the ..cap alpha lambda.. potential. For all our ..cap alpha lambda.. potentials the binding energy of /sup 6//sub ..lambda lambda../He predicted from /sup 10//sub ..lambda lambda../Be is 1 MeV or more below the experimental value. A brief discussion is given of the implication of the phenomenological strength of ..lambda lambda.. interaction we obtain and also the implication of ..lambda lambda.. hypernuclei for the H-dibaryon. 19 refs., 2 figs., 1 tab.

  2. Nuclear physics and astrophysics. Progress report for period June 15, 1992--June 14, 1993

    SciTech Connect

    Schramm, D.N.; Olinto, A.V.

    1993-06-01

    The authors report on recent progress of research at the interface of nuclear physics and astrophysics. During the past year, the authors continued to work on Big Bang and stellar nucleosynthesis, the solar neutrino problem, the equation of state for dense matter, the quark-hadron phase transition, and the origin of gamma-ray bursts; and began studying the consequences of nuclear reaction rates in the presence of strong magnetic fields. They have shown that the primordial production of B and Be cannot explain recent detections of these elements in halo stars and have looked at spallation as the likely source of these elements. By looking at nucleosynthesis with inhomogeneous initial conditions, they concluded that the Universe must have been very smooth before nucleosynthesis. They have also constrained neutrino oscillations and primordial magnetic fields by Big Bang nucleosynthesis. On the solar neutrino problem, they have analyzed the implications of the SAGE and GALLEX experiments. They also showed that the presence of dibaryons in neutron stars depends weakly on uncertainties of nuclear equations of state. They have started to investigate the consequences of strong magnetic fields on nuclear reactions and implications for neutron star cooling and supernova nucleosynthesis.

  3. Witnessing the Hadronic Collision Events at Close Quarters

    NASA Astrophysics Data System (ADS)

    Jain, Arun K.; Joshi, Bhushan N.

    It is seen that in the three body final state of a nucleon knockout reaction the residual nucleus not only bears testimony to the dynamics of the knocked out nucleon before the event but also can testify the happening at the time of the hard collision event. This arises mainly because of the distorting optical potentials of the residual nucleus with the knockout partners. In 40Ca(p, 2p) knockout reaction the optical distortion effects are large enough to be able to differentiate between strong peripheral bruising or the deep interpenetration of the two protons at the time of knockout. Similar effect is witnessed in the proton knockout using pions. Many stronger evidences of the effect of varying behaviour of the knockout vertex exist in the nucleon cluster knockout reactions which were only viewed as unexplained large anomalies. Evidences are provided where the different short distance behaviour of the knockout vertex t-matrix effective interaction produced huge differences in the finite range (FR) distorted wave impulse approximation (DWIA) predictions of various knockout reactions. These observations enhance the possibility of observing the multiquark objects (dibaryons, pentaquark eta.) through nucleon knockout reactions if they are produced at the knockout vertex by the incident hadron beam.

  4. Structure near the K- + p + p threshold in the in-flight 3He(K-, Λp)n reaction

    NASA Astrophysics Data System (ADS)

    Sada, Y.; Ajimura, S.; Bazzi, M.; Beer, G.; Bhang, H.; Bragadireanu, M.; Buehler, P.; Busso, L.; Cargnelli, M.; Choi, S.; Curceanu, C.; Enomoto, S.; Faso, D.; Fujioka, H.; Fujiwara, Y.; Fukuda, T.; Guaraldo, C.; Hashimoto, T.; Hayano, R. S.; Hiraiwa, T.; Iio, M.; Iliescu, M.; Inoue, K.; Ishiguro, Y.; Ishikawa, T.; Ishimoto, S.; Ishiwatari, T.; Itahashi, K.; Iwai, M.; Iwasaki, M.; Kato, Y.; Kawasaki, S.; Kienle, P.; Kou, H.; Ma, Y.; Marton, J.; Matsuda, Y.; Mizoi, Y.; Morra, O.; Nagae, T.; Noumi, H.; Ohnishi, H.; Okada, S.; Outa, H.; Piscicchia, K.; Romero Vidal, A.; Sakaguchi, A.; Sakuma, F.; Sato, M.; Scordo, A.; Sekimoto, M.; Shi, H.; Sirghi, D.; Sirghi, F.; Suzuki, K.; Suzuki, S.; Suzuki, T.; Tanida, K.; Tatsuno, H.; Tokuda, M.; Tomono, D.; Toyoda, A.; Tsukada, K.; Vazquez Doce, O.; Widmann, E.; Wuenschek, B. K.; Yamaga, T.; Yamazaki, T.; Yim, H.; Zhang, Q.; Zmeskal, J.

    2016-05-01

    To search for an S = -1 di-baryonic state which decays to Λ p, the 3He(K^-,Λ p)n_missing reaction was studied at 1.0 GeV/c. Unobserved neutrons were kinematically identified from the missing mass MX of the 3He(K^-,Λ p)X reaction in order to have a large acceptance for the Λ pn final state. The observed Λ pn events, distributed widely over the kinematically allowed region of the Dalitz plot, establish that the major component comes from a three-nucleon absorption process. A concentration of events at a specific neutron kinetic energy was observed in a region of low momentum transfer to the Λ p. To account for the observed peak structure, the simplest S-wave pole was assumed to exist in the reaction channel, having a Breit-Wigner form in energy and with a Gaussian form factor. A minimum χ ^2 method was applied to deduce its mass, M_X = 2355^{+6}_{-8} (stat.) ± 12 (syst.) MeV/c^2, and decay width, Γ _X = 110^{+19}_{-17} (stat.) ± 27 (syst.) MeV/c^2, respectively. The form factor parameter Q_X ˜ 400 MeV/c implies that the range of the interaction is about 0.5 fm.

  5. Experimental and theoretical high energy physics research. Annual grant progress report (FDP), January 15, 1993--January 14, 1993

    SciTech Connect

    Cline, D.B.

    1993-10-01

    Progress on seven tasks is reported. (I)UCLA hadronization model, antiproton decay, PEP4/9 e{sup +}e{sup {minus}} analysis: In addition to these topics, work on CP and CPT phenomenology at a {phi} factory and letters of support on the hadronization project are included. (II)ICARUS detector and rare B decays with hadron beams and colliders: Developments are summarized and some typcial events as shown; in addition, the RD5 collaboration at CERN and the asymmetric {phi} factory project are sketched. (III)Theoretical physics: Feynman diagram calculations in gauge theory; supersymmetric standard model; effects of quantum gravity in breaking of global symmetries; models of quark and lepton substructure; renormalized field theory; large-scale structure in the universe and particle-astrophysics/early universe cosmology. (IV)H dibaryon search at BNL, kaon experiments (E799/KTeV) at Fermilab: Project design and some scatterplots are given. (V)UCLA participation in the experiment CDF at Fermilab. (VI)Detectors for hadron physics at ultrahigh energy colliders: Scintillating fiber and visible light photon counter research. (VII)Administrative support and conference organization.

  6. An Effective Field Theory Calculation of n(p, d)gamma Cross-section for Big Bang Nucleo-synthesis

    NASA Astrophysics Data System (ADS)

    Kamand, Rasha Adnan

    Studying the nuclear reaction n(p, d)gamma and calculating its cross-section is not only a matter of interest from theoretical particle physics point of view but also from the viewpoint of cosmology. We now know that the universe is made up of only ≈ 5% baryonic matter. So, computing the density of baryons is of particular importance to physicists in general and cosmologists in particular. Deuterium production during Big Bang Nucleo-synthesis (BBN) is very sensitive to the density of baryons, thus baryon density can be inferred from the abundance of deuterium. In order to calculate deuterium abundance one needs to use the cross-section of np --> dgamma reaction as one of the inputs; hence the importance of this cross-section calculation. In this document, a leading-order (LO) calculation of n( p, d)gamma cross-section is presented using the framework of pion-less effective field theory with dibaryon fields. The computation yielded a numerical value of sigmaLO = 494 mb which is then compared to the experimental value.

  7. Experimental and theoretical high energy physics research. [UCLA

    SciTech Connect

    Buchanan, Charles D.; Cline, David B.; Byers, N.; Ferrara, S.; Peccei, R.; Hauser, Jay; Muller, Thomas; Atac, Muzaffer; Slater, William; Cousins, Robert; Arisaka, Katsushi

    1992-01-01

    Progress in the various components of the UCLA High-Energy Physics Research program is summarized, including some representative figures and lists of resulting presentations and published papers. Principal efforts were directed at the following: (I) UCLA hadronization model, PEP4/9 e{sup +}e{sup {minus}} analysis, {bar P} decay; (II) ICARUS and astroparticle physics (physics goals, technical progress on electronics, data acquisition, and detector performance, long baseline neutrino beam from CERN to the Gran Sasso and ICARUS, future ICARUS program, and WIMP experiment with xenon), B physics with hadron beams and colliders, high-energy collider physics, and the {phi} factory project; (III) theoretical high-energy physics; (IV) H dibaryon search, search for K{sub L}{sup 0} {yields} {pi}{sup 0}{gamma}{gamma} and {pi}{sup 0}{nu}{bar {nu}}, and detector design and construction for the FNAL-KTeV project; (V) UCLA participation in the experiment CDF at Fermilab; and (VI) VLPC/scintillating fiber R D.

  8. Study ofe+e- to Lambda anti-Lambda, Lambda anti-Sigma^0,Sigma^0 anti-Sigma^0 using Initial State Radiation with BaBar

    SciTech Connect

    Aubert, B.

    2007-09-14

    We study the e+e- --> Lambda anti-Lambda gamma, Lambda anti-Sigma0 gamma, Sigma0 anti-Sigma0 gamma processes using 230 fb-1 of integrated luminosity collected by the BaBar detector at e+e- center-of-mass energy of 10.58 GeV. From the analysis of the baryon-antibaryon mass spectra the cross sections for e+e- --> Lambda anti-Lambda, Lambda anti-Sigma0, Sigma0 anti-Sigma0 are measured in the dibaryon mass range from threshold up to 3 GeV/c{sup 2}. The ratio of electric and magnetic form factors, |G{sub E}/G{sub M}|, is measured for e+e- --> Lambda anti-Lambda, and limits on the relative phase between Lambda form factors are obtained. We also measure the J/psi --> Lambda anti-Lambda, Sigma0 anti-Sigma0 and psi(2S) --> Lambda anti-Lambda branching fractions.

  9. H particle searches at Brookhaven

    SciTech Connect

    Chrien, R.E.

    1997-09-01

    Following the suggestion by R.L. Jaffe twenty years ago, researchers have been trying to establish the existence of a six-quark object, termed the H dibaryon, predicted by the phenomenological quark bag model. This object quickly became the focus of experimental searches at several locations, including the AGS. This search still continues, with perhaps the most active program being carried out at the 2.0 GeV/c beam line at the BNL-AGS. The research was considerably enhanced by the writing of two notable papers at BNL by Aerts and Dover, which gave quantitative predictions for H-production cross sections in two very different reaction mechanisms. One of these, the formation of cascade atomic deuterium to form the H by fusion, had been first suggested by P.D. Barnes. The 2.0 GeV/c line at the AGS was specifically designed to provide an adequate kaon flux for double strangeness and charge exchange reactions. It has been used for two H searches, E813 and E836, as well as for several {Lambda}{Lambda} searches, E885 and E906. These four experiments are setting significant limits on H-production. The results of these experiments are discussed, and descriptions of related H searches at Brookhaven are given.

  10. Photoproduction of Structure in the dπ System Near the NΔ mass: Sign of a Quasi-Bound State?

    NASA Astrophysics Data System (ADS)

    Schumacher, Reinhard

    2015-04-01

    Results from nucleon-nucleon and pion-deuteron scattering analysis show attractive resonance-like behavior in certain partial waves. But evidence for clear-cut baryon-baryon (quasi-) bound states other than the deuteron remains lacking, despite theoretical expectations that they can exist. In recent years some measurements using pd scattering have interpreted a broad bump in the dππ invariant mass distribution in terms of a ΔΔ dibaryonic resonance. If such a quasi-bound state exists, then one supposes that an NΔ quasi-bound state exists also, as supported by recent Fadeev-model calculations of the πNN system. Here we discuss ongoing work looking at the γd --> dπ+π- reaction using the CLAS detector at Jefferson Lab. A Dalitz-plot analysis shows structure in the invariant mass distributions in (dπ) + + and (dπ) 0 systems. Both are near the center of the NΔ mass distribution. Possible interpretations of this observation will be discussed. (for the CLAS Collaboration).

  11. Experimental and theoretical high energy physics research. Annual progress report, September 1, 1991--September 31, 1992

    SciTech Connect

    Not Available

    1992-10-01

    Progress in the various components of the UCLA High-Energy Physics Research program is summarized, including some representative figures and lists of resulting presentations and published papers. Principal efforts were directed at the following: (I) UCLA hadronization model, PEP4/9 e{sup +}e{sup {minus}} analysis, {bar P} decay; (II) ICARUS and astroparticle physics (physics goals, technical progress on electronics, data acquisition, and detector performance, long baseline neutrino beam from CERN to the Gran Sasso and ICARUS, future ICARUS program, and WIMP experiment with xenon), B physics with hadron beams and colliders, high-energy collider physics, and the {phi} factory project; (III) theoretical high-energy physics; (IV) H dibaryon search, search for K{sub L}{sup 0} {yields} {pi}{sup 0}{gamma}{gamma} and {pi}{sup 0}{nu}{bar {nu}}, and detector design and construction for the FNAL-KTeV project; (V) UCLA participation in the experiment CDF at Fermilab; and (VI) VLPC/scintillating fiber R & D.

  12. Spin structure in high energy processes: Proceedings

    SciTech Connect

    DePorcel, L.; Dunwoodie, C.

    1994-12-01

    This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z{sup 0}s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ({sup 3}HE) and the Bjoerken sum rule; a consumer`s guide to lattice QCD results; top ten models constrained by b {yields} sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere.

  13. Production of strange clusters in relativistic heavy ion collisions

    SciTech Connect

    Dover, C.B.; Baltz, A.J.; Pang, Yang; Schlagel, T.J.; Kahana, S.H.

    1993-02-01

    We address a number of issues related to the production of strangeness in high energy heavy ion collisions, including the possibility that stable states of multi-strange hyperonic or quark matter might exist, and the prospects that such objects may be created and detected in the laboratory. We make use of events generated by the cascade code ARC to estimate the rapidity distribution dN/dy of strange clusters produced in Si+Au and Au+Au collisions at AGS energies. These calculations are performed in a simple coalescence model, which yields a consistent description of the strange cluster (d, [sup 3]HE, [sup 3]H, [sup 4]He) production at these energies. If a doubly strange, weakly bound [Lambda][Lambda] dibaryon exists, we find that it is produced rather copiously in Au+Au collisions, with dN/dy [approximately]0.1 at raid-rapidity. If one adds another non-strange or strange baryon to a cluster, the production rate decreases by roughly one or two orders of magnitude, respectively. For instance, we predict that the hypernucleus [sub [Lambda][Lambda

  14. Experimental and theoretical high energy physics research

    NASA Astrophysics Data System (ADS)

    Progress in the various components of the UCLA High-Energy Physics Research program is summarized, including some representative figures and lists of resulting presentations and published papers. Principal efforts were in the following areas: (1) UCLA hadronization model, PEP4/9 e(+)e(-) analysis, and (bar-P) decay; (2) ICARUS and astroparticle physics (physics goals, technical progress on electronics, data acquisition, detector performance, long baseline neutrino beam from CERN to the Gran Sasso and ICARUS, future ICARUS program, and WIMP experiment with xenon), B physics with hadron beams and colliders, high-energy collider physics, and the phi factory project; (3) theoretical high-energy physics; (4) H dibaryon search, search for K(sub L)(sup 0) yields (pi)(sup 0)(gamma)(gamma) and (pi)(sup 0)(nu)(bar-nu), and detector design and construction for the FNAL-KTeV project; (5) UCLA participation in the experiment CDF at Fermilab; and (6) VLPC/scintillating fiber R & D.

  15. Double Lambda and Xi hypernuclei

    NASA Astrophysics Data System (ADS)

    Nakazawa, Kazuma

    2014-09-01

    Nuclei with double strangeness (S = -2) provide the key information to understand Baryon-Baryon interaction under the SU(3)f symmetry. Therefore we have carried out the experiments at KEK for quarter a century. Recently, the interaction in S = -2 sector is noted to derive the information of the EOS of neutron star. The Lambda-Lambda interaction has been presented to be weak attractive by NAGARA event which showed the production and decay of 6He double-hypernucleus. The event also presented the lower mass limit of H dibaryon. In other five events, we obtained the knowledge about an excitation level of 10Be double-hypernucleus under the consistency with NAGARA event. Moreover, very recently, we have discovered a Xi-14N system which was deeply bound far from the atomic 3D level (0.17 MeV) for a captured Xi hyperon. Since a 8Li nucleus was associated with the decay of one of twin-hypernuclei, the event was uniquely identified as Xi- + 14N ==> 10BeL + 5HeL. The system was selected from 8 million pictures on the test running for development of ``Overall Scanning'' to be used in the coming experiment. This is the first evidence of Xi hypernucleus to be bound and it is impacting for the study of Xi-N interaction. At J-PARC facility, for the further study of hyperon-hyperon interaction, we plan to perform the E07 experiment at J-PARC. In the workshop, we will review the above knowledge obtained by the experiments at KEK-PS, and discuss developed technologies to detected 102 or more double-hypernuclei in the E07 experiment at J-PARC. Nuclei with double strangeness (S = -2) provide the key information to understand Baryon-Baryon interaction under the SU(3)f symmetry. Therefore we have carried out the experiments at KEK for quarter a century. Recently, the interaction in S = -2 sector is noted to derive the information of the EOS of neutron star. The Lambda-Lambda interaction has been presented to be weak attractive by NAGARA event which showed the production and decay of 6He

  16. High statistics analysis using anisotropic clover lattices: (III) Baryon-baryon interactions

    SciTech Connect

    Beane, S; Detmold, W; Lin, H; Luu, T; Orginos, K; Savage, M; Torok, A; Walker-Loud, A

    2010-01-19

    Low-energy baryon-baryon interactions are calculated in a high-statistics lattice QCD study on a single ensemble of anisotropic clover gauge-field configurations at a pion mass of m{sub {pi}} {approx} 390 MeV, a spatial volume of L{sup 3} {approx} (2.5 fm){sup 3}, and a spatial lattice spacing of b {approx} 0.123 fm. Luescher's method is used to extract nucleon-nucleon, hyperon-nucleon and hyperon-hyperon scattering phase shifts at one momentum from the one- and two-baryon ground-state energies in the lattice volume. The isospin-3/2 N{Sigma} interactions are found to be highly spin-dependent, and the interaction in the {sup 3}S{sub 1} channel is found to be strong. In contrast, the N{Lambda} interactions are found to be spin-independent, within the uncertainties of the calculation, consistent with the absence of one-pion-exchange. The only channel for which a negative energy-shift is found is {Lambda}{Lambda}, indicating that the {Lambda}{Lambda} interaction is attractive, as anticipated from model-dependent discussions regarding the H-dibaryon. The NN scattering lengths are found to be small, clearly indicating the absence of any fine-tuning in the NN-sector at this pion mass. This is consistent with our previous Lattice QCD calculation of NN interactions. The behavior of the signal-to-noise ratio in the baryon-baryon correlation functions, and in the ratio of correlation functions that yields the ground-state energy splitting is explored. In particular, focus is placed on the window of time slices for which the signal-to-noise ratio does not degrade exponentially, as this provides the opportunity to extract quantitative information about multi-baryon systems.

  17. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies

    SciTech Connect

    Not Available

    1990-10-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988--91. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons that we have been involved with for more than ten years. Its purpose has been to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The give complex isospin-one amplitudes have been fairly well determined, partly as a result of this work. Our work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues our studies of this interaction in regions where it has not been well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where our data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei.

  18. Electroproduction of kaons and light hypernuclei

    SciTech Connect

    Geesaman, D.F.; Jackson, H.E.; Jones, C.E.

    1995-08-01

    A detailed investigation of the basic hyperon-nucleon interactions in nuclei is one of the aims of Experiment 91-016, approved with high priority at CEBAF, to study the electroproduction of kaons on targets of deuterium, {sup 3}He, and {sup 4}He. Inasmuch as both the electron and K{sup +} are particles that interact relatively weakly with nucleons, electroproduction of light hypernuclei provides a low-distortion method for investigating the fundamental interactions between nucleons, {Alpha}`s, and {Epsilon}`s in few-body systems. In particular, the (e,e`K{sup +}) reactions on cryogenic targets of D, {sup 3}He, and {sup 4}He will be studied at incident electron energies near 3 GeV with coincident detection of the emergent e and K{sup +} in the HMS and SOS magnetic spectrometers in Hall C. Construction of the He target, operating at {approximately}10 atm, {approximately}50 K and capable of dissipating {approximately}30 W, is expected to be complete prior to commencement of production runs in Hall C. The first data runs for E91-016, expected to begin late in FY 1995, will also be the basis for a doctoral thesis at Hampton University. In addition to providing new information on the phases of hyperon-nucleon interactions, measurements of cross sections for hypernuclear formation, and interference phenomena, the data may provide evidence for the presence of bound {Epsilon}`s and strange di-baryonic states that are the subject of considerable theoretical discussion.

  19. High Statistics Analysis using Anisotropic Clover Lattices: (III) Baryon-Baryon Interactions

    SciTech Connect

    Silas Beane; Detmold, William; Lin, Huey-Wen; Luu, Thomas C.; Orginos, Kostas; Savage, Martin; Torok, Aaron M.; Walker-Loud, Andre

    2010-03-01

    Low-energy baryon-baryon interactions are calculated in a high-statistics lattice QCD study on a single ensemble of anisotropic clover gauge-field configurations at a pion mass of m_pi ~ 390 MeV, a spatial volume of L^3 ~ (2.5 fm)^3, and a spatial lattice spacing of b ~ 0.123 fm. Luscher’s method is used to extract nucleon-nucleon, hyperon-nucleon and hyperon-hyperon scattering phase shifts at one momentum from the one- and two-baryon ground-state energies in the lattice volume. The N-Sigma interactions are found to be highly spin-dependent, and the interaction in the ^3 S _1 channel is found to be strong. In contrast, the N-Lambda interactions are found to be spin-independent, within the uncertainties of the calculation, consistent with the absence of one-pion-exchange. The only channel for which a negative energy-shift is found is Lambda-Lambda, indicating that the Lambda-Lambda interaction is attractive, as anticipated from model-dependent discussions regarding the H-dibaryon. The NN scattering lengths are found to be small, clearly indicating the absence of any fine-tuning in the NN-sector at this pion mass. This is consistent with our previous Lattice QCD calculation of the NN interactions. The behavior of the signal-to-noise ratio in the baryon-baryon correlation functions, and in the ratio of correlation functions that yields the ground-state energy splitting

  20. Production of strange clusters in relativistic heavy ion collisions

    SciTech Connect

    Dover, C.B.; Baltz, A.J.; Pang, Yang; Schlagel, T.J.; Kahana, S.H.

    1993-02-01

    We address a number of issues related to the production of strangeness in high energy heavy ion collisions, including the possibility that stable states of multi-strange hyperonic or quark matter might exist, and the prospects that such objects may be created and detected in the laboratory. We make use of events generated by the cascade code ARC to estimate the rapidity distribution dN/dy of strange clusters produced in Si+Au and Au+Au collisions at AGS energies. These calculations are performed in a simple coalescence model, which yields a consistent description of the strange cluster (d, {sup 3}HE, {sup 3}H, {sup 4}He) production at these energies. If a doubly strange, weakly bound {Lambda}{Lambda} dibaryon exists, we find that it is produced rather copiously in Au+Au collisions, with dN/dy {approximately}0.1 at raid-rapidity. If one adds another non-strange or strange baryon to a cluster, the production rate decreases by roughly one or two orders of magnitude, respectively. For instance, we predict that the hypernucleus {sub {Lambda}{Lambda}}{sup 6}He should have dN/dy {approximately}5 {times} 10{sup {minus}6} for Au+Au central collisions. It should be possible to measure the successive {Lambda} {yields} p{pi}{minus} weak decays of this object. We comment on the possibility that conventional multi-strange hypernuclei may serve as ``doorway states`` for the production of stable configurations of strange quark matter, if such states exist.

  1. H-cluster stars

    NASA Astrophysics Data System (ADS)

    Lai, X. Y.; Gao, C. Y.; Xu, R. X.

    2013-06-01

    The study of dense matter at ultrahigh density has a very long history, which is meaningful for us to understand not only cosmic events in extreme circumstances but also fundamental laws of physics. It is well known that the state of cold matter at supranuclear density depends on the non-perturbative nature of quantum chromodynamics (QCD) and is essential for modelling pulsars. A so-called H-cluster matter is proposed in this paper as the nature of dense matter in reality. In compact stars at only a few nuclear densities but low temperature, quarks could be interacting strongly with each other there. That might render quarks grouped in clusters, although the hypothetical quark clusters in cold dense matter have not been confirmed due to the lack of both theoretical and experimental evidence. Motivated by recent lattice QCD simulations of the H-dibaryons (with structure uuddss), we therefore consider here a possible kind of quark clusters, H-clusters, that could emerge inside compact stars during their initial cooling as the dominant components inside (the degree of freedom could then be H-clusters there). Taking into account the in-medium stiffening effect, we find that at baryon densities of compact stars H-cluster matter could be more stable than nuclear matter. We also find that for the H-cluster matter with lattice structure, the equation of state could be so stiff that it would seem to be `superluminal' in the most dense region. However, the real sound speed for H-cluster matter is in fact difficult to calculate, so at this stage we do not put constraints on our model from the usual requirement of causality. We study the stars composed of H-clusters, i.e. H-cluster stars, and derive the dependence of their maximum mass on the in-medium stiffening effect, showing that the maximum mass could be well above 2 M⊙ as observed and that the resultant mass-radius relation fits the measurement of the rapid burster under reasonable parameters. Besides a general

  2. Measurement of the pp. -->. pi. d spin correlation parameters A/sub SL/ and A/sub LL/ at energies between 500 and 800 MeV

    SciTech Connect

    Barlow, D.B.

    1984-11-01

    Angular distributions of the spin correlation parameters A/sub SL/ and A/sub LL/ for the inelastic reaction pp..--> pi..d have been measured at pion center-of-mass angles between 40 and 130/sup 0/, at energies of 500, 650, and 800 MeV. Additional measurements of A/sub LL/(THETA) were made at 600, 700, and 750 MeV. The reaction was studied using an incident beam of either longitudinally polarized protons. Both the final state pion and deuteron were detected in a two-armed detector system. The momenta of particles detected in the deuteron arm were analyzed with a magnetic spectrometer which allowed the deuterons to be distinguished from particles produced by quasi-free, three-body, or other background reactions. A/sub SL/ was found to be negative (approx. = -0.5) at 500 MeV. It became increasingly more negative as energy increased, going down to as low as -0.88 at forward angles at 800 MeV. A/sub SL/ showed only a slight angular dependence in the entire energy range. The angular distribution of A/sub LL/ was found to be almost flat at 500 (approx. = -0.5) and 600 MeV (approx. = -0.4). As energy increased A/sub LL/ became less negative and began to peak at theta/sub cm/ = 90/sup 0/. At 800 MeV A/sub LL/ was positive at almost all measured angles and had a well defined peak at theta/sub cm/ = 90/sup 0/ which reached a maximum of about +0.4. The data were compared to several partial wave analyses and to theoretical calculations based on unified theories of NN..-->..NN, ..pi..d..--> pi..d, and NN..--> pi..d reactions. In general these later calculations were found to be unsuccessful in fitting our data. Partial wave analyses, which included the present data, fitted the data reasonably well and did not indicate the need for any unusual (dibaryon like) structures in any of the partial waves. 52 references.

  3. Baryon-baryon interactions in the SU6 quark model and their applications to light nuclear systems

    NASA Astrophysics Data System (ADS)

    Fujiwara, Y.; Suzuki, Y.; Nakamoto, C.

    2007-04-01

    Interactions between the octet-baryons ( B8) in the spin-flavor SU6 quark model are investigated in a unified coupled-channels framework of the resonating-group method (RGM). The interaction Hamiltonian for quarks consists of the phenomenological confinement potential, the color Fermi-Breit interaction with explicit flavor-symmetry breaking (FSB), and effective-meson exchange potentials of scalar-, pseudoscalar- and vector-meson types. The model parameters are determined to reproduce the properties of the nucleon-nucleon ( NN) system and the low-energy cross section data for the hyperon-nucleon interactions. Mainly due to the introduction of the vector mesons, the NN phase shifts at non-relativistic energies up to T=350 MeV are greatly improved in comparison with the previous quark-model NN interactions. The deuteron properties and the low-energy observables of the B8B8 interactions, including the inelastic capture ratio at rest for the Σ-p scattering, are examined in the particle basis with the pion-Coulomb correction. The nuclear saturation properties and the single-particle (s.p.) potentials of B8 in nuclear medium are examined through the G-matrix calculations, using the quark-exchange kernel. The Σ s.p. potential is weakly repulsive in symmetric nuclear matter. The s.p. spin-orbit strength for Λ is very small, due to the strong antisymmetric spin-orbit force generated from the Fermi-Breit interaction. The qualitative behavior of the B8B8 interactions is systematically understood by (1) the spin-flavor SU6 symmetry of B8, (2) the special role of the pion exchange, and (3) the FSB of the underlying quark Hamiltonian. In particular, the B8B8 interaction becomes less attractive according to the increase of strangeness, implying that there exists no B8B8 di-baryon bound state except for the deuteron. The strong ΛN-ΣN coupling results from the important tensor component of the one-pion exchange. The ΛΛ-ΞN-ΣΣ coupling in the strangeness S=-2 and isospin I=0

  4. Nuclear Structure in China 2010

    NASA Astrophysics Data System (ADS)

    Bai, Hong-Bo; Meng, Jie; Zhao, En-Guang; Zhou, Shan-Gui

    2011-08-01

    Personal view on nuclear physics research / Jie Meng -- High-spin level structures in [symbol]Zr / X. P. Cao ... [et al.] -- Constraining the symmetry energy from the neutron skin thickness of tin isotopes / Lie-Wen Chen ... [et al.] -- Wobbling rotation in atomic nuclei / Y. S. Chen and Zao-Chun Gao -- The mixing of scalar mesons and the possible nonstrange dibaryons / L. R. Dai ... [et al.] -- Net baryon productions and gluon saturation in the SPS, RHIC and LHC energy regions / Sheng-Qin Feng -- Production of heavy isotopes with collisions between two actinide nuclides / Z. Q. Feng ... [et al.] -- The projected configuration interaction method / Zao-Chun Gao and Yong-Shou Chen -- Applications of Nilsson mean-field plus extended pairing model to rare-earth nuclei / Xin Guan ... [et al.] -- Complex scaling method and the resonant states / Jian-You Guo ... [et al.] -- Probing the equation of state by deep sub-barrier fusion reactions / Hong-Jun Hao and Jun-Long Tian -- Doublet structure study in A[symbol]105 mass region / C. Y. He ... [et al.] -- Rotational bands in transfermium nuclei / X. T. He -- Shape coexistence and shape evolution [symbol]Yb / H. Hua ... [et al.] -- Multistep shell model method in the complex energy plane / R. J. Liotta -- The evolution of protoneutron stars with kaon condensate / Ang Li -- High spin structures in the [symbol]Lu nucleus / Li Cong-Bo ... [et al.] -- Nuclear stopping and equation of state / QingFeng Li and Ying Yuan -- Covariant description of the low-lying states in neutron-deficient Kr isotopes / Z. X. Li ... [et al.] -- Isospin corrections for superallowed [symbol] transitions / HaoZhao Liang ... [et al.] -- The positive-parity band structures in [symbol]Ag / C. Liu ... [et al.] -- New band structures in odd-odd [symbol]I and [symbol]I / Liu GongYe ... [et al.] -- The sd-pair shell model and interacting boson model / Yan-An Luo ... [et al.] -- Cross-section distributions of fragments in the calcium isotopes projectile

  5. Nuclear Structure in China 2010

    NASA Astrophysics Data System (ADS)

    Bai, Hong-Bo; Meng, Jie; Zhao, En-Guang; Zhou, Shan-Gui

    2011-08-01

    Personal view on nuclear physics research / Jie Meng -- High-spin level structures in [symbol]Zr / X. P. Cao ... [et al.] -- Constraining the symmetry energy from the neutron skin thickness of tin isotopes / Lie-Wen Chen ... [et al.] -- Wobbling rotation in atomic nuclei / Y. S. Chen and Zao-Chun Gao -- The mixing of scalar mesons and the possible nonstrange dibaryons / L. R. Dai ... [et al.] -- Net baryon productions and gluon saturation in the SPS, RHIC and LHC energy regions / Sheng-Qin Feng -- Production of heavy isotopes with collisions between two actinide nuclides / Z. Q. Feng ... [et al.] -- The projected configuration interaction method / Zao-Chun Gao and Yong-Shou Chen -- Applications of Nilsson mean-field plus extended pairing model to rare-earth nuclei / Xin Guan ... [et al.] -- Complex scaling method and the resonant states / Jian-You Guo ... [et al.] -- Probing the equation of state by deep sub-barrier fusion reactions / Hong-Jun Hao and Jun-Long Tian -- Doublet structure study in A[symbol]105 mass region / C. Y. He ... [et al.] -- Rotational bands in transfermium nuclei / X. T. He -- Shape coexistence and shape evolution [symbol]Yb / H. Hua ... [et al.] -- Multistep shell model method in the complex energy plane / R. J. Liotta -- The evolution of protoneutron stars with kaon condensate / Ang Li -- High spin structures in the [symbol]Lu nucleus / Li Cong-Bo ... [et al.] -- Nuclear stopping and equation of state / QingFeng Li and Ying Yuan -- Covariant description of the low-lying states in neutron-deficient Kr isotopes / Z. X. Li ... [et al.] -- Isospin corrections for superallowed [symbol] transitions / HaoZhao Liang ... [et al.] -- The positive-parity band structures in [symbol]Ag / C. Liu ... [et al.] -- New band structures in odd-odd [symbol]I and [symbol]I / Liu GongYe ... [et al.] -- The sd-pair shell model and interacting boson model / Yan-An Luo ... [et al.] -- Cross-section distributions of fragments in the calcium isotopes projectile