Unbound Resonances in Light Nuclei
NASA Astrophysics Data System (ADS)
Havens, Elizabeth; Finck, Joseph; Gueye, Paul; Thoennessen, Michael; MoNA Collaboration
2014-09-01
Currently there has been no comprehensive study undertaken to compile experimental results from neutron unbound spectroscopy using invariant mass measurements, gamma resolutions, and half-lives. At Central Michigan University, Hampton University, and the NSCL, a project was initiated to catalog all unbound resonances in light nuclei (Z = 1-12). Unbound resonances were characterized by having a confirmed neutron decay branch and/or an energy level greater than the neutron binding energy listed for that isotope according to either the National Nuclear Data Center's Evaluated Nuclear Structure Files or Experimental Unevaluated Nuclear Data List and the referred journals therein. Unbound resonances will be presented for twelve elements: H, He, Li, Be, B, C, N, O, Fl, Ne, Na, and Mg. The isotopes in which unbound resonances occur will be identified, along with unbound energy levels for these isotopes. If known, each unbound resonance's gamma resolution, half-life, method of production and journal reference were also determined and a selection of these will be presented.
Neutron unbound resonances cataloged by isotope and invariant mass measurements for nuclei Z = 1-12
NASA Astrophysics Data System (ADS)
Havens, Elizabeth; Finck, Joseph; Gueye, Paul; Thoennessen, Michael; MoNA Collaboration
2015-10-01
Prior to 2014, no comprehensive study had been undertaken to compile experimental results from neutron unbound spectroscopy using invariant mass measurements, gamma resolutions and half-lives. Through the collaborative efforts of Central Michigan University, Hampton University and the NSCL, a project was initiated to catalog all unbound resonances in light nuclei (Z = 1-12). Unbound resonances were characterized by having a confirmed neutron decay branch and/or an energy level greater than the neutron binding energy listed for that isotope, according to either the NNDC's ENSDF or XUNDL and the referred journals therein. This was initially compiled in July 2014 and presented in October of that year. Recent discoveries and updates to NNDC have added ten isotopes and their resonances. Additionally, various corrections to previously compiled resonances have been made and equivalent evaluated and unevaluated invariant mass measurements have been consolidated into single entries. The neutron separation energy is noted for each isotope. The isotopes in which unbound resonances occur have been identified and, if known, each unbound resonance's gamma resolution, half-life, method of production and journal reference were also determined.
ERIC Educational Resources Information Center
Cerny, Joseph; Poskanzer, Arthur M.
1978-01-01
Among the light elements, nuclei with unequal numbers of protons and neutrons are highly unstable. Some survive just long enough to be detected and exhibit unusual regimes of radioactive decay. ( Autor/MA)
Quaglioni, S; Navratil, P; Roth, R
2009-12-15
The exact treatment of nuclei starting from the constituent nucleons and the fundamental interactions among them has been a long-standing goal in nuclear physics. Above all nuclear scattering and reactions, which require the solution of the many-body quantum-mechanical problem in the continuum, represent an extraordinary theoretical as well as computational challenge for ab initio approaches.We present a new ab initio many-body approach which derives from the combination of the ab initio no-core shell model with the resonating-group method [4]. By complementing a microscopic cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, this approach is capable of describing simultaneously both bound and scattering states in light nuclei. We will discuss applications to neutron and proton scattering on sand light p-shell nuclei using realistic nucleon-nucleon potentials, and outline the progress toward the treatment of more complex reactions.
Nakamura, Satoshi N.
2014-04-01
"Strange" means 1) unusual or surprising, especially in a way that is difficult to explain or understand or 2) having strangeness degree of freedom. Light nuclear systems with strangeness, light hypernuclei, are perfect playground to study baryon force which would be a bridge between well established nuclear force in low energy region and QCD, the first principle of the strong interaction. Overview of study of light hypernuclei is given and recent experimental findings are reviewed.
NASA Astrophysics Data System (ADS)
Kondev, F. G.; Carpenter, M. P.; Janssens, R. V. F.; Abu Saleem, K.; Ahmad, I.; Amro, H.; Cizewski, J. A.; Danchev, M.; Davids, C. N.; Hartley, D. J.; Heinz, A.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Ma, W. C.; Poli, G. L.; Ressler, J.; Reviol, W.; Riedinger, L. L.; Seweryniak, D.; Smith, M. B.; Wiedenhöver, I.
2001-07-01
Excited states in the proton-unbound 173,175,177Au nuclei were identified for the first time. Level structures associated with three different shapes were observed in 175Au. While the yrast lines of 175Au and 177Au consist of a prolate band built upon the intruder 1/2+[660] (i13/2) proton orbital, no sign of collectivity was observed in the lighter 173Au isotope. Implications for the deformation associated with these structures are discussed with a focus on shape co-existence in the vicinity of the proton-drip line.
NASA Astrophysics Data System (ADS)
Gao, H.
2002-04-01
In the last several years, tremendous advances both in experiment and theory have been made in understanding the structure of light nuclei. The experimental advances have benefited greatly from the new, high intensity CW machine (CEBAF) at Jefferson Lab and new experimental techniques utilizing polarization degrees of freedom at various laboratories. Tremendous progress has also been made in nuclear few-body theory, from a successful standard model of nuclear physics based on modern two-nucleon potentials as well as modern three-nucleon forces to the exact three-body calculation extended into the continuum by solving the corresponding Faddeev equations. In this talk, I will review recent experimental progress in understanding the structure of light nuclei focusing on the results of deuteron elastic form factors, deuteron tensor polarization, deuteron photodisintegration, and that of the 3He magnetic form factor. I will also highlight some recent results on the experimental search for the three-nucleon force, the short-range nucleon-nucleon correlation, and the nucleon structure study using a polarized 3He target as an effective neutron target. To summarize, I will provide some future outlook on this subject in the light of the upcoming BLAST program at the MIT-Bates Laboratory and the possible future 12 GeV upgrade at the Jefferson Lab.
Structure functions for light nuclei
S.A. Kulagin, R. Petti
2010-11-01
We discuss the nuclear EMC effect with particular emphasis on recent data for light nuclei including 2H, 3He, 4He, 9Be, 12C and 14N. In order to verify the consistency of available data, we calculate the \\chi^2 deviation between different data sets. We find a good agreement between the results from the NMC, SLAC E139, and HERMES experiments. However, our analysis indicates an overall normalization offset of about 2% in the data from the recent JLab E03-103 experiment with respect to previous data for nuclei heavier than 3He. We also discuss the extraction of the neutron/proton structure function ratio F2n/F2p from the nuclear ratios 3He/2H and 2H/1H. Our analysis shows that the E03-103 data on 3He/2H require a renormalization of about 3% in order to be consistent with the F2n/F2p ratio obtained from the NMC experiment. After such a renormalization, the 3He data from the E03-103 data and HERMES experiments are in a good agreement. Finally, we present a detailed comparison between data and model calculations, which include a description of the nuclear binding, Fermi motion and off-shell corrections to the structure functions of bound proton and neutron, as well as the nuclear pion and shadowing corrections. Overall, a good agreement with the available data for all nuclei is obtained.
Structure functions for light nuclei
Kulagin, S. A.; Petti, R.
2010-11-15
We discuss the nuclear EMC effect with particular emphasis on recent data for light nuclei including {sup 2}H, {sup 3}He, {sup 4}He, {sup 9}Be, {sup 12}C, and {sup 14}N. In order to verify the consistency of available data, we calculate the {chi}{sup 2} deviation between different data sets. We find a good agreement between the results from the NMC, SLAC E139, and HERMES experiments. However, our analysis indicates an overall normalization offset of about 2% in the data from the recent JLab E03-103 experiment with respect to previous data for nuclei heavier than {sup 3}He. We also discuss the extraction of the neutron/proton structure function ratio F{sub 2}{sup n}/F{sub 2}{sup p} from the nuclear ratios {sup 3}He/{sup 2}H and {sup 2}H/{sup 1}H. Our analysis shows that the E03-103 data on {sup 3}He/{sup 2}H require a renormalization of about 3% in order to be consistent with the F{sub 2}{sup n}/F{sub 2}{sup p} ratio obtained from the NMC experiment. After such a renormalization, the {sup 3}He data from the E03-103 and HERMES experiments are in a good agreement. Finally, we present a detailed comparison between data and model calculations, which include a description of the nuclear binding, Fermi motion, and off-shell corrections to the structure functions of bound proton and neutron, as well as the nuclear pion and shadowing corrections. Overall, a good agreement with the available data for all nuclei is obtained.
Unified studies of structure and reactions in light unstable nuclei
NASA Astrophysics Data System (ADS)
Ito, Makoto
2016-06-01
The generalized two-center cluster model (GTCM), which can treat covalent, ionic and atomic configurations in general systems with two inert cores plus valence nucleons, is formulated in the basis of the microscopic cluster model. In this model, the covalent configurations constructed by the molecular orbital (MO) method and the atomic (or ionic) configuration obtained by the valence bonding (VB) method can be described in a consistent manner. GTCM is applied to the light neutron-rich system, 10,12Be = α + α + XN (X = 2,4), and the unified studies of the structural changes and the reaction problem are performed. In the structure study, the calculated energy levels are characterized in terms of the chemical bonding like structures, such as the covalent MO or ionic VB structures. The chemical bonding structures changes from level to level within a small energy interval. In the unbound region, the structure problem with the total system of α + α + XN and the reaction problem, induced by the collision of an asymptotic VB state of α+6,8He, are combined by GTCM. The properties of unbound resonant states are discussed in a close connection to the reaction mechanism, and some enhancement factors originated from the properties of the intrinsic states are predicted in the reaction observables. The unified calculation of the structures and the reactions is applied to the Coulomb shift problem in the mirror system, such the 10Be and 10C nuclei. The Coulomb displacement energy of the mirror systems are discussed.
Electromagnetic structure of light nuclei
Pastore, Saori
2016-03-25
Here, the present understanding of nuclear electromagnetic properties including electromagnetic moments, form factors and transitions in nuclei with A ≤ 10 is reviewed. Emphasis is on calculations based on nuclear Hamiltonians that include two- and three-nucleon realistic potentials, along with one- and two-body electromagnetic currents derived from a chiral effective field theory with pions and nucleons.
Quantum Monte Carlo calculations of light nuclei.
Pieper, S. C.; Physics
2008-01-01
Variational Monte Carlo and Green's function Monte Carlo are powerful tools for cal- culations of properties of light nuclei using realistic two-nucleon (NN) and three-nucleon (NNN) potentials. Recently the GFMC method has been extended to multiple states with the same quantum numbers. The combination of the Argonne v18 two-nucleon and Illinois-2 three-nucleon potentials gives a good prediction of many energies of nuclei up to 12 C. A number of other recent results are presented: comparison of binding energies with those obtained by the no-core shell model; the incompatibility of modern nuclear Hamiltonians with a bound tetra-neutron; difficulties in computing RMS radii of very weakly bound nuclei, such as 6He; center-of-mass effects on spectroscopic factors; and the possible use of an artificial external well in calculations of neutron-rich isotopes.
Flux of light antimatter nuclei near Earth
Baret, B.; Barrau, A.; Buenerd, M.; Derome, L.; Duperray, R.; Protasov, K.; Vratogna, S.; Maurin, D.
2006-07-11
The fluxes of light antinuclei A{<=} 4 induced near earth by Cosmic Ray (CR) interactions with the interstellar matter (ISM) in the Galaxy are calculated in a phenomenological framework. The hadronic production cross-section for antinucleons is based on a recent parametrization of a wide set of accelerator data. The production of light nuclei is calculated using coalescence models. The non annihilating inelastic scattering process for the antideuterons is discussed and taken into account for the first time via a more realistic procedure than used so far for antiprotons.
Few-Body Models of Light Nuclei
NASA Astrophysics Data System (ADS)
Ershov, S. N.; Vaagen, J. S.; Zhukov, M. V.
2015-06-01
Experiments confirm a variety of cluster structures in many light nuclei. The observation of nuclear halos at drip-lines has accentuated the question of the degrees of freedom for bound and low-lying continuum states. In these cases the many-body dynamics of nuclear structure may be well approximated by few-body cluster models that often suggest conceptually simple approaches explaining successfully many features of light nuclei. Thus few-body cluster models have been successfully used for description of the nuclear structure of weakly bound halo nuclei and their emergent cluster degrees of freedom. They have attractive features supplying in a most transparent way the asymptotic behavior and continuum properties of weakly bound systems. Such models assume a separation in internal cluster (core) degrees of freedom and the relative motion of few-body constituents. Such separation is only an approximation, and low-lying states appear where the core cannot be considered as inert system and additional degrees of freedom connected to excited core states have to be taken into account. For fixed total angular momentum a coupling to excited core states having different spins involves additional partial waves into the consideration. This allows to account for some emergent (collective) core degrees of freedom and gives a more realistic description of nuclear properties. It is an analogue to increasing the number of shells within the framework of shell-model approaches. Some examples from recent nuclear structure exploration within few-body halo cluster models are presented.
Nuclear clusters and structure in light nuclei
Kokalova, Tz.; Oertzen, W. von; Thummerer, S.; Bohlen, H.G.; Milin, M.; Tumino, A.; De Angelis, G.; Farnea, E.; Axiotis, M.; Marginean, N.; Napoli, D.R.; Lenzi, S.M.; Ur, C.; Rousseau, M.; Papka, P.
2004-02-27
We have studied the {gamma}-decay properties of 21Ne up to the limits of the particle emission thresholds in order to establish the band structure. The GASP {gamma}-ray detector array together with the multi-detector array, ISIS, were used for the selection of the reaction channels. The reaction 16O(7Li,pn)21Ne has been studied at E=29 MeV. The observed decays in 21Ne, support the identification of parity doublets with states of opposite parity connected by strong dipole transitions. The behaviour of the octupole deformed bands in 21Ne is interpreted as consisting of an intrinsic reflection asymmetric (4He+16O)-structure with an additional valence neutron in {sigma}- and {pi}-orbitals. Using the same experimental set-up the emission of the light unbound cluster 8Be has been studied in the reaction 18O+13C{yields}31Si{yields}23Ne+8Be. The emission has been studied relative to the sequential emission of 2{alpha}-particles.
Search for Hyperdeformation in Light Xe Nuclei
NASA Astrophysics Data System (ADS)
Nyako, B. M.; Papp, F.; Gal, J.; Molnar, J.; Timar, J.; Algora, A.; Dombradi, Zs.; Kalinka, G.; Zolnai, L.; Juhasz, K.; Singh, A. K.; Huebel, H.; Al-Khatib, A.; Bringel, P.; Buerger, A.; Neusser, A.; Schoenwasser, G.; Herskind, B.; Hagemann, G. B.; Hansen, C. R.; Sletten, G.; Scheurer, J. N.; Hannachi, F.; Kmiecik, M.; Maj, A.; Styczen, J.; Zuber, K.; Hauschild, K.; Korichi, A.; Lopez-Martens, A.; Roccaz, J.; Siem, S.; Bednarczyk, P.; Byrski, Th.; Curien, D.; Dorvaux, O.; Duchene, G.; Gall, B.; Khalfallah, F.; Piqueras, I.; Robin, J.; Patel, S. B.; Evans, A. O.; Rainovski, G.; Airoldi, A.; Benzoni, G.; Bracco, A.; Camera, F.; Million, B.; Mason, P.; Paleni, A.; Sacchi, R.; Wieland, O.; La Rana, G.; Moro, R.; Petrache, C. M.; Petrache, D.; de Angelis, G.; Fallon, P.; Lee, I.-Y.; Lisle, J. C.; Cederwall, B.; Lagergren, K.; Lieder, R. M.; Podsvirova, E.; Gast, W.; Jaeger, H.; Redon, N.; Goergen, A.
2005-04-01
The ultimate search for hyperdeformation (HD) at high spins with the EUROBALL spectrometer was performed for 126Ba as a hyper long (HLHD) experiment. The DIAMANT ancillary detector was used to tag γ -rays in coincidence with the emitted light charged particles. Using γ -energy correlation methods, the particle--xn-γ data have been analysed to search for hyperdeformed structures in the corresponding residual nuclei. Data in coincidence with one α particle indicate the presence of normal deformed collective bands up to very high spins and the possible occurrence of HD-like ridge structures in 122Xe.
Anisotropic multicluster model in light nuclei
NASA Astrophysics Data System (ADS)
Gijón, A.; Gálvez, F. J.; Arias de Saavedra, F.; Buendía, E.
2016-06-01
Multicluster models consider that the nucleons can be moving around different centers in the nuclei. These models have been widely used to describe light nuclei but always considering that the mean field is composed of isotropic harmonic oscillators with different centers. In this work, we propose an extension of these models by using anisotropic harmonic oscillators. The strengths of these oscillators, the distance among the different centers and the disposition of the nucleons inside every cluster are free parameters which have been fixed using the variational criterion. All the one-body and two-body matrix elements have been analytically calculated. Only a numerical integration on the Euler angles is needed to carry out the projection on the values of the total spin of the state and its third component. We have studied the ground state and the first excited states of 8Be, 12C and 10Be getting good results for the energies. The disposition of the nucleons in the different clusters have also been analyzed by using projection on the different Cartesian planes getting much more information than when the radial one-body density is used.
Clusters and Halos in Light Nuclei
NASA Astrophysics Data System (ADS)
Neff, Thomas; Feldmeier, Hans
2009-08-01
The structure of light nuclei in the p- and sd-shell features exotic phenomena like halos and clustering. In the Fermionic Molecular Dynamics (FMD) approach we aim at a consistent microscopic description of well bound nuclei and of loosely bound exotic systems. This is possible due to the flexibility of the single-particle basis states using Gaussian wave-packets localized in phase space. Many-body basis states are Slater determinants projected on parity, angular and total linear momentum. The structure of 12C is discussed. Here the ground state band can be well described within a shell model picture but excited states above the three-α threshold, including the famous Hoyle state, show a pronounced cluster structure. As another example we study the structure of the Neon isotopes 17-22Ne. In 17Ne we find a large s2 occupation related to a large charge radius. The charge radius decreases for 18Ne but gets again very large for 19Ne and 20Ne which is explained by significant admixtures of 3He and 4He cluster components into to the ground state wave functions.
Clusters in neutron-rich light nuclei
NASA Astrophysics Data System (ADS)
Jelavić Malenica, D.; Milin, M.; Di Pietro, A.; Figuera, P.; Lattuada, M.; Miljanić, D.; Musumarra, A.; Pellegriti, M. G.; Prepolec, L.; Scuderi, V.; Skukan, N.; Soić, N.; Torresi, D.; Uroić, M.
2016-05-01
Due to their high selectivity, transfer and sequential decay reactions are powerful tools for studies of both single particle (nucleon) and cluster states in light nuclei. Their use is particularly simple for investigations of α-particle clustering (because α-particle has Jπ=0+, which simplifies spin and parity assignments to observed cluster states), but they are also easily applicable to other types of clustering. Recent results on clustering in neutron-rich isotopes of beryllium, boron and carbon obtained measuring the 10B+10B reactions (at 50 and 72 MeV) are presented. The highly efficient and segmented detector systems used, built from 4 Double Sided Silicon Strip Detectors (DSSSD) allowed detection of double and multiple coincidences and, in that way, studies of states populated in transfer reactions, as well as their sequential decay.
NASA Astrophysics Data System (ADS)
Mukha, I.; Sümmerer, K.; Acosta, L.; Alvarez, M. A. G.; Casarejos, E.; Chatillon, A.; Cortina-Gil, D.; Egorova, I. A.; Espino, J. M.; Fomichev, A.; García-Ramos, J. E.; Geissel, H.; Gómez-Camacho, J.; Grigorenko, L.; Hofmann, J.; Kiselev, O.; Korsheninnikov, A.; Kurz, N.; Litvinov, Yu. A.; Litvinova, E.; Martel, I.; Nociforo, C.; Ott, W.; Pfützner, M.; Rodríguez-Tajes, C.; Roeckl, E.; Stanoiu, M.; Timofeyuk, N. K.; Weick, H.; Woods, P. J.
2010-11-01
A powerful method of investigating proton-unbound nuclear states by tracking their decay products in flight is discussed in detail. To verify the method, four known levels in F15, Ne16, and Na19 were investigated by measuring the angular correlations between protons and the respective heavy-ion fragments stemming from the precursor decays in flight. The parent nuclei of interest were produced in nuclear reactions of one-neutron removal from Ne17 and Mg20 projectiles at energies of 410-450 A MeV. The trajectories of the respective decay products, O14 + p + p and Ne18 + p + p, were measured by applying a tracking technique with microstrip detectors. These data were used to reconstruct the angular correlations of the fragments, which provided information on energies and widths of the parent states. In addition for reproducing properties of known states, evidence for hitherto unknown excited states in F15 and Ne16 was found. This tracking technique has an advantage in studies of exotic nuclei beyond the proton drip line measuring the resonance energies and widths with a high precision although by using low-intensity beams and very thick targets.
Light nuclei production in fusion of heavy ions
Antonenko, N.V.; Ivanova, S.P.; Jolos, R.V.; Scheid, W. Joint Institute for Nuclear Research, 141980 Dubna )
1994-10-01
A possible mechanism of the production of light nuclei in fusion reactions is considered. It is shown that the decay of the dinuclear system during its evolution to a compound nucleus yields a substantial rate for the production of light nuclei. The cross section of this process is calculated for the reaction [sup 58]Ni+[sup 58]Ni. The coupling of other modes of motion causes an increase of the asymmetric decay of the dinuclear system.
Quantum Monte Carlo calculations of light nuclei
Pieper, S.C.
1998-12-01
Quantum Monte Carlo calculations using realistic two- and three-nucleon interactions are presented for nuclei with up to eight nucleons. We have computed the ground and a few excited states of all such nuclei with Greens function Monte Carlo (GFMC) and all of the experimentally known excited states using variational Monte Carlo (VMC). The GFMC calculations show that for a given Hamiltonian, the VMC calculations of excitation spectra are reliable, but the VMC ground-state energies are significantly above the exact values. We find that the Hamiltonian we are using (which was developed based on {sup 3}H,{sup 4}He, and nuclear matter calculations) underpredicts the binding energy of p-shell nuclei. However our results for excitation spectra are very good and one can see both shell-model and collective spectra resulting from fundamental many-nucleon calculations. Possible improvements in the three-nucleon potential are also be discussed. {copyright} {ital 1998 American Institute of Physics.}
Quantum Monte Carlo calculations of light nuclei
Pieper, Steven C.
1998-12-21
Quantum Monte Carlo calculations using realistic two- and three-nucleon interactions are presented for nuclei with up to eight nucleons. We have computed the ground and a few excited states of all such nuclei with Greens function Monte Carlo (GFMC) and all of the experimentally known excited states using variational Monte Carlo (VMC). The GFMC calculations show that for a given Hamiltonian, the VMC calculations of excitation spectra are reliable, but the VMC ground-state energies are significantly above the exact values. We find that the Hamiltonian we are using (which was developed based on {sup 3}H,{sup 4}He, and nuclear matter calculations) underpredicts the binding energy of p-shell nuclei. However our results for excitation spectra are very good and one can see both shell-model and collective spectra resulting from fundamental many-nucleon calculations. Possible improvements in the three-nucleon potential are also be discussed.
Quantum Monte Carlo calculations of light nuclei.
Pieper, S. C.
1998-08-25
Quantum Monte Carlo calculations using realistic two- and three-nucleon interactions are presented for nuclei with up to eight nucleons. We have computed the ground and a few excited states of all such nuclei with Greens function Monte Carlo (GFMC) and all of the experimentally known excited states using variational Monte Carlo (VMC). The GFMC calculations show that for a given Hamiltonian, the VMC calculations of excitation spectra are reliable, but the VMC ground-state energies are significantly above the exact values. We find that the Hamiltonian we are using (which was developed based on {sup 3}H, {sup 4}He, and nuclear matter calculations) underpredicts the binding energy of p-shell nuclei. However our results for excitation spectra are very good and one can see both shell-model and collective spectra resulting from fundamental many-nucleon calculations. Possible improvements in the three-nucleon potential are also be discussed.
Form Factors and Radii of Light Nuclei
Sick, Ingo
2015-09-15
We discuss the determination of electromagnetic form factors from the world data on electron–nucleus scattering for nuclei Z ≤ 3, with particular emphasis on the derivation of the moments required for comparison with measurements from electronic/muonic atoms and isotope shifts.
Form Factors and Radii of Light Nuclei
NASA Astrophysics Data System (ADS)
Sick, Ingo
2015-09-01
We discuss the determination of electromagnetic form factors from the world data on electron-nucleus scattering for nuclei Z ≤ 3, with particular emphasis on the derivation of the moments required for comparison with measurements from electronic/muonic atoms and isotope shifts.
Green's function calculations of light nuclei
NASA Astrophysics Data System (ADS)
Sun, ZhongHao; Wu, Qiang; Xu, FuRong
2016-09-01
The influence of short-range correlations in nuclei was investigated with realistic nuclear force. The nucleon-nucleon interaction was renormalized with V lowk technique and applied to the Green's function calculations. The Dyson equation was reformulated with algebraic diagrammatic constructions. We also analyzed the binding energy of 4He, calculated with chiral potential and CD-Bonn potential. The properties of Green's function with realistic nuclear forces are also discussed.
New measurements of the EMC effect in light nuclei
A. Daniel
2009-12-01
Modifications of structure functions in nuclei (EMC effect) suggest that the nuclear quark distribution function is not just the incoherent sum of the proton and neutron distributions, and made clear the importance of nuclear effects even in high energy measurements. Jefferson Lab experiment E03-103 made precise measurements of the EMC effect in few-body and heavy nuclei with emphasis on the large x region. Data from the light nuclei suggests that the nuclear dependence of the high x quark distribution may depend on the nucleon's local environment, rather than being a purely bulk effect.
Ab initio no core full configuration approach for light nuclei
NASA Astrophysics Data System (ADS)
Kim, Youngman; Shin, Ik Jae; Maris, Pieter; Vary, James P.; Forssén, Christian; Rotureau, Jimmy
2014-07-01
Comprehensive understanding of the structure and reactions of light nuclei poses theoretical and computational challenges. Still, a number of ab initio approaches have been developed to calculate the properties of atomic nuclei using fundamental interactions among nucleons. Among them, we work with the ab initio no core full configuration (NCFC) method and ab initio no core Gamow Shell Model (GSM). We first review these approaches and present some recent results.
Ab initio no core full configuration approach for light nuclei
NASA Astrophysics Data System (ADS)
Kim, Youngman; Shin, Ik Jae; Maris, Pieter; Vary, James P.; Forssén, Christian; Rotureau, Jimmy
2015-10-01
Comprehensive understanding of the structure and reactions of light nuclei poses theoretical and computational challenges. Still, a number of ab initio approaches have been developed to calculate the properties of atomic nuclei using fundamental interactions among nucleons. Among them, we work with the ab initio no core full configuration (NCFC) method and ab initio no core Gamow Shell Model (GSM). We first review these approaches and present some recent results.
Quantum Monte Carlo calculations for light nuclei.
Wiringa, R. B.
1998-10-23
Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 are made using a realistic Hamiltonian that fits NN scattering data. Results for more than 40 different (J{pi}, T) states, plus isobaric analogs, are obtained and the known excitation spectra are reproduced reasonably well. Various density and momentum distributions and electromagnetic form factors and moments have also been computed. These are the first microscopic calculations that directly produce nuclear shell structure from realistic NN interactions.
Matter Radii of Light Halo Nuclei
NASA Astrophysics Data System (ADS)
Al-Khalili, J. S.; Tostevin, J. A.
1996-05-01
We reexamine the matter radii of diffuse halo nuclei, as deduced from reaction cross section measurements at high energy. Careful consideration is given to the intrinsic few-body structure of these projectiles and the adiabatic nature of the projectile-target interaction. Using 11Li, 11Be, and 8B as examples we show that data require significantly larger matter radii than previously reported. The revised value for 11Li of 3.55 fm is consistent with three-body models with significant 1s-intruder state components, which reproduce experimental 9Li momentum distributions following 11Li breakup, but were hitherto thought to be at variance with cross section data.
Light element production by low energy nuclei from massive stars
NASA Technical Reports Server (NTRS)
Vangioni-Flam, E.; Casse, M.; Ramaty, R.
1997-01-01
The Orion complex is a source of gamma rays attributed to the de-excitation of fast carbon and oxygen nuclei excited through interactions with ambient hydrogen and helium. This has consequences for the production and evolution of light isotopes in the Galaxy, as massive stars appear as prolific sources of C-O rich low energy nuclei. The different stages of massive star evolution are considered in relation to the acceleration of nuclei to moderate energies. It is concluded that the low energy nuclear component originating from massive stars plays a larger role than the usual Galactic cosmic rays in shaping the evolution of Li-6, Be-9, B-10 and B-11, especially in the early Galactic evolution. The enhancement of the B-11/B-10 ratio observed in meteorites and in the interstellar medium is attributed to the interaction of low energy carbon nuclei with ambient H and to a lesser degree, to neutrino spallation.
MCNP6 fragmentation of light nuclei at intermediate energies
NASA Astrophysics Data System (ADS)
Mashnik, Stepan G.; Kerby, Leslie M.
2014-11-01
Fragmentation reactions induced on light target nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the latest Los Alamos Monte Carlo transport code MCNP6 and with its cascade-exciton model (CEM) and Los Alamos version of the quark-gluon string model (LAQGSM) event generators, version 03.03, used as stand-alone codes. Such reactions are involved in different applications, like cosmic-ray-induced single event upsets (SEU's), radiation protection, and cancer therapy with proton and ion beams, among others; therefore, it is important that MCNP6 simulates them as well as possible. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. Both CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to 4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.
Photodisintegration of Light Nuclei with CLAS
Ilieva, Yordanka Yordanova; Zachariou, Nicholas
2013-08-01
We report preliminary results of photodisintegration of deuteron and {sup 3}He measured with CLAS at Jefferson Lab. We have extracted the beam-spin asymmetry for the {vector {gamma}}d {yields} pn reaction at photon energies from 1.1 GeV to 2.3 GeV and proton center-of-mass (c.m.) angles between 35{degrees} and 135{degrees} . Our data show interesting evolution of the angular dependence of the observable as the photon energy increases. The energy dependence of the beam-spin asymmetry at 90 shows a change of slope at photon energy of 1.6 GeV. A comparison of our data with model calculations suggests that a fully non-perturbative treatment of the underlying dynamics may be able to describe the data better than a model based on hard scattering. We have observed onset of dimensional scaling in the cross section of two-body photodisintegration of {sup 3}He at remarkably low energy and momentum transfer, which suggests that partonic degrees of freedom may be relevant for the description of nuclei at energies lower than previously considered.
Electric dipole moments of light nuclei from {chi}EFT
Higa, Renato
2013-03-25
I present recent calculations of EDMs of light nuclei using chiral effective field theory techniques. At leading-order, we argue that they can be expressed in terms of six CP-violating low-energy constants. With our expressions, eventual non-zero measurements of EDMs of deuteron, helion, and triton can be combined to disentangle the different sources of CP-violation.
Thermal-neutron capture in light nuclei
Raman, S.; Jurney, E.T.; Lynn, J.E.
1996-10-01
We have made considerable progress toward the goal of carrying out thermal-neutron capture {gamma}-ray measurements on all stable isotopes below A=60. Information processed till now has significantly augmented the existing knowledge on the detailed nuclear level structure of many light nuclides. Most of this knowledge comes from our {gamma}-ray energies, level placements, and branching ratios of secondary transitions between low-lying states. Spectroscopic information is also contained in the cross sections of the primary transitions originating from the capturing state. This is deduced from the success of ``direct`` theories of neutron capture for many nuclides, especially those of light and near closed-shell character. 23 refs, 1 tab, 3 figs.
Shell And Halo Structure In Neutron-Rich Light Nuclei
Nociforo, C.
2010-06-01
Spectroscopic investigations performed at the neutron drip line in case of sd shell nuclei have recently shown the existence of the new magic numbers Z = 8 and N = 14,16. Predictions within the nuclear shell model calculations for the {sup 23,24}O ground state have been confirmed measuring their neutron occupancy in breakup reactions performed by using the inflight radioactive ion beams produced at the Fragment Separator FRS of GSI. Some perspectives of studying the evolution of magic numbers in this region of light exotic nuclei are given.
Vaporization of comet nuclei - Light curves and life times
NASA Technical Reports Server (NTRS)
Cowan, J. J.; Ahearn, M. F.
1979-01-01
The effects of vaporization from the nucleus of a comet are examined and it is shown that a latitude dependence of vaporization can explain the asymmetries in cometary light curves. An attempt is made to explain the observed variation in molecular production rates with heliocentric distance when employing CO2 and clathrate hydrate ice as cometary nuclei substances. The energy balance equation and the vapor pressure equations of water and CO2 are used in calculating the vaporization from a surface. Calculations were carried out from both dry-ice and water-ice nuclei, using a variety of different effective visual albedos, but primarily for a thermal infrared of 0 (emission). Attention is given to cometary lifetimes and light curves and it was determined that the asymmetry in light curves occurs (occasionally) as a 'seasonal' effect due to a variation in the angle between the comet's rotation axis and the sun-comet line.
Enumeration of islets by nuclei counting and light microscopic analysis.
Pisania, Anna; Papas, Klearchos K; Powers, Daryl E; Rappel, Michael J; Omer, Abdulkadir; Bonner-Weir, Susan; Weir, Gordon C; Colton, Clark K
2010-11-01
Islet enumeration in impure preparations by conventional dithizone staining and visual counting is inaccurate and operator dependent. We examined nuclei counting for measuring the total number of cells in islet preparations, and we combined it with morphological analysis by light microscopy (LM) for estimating the volume fraction of islets in impure preparations. Cells and islets were disrupted with lysis solution and shear, and accuracy of counting successively diluted nuclei suspensions was verified with (1) visual counting in a hemocytometer after staining with crystal violet, and automatic counting by (2) aperture electrical resistance measurement and (3) flow cytometer measurement after staining with 7-aminoactinomycin-D. DNA content averaged 6.5 and 6.9 pg of DNA per cell for rat and human islets, respectively, in agreement with literature estimates. With pure rat islet preparations, precision improved with increasing counts, and samples with about ≥160 islets provided a coefficient of variation of about 6%. Aliquots of human islet preparations were processed for LM analysis by stereological point counting. Total nuclei counts and islet volume fraction from LM analysis were combined to obtain the number of islet equivalents (IEs). Total number of IE by the standard method of dithizone staining/manual counting was overestimated by about 90% compared with LM/nuclei counting for 12 freshly isolated human islet research preparations. Nuclei counting combined with islet volume fraction measurements from LM is a novel method for achieving accurate islet enumeration. PMID:20697375
Comparison of Muon Capture in Light and in Heavy Nuclei
Measday, David F.; Stocki, Trevor J.
2007-10-26
We have recently completed an experimental study at TRIUMF of muon capture in the following elements, N, Al, Si, Ca, Fe, Ni, I, Au, and Bi. We detected the nuclear gamma rays emitted by the product nuclei after muon capture. The energy of the gamma ray identifies the source nuclide, and thus the reaction which has occurred. Our data are of better quality, and more comprehensive than any other data set in the literature. The ({mu}{sup -},{nu}n) reaction is always dominant. In light nuclei, reactions such as ({mu}{sup -},{nu}p) and ({mu}{sup -},{nu}pn) can occur, but not for heavy nuclei. However the reverse is true for reactions such as ({mu}{sup -},{nu}3n) and ({mu}{sup -},{nu}4n), which are very rare in light nuclei, but easily detected in heavy elements. We shall discuss how such information can be useful in calculations of neutrino-nucleus interactions, and of electron-capture in supernovae.
Backbending phenomena in light nuclei at A{approx}60
El-Kameesy, S. U.; Alharbi, H. H.; Alhendi, H. A.
2006-04-26
Recent studies of the backbending phenomenon in medium light weight nuclei near A{approx} 60 expanded greatly our interest about how the single particle orbits are nonlinearly affected by the collective motion. As a consequence we have applied a modified version of the exponential model in mass region at A {approx} 60. A firm conclusion is obtained concerning the successful validity of the proposed modified model in describing the backbending phenomenon in this region. Comparison with different theoretical descriptions is discussed.
Light Nuclei Studied with Nucleon Transfer Reactions Using Exotic Beams
Wuosmaa, A. H.; Rehm, K. E.; Greene, J. P.; Henderson, D. J.; Janssens, R. V. F.; Jiang, C. L.; Moore, E. F.; Pardo, R. C.; Peterson, D.; Pieper, S. C.; Savard, G.; Schiffer, J. P.; Sinha, S.; Tang, X.; Wiringa, R. B.; Jisonna, L.; Segel, R. E.; Paul, M.
2006-04-26
Single-neutron transfer with the (d,p) reaction in inverse kinematics has been used to study the properties of the light nuclei 9Li and 7He. The results for 9Li and 7He are compared to the predictions of ab-initio models of nuclear structure. Different possibilities for excited states in 7He are discussed in the context of other recent experimental studies of 7He.
Light-Particle Emission from Fissioning Hot Rotating Nuclei
NASA Astrophysics Data System (ADS)
Bartel, Johann; Pomorski, Krzysztof; Nerlo-Pomorska, Bożena
2012-05-01
The decay process of hot and rotating compound nuclei is studied. In particular the competition between fission and n, p and α-particle emission is discussed. The nuclear fission process is described by a Langevin equation coupled to Master equations for particle evaporation. Light particle emission rates obtained with the Weisskopf theory and the semiclassical phase-space distribution-function approach are compared. Coulomb barriers for the emission of charged particles are studied.
Composite particle representation for light sd shell nuclei
Collinson, D.F.
1986-01-01
The Composite Particle Representation is applied to light sd shell nuclei /sup 20/O, /sup 20/F and /sup 20/Ne. The energy spectrum is found to agree exactly with the shell model in all cases. The CPR theory is then used to examine the possible boson structure of sd shell wavefunctions. Only in the case of /sup 20/O are the wavefunctions found to have a high boson probability.
Precision measurement of the mass difference between light nuclei and anti-nuclei
NASA Astrophysics Data System (ADS)
Alice Collaboration; 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, Subhasis; Chattopadhyay, Sukalyan; 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.; Goméz Coral, D. M.; 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.
2015-10-01
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons (d) and anti-deuterons (), and 3He and nuclei carried out with the ALICE (A Large Ion Collider Experiment) detector in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV. Our direct measurement of the mass-over-charge differences confirms CPT invariance to an unprecedented precision in the sector of light nuclei. This fundamental symmetry of nature, which exchanges particles with anti-particles, implies that all physics laws are the same under the simultaneous reversal of charge(s) (charge conjugation C), reflection of spatial coordinates (parity transformation P) and time inversion (T).
Light nuclei with improved order-by-order chiral interactions
NASA Astrophysics Data System (ADS)
Maris, Pieter; Vary, James
2015-10-01
We present recent results for light nuclei obtained with improved NN interactions derived from chiral effective field theory up to N4LO. The many-body calculations are performed order-by-order in the chiral expansion. We show results for the ground state energies and the low-lying spectrum; in addition we discuss other observables such as magnetic and quadrupole moments. We discuss both the theoretical uncertainties due to the truncation of the chiral expansion, as well as the numerical uncertainties associated with the many-body method. Depending on the value chiral order, additional renormalization using the Similarity Renormalization Group is needed in order to improve numerical convergence of the many-body calculations. Supported by the US DOE grants DESC0008485 (SciDAC/NUCLEI) and DE-FG02-87ER40371. Computational resources provided by NERSC (supported by US DOE contract DE-AC02-05CH11231).
Collective modes in light nuclei from first principles.
Dytrych, T; Launey, K D; Draayer, J P; Maris, P; Vary, J P; Saule, E; Catalyurek, U; Sosonkina, M; Langr, D; Caprio, M A
2013-12-20
Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of 6Li, 8Be, and 6He are shown to exhibit orderly patterns that favor spatial configurations with strong quadrupole deformation and complementary low intrinsic spin values, a picture that is consistent with the nuclear symplectic model. The results also suggest a pragmatic path forward to accommodate deformation-driven collective features in ab initio analyses when they dominate the nuclear landscape. PMID:24483740
Ab initio calculations of reactions with light nuclei
NASA Astrophysics Data System (ADS)
Quaglioni, Sofia; Hupin, Guillaume; Calci, Angelo; Navrátil, Petr; Roth, Robert
2016-03-01
An ab initio (i.e., from first principles) theoretical framework capable of providing a unified description of the structure and low-energy reaction properties of light nuclei is desirable to further our understanding of the fundamental interactions among nucleons, and provide accurate predictions of crucial reaction rates for nuclear astrophysics, fusion-energy research, and other applications. In this contribution we review ab initio calculations for nucleon and deuterium scattering on light nuclei starting from chiral two- and three-body Hamiltonians, obtained within the framework of the ab initio no-core shell model with continuum. This is a unified approach to nuclear bound and scattering states, in which square-integrable energy eigenstates of the A-nucleon system are coupled to (A-a)+a target-plus-projectile wave functions in the spirit of the resonating group method to obtain an efficient description of the many-body nuclear dynamics both at short and medium distances and at long ranges.
Strictly finite-range potential for light and heavy nuclei
NASA Astrophysics Data System (ADS)
Salamon, P.; Lovas, R. G.; Betan, R. M. Id; Vertse, T.; Balkay, L.
2014-05-01
Strictly finite-range (SFR) potentials are exactly zero beyond their finite range. Single-particle energies and densities, as well as S-matrix pole trajectories, are studied in a few SFR potentials suited for the description of neutrons interacting with light and heavy nuclei. The SFR potentials considered are the standard cutoff Woods-Saxon (CWS) potentials and two potentials approaching zero smoothly: the SV potential introduced by Salamon and Vertse [Phys. Rev. C 77, 037302 (2008), 10.1103/PhysRevC.77.037302] and the SS potential of Sahu and Sahu [Int. J. Mod. Phys. E 21, 1250067 (2012), 10.1142/S021830131250067X]. The parameters of these latter potentials were set so that the potentials may be similar to the CWS shape. The range of the SV and SS potentials scales with the cube root of the mass number of the core like the nuclear radius itself. For light nuclei a single term of the SV potential (with a single parameter) is enough for a good description of the neutron-nucleus interaction. The trajectories are compared with a benchmark for which the starting points (belonging to potential depth zero) can be determined independently. Even the CWS potential is found to conform to this benchmark if the range is identified with the cutoff radius. For the CWS potentials some trajectories show irregular shapes, while for the SV and SS potentials all trajectories behave regularly.
Dipole oscillation modes in light α -clustering nuclei
NASA Astrophysics Data System (ADS)
He, W. B.; Ma, Y. G.; Cao, X. G.; Cai, X. Z.; Zhang, G. Q.
2016-07-01
The α cluster states are discussed in a model frame of extended quantum molecular dynamics. Different α cluster structures are studied in detail, such as 8Be two-α cluster structure, 12C triangle structure, 12 chain structure, 16O chain structure, 16O kite structure, and 16O square structure. The properties studied include the width of wave packets for different α clusters, momentum distribution, and the binding energy among α clusters. We also discuss how the α cluster degree of freedom affects nuclear collective vibrations. The cluster configurations in 12C and 16O are found to have corresponding characteristic spectra of giant dipole resonance (GDR), and the coherences of different α clusters' dipole oscillations are described in detail. The geometrical and dynamical symmetries of α -clustering configurations are responsible for the number and centroid energies of peaks of GDR spectra. Therefore, the GDR can be regarded as an effective probe to diagnose different α cluster configurations in light nuclei.
Elastic scattering, fusion, and breakup of light exotic nuclei
NASA Astrophysics Data System (ADS)
Kolata, J. J.; Guimarães, V.; Aguilera, E. F.
2016-05-01
The present status of fusion reactions involving light ( A < 20) radioactive projectiles at energies around the Coulomb barrier ( E < 10 MeV per nucleon) is reviewed, emphasizing measurements made within the last decade. Data on elastic scattering (providing total reaction cross section information) and breakup channels for the involved systems, demonstrating the relationship between these and the fusion channel, are also reviewed. Similarities and differences in the behavior of fusion and total reaction cross section data concerning halo nuclei, weakly-bound but less exotic projectiles, and strongly-bound systems are discussed. One difference in the behavior of fusion excitation functions near the Coulomb barrier seems to emerge between neutron-halo and proton-halo systems. The role of charge has been investigated by comparing the fusion excitation functions, properly scaled, for different neutron- and proton-rich systems. Possible physical explanations for the observed differences are also reviewed.
Recent results on nuclear structure functions for light nuclei
Kulagin, S. A.; Petti, R.
2011-09-21
We discuss the nuclear EMC effect with particular emphasis on recent data for light nuclei including {sup 2}H, {sup 3}He, {sup 4}He, {sup 9}Be, {sup 12}C and {sup 14}N. In order to verify the consistency of available data, we calculate the {chi}{sup 2} deviation between different data sets. We find a good agreement between the results from the NMC, SLAC E139, and HERMES experiments. However, our analysis indicates an overall normalization offset of about 2% in the data from the recent JLab E03-103 experiment with respect to previous data for nuclei heavier than {sup 3}He. We also discuss the extraction of the neutron/proton structure function ratio F{sub 2}{sup n}/F{sub 2}{sup p} from the nuclear ratios {sup 3}He/{sup 2}H and {sup 2}H/{sup 1}H. Our analysis shows that the E03-103 data on {sup 3}He/{sup 2}H require a renormalization of about 3% in order to be consistent with the F{sub 2}{sup n}/F{sub 2}{sup p} ratio obtained from the NMC experiment. After such a renormalization, the {sup 3}He data from the E03-103 data and HERMES experiments are in a good agreement. We also present a detailed comparison between data and model calculations, which include a description of the nuclear binding, Fermi motion and off-shell corrections to the structure functions of bound proton and neutron, as well as the nuclear pion and shadowing corrections.
Systematics of light nuclei in a relativistic model
Price, C.E.
1988-01-01
The results of relativistic mean field calculations for non-spherical nuclei are presented and discussed. The need for non-linear scalar meson self-couplings in order to describe the properties of s-d shell nuclei is emphasized along with the importance of self-consistency in calculations of magnetic moments of odd-mass nuclei. 16 refs., 3 figs., 2 tabs.
MCNP6 simulation of light and medium nuclei fragmentation at intermediate energies
NASA Astrophysics Data System (ADS)
Mashnik, Stepan G.; Kerby, Leslie M.
2016-05-01
Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to 4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.
MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies
Mashnik, Stepan Georgievich; Kerby, Leslie Marie
2015-08-24
Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to sup>4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.
Heavy nuclei confinement effect in a pulsed light field
NASA Astrophysics Data System (ADS)
Starodub, S. S.; Roshchupkin, S. P.
2011-04-01
It is a model theoretical work of the applied character in which: "Outside the framework of the dipole approximation (with an accuracy of about v/c) the effective interaction force between stripped uranium nuclei in the presence pulsed field of two laser waves extending towards each other is theoretically studied. It is shown that the effective interaction force between uranium nuclei, can become an attractive force on certain time intervals in the presence of the pulsed laser field. As a result the pulsed laser field can slow down backward motion of nuclei in 7 times."
Systematics of proton and diproton separation energies for light nuclei
Cole, B.J.
1997-10-01
A simple method to estimate proton and two-proton separation energies of proton-rich nuclei is presented that is sufficiently accurate to allow the prediction of suitable candidates for observable diproton decay. The method is based on the systematics of measured particle separation energies. Predictions for proton-rich nuclei with Z=18{minus}24 are compared with the results of previous calculations. {copyright} {ital 1997} {ital The American Physical Society}
Magnetic structure of light nuclei from lattice QCD
Chang, Emmanuel; Detmold, William; Orginos, Kostas; Parreño, Assumpta; Savage, Martin J.; Tiburzi, Brian C.; Beane, Silas R.
2015-12-09
Lattice QCD with background magnetic fields is used to calculate the magnetic moments and magnetic polarizabilities of the nucleons and of light nuclei with $A\\le4$, along with the cross-section for the $M1$ transition $np\\rightarrow d\\gamma$, at the flavor SU(3)-symmetric point where the pion mass is $m_\\pi\\sim 806$ MeV. These magnetic properties are extracted from nucleon and nuclear energies in six uniform magnetic fields of varying strengths. The magnetic moments are presented in a recent Letter. For the charged states, the extraction of the polarizability requires careful treatment of Landau levels, which enter non-trivially in the method that is employed. The nucleon polarizabilities are found to be of similar magnitude to their physical values, with $\\beta_p=5.22(+0.66/-0.45)(0.23) \\times 10^{-4}$ fm$^3$ and $\\beta_n=1.253(+0.056/-0.067)(0.055) \\times 10^{-4}$ fm$^3$, exhibiting a significant isovector component. The dineutron is bound at these heavy quark masses and its magnetic polarizability, $\\beta_{nn}=1.872(+0.121/-0.113)(0.082) \\times 10^{-4}$ fm$^3$ differs significantly from twice that of the neutron. A linear combination of deuteron scalar and tensor polarizabilities is determined by the energies of the $j_z=\\pm 1$ deuteron states, and is found to be $\\beta_{d,\\pm 1}=4.4(+1.6/-1.5)(0.2) \\times 10^{-4}$ fm$^3$. The magnetic polarizabilities of the three-nucleon and four-nucleon systems are found to be positive and similar in size to those of the proton, $\\beta_{^{3}\\rm He}=5.4(+2.2/-2.1)(0.2) \\times 10^{-4}$ fm$^3$, $\\beta_{^{3}\\rm H}=2.6(1.7)(0.1) \\times 10^{-4}$ fm$^3$, $\\beta_{^{4}\\rm He}=3.4(+2.0/-1.9)(0.2) \\times 10^{-4}$ fm$^3$. Mixing between the $j_z=0$ deuteron state and the spin-singlet $np$ state induced by the background magnetic field is used to extract the short-distance two-nucleon counterterm, ${\\bar L}_1$, of the pionless effective theory for $NN$ systems (equivalent to the meson-exchange current
Magnetic structure of light nuclei from lattice QCD
Chang, Emmanuel; Detmold, William; Orginos, Kostas; Parreño, Assumpta; Savage, Martin J.; Tiburzi, Brian C.; Beane, Silas R.
2015-12-09
Lattice QCD with background magnetic fields is used to calculate the magnetic moments and magnetic polarizabilities of the nucleons and of light nuclei withmore » $$A\\le4$$, along with the cross-section for the $M1$ transition $$np\\rightarrow d\\gamma$$, at the flavor SU(3)-symmetric point where the pion mass is $$m_\\pi\\sim 806$$ MeV. These magnetic properties are extracted from nucleon and nuclear energies in six uniform magnetic fields of varying strengths. The magnetic moments are presented in a recent Letter. For the charged states, the extraction of the polarizability requires careful treatment of Landau levels, which enter non-trivially in the method that is employed. The nucleon polarizabilities are found to be of similar magnitude to their physical values, with $$\\beta_p=5.22(+0.66/-0.45)(0.23) \\times 10^{-4}$$ fm$^3$ and $$\\beta_n=1.253(+0.056/-0.067)(0.055) \\times 10^{-4}$$ fm$^3$, exhibiting a significant isovector component. The dineutron is bound at these heavy quark masses and its magnetic polarizability, $$\\beta_{nn}=1.872(+0.121/-0.113)(0.082) \\times 10^{-4}$$ fm$^3$ differs significantly from twice that of the neutron. A linear combination of deuteron scalar and tensor polarizabilities is determined by the energies of the $$j_z=\\pm 1$$ deuteron states, and is found to be $$\\beta_{d,\\pm 1}=4.4(+1.6/-1.5)(0.2) \\times 10^{-4}$$ fm$^3$. The magnetic polarizabilities of the three-nucleon and four-nucleon systems are found to be positive and similar in size to those of the proton, $$\\beta_{^{3}\\rm He}=5.4(+2.2/-2.1)(0.2) \\times 10^{-4}$$ fm$^3$, $$\\beta_{^{3}\\rm H}=2.6(1.7)(0.1) \\times 10^{-4}$$ fm$^3$, $$\\beta_{^{4}\\rm He}=3.4(+2.0/-1.9)(0.2) \\times 10^{-4}$$ fm$^3$. Mixing between the $j_z=0$ deuteron state and the spin-singlet $np$ state induced by the background magnetic field is used to extract the short-distance two-nucleon counterterm, $${\\bar L}_1$$, of the pionless effective theory for $NN$ systems (equivalent to the
Halo or skin in the excited states of some light mirror nuclei
NASA Astrophysics Data System (ADS)
Chen, J. G.; Cai, X. Z.; Shen, W. Q.; Ma, Y. G.; Ren, Z. Z.; Zhang, H. Y.; Jiang, W. Z.; Zhong, C.; Wei, Y. B.; Guo, W.; Zhou, X. F.; Wang, K.; Ma, G. L.
2005-01-01
The properties of three pairs of mirror nuclei 13N- 13C, 15N- 15O and 21Na- 21Ne (these mirror nuclei are all made of a good inert core plus an unpaired valence nucleon) are investigated by using the nonlinear relativistic mean-field (RMF) theory. It is found that the calculated binding energies with two different parameter sets are very close to the experimental ones for both the ground states and the excited states except for the large deformed nuclei. The calculations show that the 2 s1/2 excited states of 15N and of 21Na are both weakly bound with a proton halo and a proton skin (or a pigmy proton skin), respectively. In addition, the 1 d5/2 excited state of 13C and the 2 s1/2 excited state of 15O are also weakly bound with a neutron skin, respectively. The ratio of the valence nucleon radius to matter radius is deduced and it can be regarded as an additional criterion for the existence of exotic structure. The unbound 2 s1/2 and 1 d5/2 excited states of 13N are also discussed.
Production of light nuclei in relativistic heavy-ion collisions
Barrette, J.; Bellwied, R.; Braun-Munzinger, P.; Cleland, W.E.; Cormier, T.M.; David, G.; Dee, J.; Diebold, G.E.; Dietzsch, O.; Germani, J.V.; Gilbert, S.; Greene, S.V.; Hall, J.R.; Hemmick, T.K.; Herrmann, N.; Hong, B.; Jayananda, K.; Kraus, D.; Kumar, B.S.; Lacasse, R.; Lissauer, D.; Llope, W.J.; Ludlam, T.W.; McCorkle, S.; Majka, R.; Mark, S.K.; Mitchell, J.T.; Muthuswamy, M.; O'Brien, E.; Pruneau, C.; Rotondo, F.S.; Sandweiss, J.; daSilva, N.C.; Sonnadara, U.; Stachel, J.; Takai, H.; Takagui, E.M.; Throwe, T.G.; Wolfe, D.; Woody, C.L.; Xu, N.; Zhang, Y.; Zhang, Z.; Zou, C. Gesellschaft fuer Schwerionenforschung, Darmstadt McGill University, Montreal, Canada H3A University of Pittsburgh, Pittsburgh, Pennsylvania 15260 State University of New York, Stony Brook, New York 11794 University of New Mexico, Albuquerque, New Mexico 87131 University of Sa
1994-08-01
We have measured cross sections for the synthesis of nuclei of mass [ital A][le]4 in collisions of 14.6[ital A] GeV/[ital c] [sup 28]Si nuclei with targets of Pb, Cu, and Al. The data are measured at close to center-of-mass rapidities, and are unique in their exploration of the centrality dependence of nucleosynthesis. Simple coalescence models that were used to study nucleosynthesis at lower energies are inadequate for the description of our measurements. Our data and improved models are used to extract parameters related to the size of the interaction volume at freeze-out.
Magnetic structure of light nuclei from lattice QCD
NASA Astrophysics Data System (ADS)
Chang, Emmanuel; Detmold, William; Orginos, Kostas; Parreño, Assumpta; Savage, Martin J.; Tiburzi, Brian C.; Beane, Silas R.; Nplqcd Collaboration
2015-12-01
Lattice QCD with background magnetic fields is used to calculate the magnetic moments and magnetic polarizabilities of the nucleons and of light nuclei with A ≤4 , along with the cross section for the M 1 transition n p →d γ , at the flavor SU(3)-symmetric point where the pion mass is mπ˜806 MeV . These magnetic properties are extracted from nucleon and nuclear energies in six uniform magnetic fields of varying strengths. The magnetic moments are presented in a recent article [S. Beane et al., Phys. Rev. Lett. 113, 252001 (2014)]. For the charged states, the extraction of the polarizability requires careful treatment of Landau levels, which enter nontrivially in the method that is employed. The nucleon polarizabilities are found to be of similar magnitude to their physical values, with βp=5.22 (+0.66/-0.45) (0.23 )×10-4 fm3 and βn=1.253 (+0.056/-0.067) (0.055 )×10-4 fm3 , exhibiting a significant isovector component. The dineutron is bound at these heavy quark masses, and its magnetic polarizability, βn n=1.872 (+0.121/-0.113) (0.082 )×10-4 fm3 , differs significantly from twice that of the neutron. A linear combination of deuteron scalar and tensor polarizabilities is determined by the energies of the jz=±1 deuteron states and is found to be βd ,±1=4.4 (+1.6/-1.5) (0.2 )×10-4 fm3 . The magnetic polarizabilities of the three-nucleon and four-nucleon systems are found to be positive and similar in size to those of the proton, β3He =5.4 (+2.2/-2.1) (0.2 )×10-4 fm3 , β3H=2.6 (1.7 )(0.1 )×10-4 fm3 , and β4He=3.4 (+2.0/-1.9) (0.2 )×10-4 fm3 . Mixing between the jz=0 deuteron state and the spin-singlet n p state induced by the background magnetic field is used to extract the short-distance two-nucleon counterterm, L¯1, of the pionless effective theory for N N systems (equivalent to the meson-exchange current contribution in nuclear potential models) that dictates the cross section for the n p →d γ process near threshold. Combined with
Magnetic moments of light nuclei from lattice quantum chromodynamics
Beane, S. R.; Chang, E.; Cohen, S.; Detmold, W.; Lin, H. W.; Orginos, K.; Parreño, A.; Savage, M. J.; Tiburzi, B. C.
2014-12-16
We present the results of lattice QCD calculations of the magnetic moments of the lightest nuclei, the deuteron, the triton and 3He, along with those of the neutron and proton. These calculations, performed at quark masses corresponding to mπ ~ 800 MeV, reveal that the structure of these nuclei at unphysically heavy quark masses closely resembles that at the physical quark masses. We find that the magnetic moment of 3He differs only slightly from that of a free neutron, as is the case in nature, indicating that the shell-model configuration of two spin-paired protons and a valence neutron captures itsmore » dominant structure. Similarly a shell-model-like moment is found for the triton, μ3H ~ μp. The deuteron magnetic moment is found to be equal to the nucleon isoscalar moment within the uncertainties of the calculations.« less
Quartet excitations and cluster spectra in light nuclei
NASA Astrophysics Data System (ADS)
Cseh, J.; Riczu, G.
2016-06-01
The relation of quarteting and clustering in atomic nuclei is discussed based on symmetry-considerations. This connection enables us to predict a complete high-energy cluster spectrum from the description of the low-energy quartet part. As an example the 28Si nucleus is considered, including its well-established ground-state region, the recently proposed superdeformed band, and the high-lying molecular resonances.
Emission of composite light fragments in collisions of relativistic nuclei
Ad'yasevich, B.P.; Antonenko, V.G.; Vinogradov, A.A.; Grigor'yan, Y.I.; Ippolitov, M.S.; Karadzhev, K.V.; Lebedev, A.L.; Man'ko, V.I.; Nikolaev, S.A.; Polunin, Y.P.; and others
1987-11-01
We discuss results of experiments on investigation of the spectra of p, d, and t from interactions of carbon nuclei with C, Cu, Sn, and Pb at 3.6 GeV per nucleon. Analysis of the data has shown the applicability of the coalescence model for description of the production of composite fragments in the near-target rapidity region in relativistic collisions. The size of the emission region is estimated.
Light (anti-)nuclei production and flow in relativistic heavy-ion collisions
NASA Astrophysics Data System (ADS)
Zhu, Lilin; Ko, Che Ming; Yin, Xuejiao
2015-12-01
Using the coalescence model based on the phase-space distributions of protons, neutrons, Λ s , and their antiparticles from a multiphase transport (AMPT) model, we study the production of light nuclei (H, H, He, H) and their antinuclei in Pb+Pb collisions at √{sN N}=2.76 TeV. The resulting transverse momentum spectra, elliptic flows, and coalescence parameters for these nuclei are presented and compared with available experimental data. We also show the constituent number scaled elliptic flows of these nuclei and discuss its implications.
Structure of Light Neutron-rich Nuclei Studied with Transfer Reactions
Wuosmaa, A. H.
2015-01-01
Transfer reactions have been used for many years to understand the shell structure of nuclei. Recent studies with rare-isotope beams extend this work and make it possible to probe the evolution of shell structure far beyond the valley of stability, requiring measurements in inverse kinematics. We present a novel technical approach to measurements in inverse kinematics, and apply this method to different transfer reactions, each of which probes different properties of light, neutron-rich nuclei.
Effects of Distortion on the Intercluster Motion in Light Nuclei
Pizzone, R. G.; Spitaleri, C.; Cherubini, S.; La Cognata, M.; Lamia, L.; Romano, S.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; Irgaziev, B.; Miljanic, D.; Tumino, A.
2009-08-26
Deuteron induced quasi-free scattering and reactions have been extensively investigated in the past few decades as well as {sup 6}Li, {sup 3}He and {sup 9}Be induced ones. This was done not only for nuclear structure and processes study but also for the important astrophysical implication (Trojan Horse Method, THM). In particular the width of the spectator momentum distribution in {sup 6}Li and deuterium, which have widely been used as a Trojan Horse nuclei, will be studied as a function of the transferred momentum. Trojan horse method applications will also be discussed in these cases.
Magnetic moments of light nuclei from lattice quantum chromodynamics
Beane, S. R.; Chang, E.; Cohen, S.; Detmold, W.; Lin, H. W.; Orginos, K.; Parreño, A.; Savage, M. J.; Tiburzi, B. C.
2014-12-16
We present the results of lattice QCD calculations of the magnetic moments of the lightest nuclei, the deuteron, the triton and ^{3}He, along with those of the neutron and proton. These calculations, performed at quark masses corresponding to m_{π} ~ 800 MeV, reveal that the structure of these nuclei at unphysically heavy quark masses closely resembles that at the physical quark masses. We find that the magnetic moment of ^{3}He differs only slightly from that of a free neutron, as is the case in nature, indicating that the shell-model configuration of two spin-paired protons and a valence neutron captures its dominant structure. Similarly a shell-model-like moment is found for the triton, μ_{3H} ~ μ_{p}. The deuteron magnetic moment is found to be equal to the nucleon isoscalar moment within the uncertainties of the calculations.
Light nuclei of even mass number in the Skyrme model
NASA Astrophysics Data System (ADS)
Battye, R. A.; Manton, N. S.; Sutcliffe, P. M.; Wood, S. W.
2009-09-01
We consider the semiclassical rigid-body quantization of Skyrmion solutions of mass numbers B=4,6,8,10, and 12. We determine the allowed quantum states for each Skyrmion and find that they often match the observed states of nuclei. The spin and isospin inertia tensors of these Skyrmions are accurately calculated for the first time and are used to determine the excitation energies of the quantum states. We calculate the energy level splittings, using a suitably chosen parameter set for each mass number. We find good qualitative and encouraging quantitative agreement with experiment. In particular, the rotational bands of beryllium-8 and carbon-12, along with isospin 1 triplets and isospin 2 quintets, are especially well reproduced. We also predict the existence of states that have not yet been observed and make predictions for the unknown quantum numbers of some observed states.
Deformed Brueckner-Hartree-Fock calculation for light nuclei
NASA Technical Reports Server (NTRS)
Braley, R. C.; Ford, W. F.; Becker, R. L.; Patterson, M. R.
1971-01-01
For the first time the Brueckner-Hartree-Fock (BHF) method was applied to nuclei whose intrinsic structure is nonspherical. One aim was to investigate whether the energy dependent reaction matrix calculated from a realistic nucleon-nucleon interaction leads to deformations similar to, or different from, those obtained from energy independent interactions in Hartree-Fock (HF) calculations. Reaction matrix elements were calculated as a function of starting energy for the Hamada-Johnston interaction, using a Pauli operator appropriate to O-16 and a shifted oscillator spectrum for virtual excited states. Binding energies, single-particle energies, radii, and shape deformations of the intrinsic state in unrenormalized as well as renormalized BHF are discussed and compared with previous HF studies. Results are presented for C-12, O-16, and Ne-20.
Study of multi-nucleon transfer reactions with light nuclei
Benzoni, G.; Montanari, D.; Bracco, A.; Blasi, N.; Camera, F.; Crespi, F. C. L.; Corsi, A.; Leoni, S.; Million, B.; Nicolini, R.; Wieland, O.; Zalite, A.; Zocca, F.; Azaiez, F.; Franchoo, S.; Stefan, I.; Ibrahim, F.; Verney, D.; Battacharyya, S.; De France, G.
2008-05-12
Multi-nucleon transfer reactions are useful tools to populate exotic nuclei, particularly the neutron-rich ones. In this view, two different experiments have been performed employing a stable ({sup 22}Ne) and a radioactive ({sup 24}Ne) beam, both impinging on a {sup 208}Pb target. The first reaction has been studied using the CLARA-PRISMA-DANTE set-up at Laboratori Nazionali di Legnaro (Legnaro-Italy), while the second reaction was performed at Ganil (Caen-France) employing a SPIRAL radioactive beam of {sup 24}Ne. In this case recoils and coincident {gamma} rays were detected with the VAMOS-EXOGAM set-up.The data show that MNT reactions can selectively populate states of different nature and, therefore, are a good tool to study nuclear structure further away from stability.
Furusawa, Shun; Yamada, Shoichi; Sumiyoshi, Kohsuke; Suzuki, Hideyuki
2013-08-01
We construct new equations of state for baryons at subnuclear densities for the use in core-collapse simulations of massive stars. The abundance of various nuclei is obtained together with thermodynamic quantities. A model free energy is constructed, based on the relativistic mean field theory for nucleons and the mass formula for nuclei with the proton number up to {approx}1000. The formulation is an extension of the previous model, in which we adopted the liquid drop model to all nuclei under the nuclear statistical equilibrium. We reformulate the new liquid drop model so that the temperature dependences of bulk energies could be taken into account. Furthermore, we extend the region in the nuclear chart, in which shell effects are included, by using theoretical mass data in addition to experimental ones. We also adopt a quantum-theoretical mass evaluation of light nuclei, which incorporates the Pauli- and self-energy shifts that are not included in the ordinary liquid drop model. The pasta phases for heavy nuclei are taken into account in the same way as in the previous model. We find that the abundances of heavy nuclei are modified by the shell effects of nuclei and temperature dependence of bulk energies. These changes may have an important effect on the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. The abundances of light nuclei are also modified by the new mass evaluation, which may affect the heating and cooling rates of supernova cores and shocked envelopes.
Light regulates expression of a Fos-related protein in rat suprachiasmatic nuclei.
Aronin, N; Sagar, S M; Sharp, F R; Schwartz, W J
1990-01-01
Mammalian circadian rhythmicity is endogenously generated by a pacemaker in the suprachiasmatic nuclei and precisely entrained to the 24-hr day/night cycle by periodic environmental light cues. We show that light alters the immunoreactive levels of a transcriptional regulatory protein, Fos, in the suprachiasmatic nuclei of albino rats. Photic regulation of Fos immunoreactivity does not occur in other retino-recipient brain areas except for the intergeniculate leaflet, which appears to be involved in mediating some of the complex effects of light on expressed circadian rhythms. Our results point to a promising new functional marker for the cellular effects of light and suggest that the expression of Fos or a related nuclear protein may be part of the mechanism for photic entrainment of the circadian clock to environmental light/dark cycles. Images PMID:2116012
Ab initio many-body calculations of light nuclei neutron and proton scattering
NASA Astrophysics Data System (ADS)
Quaglioni, Sofia
2008-10-01
One of the greatest challenges of nuclear physics today is the development of a quantitative microscopic theory of low-energy reactions on light nuclei. At the same time, technical progress on the theoretical front is urgent to match the major experimental advances in the study of exotic nuclei at the radioactive beam facilities. We build a new ab initio many-body approachootnotetextS. Quaglioni and P. Navratil, arXiv:0804.1560. capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group methodootnotetextY. C. Tang et al., Phys. Rep. 47, 167 (1978); K. Langanke and H. Friedrich, Advances in Nuclear Physics, chapter 4., Plenum, New York, 1987. with the ab initio no-core shell model.ootnotetextP. Navratil, J. P. Vary, and B. R. Barrett, Phys. Rev. Lett. 84, 5728 (2000); Phys. Rev. C 62, 054311 (2000).. In this way, we complement a microscopic-cluster technique with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters, while preserving Pauli principle and translational symmetry. I will present results for neutron and proton scattering on light nuclei, including n- and p-^4He phase shifts, and low-lying states of one-neutron halo p-shell nuclei, obtained using realistic nucleon-nucleon potentials. In particular, I will address the parity inversion of the ^11Be ground state.
Medium Modification of the Light Vector Mesons in Nuclei
Nasseripour, R.; Djalali, C.; Wood, M.; Weygand, D.
2008-10-13
Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the {rho} vector mesons were investigated via their rare leptonic decay to e+e{sup -}. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The {rho} meson mass distributions were extracted for each of the targets. Statistically significant results regarding medium modification of the rho meson in the nuclear medium rule out large medium effects. Transparency studies of the {omega} and {phi} vector mesons allows a determination of their widths in the medium.
Medium Modification of the Light Vector Mesons in Nuclei
Nasseripour, Rakhsha; Djalali, Chaden; Wood, Michael; Weygand, Dennis
2008-11-01
Theoretical calculations predict the modification of properties of vector mesons, such as a shift in their masses and/or broadening of their widths in dense nuclear matter. These effects can be related to partial restoration of chiral symmetry at high density or temperature. Photoproduction of vector mesons off nuclei were performed at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). The data were taken with a beam of tagged photons with energies up to 4 GeV on various nuclear targets. The properties of the rho vector mesons were investigated via their rare leptonic decay to e+e?. This decay channel is preferred over hadronic modes in order to eliminate final state interactions in the nuclear matter. The combinatorial background in the mass spectrum was removed by a self-normalizing mixed-event technique. The rho meson mass distributions were extracted for each of the targets. Statistically significant results regarding medium modification of the rho meson in the nuc
(Multi-)strange hadron and light (anti-)nuclei production with ALICE at the LHC
NASA Astrophysics Data System (ADS)
Lea, Ramona
2016-01-01
Thanks to its excellent tracking performance and particle identification capabilities, the ALICE detector allows for the identification of light (anti-)(hyper)nuclei and for the measurement of (multi-)strange particles over a wide range of transverse momentum. Deuterons, 3He and 4He and their corresponding anti-nuclei are identified via their specific energy loss in the Time Projection Chamber and the velocity measurement provided by the Time-Of-Flight detector. Strange and multi-strange baryons and mesons as well as (anti-)hypertritons are reconstructed via their topological decays. Detailed measurements of (multi-)strange hadron production in pp, p-Pb and Pb-Pb collision and of light (anti-)nuclei and (anti-)hypertritons in Pb-Pb collisions with ALICE at the LHC are presented. The experimental results will be compared with the predictions of both statistical hadronization and coalescence models.
Influence of shell effects on the formation of light nuclei in collisions of heavy ions
Antonenko, N.V.; Dzholos, R.V. )
1989-07-01
Various approaches to calculation of the coefficients of the transport equation which describes the process of multinucleon transfers, are analyzed. It is shown that, without resorting to the averaging of matrix elements over many shell configurations, one can obtain expressions for transition probabilities that include the effects of nuclear shell structure. On this basis, the yield of light nuclei in reactions induced by heavy ions is studied in the framework of the degenerate-shell model. The calculations, which are carried out on the assumption that the wave functions of high-lying one-particle states of the system are not concentrated in one nucleus but are distributed over the two nuclei proportionally to their volumes, lead to an appreciable increase of the yield of light elements as compared to calculations in which one-particle states are assumed to belong to only one of the nuclei forming the double system.
Frequency of light-flashes induced by Cerenkov radiation from heavy cosmic-ray nuclei
NASA Technical Reports Server (NTRS)
Madey, R.; Mcnulty, P. J.
1972-01-01
The expected frequency was calculated for light flashes induced in the dark-adapted eye by Cerenkov radiation from the flux of heavy nuclei that exists in space beyond the geomagnetic field. The expected frequency of light flashes depends on the threshold number of photons that must be absorbed in a rod cluster. The results of the calculation are presented as a curve of the mean frequency of light flashes versus the threshold number of absorbed photons. The results are not sensitive to variations in the path length from 5 to 15 grams per square centimeter of water-equivalent before the nucleus reaches the retina. Calculations were based on the fluxes and energy spectra of galactic cosmic ray nuclei of helium to iron, measured at a time of minimum solar modulation. The expected light flash frequencies induced by Cerenkov radiation are consistent with the frequencies reported by the astronauts on Apollo missions 11 through 14.
NASA Astrophysics Data System (ADS)
Furusawa, S.; Nagakura, H.; Sumiyoshi, K.; Yamada, S.
2016-01-01
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ∼ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.
Light Nuclei and HyperNuclei from Quantum Chromodynamics in the Limit of SU(3) Flavor Symmetry
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.
Halos and rainbows: The elastic scattering of light exotic nuclei
Satchler, G.R.; Hussein, M.H.
1993-10-01
The scattering of an exotic light nucleus with a halo is compared with that of a normal nucleus. Four, sometimes opposing effects arising from the halo are identified. Semiclassical expressions are derived which embody these effects. The cases of {sup 11}Li and {sup 11}C scattering from {sup 12}C at E/A = 60 MeV are compared. We conclude that the {sup 11}Li differential cross sections are probably smaller than those for {sup 11}C, in agreement with recent analyses of the measurements.
NASA Astrophysics Data System (ADS)
Arifler, Dizem; MacAulay, Calum; Follen, Michele; Guillaud, Martial
2014-03-01
Dysplastic progression in epithelial tissues is linked to changes in morphology and internal structure of cell nuclei. These changes lead to alterations in nuclear light scattering profiles that can potentially be monitored for diagnostic purposes. Numerical tools allow for simulation of complex nuclear models and are particularly useful for quantifying the optical response of cell nuclei as dysplasia progresses. In this study, we first analyze a set of quantitative histopathology images from twenty cervical biopsy sections stained with Feulgen-thionin. Since Feulgen-thionin is stoichiometric for DNA, the images enable us to obtain detailed information on size, shape, and chromatin content of all the segmented nuclei. We use this extensive data set to construct realistic three-dimensional computational models of cervical cell nuclei that are representative of four diagnostic categories, namely normal or negative for dysplasia, mild dysplasia, moderate dysplasia, and severe dysplasia or carcinoma in situ (CIS). We then carry out finite-difference time-domain simulations to compute the light scattering response of the constructed models as a function of the polar scattering angle and the azimuthal scattering angle. The results show that these two-dimensional scattering patterns exhibit characteristic intensity ridges that change form with progression of dysplasia; pattern processing reveals that Haralick features can be used to distinguish moderately and severely dysplastic or CIS nuclei from normal and mildly dysplastic nuclei. Our numerical study also suggests that different angular ranges need to be considered separately to fully exploit the diagnostic potential of two-dimensional light scattering measurements.
From Nucleons To Nuclei To Fusion Reactions
Quaglioni, S; Navratil, P; Roth, R; Horiuchi, W
2012-02-15
Nuclei are prototypes of many-body open quantum systems. Complex aggregates of protons and neutrons that interact through forces arising from quantum chromo-dynamics, nuclei exhibit both bound and unbound states, which can be strongly coupled. In this respect, one of the major challenges for computational nuclear physics, is to provide a unified description of structural and reaction properties of nuclei that is based on the fundamental underlying physics: the constituent nucleons and the realistic interactions among them. This requires a combination of innovative theoretical approaches and high-performance computing. In this contribution, we present one of such promising techniques, the ab initio no-core shell model/resonating-group method, and discuss applications to light nuclei scattering and fusion reactions that power stars and Earth-base fusion facilities.
Structure of Light Neutron-Rich Nuclei around N = 14 Using Quasi-Free Scattering
NASA Astrophysics Data System (ADS)
Alvarez-Pol, Héctor; Díaz-Fernández, Paloma; Cortina-Gil, Dolores; Caamaño, Manuel; Fernández-Domínguez, Beatriz; Mostazo, Magdalena; Pietras, Ben; Beceiro-Novo, Saul; Benlliure, José; Casarejos, Enrique; Alcántara, Juan
Light neutron-rich nuclei around N = 14 (23O, 22O and 21N) have been for the first time investigated using quasi-free scattering (p,2p) and (p,pn) reactions at the LAND/R3B setup at GSI (Darmstadt, Germany). The inclusive cross sections and the momentum distributions have been measured in inverse kinematics at relativistic energies, supporting previous observations of the existence of a change of the structure of these nuclei when we move from N = 14 to 15 (from 0d5/2 shell to the 1s1/2).
``Tomography'' of the Cluster Structure of Light Nuclei via Relativistic Dissociation
NASA Astrophysics Data System (ADS)
Zarubin, P. I.
These lecture notes present the capabilities of relativistic nuclear physics for the development of the physics of nuclear clusters. Nuclear track emulsion continues to be an effective technique for pilot studies that allows one, in particular, to study the cluster dissociation of a wide variety of light relativistic nuclei within a common approach. Despite the fact that the capabilities of the relativistic fragmentation for the study of nuclear clustering were recognized quite a long time ago, electronic experiments have not been able to come closer to an integrated analysis of ensembles of relativistic fragments. The continued pause in the investigation of the ``fine'' structure of relativistic fragmentation has led to resumption of regular exposures of nuclear emulsions in beams of light nuclei produced for the first time at the Nuclotron of the Joint Institute for Nuclear Research (JINR, Dubna). To date, an analysis of the peripheral interactions of relativistic isotopes of beryllium, boron, carbon and nitrogen, including radioactive ones, with nuclei of the emulsion composition, has been performed, which allows the clustering pattern to be presented for a whole family of light nuclei.
Data Covariances from R-Matrix Analyses of Light Nuclei
Hale, G.M. Paris, M.W.
2015-01-15
After first reviewing the parametric description of light-element reactions in multichannel systems using R-matrix theory and features of the general LANL R-matrix analysis code EDA, we describe how its chi-square minimization procedure gives parameter covariances. This information is used, together with analytically calculated sensitivity derivatives, to obtain cross section covariances for all reactions included in the analysis by first-order error propagation. Examples are given of the covariances obtained for systems with few resonances ({sup 5}He) and with many resonances ({sup 13}C ). We discuss the prevalent problem of this method leading to cross section uncertainty estimates that are unreasonably small for large data sets. The answer to this problem appears to be using parameter confidence intervals in place of standard errors.
Data Covariances from R-Matrix Analyses of Light Nuclei
NASA Astrophysics Data System (ADS)
Hale, G. M.; Paris, M. W.
2015-01-01
After first reviewing the parametric description of light-element reactions in multichannel systems using R-matrix theory and features of the general LANL R-matrix analysis code EDA, we describe how its chi-square minimization procedure gives parameter covariances. This information is used, together with analytically calculated sensitivity derivatives, to obtain cross section covariances for all reactions included in the analysis by first-order error propagation. Examples are given of the covariances obtained for systems with few resonances (5He) and with many resonances (13C). We discuss the prevalent problem of this method leading to cross section uncertainty estimates that are unreasonably small for large data sets. The answer to this problem appears to be using parameter confidence intervals in place of standard errors.
Large scale calculations for cluster structure of light nuclei with Skyrme interaction
NASA Astrophysics Data System (ADS)
Fukuoka, Y.; Funaki, Y.; Nakatsukasa, T.; Yabana, K.
2013-04-01
We present a computational approach to describe structure of light nuclei including cluster states. Apart from the use of an empirical nuclear force, Skyrme interaction, our scheme does not utilize any a priori knowledge on the structure of nuclei. In our framework, we first generate a number of Slater determinants in a stochastic way. We then make projections of parity and angular momentum, and perform configuration mixing calculation. We show results for 12C and 16O nuclei. Our calculation provides a reasonable description for the ground state rotational band, Hoyle state, and low-lying negative parity states of 12C. We may also describe the 0+2 rotational band of 16O, although excitation energies are slightly overestimated.
Glial and light-dependent glutamate metabolism in the suprachiasmatic nuclei.
Leone, M J; Beaule, C; Marpegan, L; Simon, T; Herzog, E D; Golombek, D A
2015-05-01
The suprachiasmatic nuclei, the main circadian clock in mammals, are entrained by light through glutamate released from retinal cells. Astrocytes are key players in glutamate metabolism but their role in the entrainment process is unknown. We studied the time dependence of glutamate uptake and glutamine synthetase (GS) activity finding diurnal oscillations in glutamate uptake (high levels during the light phase) and daily and circadian fluctuations in GS activity (higher during the light phase and the subjective day). These results show that glutamate-related astroglial processes exhibit diurnal and circadian variations, which could affect photic entrainment of the circadian system. PMID:25798929
Interplay of fission modes in mass distribution of light actinide nuclei 225,227Pa
NASA Astrophysics Data System (ADS)
Dubey, R.; Sugathan, P.; Jhingan, A.; Kaur, Gurpreet; Mukul, Ish; Mohanto, G.; Siwal, D.; Saneesh, N.; Banerjee, T.; Thakur, Meenu; Mahajan, Ruchi; Kumar, N.; Chatterjee, M. B.
2016-01-01
Fission-fragment mass distributions were measured for 225,227Pa nuclei formed in fusion reactions of 19F + 206,208Pb around fusion barrier energies. Mass-angle correlations do not indicate any quasi-fission like events in this bombarding energy range. Mass distributions were fitted by Gaussian distribution and mass variance extracted. At below-barrier energies, the mass variance was found to increase with decrease in energy for both nuclei. Results from present work were compared with existing data for induced fission of 224,226Th and 228U around barrier energies. Enhancement in mass variance of 225,227Pa nuclei at below-barrier energies shows evidence for presence of asymmetric fission events mixed with symmetric fission events. This is in agreement with the results of mass distributions of nearby nuclei 224,226Th and 228U where two-mode fission process was observed. Two-mode feature of fission arises due to the shell effects changing the landscape of the potential-energy surfaces at low excitation energies. The excitation-energy dependence of the mass variance gives strong evidence for survival of microscopic shell effects in fission of light actinide nuclei 225,227Pa with initial excitation energy ∼30-50 MeV.
Studies of K-absorption on light nuclei and the search for bound nuclear kaonic states
NASA Astrophysics Data System (ADS)
Filippi, Alessandra; Piano, Stefano
2011-09-01
The available experimental data on K-absorption on nuclei are rather old and scarce: they are not enough to understand the possible formation of aggregates of nucleons bound together by a kaon, known as "Bound Kaonic Nuclear States". The existence of such structures, suggested by a few theoretical models, has not been experimentally ascertained yet. To be observed, their width should be less than their binding energy. A possible decay channel for such states is the non mesonic one, leading to hyperon-nucleon (or light nuclei) final states. Therefore, experimental investigations of possible signatures are mainly based on the analysis of hyperon-nucleon(s) correlations (for instance, of Λp(d,t) pairs) and of invariant mass spectra. Complementary information may also be gathered from missing mass distributions. Recent experiments revived, with much larger statistics, the study of K-A absorption in light nuclei: namely, KEK-E549 studied the K-interactions on 4He, while FINUDA at DAΦNE collected a large statistics on K-6,7Li, K-9Be and K-12C. The experimental results obtained so far by the various experiments studying the K-absorption in nuclei are here summarized.
Lifetime Measurements of Tagged Exotic- and Unbound Nuclear States
Cullen, D. M.
2011-11-30
A new Differential Plunger device for measuring pico-second lifetimes of Unbound Nuclear States (DPUNS) is being built at The University of Manchester. DPUNS has been designed to work with alpha-, beta- and isomer-tagging methods using the existing JUROGAM II--RITU--GREAT infrastructure at the University of Jyvaskyla, Finland. The importance of proton emission from nuclei is that it provides valuable nuclear-structure information as direct input to nuclear models beyond the drip line. New experimental data beyond the drip line can provide new extensions to these models especially with the possible coupling of weakly bound and unbound states to the continuum. The results of the first experiments to measure lifetimes of unbound nuclear states with this method was discussed along with possible future experiments which can be addressed with DPUNS using proton-, isomer- and alpha-tagging.
Ab initio no core calculations of light nuclei and preludes to Hamiltonian quantum field theory
Vary, J. P.; Maris, P.; Honkanen, H.; Li, J.; Shirokov, A. M.; Brodsky, S. J.; Harindranath, A.
2009-12-17
Recent advances in ab initio quantum many-body methods and growth in computer power now enable highly precise calculations of nuclear structure. The precision has attained a level sufficient to make clear statements on the nature of 3-body forces in nuclear physics. Total binding energies, spin-dependent structure effects, and electroweak properties of light nuclei play major roles in pinpointing properties of the underlying strong interaction. Eventually, we anticipate a theory bridge with immense predictive power from QCD through nuclear forces to nuclear structure and nuclear reactions. Light front Hamiltonian quantum field theory offers an attractive pathway and we outline key elements.
Ab initio no core calculations of light nuclei and preludes to Hamiltonian quantum field theory
Vary, J.P.; Maris, P.; Shirokov, A.M.; Honkanen, H.; li, J.; Brodsky, S.J.; Harindranath, A.; Teramond, G.F.de; /Costa Rica U.
2009-08-03
Recent advances in ab initio quantum many-body methods and growth in computer power now enable highly precise calculations of nuclear structure. The precision has attained a level sufficient to make clear statements on the nature of 3-body forces in nuclear physics. Total binding energies, spin-dependent structure effects, and electroweak properties of light nuclei play major roles in pinpointing properties of the underlying strong interaction. Eventually,we anticipate a theory bridge with immense predictive power from QCD through nuclear forces to nuclear structure and nuclear reactions. Light front Hamiltonian quantum field theory offers an attractive pathway and we outline key elements.
The influence of s states near threshold on the structure of light nuclei
NASA Astrophysics Data System (ADS)
Hoffman, Calem
2015-10-01
A recent work identified the role of neutron s states, and their proximity to the neutron separation threshold, on the ordering of the 1s1 / 2 and 0d5 / 2 single-particle levels in light nuclei. A simple Woods-Saxon potential was used to reproduce the systematic data available for these two levels with great success by accounting for the s state binding energy. This talk will explore other noticeable trends in light nuclei involving neutron s states and utilizing simple potential models determine the role binding energy plays. The trends and calculations will aim to provide descriptions of data and predictions of yet to be found two-particle two-hole excited states in N = 8 and 10 nuclei ranging from Z = 4-9, as well as the energies of mirror states in neutron deficient Al and Na isotopes. Results will be compared with state-of-the-art calculations. Possible future measurements capable of probing these predictions will be discussed as well. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract Number DE-AC02-06CH11357.
Thermonuclear breakup reactions of light nuclei. I - Processes and effects. [in astrophysic plasmas
NASA Technical Reports Server (NTRS)
Guessoum, Nidhal; Gould, Robert J.
1989-01-01
Temperature and density conditions are considered for the occurrence of breakup reactions of light nuclei in astrophysical plasmas. The proton-induced endothermic process is shown to be the principal mechanism for nuclear breakdown in a plasma. The phenomenon occurs at a temperature of about 1 MeV, which is a fraction of the typical binding energy per nucleon in nuclei. The temperature for breakup of He-4 is about twice as large, because of the higher binding energy. Depending on the temperature attained in the plasma, the initial concentration of elements heavier than hydrogen can be depleted. However, if it attains a temperature of about 1 MeV, breaking up the metals (C, N, O, Ne, Mg) but not He-4, an increase in the He-4 abundance by as much as 10 percent can result, since these elements essentially break down to alpha particles.
Evidence for survival of the α cluster structure in light nuclei through the fusion process
NASA Astrophysics Data System (ADS)
Vadas, J.; Steinbach, T. K.; Schmidt, J.; Singh, Varinderjit; Haycraft, C.; Hudan, S.; deSouza, R. T.; Baby, L. T.; Kuvin, S. A.; Wiedenhöver, I.
2015-12-01
Background: Despite the importance of light-ion fusion in nucleosynthesis, a limited amount of data exist regarding the de-excitation following fusion for such systems. Purpose: To explore the characteristics of α emission associated with the decay of light fused systems at low excitation energy. Method: α particles were detected in coincidence with evaporation residues (ER) formed by the fusion of 18O and 12C nuclei. Both α particles and ERs were identified on the basis of their energy and time-of-flight. ERs were characterized by their energy spectra and angular distributions while the α particles were characterized by their energy spectra, angular distributions, and cross sections. Results: While the energy spectra and angular distributions for the α particles are relatively well reproduced by the statistical model codes, evapor and pace4 the measured cross section is substantially underpredicted by the models. Examination of the relative α emission probability for similar systems reveals that this underprediction is a more general feature of such light-ion reactions. Conclusion: Comparison of the measured relative α cross section at low Ec .m . for 18O+12C ,16O+12C , and 16O+13C indicates that the α cluster structure of the initial projectile and target nuclei influences the α emission following fusion. The underprediction of the relative α emission by the statistical model codes emphasizes that the failure of these models to account for α cluster structure is significant.
Statistical error propagation in ab initio no-core full configuration calculations of light nuclei
NASA Astrophysics Data System (ADS)
Navarro Pérez, R.; Amaro, J. E.; Ruiz Arriola, E.; Maris, P.; Vary, J. P.
2015-12-01
We propagate the statistical uncertainty of experimental N N scattering data into the binding energy of 3H and 4He. We also study the sensitivity of the magnetic moment and proton radius of the 3H to changes in the N N interaction. The calculations are made with the no-core full configuration method in a sufficiently large harmonic oscillator basis. For those light nuclei we obtain Δ Estat(3H) =0.015 MeV and Δ Estat(4He) =0.055 MeV .
Effective Field Theory and Time-Reversal Violation in Light Nuclei
NASA Astrophysics Data System (ADS)
Mereghetti, E.; van Kolck, U.
2015-10-01
Thanks to the unnaturally small value of the QCD vacuum angle [Formula: see text], time-reversal violation ([Formula: see text]) offers a window into physics beyond the Standard Model (SM) of particle physics. We review the effective field theory framework that establishes a clean connection between (a) [Formula: see text] mechanisms, which can be represented by higher-dimensional operators involving SM fields and symmetries, and (b) hadronic interactions, which allow for controlled calculations of low-energy observables involving strong interactions. The chiral properties of [Formula: see text] mechanisms lead to a pattern that should be identifiable in measurements of the electric dipole moments of the nucleon and light nuclei.
The absorption of ultraviolet light by cell nuclei. A technique for identifying neoplastic change
Baisden, C.R.; Booker, D.; Wright, R.D. )
1989-11-01
A technique for measuring the absorption of 260-nm ultraviolet light by cell nuclei is described. The results of such measurements of normal thyroid epithelial cells and benign and malignant thyroid neoplastic cells demonstrate a progressive increase in absorbance that correlates with the histologic appearance of neoplasia. The possible theoretic basis for this phenomenon is explored. The increased nuclear absorbance observed in neoplastic cells is hypothesized to result from the disruption of hydrogen bonds between the DNA base pairs, which allows unwinding of the double helix and loss of the normal control of mitosis.
NASA Technical Reports Server (NTRS)
Bidasaria, H. B.; Townsend, L. W.
1982-01-01
Utilizing an optical model potential approximation to the exact nucleus-nucleus multiple-scattering series, optical potentials for nucleon-nucleus and nucleus-nucleus collisions are analytically derived. These expressions are applicable to light and medium cosmic ray nuclei as their single-particle density distributions are analytically determined, without approximation, from their actual harmonic well charge density distributions. Pauli correlation effects are included through the use of a simple Gaussian function to replace the usual expression obtained in the infinite nuclear matter approximation.
Study of the hadronic interactions of kaons in light nuclei at DA{Phi}ne
Vazquez Doce, O.
2010-08-05
The AMADEUS experiment at the Da{Phi}ne accelerator of the Frascati National Laboratories (Italy) of INFN, will perform, for the first time, full-acceptance studies of antikaon interaction in light nuclei, with a complete experimental program for the case of the kaonic clusters. Studying the absorption of antikaon by the nucleus will provide information concerning the K-barN interaction and the modification of the kaon mass in the nuclear medium.A preliminar study of these kind of hadronic interactions is being done by the AMADEUS collaboration by analyzing the existent KLOE data.
A new measurement of the flux of the light cosmic-ray nuclei at high energies
NASA Technical Reports Server (NTRS)
Buckley, J.; Dwyer, J.; Mueller, D.; Swordy, S.; Tang, K. K.
1994-01-01
A new cosmic-ray detector utilizing a ring-imaging Cerenkov counter to determine the energy of light cosmic-ray nuclei was flown on high-altitude balloon from Fort Sumner, NM, in 1991 September. We describe the design and performance of this instrument and discuss the data analysis procedures. The measurement provides a new determination of the absolute flux and differential energy spectrum of the primary cosmic-ray species helium between 40 and 320 GeV/nucleon. The experiment also yields the spectra of carbon and oxygen and some information on the intensities of the secondary nuclei Li, Be, and B. A comparison between our results and previous measurements of heavier nuclei (Z greater than or equal to 4) from HEAO 3 and Spacelab 2 indicates good consistency between these measurements. The data set is compared with the results of a leaky box propagation model. We find good agreement with this model if the abundance of helium relative to oxygen at the source is taken to be 25 +/- 6 and if the source spectrum is given by a power law in energy proportional to E(exp -2.15).
Uniform Continuity on Unbounded Intervals
ERIC Educational Resources Information Center
Pouso, Rodrigo Lopez
2008-01-01
We present a teaching approach to uniform continuity on unbounded intervals which, hopefully, may help to meet the following pedagogical objectives: (i) To provide students with efficient and simple criteria to decide whether a continuous function is also uniformly continuous; and (ii) To provide students with skill to recognize graphically…
NASA Technical Reports Server (NTRS)
Chen, Y. R.; Roux, S. J.
1986-01-01
A nucleoside triphosphatase (NTPase) present in highly purified preparations of pea nuclei was partially characterized. The activity of this enzyme was stimulated by divalent cations (Mg2+ = Mn2+ > Ca2+), but was not affected by the monovalent cations, Na+ and K+. The Mg(2+)-dependent activity was further stimulated by concentrations of Ca2+ in the low micromolar range. It could catalyze the hydrolysis of ATP, GTP, UTP, and CTP, all with a pH optimum of 7.5. The nuclear NTPase activity was not inhibited by vanadate, oligomycin, or nitrate, but was inhibited by relatively low concentrations of quercetin and the calmodulin inhibitor, compound 48/80. The NTPase was stimulated more than 50% by red light, and this effect was reversed by subsequent irradiation with far-red light. The photoreversibility of the stimulation indicated that the photoreceptor for this response was phytochrome, an important regulator of photomorphogenesis and gene expression in plants.
Signatures of α Clustering in Light Nuclei from Relativistic Nuclear Collisions
NASA Astrophysics Data System (ADS)
Broniowski, Wojciech; Ruiz Arriola, Enrique
2014-03-01
We argue that relativistic nuclear collisions may provide experimental evidence of α clustering in light nuclei. A light α-clustered nucleus has a large intrinsic deformation. When collided against a heavy nucleus at very high energies, this deformation transforms into the deformation of the fireball in the transverse plane. The subsequent collective evolution of the fireball leads to harmonic flow reflecting the deformation of the initial shape, which can be measured with standard methods of relativistic heavy-ion collisions. We illustrate the feasibility of the idea by modeling the C12-Pb208 collisions and point out that very significant quantitative and qualitative differences between the α-clustered and uniform C12 nucleus occur in such quantities as the triangular flow, its event-by-event fluctuations, or the correlations of the elliptic and triangular flows. The proposal offers a possibility of studying low-energy nuclear structure phenomena with "snapshots" made with relativistic heavy-ion collisions.
RELATIVE COMPOSITION AND ENERGY SPECTRA OF LIGHT NUCLEI IN COSMIC RAYS: RESULTS FROM AMS-01
Aguilar, M.; Alcaraz, J.; Berdugo, J.; Allaby, J.; Alpat, B.; Ambrosi, G.; Azzarello, P.; Battiston, R.; Anderhub, H.; Ao, L.; Arefiev, A.; Arruda, L.; Barao, F.; Barreira, G.; Basile, M.; Bellagamba, L.; Bartoloni, A.; Becker, R.; Becker, U.; Bene, P.
2010-11-20
Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper, the relative abundances of light-nuclei lithium, beryllium, boron, and carbon are presented. The secondary-to-primary ratios Li/C, Be/C, and B/C have been measured in the kinetic energy range 0.35-45 GeV nucleon{sup -1}. The isotopic ratio {sup 7}Li/{sup 6}Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary-to-secondary ratios Li/Be, Li/B, and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10%-15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data.
MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies
Mashnik, Stepan Georgievich; Kerby, Leslie Marie
2015-05-22
MCNP6, the latest and most advanced LANL Monte Carlo transport code, representing a merger of MCNP5 and MCNPX, is actually much more than the sum of those two computer codes; MCNP6 is available to the public via RSICC at Oak Ridge, TN, USA. In the present work, MCNP6 was validated and verified (V&V) against different experimental data on intermediate-energy fragmentation reactions, and results by several other codes, using mainly the latest modifications of the Cascade-Exciton Model (CEM) and of the Los Alamos version of the Quark-Gluon String Model (LAQGSM) event generators CEM03.03 and LAQGSM03.03. It was found that MCNP6 using CEM03.03 and LAQGSM03.03 describes well fragmentation reactions induced on light and medium target nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below, and can serve as a reliable simulation tool for different applications, like cosmic-ray-induced single event upsets (SEU’s), radiation protection, and cancer therapy with proton and ion beams, to name just a few. Future improvements of the predicting capabilities of MCNP6 for such reactions are possible, and are discussed in this work.
Do light nuclei display a universal γ-ray strength function?
NASA Astrophysics Data System (ADS)
Guttormsen, M.; Larsen, A. C.; Bürger, A.; Görgen, A.; Nyhus, H. T.; Siem, S.; Syed, N. U. H.; Toft, H. K.; Tveten, G. M.; Harissopulos, S.; Konstantinopoulos, T.; Lagoyannis, A.; Perdikakis, G.; Spyrou, A.; Kmiecik, M.; Mazurek, K.; Krtička, T.; Lönnroth, T.; Norrby, M.; Schiller, A.; Voinov, A.
2012-02-01
In this work we focus on properties in the quasi-continuum of light nuclei. Generally, both level density and γ-ray strength function (γ-SF) differ from nucleus to nucleus. In order to investigate this closer, we have performed particle-γ coincidences using the reactions (p, p'), (p, d) and (p, t) on a 46Ti target. In particular, the very rich data set of the 46Ti(p, p')46Ti inelastic scattering reaction allows analysis of the coincidence data for many independent data sets. Using the Oslo method, we find one common level density for all data sets. If transitions to well-separated low-energy levels are included, the deduced γ-SF may change by a factor of 2 - 3, due strong to Porter-Thomas fluctuations. However, a universal γ-SF with small fluctuations is found provided that only excitation energies above 3 MeV are taken into account. The nuclear structure of the titaniums is discussed within a combinatorial quasi-particle model, showing that only few Nilsson orbitals participate in building up the level density for these light nuclei.
A novel light-dependent activation of DAGK and PKC in bovine photoreceptor nuclei.
Natalini, Paola M; Mateos, Melina V; Ilincheta de Boschero, Mónica G; Giusto, Norma M
2014-08-01
In this work, we describe a selective light-dependent distribution of the lipid kinase 1,2-diacylglycerol kinase (EC 2.7.1.107, DAGK) and the phosphorylated protein kinase C alpha (pPKCα) in a nuclear fraction of photoreceptor cells from bovine retinas. A nuclear fraction enriched in small nuclei from photoreceptor cells (PNF), was obtained when a modified nuclear isolation protocol developed by our laboratory was used. We measured and compared DAGK activity as phosphatidic acid (PA) formation in PNF obtained from retinas exposed to light and in retinas kept in darkness using [γ-(32)P]ATP or [(3)H]DAG. In the absence of exogenous substrates and detergents, no changes in DAGK activity were observed. However, when DAGK activity assays were performed in the presence of exogenous substrates, such as stearoyl arachidonoyl glycerol (SAG) or dioleoyl glycerol (DOG), and different detergents (used to make different DAGK isoforms evident), we observed significant light effects on DAGK activity, suggesting the presence of several DAGK isoforms in PNF. Under conditions favoring DAGKζ activity (DOG, Triton X-100, dioleoyl phosphatidylserine and R59022) we observed an increase in PA formation in PNF from retinas exposed to light with respect to those exposed to darkness. In contrast, under conditions favoring DAGKɛ (SAG, octylglucoside and R59022) we observed a decrease in its activity. These results suggest different physiological roles of the above-mentioned DAGK isoforms. Western blot analysis showed that whereas light stimulation of bovine retinas increases DAGKζ nuclear content, it decreases DAGKɛ and DAGKβ content in PNF. The role of PIP2-phospholipase C in light-stimulated DAGK activity was demonstrated using U73122. Light was also observed to induce enhanced pPKCα content in PNF. The selective distribution of DAGKζ and ɛ in PNF could be a light-dependent mechanism that in vertebrate retina promotes selective DAG removal and PKC regulation. PMID:24950064
Furusawa, Shun; Nagakura, Hiroki; Yamada, Shoichi; Sumiyoshi, Kohsuke
2013-09-01
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability (SASI). The time evolution of shock waves is calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions, and alpha particles are taken into account in the hydrodynamical simulations. In addition, the effects of ordinary charged-current interactions with nucleons is addressed in the simulations. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as {approx}10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles are heated near the shock wave, which is important when the shock wave expands and the density and temperature of matter become low. It is also found that the models with heating by light nuclei evolve differently in the non-linear phase of SASI than do models that lack heating by light nuclei. This result is because matter in the gain region has a varying density and temperature and therefore sub-regions appear that are locally rich in deuterons and alpha particles. Although the light nuclei are never dominant heating sources and they work favorably for shock revival in some cases and unfavorably in other cases, they are non-negligible and warrant further investigation.
Spline interpolation on unbounded domains
NASA Astrophysics Data System (ADS)
Skeel, Robert D.
2016-06-01
Spline interpolation is a splendid tool for multiscale approximation on unbounded domains. In particular, it is well suited for use by the multilevel summation method (MSM) for calculating a sum of pairwise interactions for a large set of particles in linear time. Outlined here is an algorithm for spline interpolation on unbounded domains that is efficient and elegant though not so simple. Further gains in efficiency are possible via quasi-interpolation, which compromises collocation but with minimal loss of accuracy. The MSM, which may also be of value for continuum models, embodies most of the best features of both hierarchical clustering methods (tree methods, fast multipole methods, hierarchical matrix methods) and FFT-based 2-level methods (particle-particle particle-mesh methods, particle-mesh Ewald methods).
Light Nuclei in the Framework of the Symplectic No-Core Shell Model
Draayer, Jerry P.; Dytrych, Tomas; Sviratcheva, Kristina D.; Bahri, Chairul; Vary, James P.; /Iowa State U. /LLNL, Livermore /SLAC
2007-04-02
A symplectic no-core shell model (Sp-NCSM) is constructed with the goal of extending the ab-initio NCSM to include strongly deformed higher-oscillator-shell configurations and to reach heavier nuclei that cannot be studied currently because the spaces encountered are too large to handle, even with the best of modern-day computers. This goal is achieved by integrating two powerful concepts: the ab-initio NCSM with that of the Sp(3,R) {contains} SU(3) group-theoretical approach. The NCSM uses modern realistic nuclear interactions in model spaces that consists of many-body configurations up to a given number of {h_bar}{Upsilon} excitations together with modern high-performance parallel computing techniques. The symplectic theory extends this picture by recognizing that when deformed configurations dominate, which they often do, the model space can be better selected so less relevant low-lying {h_bar}{Upsilon} configurations yield to more relevant high-lying {h_bar}{Upsilon} configurations, ones that respect a near symplectic symmetry found in the Hamiltonian. Results from an application of the Sp-NCSM to light nuclei are compared with those for the NCSM and with experiment.
Does the α Cluster Structure in Light Nuclei Persist Through the Fusion Process?
NASA Astrophysics Data System (ADS)
Vadas, Justin; Steinbach, Tracy; Schmidt, Jon; Singh, Varinderjit; Hudan, Sylvie; Desouza, Romualdo; Baby, Lagy; Kuvin, Sean; Wiedenhover, Ingo
2016-03-01
Despite the importance of light-ion fusion in nucleosynthesis, a limited amount of data exist regarding the de-excitation following fusion for such systems. The characteristics of α emission following the fusion of 18O and 12C nuclei have been explored. Alpha particles were detected in coincidence with evaporation residues (ER) and identified on the basis of their energy and time-of-flight. ERs were characterized by their energy spectra and angular distributions while the α particles were characterized by their energy spectra, angular distributions, and cross-sections. While the energy spectra and angular distributions for the α particles are relatively well reproduced by statistical model codes, the measured cross-section is substantially underpredicted by the models. Comparison of the measured relative α cross-section at low Ec.m. for 18O+12C, 16O+12C, and 16O+13C indicates that the α cluster structure of the initial projectile and target nuclei influences the α emission following fusion. The underprediction of the relative α emission by the statistical model codes suggests that the failure of these models to account for α cluster structure is significant. Supported by DOE Grant No. DE-FG02-88ER-40404 and NSF Grant No. 1342962.
Spectra and scattering of light lattice nuclei from effective field theory
NASA Astrophysics Data System (ADS)
Kirscher, J.; Barnea, N.; Gazit, D.; Pederiva, F.; van Kolck, U.
2015-11-01
An effective field theory is used to describe light nuclei, calculated from quantum chromodynamics on a lattice at unphysically large pion masses. The theory is calibrated at leading order to two available data sets on two- and three-body nuclei for two pion masses. At those pion masses we predict the quartet and doublet neutron-deuteron scattering lengths, and the α -particle binding energy. For mπ=510 MeV we obtain, respectively, 4anD=2.3 ±1.3 fm, 2anD=2.2 ±2.1 fm, and Bα=35 ±22 MeV, while for mπ=805 MeV 4anD=1.6 ±1.3 fm, 2anD=0.62 ±1.0 fm, and Bα=94 ±45 MeV are found. Phillips- and Tjon-like correlations to the triton binding energy are established. We find the theoretical uncertainty in the respective correlation bands to be independent of the pion mass. As a benchmark, we present results for the physical pion mass, using experimental two-body scattering lengths and the triton binding energy as input. Hints of subtle changes in the structure of the triton and α particle are discussed.
(α ,γ ) cross section measurements in the region of light p nuclei
NASA Astrophysics Data System (ADS)
Quinn, S. J.; Spyrou, A.; Simon, A.; Battaglia, A.; Bowers, M.; Bucher, B.; Casarella, C.; Couder, M.; DeYoung, P. A.; Dombos, A. C.; Görres, J.; Kontos, A.; Li, Q.; Long, A.; Moran, M.; Paul, N.; Pereira, J.; Robertson, D.; Smith, K.; Smith, M. K.; Stech, E.; Talwar, R.; Tan, W. P.; Wiescher, M.
2015-10-01
The 90Zr(α ,γ )94Mo,92Zr(α ,γ )96Mo, and 74Ge(α ,γ )78Se reaction cross sections were measured for the first time in an effort to expand the existing experimental database for (α ,γ ) reactions relevant for the production of p nuclei in the universe. In particular, the 90Zr(α ,γ )94Mo reaction was identified by a sensitivity study for its potential impact on the γ -process mass flow in the region of light p nuclei. The measurements were performed for energies Eα=9.5 - 12.0 MeV at the University of Notre Dame using the SuN detector and the γ -summing technique. The results are compared to theoretical calculations from the talys and non-smoker nuclear reaction codes, and it is shown that the data greatly reduce the uncertainty in the cross section for the measured energies. The talys parameters that provide the best description of the experimental data are reported.
NASA Astrophysics Data System (ADS)
Tuttle-Timm, Matthew; Rabeh, Ali; Frank, Nathan; Brett, Jaclyn; Deyoung, Paul; Jones, Michael; Thoennessen, Michael; MoNA Collaboration
2015-10-01
The nuclear structure of a state in a given isotope is determined by which nucleons occupy the bound and unbound energy levels. This state determines the energy of decay, which can be calculated from the energy and momentum of the fragment and neutron. From the calculated decay energy, information about an isotope's nuclear structure can be found. At a National Superconducting Cyclotron Laboratory experiment, a 101.3 MeV/u 27Ne ion beam hit a liquid deuterium target, causing reactions which produced several isotopes. Many of these isotopes decayed, resulting in a charged fragment and one or more neutrons. A superconducting dipole magnet bent the path of the fragments into a series of charged-particle detectors. Neutrons from these decays were measured as they interacted with arrays of scintillating plastic bars. One of the isotopes produced was 26F, formed by 1-proton stripping from the 27Ne beam. This 26F decayed into 25F + n. By calculating the decay energy for this interaction, the first resonant neutron-unbound state in 26F, which has not been significantly observed, will be characterized. In addition, resonances of other unbound nuclear systems may also be included to compare/contrast with these results. This material is based upon work supported by the National Science Foundation under Grants PHY-1306074 and PHY-1404236.
Ab-Initio Hamiltonian Approach to Light Nuclei And to Quantum Field Theory
Vary, J.P.; Honkanen, H.; Li, Jun; Maris, P.; Shirokov, A.M.; Brodsky, S.J.; Harindranath, A.; de Teramond, G.F.; Ng, E.G.; Yang, C.; Sosonkina, M.; /Ames Lab
2012-06-22
Nuclear structure physics is on the threshold of confronting several long-standing problems such as the origin of shell structure from basic nucleon-nucleon and three-nucleon interactions. At the same time those interactions are being developed with increasing contact to QCD, the underlying theory of the strong interactions, using effective field theory. The motivation is clear - QCD offers the promise of great predictive power spanning phenomena on multiple scales from quarks and gluons to nuclear structure. However, new tools that involve non-perturbative methods are required to build bridges from one scale to the next. We present an overview of recent theoretical and computational progress with a Hamiltonian approach to build these bridges and provide illustrative results for the nuclear structure of light nuclei and quantum field theory.
Production of Light-element Primary Process Nuclei in Neutrino-driven Winds
NASA Astrophysics Data System (ADS)
Arcones, A.; Montes, F.
2011-04-01
We present first comparisons between light-element primary process (LEPP) abundances observed in some ultra metal-poor (UMP) stars and nucleosynthesis calculations based on long-time hydrodynamical simulations of core-collapse supernovae and their neutrino-driven wind. UMP star observations indicate that Z >= 38 elements include the contributions of at least two nucleosynthesis components: r-process nuclei that are synthesized by rapid neutron capture in a yet unknown site and LEPP elements (mainly Sr, Y, and Zr). We show that neutrino-driven wind simulations can explain the observed LEPP pattern. We explore in detail the sensitivity of the calculated abundances to the electron fraction, which is a key nucleosynthesis parameter but poorly known due to uncertainties in neutrino interactions and transport. Our results show that the observed LEPP pattern can be reproduced in proton- and neutron-rich winds.
Chiral Three-Nucleon Interactions in Light Nuclei, Neutron-α Scattering, and Neutron Matter
NASA Astrophysics Data System (ADS)
Lynn, J. E.; Tews, I.; Carlson, J.; Gandolfi, S.; Gezerlis, A.; Schmidt, K. E.; Schwenk, A.
2016-02-01
We present quantum Monte Carlo calculations of light nuclei, neutron-α scattering, and neutron matter using local two- and three-nucleon (3 N ) interactions derived from chiral effective field theory up to next-to-next-to-leading order (N2LO ). The two undetermined 3 N low-energy couplings are fit to the 4He binding energy and, for the first time, to the spin-orbit splitting in the neutron-α P -wave phase shifts. Furthermore, we investigate different choices of local 3 N -operator structures and find that chiral interactions at N2LO are able to simultaneously reproduce the properties of A =3 ,4 ,5 systems and of neutron matter, in contrast to commonly used phenomenological 3 N interactions.
Gamma ray astronomy and the origin of the light nuclei. [cosmic ray and interstellar gas reactions
NASA Technical Reports Server (NTRS)
Reeves, H.
1978-01-01
Nuclear reactions induced by the collisions of the protons and alphas of the galactic cosmic ray with heavy nuclei of the interstellar gas are responsible for the continuous production of the light elements lithium, beryllium, and boron in the galaxy. To better than one order of magnitude, the observed ratios of these abundances to hydrogen abundance and the nuclidic abundance ratios between themselves are accounted for by simply considering the effect of fast protons and alphas with a flux and an energy spectrum as observed in galactic cosmic rays, for a period comparable with the life of our galaxy. The role of gamma ray astronomy in solving problems that occur when accurate agreement is sought with increasingly accurate data is discussed.
Correlation Analysis of Optical and Radio Light Curves for a Large Sample of Active Galactic Nuclei
NASA Astrophysics Data System (ADS)
Clements, S. D.; Smith, A. G.; Aller, H. D.; Aller, M. F.
1995-08-01
The Rosemary Hill Observatory has accumulated internally consistent light curves extending over as much as 26 years for a large sample of active galactic nuclei. Forty-six of these optical records have been compared with similar radio records from the University of Michigan Radio Astronomy Observatory and the Algonquin Radio Observatory. For 18 objects, pairs of records were sufficiently long and unconfused to allow reliable application of the Discrete Correlation Function analysis; this group included 8 BL Lacertids, 8 quasars, and 2 Seyfert galaxies. Nine of the 18 sources showed positive radio-optical correlations, with the radio events lagging the optical by intervals ranging from 0 to 14 months. Consistent with the relativistic beaming model of the BL Lacertids, the group displaying correlations was dominated by this type of object.
PRODUCTION OF LIGHT-ELEMENT PRIMARY PROCESS NUCLEI IN NEUTRINO-DRIVEN WINDS
Arcones, A.; Montes, F.
2011-04-10
We present first comparisons between light-element primary process (LEPP) abundances observed in some ultra metal-poor (UMP) stars and nucleosynthesis calculations based on long-time hydrodynamical simulations of core-collapse supernovae and their neutrino-driven wind. UMP star observations indicate that Z {>=} 38 elements include the contributions of at least two nucleosynthesis components: r-process nuclei that are synthesized by rapid neutron capture in a yet unknown site and LEPP elements (mainly Sr, Y, and Zr). We show that neutrino-driven wind simulations can explain the observed LEPP pattern. We explore in detail the sensitivity of the calculated abundances to the electron fraction, which is a key nucleosynthesis parameter but poorly known due to uncertainties in neutrino interactions and transport. Our results show that the observed LEPP pattern can be reproduced in proton- and neutron-rich winds.
Finite nuclei in relativistic models with a light chiral scalar meson
Furnstahl, R.J. ); Serot, B.D. )
1993-05-01
Relativistic chiral models with a light scalar meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. The scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon ([ital NN]) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. These deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario, which features a heavy chiral scalar and dynamical generation of the [ital NN] attraction, is discussed.
Finite nuclei in relativistic models with a light chiral scalar meson
Serot, B.D.; Furnstahl, R.J.
1993-10-01
Relativistic chiral models with a light scalar, meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. In these models, the scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon (NN) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. There deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario for chiral hadronic models, which features a heavy chiral scalar and dynamical generation of the NN attraction, is discussed.
Furusawa, Shun; Yamada, Shoichi; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Suzuki, Hideyuki
2014-05-02
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ∼ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.
NASA Astrophysics Data System (ADS)
Furusawa, Shun; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Yamada, Shoichi; Suzuki, Hideyuki
2014-05-01
We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light nuclei on the standing accretion shock instability. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged-current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. We show that the heating rates of deuterons reach as high as ˜ 10% of those of nucleons around the bottom of the gain region. On the other hands, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light nuclei have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light nuclei, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.
Self-adjointness of deformed unbounded operators
Much, Albert
2015-09-15
We consider deformations of unbounded operators by using the novel construction tool of warped convolutions. By using the Kato-Rellich theorem, we show that unbounded self-adjoint deformed operators are self-adjoint if they satisfy a certain condition. This condition proves itself to be necessary for the oscillatory integral to be well-defined. Moreover, different proofs are given for self-adjointness of deformed unbounded operators in the context of quantum mechanics and quantum field theory.
Investigation of the low energy kaons hadronic interactions in light nuclei by AMADEUS
NASA Astrophysics Data System (ADS)
Piscicchia, K.; Bazzi, M.; Berucci, C.; Bosnar, D.; Bragadireanu, A. M.; Cargnelli, M.; Clozza, A.; Curceanu, C.; Grande, R. Del; D'uffizi, A.; Fabbietti, L.; Fiorini, C.; Ghio, F.; Guaraldo, C.; Iliescu, M.; Sandri, P. Levi; Marton, J.; Moskal, P.; Pietreanu, D.; Lener, M. Poli; Quaglia, R.; Romero Vidal, A.; Sbardella, E.; Scordo, A.; Shi, H.; Skurzok, M.; Silarski, M.; Sirghi, D.; Sirghi, F.; Tucakovic, I.; Doce, O. Vazquez; Widmann, E.; Zmeskal, J.
2015-08-01
The AMADEUS experiment aims to provide unique quality data for K - interaction with nucleons and light nuclei, both at-rest and in-flight (for K - momenta of about 100 MeV). The goal is to solve longstanding open issues in the non-perturbative QCD in the strangeness sector, like the nature of the Λ(1405) state, the resonant versus non-resonant yield in nuclear K - capture and the properties of kaonic nuclear clusters which are strongly related to the multi-nucleon absorption processes. We can take advantage of the DA ΦNE collider representing a unique source of monochromatic low-momentum kaons, whose nuclear interaction with the materials of the KLOE detector (used as an active target) furnish us excellent acceptance and resolution data for K - capture on H, 4He, 9Be and 12C, both at-rest and in-flight. AMADEUS step 0 consisted in the analysis of the 2004-2005 KLOE data. A second step consisted in the implementation in the central region of the KLOE detector of a pure graphite target, providing a high statistic sample of K - 12 C nuclear captures at rest. For the future, new setups for various dedicated targets are under preparation.
Precise Electromagnetic Tests of Ab Initio Calculations of Light Nuclei: States in {sup 10}Be
McCutchan, E. A.; Lister, C. J.; Wiringa, R. B.; Pieper, Steven C.; Seweryniak, D.; Greene, J. P.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Zhu, S.; Chiara, C. J.; Stefanescu, I.
2009-11-06
In order to test ab initio calculations of light nuclei, we have remeasured lifetimes in {sup 10}Be using the Doppler shift attenuation method (DSAM) following the {sup 7}Li({sup 7}Li,alpha){sup 10}Be reaction at 8 and 10 MeV. The new experiments significantly reduce systematic uncertainties in the DSAM technique. The J{sup p}i=2{sub 1}{sup +} state at 3.37 MeV has tau=205+-(5){sub stat}+-(7){sub sys} fs corresponding to a B(E2arrow down) of 9.2(3)e{sup 2} fm{sup 4} in broad agreement with many calculations. The J{sup p}i=2{sub 2}{sup +} state at 5.96 MeV was found to have a B(E2arrow down) of 0.11(2)e{sup 2} fm{sup 4} and provides a more discriminating test of nuclear models. New Green's function Monte Carlo calculations for these states and transitions with a number of Hamiltonians are also reported and compared to experiment.
One-neutron knockout from light neutron-rich nuclei at relativistic energies
Rodriguez-Tajes, C.; Alvarez-Pol, H.; Benjamim, E.; Benlliure, J.; Caamano, M.; Casarejos, E.; Cortina-Gil, D.; Gascon, M.; Kurtukian, T.; Perez-Loureiro, D.; Aumann, T.; Chatillon, A.; Geissel, H.; Nociforo, C.; Prochazka, A.; Simon, H.; Suemmerer, K.; Weick, H.; Winkler, M.; Borge, M. J. G.
2010-08-15
One-neutron knockout reactions from neutron-rich nuclei, with Z=6-13 and N=8-22, were studied at the Fragment Separator (GSI) at high beam energies, around 700 MeV/nucleon. Structural phenomena such as the formation of one-neutron halos in odd-mass carbon isotopes ({sup 15,17,19}C) will be discussed. In addition, one-neutron knockout measurements from {sup 22}N were carried out for the first time and demonstrate clearly the change from a 0d{sub 5/2} to a 1s{sub 1/2} orbital for the valence neutron, an effect that is expected above N=14 and that was also observed in {sup 23}O and {sup 24}F. The possibility of an anomalous structure of {sup 26}F, due to a significant 1s{sub 1/2} neutron admixture, will also be discussed in the light of the experimental data obtained in this work. Finally, the ground-state configuration of neutron-rich neon isotopes ({sup 24-28}Ne) was studied, providing new information in a region that is relatively close to the island of inversion.
Nuclear matter saturation with chiral three-nucleon interactions fitted to light nuclei properties
NASA Astrophysics Data System (ADS)
Logoteta, Domenico; Bombaci, Ignazio; Kievsky, Alejandro
2016-07-01
The energy per particle of symmetric nuclear matter and pure neutron matter is calculated using the many-body Brueckner-Hartree-Fock approach and employing the Chiral Next-to-next-to-next-to leading order (N3LO) nucleon-nucleon (NN) potential, supplemented with various parametrizations of the Chiral Next-to-next-to leading order (N2LO) three-nucleon interaction. Such combination is able to reproduce several observables of the physics of light nuclei for suitable choices of the parameters entering in the three-nucleon interaction. We find that some of these parametrizations provide a satisfactory saturation point of symmetric nuclear matter and values of the symmetry energy and its slope parameter L in very good agreement with those extracted from various nuclear experimental data. Thus, our results represent a significant step toward a unified description of few- and many-body nuclear systems starting from two- and three-nucleon interactions based on the symmetries of QCD.
NASA Astrophysics Data System (ADS)
Robinson, Andrew
Dusty molecular tori play a central role in unification models for active galactic nuclei (AGN) and are also the dominant source of their mid-IR emission. Our limited knowledge of the size and structure of AGN tori and how these properties vary with luminosity hinders our ability to understand the observed spectral energy distribution and hence AGN demographics. Ultimately this inhibits our ability to understand the obscured AGN population and the cosmic evolution of super-massive black holes. Although the torus is, in general, inaccessible to direct imaging, its properties can be studied by analyzing the time response of the dust emission from the torus with respect to variations in the AGN continuum luminosity; a technique known as reverberation mapping. With this goal, we have completed a 2.5-year monitoring campaign on 12 broad-line AGN, using the Spitzer Space Telescope supported by ground-based optical observations, to measure the temporal response of thetorus 3.5 and 4.6μm mid-IR dust emission to variations in the AGN UV/optical continuum. The data obtained from the first 1.5 years in Spitzer Cycle 8 have been analysed. The aim of this project is to complete the time series analysis of the complete 2.5 year light curves, and to model these light curves in order extract structural and physical information contained in data, such as the size of the torus, its radial depth, opening angle, inclination and dust composition. This project will help to maximize the scientific returns on a significant investment of Spitzer Space Telescope time and supports the NASA strategic goal to "explore the origin and evolution of the galaxies, stars and planets that make up our universe".
NASA Astrophysics Data System (ADS)
Sutter, Kiplangat
This thesis illustrates the utilization of Density functional theory (DFT) in calculations of gas and solution phase Nuclear Magnetic Resonance (NMR) properties of light and heavy nuclei. Computing NMR properties is still a challenge and there are many unknown factors that are still being explored. For instance, influence of hydrogen-bonding; thermal motion; vibration; rotation and solvent effects. In one of the theoretical studies of 195Pt NMR chemical shift in cisplatin and its derivatives illustrated in Chapter 2 and 3 of this thesis. The importance of representing explicit solvent molecules explicitly around the Pt center in cisplatin complexes was outlined. In the same complexes, solvent effect contributed about half of the J(Pt-N) coupling constant. Indicating the significance of considering the surrounding solvent molecules in elucidating the NMR measurements of cisplatin binding to DNA. In chapter 4, we explore the Spin-Orbit (SO) effects on the 29Si and 13C chemical shifts induced by surrounding metal and ligands. The unusual Ni, Pd, Pt trends in SO effects to the 29Si in metallasilatrane complexes X-Si-(mu-mt)4-M-Y was interpreted based on electronic and relativistic effects rather than by structural differences between the complexes. In addition, we develop a non-linear model for predicting NMR SO effects in a series of organics bonded to heavy nuclei halides. In chapter 5, we extend the idea of "Chemist's orbitals" LMO analysis to the quantum chemical proton NMR computation of systems with internal resonance-assisted hydrogen bonds. Consequently, we explicitly link the relationship between the NMR parameters related to H-bonded systems and intuitive picture of a chemical bond from quantum calculations. The analysis shows how NMR signatures characteristic of H-bond can be explained by local bonding and electron delocalization concepts. One shortcoming of some of the anti-cancer agents like cisplatin is that they are toxic and researchers are looking for
ERIC Educational Resources Information Center
Ebersbach, Mirjam; Luwel, Koen; Verschaffel, Lieven
2015-01-01
Children's estimation skills on a bounded and unbounded number line task were assessed in the light of their familiarity with numbers. Kindergartners, first graders, and second graders (N = 120) estimated the position of numbers on a 1--100 number line, marked with either two reference points (i.e., 1 and 10: unbounded condition) or three…
NASA Astrophysics Data System (ADS)
Johansson, H. T.; Aksyutina, Yu.; Aumann, T.; Boretzky, K.; Borge, M. J. G.; Chatillon, A.; Chulkov, L. V.; Cortina-Gil, D.; Datta Pramanik, U.; Emling, H.; Forssén, C.; Fynbo, H. O. U.; Geissel, H.; Ickert, G.; Jonson, B.; Kulessa, R.; Langer, C.; Lantz, M.; LeBleis, T.; Mahata, K.; Meister, M.; Münzenberg, G.; Nilsson, T.; Nyman, G.; Palit, R.; Paschalis, S.; Prokopowicz, W.; Reifarth, R.; Richter, A.; Riisager, K.; Schrieder, G.; Simon, H.; Sümmerer, K.; Tengblad, O.; Weick, H.; Zhukov, M. V.
2010-10-01
The unbound nuclei 9He and 10He have been produced in proton-knockout reactions from a 280 MeV/u 11Li beam impinging on a liquid hydrogen target at the ALADIN-LAND setup at GSI. Information on their nuclear structure has been obtained from the relative-energy spectra, He8+n and He8+2n, employing reaction models incorporating the structure of 11Li. The He8+n relative-energy spectrum is dominated by a strong peak-like structure at low energy, which may be interpreted within the effective-range approximation as the result of an s-wave interaction with a neutron scattering length of -3.17(66) fm. This spectrum also shows evidence for resonance states at 1.33(8) MeV and at 2.4 MeV above the He8+n threshold. It is argued that the s-state might not be the 9He ground state. For He8+n+n, the analysis of the relative-energy spectrum gives two alternative possibilities for an interpretation: either a narrow resonance at 1.42(10) MeV ( Γ=1.11(76) MeV) superimposed on a correlated background, or two overlapping resonances, a ground state at 1.54(11) MeV ( Γ=1.91(41) MeV) together with an excited state at 3.99(26) MeV ( Γ=1.64(89) MeV). The two possible interpretations are discussed.
Womble, Phillip C.; Barzilov, Alexander; Novikov, Ivan; Howard, Joseph; Musser, Jason
2009-03-10
Neutron-induced gamma-ray reactions are extensively used in the nondestructive analysis of materials and other areas where the information about the chemical composition of a substance is crucial. The common technique to find the intensity of the gamma ray is to fit gamma-ray line shape with an analytical function, for example, a Gaussian. However, the Gaussian fitting may fail if the gamma-ray peak is Doppler-broadened since this leads to the miscalculation of the area of the peak and, therefore, to misidentification of the material. Due to momentum considerations, Doppler-broadening occurs primarily with gamma rays from neutron-induced inelastic scattering reactions with light nuclei. The recoiling nucleus of interest must have excited states whose lifetimes are much smaller than the time of flight in the material. We have examined various light nuclei bombarded by 14 MeV neutrons to predict when the peak shape of a neutron-induced gamma ray emitted from these nuclei will be Doppler-broadened. We have found that nearly all the gamma rays from neutron-induced gamma-ray reactions on light elements (A<20) are Doppler-broadened with only a few exceptions. This means that utilization of resolution curves derived from isotopic sources or thermal neutron capture reactions have little value in the analysis.
New Measurements of the EMC Effect in Light Nuclei and at Large x
Gaskell, D.
2008-10-13
The modification of structure functions in nuclei (the EMC effect) has been the focus of intense experimental and theoretical study since the original observation in 1983. The EMC effect unequivocally demonstrates that quark distributions in nuclei are not simply the incoherent sum of the nucleon quark distributions. However, progress in understanding the root cause of these modifications has been hampered by the complexity of nuclear structure, making it difficult to disentangle the ''conventional'' nuclear effects of Fermi motion and binding from true medium modifications to nucleon structure. Experiment E03--103 at Jefferson Lab made measurements of nuclear structure function ratios from few--body nuclei ({sup 3}He and {sup 4}He) to deuterium, where the nuclear structure is well known, and for a range of nuclei, A = 3 to 197, at large x, where effects from Fermi motion and binding dominate.
NASA Technical Reports Server (NTRS)
Cucinotta, Francis A.; Wilson, John W.
1996-01-01
The angular momentum independent statistical decay model is often applied using a Monte-Carlo simulation to describe the decay of prefragment nuclei in heavy ion reactions. This paper presents an analytical approach to the decay problem of nuclei with mass number less than 60, which is important for galactic cosmic ray (GCR) studies. This decay problem of nuclei with mass number less than 60 incorporates well-known levels of the lightest nuclei (A less than 11) to improve convergence and accuracy. A sensitivity study of the model level density function is used to determine the impact on mass and charge distributions in nuclear fragmentation. This angular momentum independent statistical decay model also describes the momentum and energy distribution of emitted particles (n, p, d, t, h, and a) from a prefragment nucleus.
Interactions of heavy nuclei, Kr, Xe and Ho, in light targets
NASA Technical Reports Server (NTRS)
Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.
1985-01-01
Over the past few years, the HEAO-3 measurements of the abundance of ultra-heavy cosmic ray nuclei (Z 26) at Earth were analyzed. In order to interpret these abundances in terms of a source composition, allowances must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. The semi-empirical formalism of Silberberg and Tsao were relied upon to predict the partial cross sections. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed.
NASA Astrophysics Data System (ADS)
Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V.; Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.
2015-05-01
In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the 6He, 8He, 11Li, and 14Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the 8Li, 9Li, and 12Be nuclei.
Interactions of heavy nuclei, Kr, Xe and Ho, in light targets
NASA Technical Reports Server (NTRS)
Kertzman, M. P.; Klarmann, J.; Newport, B. J.; Stone, E. C.; Waddington, C. J.; Binns, W. R.; Garrard, T. L.; Israel, M. H.
1985-01-01
Over the past few years, the HEAO-3 measurements of the abundances of ultra-heavy cosmic ray nuclei (Z 26) at earth have been analyzed. In order to interpret these abundances in terms of a source composition, allowance must be made for the propagation of the nuclei in the interstellar medium. Vital to any calculation of the propagation is a knowlege of the total and partial interaction cross sections for these heavy nuclei on hydrogen. Until recently, data on such reactions have been scarce. However, now that relativistic heavy ion beams are available at the LBL Bevalac, some of the cross sections of interest can be measured at energies close to those of the cosmic ray nuclei being observed. During a recent calibration at the Bevalac of an array similar to the HEAO-C3 UH-nuclei detector, targets of raphite (C), polyethylene (CH2), and aluminum were exposed to five heavy ion beams ranging in charge (Z) from 36 to 92. Total and partial charge changing cross sections for the various beam nuclei on hydrogen can be determined from the measured cross sections on C and CH2, and will be applied to the propagation problem. The cross sections on Al can be used to correct the abundances of UH cosmic rays observed in the HEAO C-3 detector for interactions in the detector itself.
Alkhazov, G. D.; Vorobyov, A. A.; Dobrovolsky, A. V. Inglessi, A. G.; Korolev, G. A.; Khanzadeev, A. V.
2015-05-15
In order to study the spatial structure of exotic nuclei, it was proposed at the Petersburg Nuclear Physics Institute (PNPI) to measure the differential cross section for small-angle proton elastic scattering in inverse kinematics. Several experiments in beams of 0.7-GeV/nucleon exotic nuclei were performed at the heavy-ion accelerator facility of GSI (Gesellschaft für Schwerionenforschung, Darmstadt, Germany) by using the IKAR ionization spectrometer developed at PNPI. The IKAR ionization chamber filled with hydrogen at a pressure of 10 bar served simultaneously as a target and as a recoil-proton detector, which measured the recoil-proton energy. The beam-particle scattering angle was also measured. The results obtained for the cross sections in question were analyzed on the basis of the Glauber-Sitenko theory using phenomenological nuclear-density distributions with two free parameters. Nuclear-matter distributions and root-mean-square radii were found for the nuclei under investigation. The size of the halo in the {sup 6}He, {sup 8}He, {sup 11}Li, and {sup 14}Be nuclei was determined among other things. Information about neutron distributions in nuclei was deduced by combining the data obtained here with the known values of the radii of proton distributions. A sizable neutron skin was revealed in the {sup 8}Li, {sup 9}Li, and {sup 12}Be nuclei.
Study of Weakly Bound Nuclei at RIKEN RIBF
NASA Astrophysics Data System (ADS)
Motobayashi, Tohru
2016-05-01
Recent highlights of studies on unbound exotic nuclei at the RIKEN RI beam factory (RIBF) are presented. They include spectroscopy of nuetron-rich oxygen isotopes ^{26}O and ^{28}O, search for four-neutron states, and studies of proton unbound states of astrophysical interest.
Martian Unbound Water Inventories: Changes with Time
NASA Astrophysics Data System (ADS)
Carr, M. H.; Head, J. W.
2014-07-01
We estimate that approximately 34 m GEL of unbound water is within 100 m of the martian surface today and 60-70 m are estimated for the end of the Hesperian. These estimates are reconciled with the geology.
Dominant Modes in Light Nuclei - Ab Initio View of Emergent Symmetries
NASA Astrophysics Data System (ADS)
Draayer, J. P.; Dytrych, T.; Launey, K. D.; Dreyfuss, A. C.; Langr, D.
2015-01-01
An innovative symmetry-guided concept is discussed with a focus on emergent symmetry patterns in complex nuclei. In particular, the ab initio symmetry-adapted no-core shell model (SA-NCSM), which capitalizes on exact as well as partial symmetries that underpin the structure of nuclei, provides remarkable insight into how simple symmetry patterns emerge in the many-body nuclear dynamics from first principles. This ab initio view is complemented by a fully microscopic no-core symplectic shell-model framework (NCSpM), which, in turn, informs key features of the primary physics responsible for the emergent phenomena of large deformation and alpha-cluster substructures in studies of the challenging Hoyle state in Carbon-12 and enhanced collectivity in intermediate-mass nuclei. Furthermore, by recognizing that deformed configurations often dominate the low-energy regime, the SA-NCSM provides a strategy for determining the nature of bound states of nuclei in terms of a relatively small subspace of the symmetry-reorganized complete model space, which opens new domains of nuclei for ab initio investigations, namely, the intermediate-mass region, including isotopes of Ne, Mg, and Si.
NASA Astrophysics Data System (ADS)
Pshenichnov, Igor; Mishustin, Igor; Greiner, Walter
2008-04-01
We study the energy deposition by beams of light and heavy nuclei in tissue-like media for their possible application in charged-particle cancer therapy. The depth-dose distributions for protons, 3He, 12C, 20Ne and 58Ni nuclei are calculated within a Monte Carlo model based on the GEANT4 toolkit. These distributions are compared with each other and with available experimental data. It is demonstrated that nuclear fragmentation reactions essentially reduce the peak-to-plateau ratio of the dose profiles for deeply penetrating energetic ions heavier than 3He. On the other hand, the shapes of depth-dose profiles for all projectiles up to 58Ni were found similar at low penetration depths.
Towards advanced study of Active Galactic Nuclei with visible light adaptive optics
NASA Astrophysics Data System (ADS)
Ammons, Stephen Mark
It is thought that the immense energies associated with accretion of matter onto black holes in Active Galactic Nuclei (AGN) and Quasi-Stellar Objects (QSOs) may "feedback," via intense photon flux or outward motion of gas, and affect certain properties of the host galaxy. In particular, AGN feedback may contribute to "quenching," or ceasing, of star formation by the expulsion or heating of cold gas, causing the host galaxy to evolve onto the red sequence (e.g., Di Matteo et al. 2005, Hopkins et al. 2006). I probe for the effects of feedback on the stellar populations of 60 X-ray-selected AGN hosts at a redshift of 1 in the Great Observatories Origins Deep Survey (GOODS) Southern field. Combining high spatial resolution optical imaging from the Hubble Space Telescope Advanced Camera for Surveys (HST ACS), and high spatial resolution near infrared data from Keck Laser Guide Star Adaptive Optics (AO) and HST Near-Infrared Camera and Multi-Object Spectrograph (NICMOS), I test for the presence of young stars on sub-kiloparsec scales, independent of dust extinction. Testing for correlations between near-ultraviolet/optical ( NUV- R ) colors and gradients and X-ray parameters such as hardness ratio and luminosity reveals new information about the nature of AGN-driven feedback. These AGN hosts display color gradients in rest-frame NUV - R as far inward as ~400 pc, suggesting stellar mixtures with nonuniform age distributions. There is little (< 0.3 mags) difference between the NUV - R gradients of the obscured (hard in X-ray) sources and the unobscured (soft in X-ray) sources, suggesting that the unobscured sources are not increasingly quenched of star formation. I compare the NUV - R colors of spiral galaxies that host AGN to non-active spirals, finding similar color gradients, but redder colors. These observations support the notion that unobscured intermediate-luminosity AGN hosts do not appear to be increasingly quenched of star formation relative to obscured sources
NASA Astrophysics Data System (ADS)
Zhilei, She; Gang, Chen; Hongge, Xu; Tingting, Zeng; Dikai, Li
2016-04-01
The centrality dependence of light (anti)nuclei and (anti)hypertriton production in Pb-Pb collisions at √{s_{NN}} = 2.76 TeV are investigated using the dynamically constrained phase-space coalescence (DCPC) model and the parton and hadron cascade (PACIAE) model. We found that the yields of light (anti)nuclei and (anti)hypertriton strongly depend on the centrality, i.e., their yields decrease rapidly with the increase of centrality; but their yield ratios are independent of centrality. The results from our theoretical model are well consistent with ALICE data. Furthermore, we found that the integrated yields of (anti)nuclei per participant nucleon increase from peripheral to central collisions, and a higher mass number corresponds to a more rapid increase of such yields. The coalescence parameters BA of light (anti)nuclei and (anti)hypernuclei are also analyzed.
8Be and 9B nuclei in dissociation of relativistic 10B and 11C nuclei
NASA Astrophysics Data System (ADS)
Artemenkov, D. A.; Bradnova, V.; Firu, E.; Kornegrutsa, N. K.; Haiduc, M.; Mamatkulov, K. Z.; Kattabekov, R. R.; Neagu, A.; Rukoyatkin, P. A.; Rusakova, V. V.; Stanoeva, R.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.
2016-02-01
Progress in the study of nuclear clustering in the relativistic 10B and 11C nuclei dissociation in nuclear track emulsion is presented. The contribution of the unbound 8Be and 9B nuclei to their structure is determined on the basis of measurements of the emission angles of relativistic He and H fragments.
8Be and 9B nuclei in dissociation of relativistic 10C and 11C nuclei
NASA Astrophysics Data System (ADS)
Artemenkov, D. A.; Bradnova, V.; Firu, E.; Kornegrutsa, N. K.; Haiduc, M.; Mamatkulov, K. Z.; Kattabekov, R. R.; Neagu, A.; Rukoyatkin, P. A.; Rusakova, V. V.; Stanoeva, R.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.
2016-05-01
Progress in the study of nuclear clustering in the relativistic 10C and 11C nuclei dissociation in nuclear track emulsion is presented. The contribution of the unbound 8Be and 9B nuclei to their structure is determined on the basis of measurements of the emission angles of relativistic He and H fragments.
Dominance of Low Spin and High Deformation in Ab Initio Approaches to the Structure of Light Nuclei
Dytrych, T.; Draayer, J. P.; Sviratcheva, K. D.; Bahri, C.; Vary, J. P.
2009-08-26
Ab initio no-core shell-model solutions for the structure of light nuclei are shown to be dominated by low-spin and high-deformation configurations. This implies that only a small fraction of the full model space is important for a description of bound-state properties of light nuclei. It further points to the fact that the coupling scheme of choice for carrying out calculations for light nuclear systems is an algebraic-based, no-core shell-model scheme that builds upon an LS coupling [SO(3) x SU(2)] foundation with the spatial part of the model space further organized into its symplectic [SO(3) subset of SU(3) subset of Sp(3, R)] structure. Results for {sup 12}C and {sup 16}O are presented with the cluster nature of the excited 0{sup +} states in {sup 16}O analyzed within this framework. The results of the analysis encourages the development of a no-core shell model code that takes advantage of algebraic methods as well as modern computational techniques. Indeed, although it is often a very challenging task to cast complex algebraic constructs into simple logical ones that execute efficiently on modern computational systems, the construction of such a next-generation code is currently underway.
Symmetry-Adapted No-Core Shell Model for Light Nuclei
NASA Astrophysics Data System (ADS)
Launey, K. D.; Dytrych, T.; Draayer, J. P.; Tobin, G. K.; Ferriss, M. C.; Langr, D.; Dreyfuss, A. C.; Maris, P.; Vary, J. P.; Bahri, C.
2014-09-01
We present results for p-shell nuclei based on the ab initio symmetry-adapted no-core shell model that utilizes an SU(3) coupling scheme. Details given for 12C are reflective of similar results found for 6Li, 8B, 8Be, and 16O, all of which exhibit a strong preference for large quadrupole deformations and a narrow set of intrinsic spin values. The outcome suggests that a small subspace of symmetry-adapted configurations can very closely approximate the exact solutions. The symmetry patterns unveiled in these results are, in turn, employed to explore ultra-large model spaces for 12C, in particular to study the elusive Hoyle state, as well as for 8Be and sd-shell nuclei including Ne and Mg.
NASA Astrophysics Data System (ADS)
Caprio, Mark A.; Maris, Pieter; Vary, James P.
2014-03-01
The emergence of rotational bands has recently been observed in no-core configuration interaction (NCCI) calculations for p-shell nuclei, as evidenced by rotational patterns for excitation energies, electromagnetic moments, and electromagnetic transitions. Yrast and low-lying excited bands are found. The results demonstrate the possibility of well-developed rotational structure in NCCI calculations, using realistic nucleon-nucleon interactions, and within finite, computationally-accessible configuration spaces. This talk will focus on results for rotation in both the even-mass and odd-mass Be isotopes (7 <= A <= 12). Supported by US DOE (DE-FG02-95ER-40934, DESC0008485 SciDAC/NUCLEI, DE-FG02-87ER40371), US NSF (0904782), and Research Corporation for Science Advancement (Cottrell Scholar Award). Computational resources provided by NERSC (US DOE DE-AC02-05CH11231).
Stark, Julian; Rothe, Thomas; Kieß, Steffen; Simon, Sven; Kienle, Alwin
2016-04-01
Single cell nuclei were investigated using two-dimensional angularly and spectrally resolved scattering microscopy. We show that even for a qualitative comparison of experimental and theoretical data, the standard Mie model of a homogeneous sphere proves to be insufficient. Hence, an accelerated finite-difference time-domain method using a graphics processor unit and domain decomposition was implemented to analyze the experimental scattering patterns. The measured cell nuclei were modeled as single spheres with randomly distributed spherical inclusions of different size and refractive index representing the nucleoli and clumps of chromatin. Taking into account the nuclear heterogeneity of a large number of inclusions yields a qualitative agreement between experimental and theoretical spectra and illustrates the impact of the nuclear micro- and nanostructure on the scattering patterns. PMID:26976736
Losa, C.; Doessing, T.; Pastore, A.; Vigezzi, E.; Broglia, R. A.
2010-06-15
We present a calculation of the properties of vibrational states in deformed, axially-symmetric even-even nuclei, within the framework of a fully self-consistent quasiparticle random phase approximation (QRPA). The same Skyrme energy density and density-dependent pairing functionals are used to calculate the mean field and the residual interaction in the particle-hole and particle-particle channels. We have tested our software in the case of spherical nuclei against fully self-consistent calculations published in the literature, finding excellent agreement. We investigate the consequences of neglecting the spin-orbit and Coulomb residual interactions in QRPA. Furthermore we discuss the improvement obtained in the QRPA result associated with the removal of spurious modes. Isoscalar and isovector responses in the deformed {sup 24-26}Mg, {sup 34}Mg isotopes are presented and compared to experimental findings.
NASA Astrophysics Data System (ADS)
Stark, Julian; Rothe, Thomas; Kieß, Steffen; Simon, Sven; Kienle, Alwin
2016-04-01
Single cell nuclei were investigated using two-dimensional angularly and spectrally resolved scattering microscopy. We show that even for a qualitative comparison of experimental and theoretical data, the standard Mie model of a homogeneous sphere proves to be insufficient. Hence, an accelerated finite-difference time-domain method using a graphics processor unit and domain decomposition was implemented to analyze the experimental scattering patterns. The measured cell nuclei were modeled as single spheres with randomly distributed spherical inclusions of different size and refractive index representing the nucleoli and clumps of chromatin. Taking into account the nuclear heterogeneity of a large number of inclusions yields a qualitative agreement between experimental and theoretical spectra and illustrates the impact of the nuclear micro- and nanostructure on the scattering patterns.
Geometrical symmetries of nuclear systems: {{ D }}_{3h} and {{ T }}_{d} symmetries in light nuclei
NASA Astrophysics Data System (ADS)
Bijker, Roelof
2016-07-01
The role of discrete (or point-group) symmetries in α-cluster nuclei is discussed in the framework of the algebraic cluster model which describes the relative motion of the α-particles. Particular attention is paid to the discrete symmetry of the geometric arrangement of the α-particles, and the consequences for the structure of the corresponding rotational bands. The method is applied to study cluster states in the nuclei 12C and 16O. The observed level sequences can be understood in a simple way as a consequence of the underlying discrete symmetry that characterizes the geometrical configuration of the α-particles, i.e. an equilateral triangle with {{ D }}3h symmetry for 12C, and a tetrahedron with {{ T }}d symmetry for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of α-particles.
Lister, C.J.; McCutchan, E.A.
2014-06-15
A new generation of ab-initio calculations, based on realistic two- and three-body forces, is having a profound impact on our view of how nuclei work. To improve the numerical methods, and the parameterization of 3-body forces, new precise data are needed. Electromagnetic transitions are very sensitive to the dynamics which drive mixing between configurations. We have made a series of precise (< 3%) measurements of electromagnetic transitions in the A=10 nuclei {sup 10}C and {sup 10}Be by using the Doppler Shift Attenuation method carefully. Many interesting features can be reproduced including the strong α clustering. New measurements on {sup 8}Be and {sup 12}Be highlight the interplay between the alpha clusters and their valence neutrons.
{alpha}-cluster structure and exotic states in a self-consistent model for light nuclei
Maruhn, J. A.; Kimura, Masaaki; Schramm, S.; Reinhard, P.-G.; Horiuchi, H.; Tohsaki, A.
2006-10-15
In this article we examine to what extent traces of {alpha} clustering can be found in mean-field ground states of n{alpha} nuclei from {sup 8}Be through {sup 36}Ar as well as in some superdeformed states in {sup 32}S, {sup 36}Ar, and {sup 40}Ca. For this purpose we calculate the overlap of the mean-field Slater determinant with one containing pure Gaussians and perfect spin and isospin symmetry, optimizing the overlap by varying the {alpha}-particle positions and radii. In some cases a coherent sum over different configurations is also employed. We find quite large overlaps for some of the lighter systems that diminish for nuclei above {sup 20}Ne but again strong clustering in {sup 36}Ar.
Exploring Light Neutron Rich Nuclei via the ({sup 7}Li,{sup 7}Be) Reaction
Cavallaro, M.; Cappuzzello, F.; Cunsolo, A.; Foti, A.; Orrigo, S. E. A.; Rodrigues, M. R. D.; Borello-Lewin, T.; Lenske, H.; Petrascu, H.; Winfield, J. S.
2008-11-11
A systematic study of the nuclei that can be described as an integer number of {alpha} particles plus three neutrons via the ({sup 7}Li,{sup 7}Be) reaction at about 8 MeV/u has shown the presence of Bound States Embedded in the Continuum in the energy spectra. These are experimental signatures of the dynamical correlations of an easily polarizable core with a single-particle state of the valence neutron.
Normal hyperbolicity and unbounded critical manifolds
NASA Astrophysics Data System (ADS)
Kuehn, Christian
2014-06-01
This work is motivated by mathematical questions arising in differential equation models for autocatalytic reactions. We extend the local theory of singularities in fast-slow polynomial vector fields to classes of unbounded manifolds which lose normal hyperbolicity due to an alignment of the tangent and normal bundles. A projective transformation is used to localize the unbounded problem. Then the blow-up method is employed to characterize the loss of normal hyperbolicity for the transformed slow manifolds. Our analysis yields a rigorous scaling law for all unbounded manifolds which exhibit a power-law decay for the alignment with a fast subsystem domain. Furthermore, the proof also provides a technical extension of the blow-up method itself by augmenting the analysis with an optimality criterion for the blow-up exponents.
Unbounded Violation of Quantum Steering Inequalities
NASA Astrophysics Data System (ADS)
Marciniak, M.; Rutkowski, A.; Yin, Z.; Horodecki, M.; Horodecki, R.
2015-10-01
We construct steering inequalities that exhibit unbounded violation. The concept was to exploit the relationship between steering violation and the uncertainty relation. To this end, we apply mutually unbiased bases and anticommuting observables, known to exhibit the strongest uncertainty. In both cases, we are able to procure unbounded violations. Our approach is much more constructive and transparent than the operator space theory approach employed to obtain large violation of Bell inequalities. Importantly, using anticommuting observables we are able to obtain a dichotomic steering inequality with unbounded violation. Thus far, there is no analogous result for Bell inequalities. Interestingly, both the dichotomic inequality and one of our inequalities cannot be directly obtained from existing uncertainty relations, which strongly suggest the existence of an unknown kind of uncertainty relation.
No-Core Shell Model Calculations in Light Nuclei with Three-Nucleon Forces
Barrett, B R; Vary, J P; Nogga, A; Navratil, P; Ormand, W E
2004-01-08
The ab initio No-Core Shell Model (NCSM) has recently been expanded to include nucleon-nucleon (NN) and three-nucleon (3N) interactions at the three-body cluster level. Here it is used to predict binding energies and spectra of p-shell nuclei based on realistic NN and 3N interactions. It is shown that 3N force (3NF) properties can be studied in these nuclear systems. First results show that interactions based on chiral perturbation theory lead to a realistic description of {sup 6}Li.
Generalized Categorial Grammar for Unbounded Dependencies Recovery
ERIC Educational Resources Information Center
Nguyen, Luan Viet
2014-01-01
Accurate recovery of predicate-argument dependencies is vital for interpretation tasks like information extraction and question answering, and unbounded dependencies may account for a significant portion of the dependencies in any given text. This thesis describes a Generalized Categorial Grammar (GCG) which, like other categorial grammars,…
Evidence for Symplectic Symmetry in Ab Initio No-Core Shell Model Results for Light Nuclei
Dytrych, Tomas; Sviratcheva, Kristina D.; Bahri, Chairul; Draayer, Jerry P.; Vary, James P.; /Iowa State U. /LLNL, Livermore /SLAC
2007-04-24
Clear evidence for symplectic symmetry in low-lying states of {sup 12}C and {sup 16}O is reported. Eigenstates of {sup 12}C and {sup 16}O, determined within the framework of the no-core shell model using the JISP16 NN realistic interaction, typically project at the 85-90% level onto a few of the most deformed symplectic basis states that span only a small fraction of the full model space. The results are nearly independent of whether the bare or renormalized effective interactions are used in the analysis. The outcome confirms Elliott's SU(3) model which underpins the symplectic scheme, and above all, points to the relevance of a symplectic no-core shell model that can reproduce experimental B(E2) values without effective charges as well as deformed spatial modes associated with clustering phenomena in nuclei.
Structure of light neutron-rich nuclei and mechanism of elastic proton scattering
Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.
2011-11-15
Differential cross sections for elastic p{sup 6}He, p{sup 8}Li, and p{sup 9}Li scattering at two energies of 70 and 700 MeV per nucleon were calculated within the Glauber theory of multiple diffractive scattering. Threeparticle wave functions ({alpha}-n-n for {sup 6}He, {alpha}-t-n for {sup 8}Li, and {sup 7}Li-n-n for {sup 9}Li) were used for realistic potentials of intercluster interactions. The sensitivity of elastic scattering to proton-nucleus interaction and to the structure of nuclei was explored. In particular, the dependence of the differential cross section on the contribution of higher order collisions, on scattering on the core and peripheral nucleons, and on the contribution of small wave-function components and their asymptotic behavior was determined. A comparison with available experimental data and with the results of calculations within different formalisms was performed.
A statistical model for simulating the emission of light particles from excited nuclei
NASA Astrophysics Data System (ADS)
Sannikov, A. V.; Savitskaya, E. N.
2016-05-01
The algorithms and basic equations of a novel evaporation model that have been implemented in the program package EVAP15 are detailed. The level density of an excited nucleus is described by the composite Gilbert-Cameron formula with parameter values as suggested by the IAEA working group RIPL-3. Special attention is paid to the cross sections of inverse reactions and, in particular, to those for the interactions of low-energy neutrons with nuclei and for crossing of the Coulomb barrier by low-energy charged particles. The model predictions are compared with a large volume of experimental data on the spectra of particles emitted in the reactions ( n, xn), ( n, xp), and ( n, xα) induced by neutrons with energy near 14 MeV and on the four spectra for the reaction ( p, xp) induced by 62-MeV protons.
Optical Spectroscopy of Unbound Asteroid Pairs
NASA Astrophysics Data System (ADS)
Duddy, Samuel; Lowry, S. C.; Christou, A.; Wolters, S. D.; Snodgrass, C.; Fitzsimmons, A.; Deller, J. F.; Hainaut, O. R.; Rozitis, B.; Weissman, P. R.; Green, S. F.
2012-10-01
The recently discovered unbound asteroid pairs have been suggested to be the result of the decoupling of binary asteroids formed either through collision processes or, more likely, rotational fission of a rubble-pile asteroid after spin-up (Vokrouhlicky et al. 2008, AJ 136, 280; Pravec et al., 2010, Nature, 466, 1085). Much of the evidence for linkage of the asteroids in each pair relies solely on the backwards integrations of their orbits. We report new results from our continuing spectroscopic survey of the unbound asteroid pairs, including the youngest known pair, (6070) Rhineland - (54827) 2001 NQ8. The survey goal is to determine whether the asteroids in each unbound pair have similar spectra and therefore composition, expected if they have formed from a common parent body. Low-resolution spectroscopy covering the range 0.4-0.95 microns was conducted using the 3.6m ESO NTT+EFOSC2 during 2011-2012 and the 4.2m WHT+ACAM. We have attempted to maintain a high level of consistency between the observations of the components in each pair to ensure that differences in the asteroid spectra are not the result of the observing method or data reduction, but purely caused by compositional differences. Our WHT data indicates that the asteroids of unbound pair 17198 - 229056 exhibit different spectra and have been assigned different taxonomies, A and R respectively. Initial analysis of our data from the NTT suggests that the asteroids in unbound pairs 6070 - 54827 and 38707 - 32957 are likely silicate-dominated asteroids. The components of pair 23998 - 205383 are potentially X-type asteroids. We present final taxonomic classifications and the likelihood of spectral similarity in each pair.
NASA Astrophysics Data System (ADS)
Seabury, E. H.; Blackburn, B. W.; Chichester, D. L.; Wharton, C. J.; Caffrey, A. J.
2007-08-01
Prompt Gamma Ray Neutron activation analysis can offer significant cost and safety advantages in the identification of explosives and toxic chemicals. As an example, the US military examined over a thousand suspect chemical munitions with Idaho National Laboratory's PINS Chemical Assay System last year. PGNAA requires, of course, a neutron source to excite the atomic nuclei of the item under test via neutron capture and inelastic neutron scattering reactions and the choice of neutron source can drastically affect PGNAA system performance. We have carried out Monte Carlo and laboratory experiments comparing DD, DT and Cf-252 neutrons incident on light and medium mass chemical elements, toward optimizing the design of future neutron-generator-based PGNAA systems for field use. We report the excitation of (n, γ) and (n, n‧) gamma rays from these elements by each type of neutron source.
Maj, A.; Kmiecik, M.; Brekiesz, M.; Grebosz, J.; Meczynski, W.; Styczen, J.; Zieblinski, M.; Zuber, K.; Bracco, A.; Camera, F.; Benzoni, G.; Million, B.; Blasi, N.; Brambilla, S.; Leoni, S.; Pignanelli, M.; Wieland, O.; Airoldi, A.; Herskind, B.; Bednarczyk, P.
2004-02-27
The high-energy and discrete {gamma}-ray spectra, as well as the charged particle angular distribution have been measured in the reaction 105 MeV 18O+28Si using the EUROBALL IV, HECTOR and EUCLIDES arrays in order to investigate the predicted Jacobi shape transition in light nuclei. A comparison of the GDR line shape data with the predictions of the thermal shape fluctuation model, based on the most recent rotating liquid drop LSD calculations, shows evidence for such Jacobi shape transition in hot, rapidly rotating 46Ti. The found narrow low-energy component in the GDR line shape is interpreted as the consequence both of the elongated shape and of the Coriolis effect.
Direct Reactions with Exotic Nuclei
Baur, G.; Typel, S.
2005-10-14
We discuss recent work on Coulomb dissociation and an effective-range theory of low-lying electromagnetic strength of halo nuclei. We propose to study Coulomb dissociation of a halo nucleus bound by a zero-range potential as a homework problem. We study the transition from stripping to bound and unbound states and point out in this context that the Trojan-Horse method is a suitable tool to investigate subthreshold resonances.
Expected impact from weak reactions with light nuclei in corecollapse supernova simulations
NASA Astrophysics Data System (ADS)
Fischer, T.; Martínez-Pinedo, G.; Hempel, M.; Huther, L.; Röpke, G.; Typel, S.; Lohs, A.
2016-02-01
We study the role of light nuclear clusters in simulations of core-collapse supernovae. Expressions for the reaction rates are developed for a large selection of charged current absorption and scattering processes with light clusters. Medium modifications are taken into account at the mean-field level. We explore the possible impact on the supernova dynamics and the neutrino signal during the mass accretion phase prior to the possible explosion onset as well as during the subsequent protoneutron star deleptnoization after the explosion onset has been launched.
Investigation of the low energy kaons hadronic interactions in light nuclei by AMADEUS
NASA Astrophysics Data System (ADS)
Piscicchia, K.; Bazzi, M.; Berucci, C.; Bosnar, D.; Bragadireanu, A. M.; Cargnelli, M.; Clozza, A.; D'Uffizi, A.; Fabietti, L.; Fiorini, C.; Ghio, F.; Guaraldo, C.; Iliescu, M.; Ishiwatari, T.; Levi Sandri, P.; Marton, J.; Pietreanu, D.; Poli Lener, M.; Quaglia, R.; Sbardella, E.; Scordo, A.; Shi, H.; Sirghi, D. L.; Sirghi, F.; Tatsuno, H.; Tucaković, I.; Vazquez Doce, O.; Widmann, E.; Zmeskal, J.
2014-11-01
The AMADEUS experiment has the aim to perform studies of the low energy hadronic interactions of negatively charged kaons with nucleons and nuclei, which are fundamental to solve longstanding open questions in the non-perturbative QCD in the strangeness sector. The DAΦNE collider provides a unique source of monochromatic low-momentum kaons, whose nuclear interaction with the materials of the KLOE detector (used as an active target) provide us excellent acceptance and resolution data for K- capture on H, 4He, 9Be and 12C, both at-rest and in-flight. AMADEUS step 0 consisted in the analysis of the 2004-2005 KLOE data. A second step consisted in the implementation in the central region of the KLOE detector of a pure graphite target, providing a high statistic sample of K- 12C nuclear captures at rest. For the future, new setups for various dedicated targets are under preparation. The aim of such investigations is to face the major open questions in hadron nuclear physics in the strangeness sector, such as the nature of the Λ(1405) state and the resonant versus non-resonant yield in nuclear K- capture, the possible existence of kaonic nuclear clusters, strongly related to a quantitative understanding of single versus multi-nucleon K- absorption.
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.
Inclusive Pion Double Charge Exchange in Light P - Nuclei at Intermediate Energies.
NASA Astrophysics Data System (ADS)
Fong, Wilson
Inclusive measurements of the doubly differential cross section for the reaction pion double charge exchange (DCX) reaction were made on ^6Li, ^7Li, ^9Be and ^{12}C. The experiments were performed at the Los Alamos Physics Facility (LAMPF) using the "Little Yellow Spectrometer", LYS. The measurements were made for both pi^+ and pi^- at T_ pi = 120, 180, and 240 MeV for three to five angles between 25^circ and 130^circ. The outgoing pion kinetic energy range was observed. These are the only known measurements of inclusive DCX cross sections on the ^6Li, ^7Li and ^9Be nuclei. The DCX reaction requires at least two nucleons to be involved in order to conserve charge. The simplest reaction model for DCX is the sequential single charge exchange model, SSCX. The measurements aimed to examine the evolution of the double peaked structure seen at high incident pion energy at forward angles as the nuclear mass, A, increases. The double peaked structure is believed to be a direct consequence of the dominant p-wave nature of the SCX reaction in the Delta -region and the two step process of SSCX. Furthermore, an examination of the effects of introducing an additional neutron into an N = Z system is made. When the additional neutron is not involved in the DCX process, it functions to draw flux away from the DCX channel, thereby reducing the DCX cross section. Calculations based on theoretical models of Oset and Kinney have been performed and a comparison made with the measured DCX cross sections. The comparison between experiment and theory shows the need for further theoretical work in inclusive DCX reactions. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617 -253-5668; Fax 617-253-1690.).
Arens, T L; Pollack, G M
2001-09-01
Circadian variations in disposition have been observed for a variety of agents, including anticonvulsants. Valproic acid (VPA), an anticonvulsant used to control generalized and partial seizures, has exhibited diurnal oscillations in steady-state concentrations during long-term administration to humans and non-human primates. The present study was conducted to assess potential diurnal changes in the disposition of VPA during prolonged i.v. infusion in rats. Animals, maintained on a strict 12-h per day light cycle, were equipped with venous cannulae and an arterial microdialysis probe. VPA was administered as a 50-mg/kg loading dose followed by a 42 mg/kg/h infusion for 70 h. Blood and microdialysate samples were obtained at timed intervals after establishment of steady-state throughout two complete light/dark cycles; and total (serum) and unbound (microdialysate) VPA was determined by gas chromatography. Modest oscillations (6-7 h period) in total and unbound VPA were observed; clearance and binding parameters were not different between light and dark periods. However, unbound clearance increased, and unbound fraction decreased, with time over the course of the infusion. These results suggest that time-dependent changes in VPA disposition occur in rats, although oscillations in steady-state concentrations do not appear to be diurnal in nature. PMID:11754040
Hypertriton and light nuclei production at Λ-production subthreshold energy in heavy-ion collisions
NASA Astrophysics Data System (ADS)
Zhang, Song; Chen, Jin-Hui; Ma, Yu-Gang; Xu, Zhang-Bu; Cai, Xiang-Zhou; Ma, Guo-Liang; Zhong, Chen
2011-08-01
High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coalescence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron (d), triton (t), helion (3He), and hypertriton (3ΛH) at subthreshold energy of Aproduction (≈ 1 GeV per nucleon). We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few μb in 36Ar+36Ar, 40Ca+40Ca and 56Ni+56Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR (Lanzhou/China) at Λ subthreshold energy are suitable for breaking new ground in hypernuclear physics.
Zhang, S.; Zu, Z.; Chen, J.H., Ma, Y.G., Cai, X-Z, Ma, G.L., Zhong, C.
2011-08-01
High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coalescence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron (d), triton (t), helion ({sup 3}He), and hypertriton ({sub {Lambda}}{sup 3}H) at subthreshold energy of Aproduction ({approx} 1 GeV per nucleon). We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor (S{sub 3} = {sup 3}{sub {Lambda}}H/({sup 3}He x {Lambda}/p)) shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few {mu}b in {sup 36}Ar+{sup 36}Ar, {sup 40}Ca+{sup 40}Ca and {sup 56}Ni+{sup 56}Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR (Lanzhou/China) at {Lambda} subthreshold energy are suitable for breaking new ground in hypernuclear physics.
Measurement of light charged particles in the decay channels of medium-mass excited compound nuclei
NASA Astrophysics Data System (ADS)
Valdré, S.; Barlini, S.; Casini, G.; Pasquali, G.; Piantelli, S.; Carboni, S.; Cinausero, M.; Gramegna, F.; Marchi, T.; Baiocco, G.; Bardelli, L.; Benzoni, G.; Bini, M.; Blasi, N.; Bracco, A.; Brambilla, S.; Bruno, M.; Camera, F.; Corsi, A.; Crespi, F.; D'Agostino, M.; Degerlier, M.; Kravchuk, V. L.; Leoni, S.; Million, B.; Montanari, D.; Morelli, L.; Nannini, A.; Nicolini, R.; Poggi, G.; Vannini, G.; Wieland, O.; Bednarczyk, P.; Ciemała, M.; Dudek, J.; Fornal, B.; Kmiecik, M.; Maj, A.; Matejska-Minda, M.; Mazurek, K.; Męczyński, W. M.; Myalski, S.; Styczeń, J.; Ziębliński, M.
2014-03-01
The 48Ti on 40Ca reactions have been studied at 300 and 600 MeV focusing on the fusion-evaporation (FE) and fusion-fission (FF) exit channels. Energy spectra and multiplicities of the emitted light charged particles have been compared to Monte Carlo simulations based on the statistical model. Indeed, in this mass region (A ~ 100) models predict that shape transitions can occur at high spin values and relatively scarce data exist in the literature about coincidence measurements between evaporation residues and light charged particles. Signals of shape transitions can be found in the variations of the lineshape of high energy gamma rays emitted from the de-excitation of GDR states gated on different region of angular momenta. For this purpose it is important to keep under control the FE and FF processes, to regulate the statistical model parameters and to control the onset of possible pre-equilibrium emissions from 300 to 600 MeV bombarding energy.
Halo Nuclei: Stepping Stones Across the Dripline
NASA Astrophysics Data System (ADS)
Simon, Haik
2013-08-01
The availability of intense secondary beams in conjunction with efficient detection setups allows for a production and study of the most extreme nuclear systems, in terms of asymmetry of proton and neutron number, in the continuum. They can be produced via transfer and knockout reactions, depending on beam energies, with beams of nuclei close to the driplines, exhibiting exotic properties themselves, as seeds. These nuclear open quantum systems far from the valley of beta stability challenge nuclear structure theory being as well as reaction theory that tries to describe their production mechanisms. Due to their strong clustering they exhibit a rather clean few-body character. From experiments momentum distributions, relative energy spectra, and spin alignment during the reaction can be determined, which leads to the observation of energy and angular correlations as well as dependent quantities like e.g. the profile function denoting a momentum width in dependence of relative energy. They are determined from momentum vectors of fragments and gamma radiation leaving the reaction zone. The link to intrinsic properties of these unbound systems has to be explored by gathering precise knowledge of the properties of the seed nuclei and compare them to the structures observed in the continuum. In this paper I will exemplify the above-mentioned methods, and apply them particularly to light systems like 10He, 10-13Li, and neutron-rich Beryllium systems. Furthermore, perspectives for the 7H and heavy Oxygen systems are discussed.
Experimental Studies of the Mechanism of Photon Absorption on Light Nuclei
Steven Morrow
2000-09-13
time a comparison between the {sup 12}C({gamma},p) reaction and the transverse part of {sup 12}C(e,e{prime}p) reaction cross section has been made. This comparison suggests that the mechanism of the 2 reactions converge when both are studied in equivalent kinematics resolving the long standing issue of anomalous excitation of the {approx} 7 MeV triplet in {sup 11}B, following {sup 12}C({gamma},p), not seen in the {sup 12}C(e,e{prime}p) case. In a further use of the ({gamma},p{gamma}{prime}) reaction the relative population of the 4.44 MeV (T = 0) and 15.1 MeV (T = 1) states in {sup 12}C, following {sup 14}N({gamma},pn), have been measured with tagged photons in the range 50.20 < E{sub {gamma}} < 71.40 MeV. A strong suppression for population of the T = 1 state in the residual nucleus as compared to the T = 0 state was observed. This is consistent with the picture of photon absorption on T = 0 ({sup 3}S{sub 1}) p-n pairs in nuclei. A measurement of the {sup 14}N({gamma},d) reaction has also been made in which the converse population of states in {sup 12}C was observed.
Two-proton decay from Isobaric Analog States of light nuclei
NASA Astrophysics Data System (ADS)
Brown, Kyle
2014-03-01
Recent experiments at the National Superconducting Cyclotron Laboratory at Michigan State University using the charged-particle array HiRA and the gamma-ray array CAESAR have shed light on a new class of two-proton emitters associated with Isobaric Analog States (IAS). The two-proton decay is to the Isobaric Analog state of the daughter, which then gamma decays. These isospin-allowed transitions occur when one-proton decays are forbidden by either energy or isospin conservation, and when two-proton decay to the ground state is isospin forbidden. Three possible examples of this decay path will be discussed (8BIAS, 12NIAS, and 16FIAS) . The known IAS of 8C in 8B was confirmed to decay by two-proton emission to the 3.56 MeV IAS in 6Li. While the IAS in 8B was previously known, it was measured in this experiment with unbiased statistics and in coincidence with the 3.56 MeV gamma-ray. The IAS in 16F was investigated for the first time in this experiment and is still under investigation. Previous work on the IAS of 12O in 12N at the Cyclotron Institute at Texas A&M will also be presented.
Simulation of a Novel Active Target for Neutron-Unbound State Measurements
NASA Astrophysics Data System (ADS)
Frank, Nathan; MoNA Collaboration
2013-10-01
Measurement of nuclei at extreme ratios of protons to neutrons is challenging due to the low production rate. New facilities will increase the production of neutron-rich isotopes, but still not reach the neutron dripline for heavier nuclei. We simulated a carbon-based active target system that could be constructed to both increase statistics while preserving the experimental resolution. This simulation is an adaptation of the in-house MoNA Collaboration C + + based simulation tool to extract the decay energy of neutron-unbound states. A number of experiments of this type have been carried out at the National Superconducting Cyclotron Laboratory (NSCL). In most experiments, we produce neutron-unbound nuclei by bombarding a Beryllium target with a radioactive beam. The nucleus of interest immediately decays into a charged particle and one or more neutrons. In this simulation, we have constructed a carbon-based active target that provides a measurement of energy loss, which is used to calculate the nuclear interaction point within the target. This additional information is used to improve the resolution or preserve the resolution of a thinner target while increasing statistics. This presentation will cover some aspects of the simulation process as well as show a resolution improvement of up to about 4 with a ~700 mg/cm2 active target compared to a Be-target. The simulation utilized experimental settings from published work. Work supported by National Science Foundation Grant #0969173.
NASA Astrophysics Data System (ADS)
Mukhamedzhanov, A.; Johnson, R. C.; Timofeyuk, N. K.
2004-05-01
The astrophysical S-factor associated with the peripheral proton capture reaction B(p,γ)A at stellar energies is related to the Asymptotic Normalization Coefficient (ANC) of the virtual decay A arrow B + p. The same ANCs play a crucial role in other peripheral processes such as transfer reactions whose cross sections are significantly higher and therefore more easily measurable than those of the direct capture processes at astrophysically relevant energies. The study of ANCs of astrophysical interest is a new and rapidly developing direction in modern experimental nuclear physics. However, in order to exploit these ideas to determine the ANCs for light proton-rich nuclei of importance to nuclear astrophysics the corresponding transfer reactions often require the use of weak radioactive beams, which generally involves more difficult and less accurate experiments than are possible with stable beams. In this talk we point out that the ANC of the virtual neutron decay of the nucleus mirror to A, which may be susceptible to study with stable beams, is related in a model independent way by the charge symmetry of nuclear forces to the ANC of the corresponding proton decay of A. Near the edge of stability, where neutron separation energies become very small, the corresponding mirror proton states manifest themselves as resonances.
Quantum duality, unbounded operators, and inductive limits
Dosi, Anar
2010-06-15
In this paper, we investigate the inductive limits of quantum normed (or operator) spaces. This construction allows us to treat the space of all noncommutative continuous functions over a quantum domain as a quantum (or local operator) space of all matrix continuous linear operators equipped with S-quantum topology. In particular, we classify all quantizations of the polynormed topologies compatible with the given duality proposing a noncommutative Arens-Mackey theorem. Further, the inductive limits of operator spaces are used to introduce locally compact and locally trace class unbounded operators on a quantum domain and prove the dual realization theorem for an abstract quantum space.
Excited states in the proton-unbound nuclide 158Ta
NASA Astrophysics Data System (ADS)
Carroll, R. J.; Page, R. D.; Joss, D. T.; O'Donnell, D.; Uusitalo, J.; Darby, I. G.; Andgren, K.; Auranen, K.; Bönig, S.; Cederwall, B.; Doncel, M.; Drummond, M. C.; Eeckhaudt, S.; Grahn, T.; Gray-Jones, C.; Greenlees, P. T.; Hadinia, B.; HerzáÅ, A.; Jakobsson, U.; Jones, P. M.; Julin, R.; Juutinen, S.; Konki, J.; Kröll, T.; Leino, M.; Leppänen, A.-P.; McPeake, C.; Nyman, M.; Pakarinen, J.; Partanen, J.; Peura, P.; Rahkila, P.; Revill, J.; Ruotsalainen, P.; Sandzelius, M.; Sarén, J.; Sayǧi, B.; Scholey, C.; Seweryniak, D.; Simpson, J.; Sorri, J.; Stolze, S.; Taylor, M. J.; Thornthwaite, A.
2016-03-01
Excited states in the neutron-deficient odd-odd proton-unbound nuclide 158Ta have been investigated in two separate experiments. In the first experiment, 166Ir nuclei were produced in the reactions of 380 MeV 78Kr ions with an isotopically enriched 92Mo target. The α -decay chain of the 9+ state in 166Ir was analyzed. Fine structure in the α decay of the 9+ state in 162Re established a 66 keV difference in excitation energy between the lowest-lying 9+ and 10+ states in 158Ta. Higher-lying states in 158Ta were populated in the reactions of 255 MeV 58Ni ions with an isotopically enriched 102Pd target. Gamma-ray decay paths that populate, depopulate, and bypass a 19- isomeric state have been identified. The general features of the deduced level scheme are discussed and the prospects for observing proton emission branches from excited states are considered.
THE 1.6 {mu}m NEAR-INFRARED NUCLEI OF 3C RADIO GALAXIES: JETS, THERMAL EMISSION, OR SCATTERED LIGHT?
Baldi, Ranieri D.; Chiaberge, Marco; Sparks, William; Macchetto, F. Duccio; Capetti, Alessandro; O'Dea, Christopher P.; Axon, David J.; Baum, Stefi A.; Quillen, Alice C.
2010-12-20
Using HST NICMOS 2 observations we have measured 1.6 {mu}m near-infrared nuclear luminosities of 100 3CR radio galaxies with z < 0.3, by modeling and subtracting the extended emission from the host galaxy. We performed a multiwavelength statistical analysis (including optical and radio data) of the properties of the nuclei following classification of the objects into FR I and FR II, and low-ionization galaxies (LIGs), high-ionization galaxies (HIGs), and broad-line objects (BLOs) using the radio morphology and optical spectra, respectively. The correlations among near-infrared, optical, and radio nuclear luminosity support the idea that the near-infrared nuclear emission of FR Is has a non-thermal origin. Despite the difference in radio morphology, the multiwavelength properties of FR II LIG nuclei are statistically indistinguishable from those of FR Is, an indication of a common structure of the central engine. All BLOs show an unresolved near-infrared nucleus and a large near-infrared excess with respect to FR II LIGs and FR Is of equal radio core luminosity. This requires the presence of an additional (and dominant) component other than the non-thermal light. Considering the shape of their spectral energy distribution, we ascribe the origin of their near-infrared light to hot circumnuclear dust. A near-infrared excess is also found in HIGs, but their nuclei are substantially fainter than those of BLO. This result indicates that substantial obscuration along the line of sight to the nuclei is still present at 1.6 {mu}m. Nonetheless, HIG nuclei cannot simply be explained in terms of dust obscuration: a significant contribution from light reflected in a circumnuclear scattering region is needed to account for their multiwavelength properties.
Production of Unbound Resonance in 23O
NASA Astrophysics Data System (ADS)
Brett, Jaclyn; Deyoung, Paul; Rabeh, Ali; Tuttle-Timm, Matthew; Frank, Nathan; Jones, Michael; Thoennessen, Michael; MoNA Collaboration
2015-10-01
The nuclear structure of a state in a given isotope is determined by which nucleons occupy the bound and unbound energy levels. This state determines the energy of decay, which can be calculated from the energy and momentum of the fragment and neutron. From the calculated decay energy, information about an isotope's nuclear structure can be found. At a National Superconducting Cyclotron Laboratory experiment, a 101.3 MeV/u 27Ne ion beam hit a liquid deuterium target, causing reactions which produced several isotopes. Many of these isotopes decayed, resulting in a charged fragment and one or more neutrons. A superconducting dipole magnet bent the path of the fragments into a series of charged-particle detectors. Neutrons from these decays were measured as they interacted with arrays of scintillating plastic bars. One of the isotopes produced was 22O, most likely formed in two ways in this experiment. Either α-stripping of the 27Ne beam resulted in 23O, which decayed into 22O + n or 2-proton stripping of the 27Ne beam resulted in 25O, which decayed into 22O + 3n. The cross-sections and the nature of decay for both of these processes will be determined. In addition, resonances of other unbound nuclear systems may also be included for cross-section production comparisons. This material is based upon work supported by the National Science Foundation under Grants PHY-1306074 and PHY-1404236.
Analysis of unbounded operators and random motion
Jorgensen, Palle E. T.
2009-11-15
We study infinite weighted graphs with view to 'limits at infinity' or boundaries at infinity. Examples of such weighted graphs arise in infinite (in practice, that means 'very' large) networks of resistors or in statistical mechanics models for classical or quantum systems. However, more generally, our analysis includes reproducing kernel Hilbert spaces and associated operators on them. If X is some infinite set of vertices or nodes, in applications the essential ingredient going into the definition is a reproducing kernel Hilbert space; it measures the differences of functions on X evaluated on pairs of points in X. Moreover, the Hilbert norm-squared in H(X) will represent a suitable measure of energy. Associated unbounded operators will define a notion or dissipation, it can be a graph Laplacian or a more abstract unbounded Hermitian operator defined from the reproducing kernel Hilbert space under study. We prove that there are two closed subspaces in reproducing kernel Hilbert space H(X) that measure quantitative notions of limits at infinity in X: one generalizes finite-energy harmonic functions in H(X) and the other a deficiency index of a natural operator in H(X) associated directly with the diffusion. We establish these results in the abstract, and we offer examples and applications. Our results are related to, but different from, potential theoretic notions of 'boundaries' in more standard random walk models. Comparisons are made.
Coupled-cluster computations of atomic nuclei.
Hagen, G; Papenbrock, T; Hjorth-Jensen, M; Dean, D J
2014-09-01
In the past decade, coupled-cluster theory has seen a renaissance in nuclear physics, with computations of neutron-rich and medium-mass nuclei. The method is efficient for nuclei with product-state references, and it describes many aspects of weakly bound and unbound nuclei. This report reviews the technical and conceptual developments of this method in nuclear physics, and the results of coupled-cluster calculations for nucleonic matter, and for exotic isotopes of helium, oxygen, calcium, and some of their neighbors. PMID:25222372
NASA Astrophysics Data System (ADS)
Yamagata-Sekihara, J.; Jido, D.; Nagahiro, H.; Hirenzaki, S.
2009-10-01
We study theoretically the in-flight (K-,N) reactions for the formation of light kaonic nuclear systems to get deeper physical insights on the spectra and to investigate the formation spectra of the reaction that will be observed at new facilities like the Japan Proton Accelerator Research Complex (J-PARC). We show the expected spectra for the formation of the K-pp, K-pn, K-nn, and K--B11 systems that are accessible by the (K-,N) experiments. By considering the conversion part of the Green’s function, we show the missing mass spectra of the (K-,N) reactions in coincident with the particle emissions due to K¯ absorption. To calculate the cross sections, we use the so-called Tρ approximation to evaluate the optical potential. As for the amplitude T, we adopt the chiral unitary amplitude of K¯N channel in vacuum for simplicity. The effects of the p-wave optical potential of Σ(1385) channel and the contributions from K¯0 mixing in He3(K-,n) reaction are also evaluated numerically. We also study the behavior of the poles of kaon Green’s function in nuclear matter. We conclude that He3(K-,n) and He3(K-,p) reaction spectra in coincident with the πΣ emission may show the structure in the kaon bound region indicating the existence of the unstable kaonic nuclear states. As for the C12(K-,p) spectra with the πΣ emission, we may also observe the structure in the bound region, however, we need to evaluate the medium effects carefully for larger nuclei.
NASA Astrophysics Data System (ADS)
Pereira, J.; Montes, F.
2016-03-01
Background: Neutrino-driven winds following core-collapse supernova explosions have been proposed as a possible site where light r -process nuclei (between Fe and Ag) might be synthesized. In these events, (α ,n ) reactions are key to moving matter towards the region of higher proton number. Abundance network calculations are very sensitive to the rates for this type of reactions. Purpose: The present work aims at evaluating the theoretical uncertainty of these (α ,n ) reactions calculated with reaction codes based on the Hauser-Feshbach model. Method: We compared several (α ,n ) rates taken from talys and the non-smoker database to determine the uncertainties owing to the existing technical differences between both codes. In addition, we evaluated the sensitivity of talys rates to variations in the α optical potentials, masses, level densities, optical potentials, preequilibrium intranuclear transition rates, level structure, radiative transmission coefficients, and width-fluctuation correction factors. Results: The main source of uncertainty at low temperature is mostly attributable to the use of different α optical potentials. Differences between talys and non-smoker at high temperatures arise from the energy-binning algorithm used by each code. We have also noticed that the (α ,n ) rates from the non-smoker database correspond to the inclusive reaction, instead of the exclusive (α ,1 n ) channel calculated in the present work and used in network calculations. Conclusions: Theoretical uncertainties in calculated reaction rates can be as high as one to two orders of magnitude and strongly dependent on the temperature of the environment. Besides direct measurements of the inclusive and exclusive (α ,1 n ) reaction rates, experimental studies of α optical potentials are crucial to improve the performance of reaction codes.
Abramov, B. M.; Borodin, Yu. A.; Bulychjov, S. A.; Dukhovskoy, I. A.; Krutenkova, A. P.; Kulikov, V. V. Martemianov, M. A.; Matsuk, M. A.; Tarasov, V. E.; Turdakina, E. N.; Khanov, A. I.
2007-07-15
Quasielastic deuteron and triton knockout from {sup 12}C and {sup 16}O nuclei has been studied infull kinematics using a 0.72-GeV/c pion beam. The momentum distributions of the intranuclear quasideuteron motion, excitation-energy spectra of the residual nuclei, and the effective numbers N{sub d}{sup eff} of quasideuterons are determined. The parameters of the quasideuteron intranuclear motion are in reasonable agreement with the results obtained in other beams. The N{sub d}{sup eff} in the nuclei from {sup 6}Li to {sup 16}O measured in full kinematics are virtually independent of the atomic number in contrast to the analogous values in the inclusive deuteron-knockout reaction induced by protons. The phenomenon of triton knockout from these nuclei is observed, which makes possible estimation of the cross section of backward pion-triton elastic scattering in yet unexplored regions of energy and momentum transfer.
Two-term formula for ground band energy symmetry in low-lying levels of light Mg-Zr nuclei
NASA Astrophysics Data System (ADS)
Devi, Vidya
2015-12-01
In this paper, two parameter single-term energy formula EJ = aJb is used to study the energy spin relationship within the ground bands of even-even Mg-Zr nuclei. The formula works better for the γ-soft nuclei as well as vibrational nuclei. We also compared it with other two-parameter formulas: Ejiri, ab, pq and soft rotor formula (SRF). We also study the symmetry of the nuclei in the framework of interacting boson model (IBM-1). The IBM-1 was employed to determine the most appropriate Hamiltonian, the Hamiltonian of the IBM-1 and O(6) symmetry calculation, for the study of these isotopes. We have also calculated energy levels and B(E2) values for number of transitions in these 76-78Se and 76-78Kr isotopes and there is a good agreement between the presented results and the previous experimental data.
A meshless method for unbounded acoustic problems.
Shojaei, Arman; Boroomand, Bijan; Soleimanifar, Ehsan
2016-05-01
In this paper an effective meshless method is proposed to solve time-harmonic acoustic problems defined on unbounded domains. To this end, the near field is discretized by a set of nodes and the far field effect is taken into account by considering radiative boundary conditions. The approximation within the near field is performed using a set of local residual-free basis functions defined on a series of finite clouds. For considering the far field effect, a series of infinite clouds are defined on which another set of residual-free bases, satisfying the radiation conditions, are considered for the approximation. Validation of the results is performed through solving some acoustic problems. PMID:27250155
Unbound star-forming molecular clouds
NASA Astrophysics Data System (ADS)
Ward, Rachel L.; Wadsley, James; Sills, Alison
2014-03-01
We explore whether observed molecular clouds could include a substantial population of unbound clouds. Using simulations which include only turbulence and gravity, we are able to match observed relations and naturally reproduce the observed scatter in the cloud size-linewidth coefficient, at fixed surface density. We identify the source of this scatter as a spread in the intrinsic virial parameter. Thus, these observational trends do not require that clouds exist in a state of dynamical equilibrium. We demonstrate that cloud virial parameters can be accurately determined observationally with an appropriate size estimator. All our simulated clouds eventually form collapsing cores, regardless of whether the cloud is bound overall. This supports the idea that molecular clouds do not have to be bound to form stars or to have observed properties like those of nearby low-mass clouds.
Bound and unbound nuclear systems at the drip lines: a one-dimensional model
NASA Astrophysics Data System (ADS)
Moschini, L.; Pérez-Bernal, F.; Vitturi, A.
2016-08-01
We construct a one-dimensional toy model to describe the main features of Borromean nuclei at the continuum threshold. The model consists of a core and two valence neutrons, unbound in the mean potential, that are bound by a residual point contact density-dependent interaction. Different discretization procedures are used (harmonic oscillator and transformed harmonic oscillator bases, or use of large rigid wall box). Resulting energies and wave functions, as well as inelastic transition intensities, are compared within the different discretization techniques, as well as with the exact results in the case of one particle and with the results of the di-neutron cluster model in the two particles case. Despite its simplicity, this model includes the main physical features of the structure of Borromean nuclei in an intuitive and computationally affordable framework, and will be extended to direct reaction calculations.
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.; Eum, J.; 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.; Goméz Coral, D. M.; 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.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hilden, T. E.; Hillemanns, H.; Hippolyte, B.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Khan, K. H.; Mohisin Khan, M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobayashi, T.; Kobdaj, C.; Kofarago, M.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kour, M.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, A.; Kumar, J.; Kumar, L.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; La Pointe, S. L.; La Rocca, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; León Monzón, I.; Leoncino, M.; Lévai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Loizides, C.; Lopez, X.; López Torres, E.; Lowe, A.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marín, A.; Markert, C.; Marquard, M.; Martin, N. A.; Martin Blanco, J.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martinez Pedreira, M.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Masui, H.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; McDonald, D.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Miśkowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira de Godoy, D. A.; Moreno, L. A. P.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Mulligan, J. D.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Oliveira da Silva, A. C.; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Paić, G.; Pajares, C.; Pal, S. K.; Pan, J.; Pandey, A. K.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Pereira da Costa, H.; Pereira de Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Peskov, V.; Pestov, Y.; Petráček, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Seeder, K. S.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Senosi, K.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, M.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Symons, T. J. M.; Szabo, A.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tanaka, N.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tariq, M.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; van der Maarel, J.; van Hoorne, J. W.; van Leeuwen, M.; Vanat, T.; Vande Vyvre, P.; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Villatoro Tello, A.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Weber, S. G.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yano, S.; Yasnopolskiy, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.; Alice Collaboration
2016-02-01
The production of (anti-)deuteron and (anti-)3He nuclei in Pb-Pb collisions at √{sNN}=2.76 TeV has been studied using the ALICE detector at the LHC. The spectra exhibit a significant hardening with increasing centrality. Combined blast-wave fits of several particles support the interpretation that this behavior is caused by an increase of radial flow. The integrated particle yields are discussed in the context of coalescence and thermal-statistical model expectations. The particle ratios, 3He/d and 3He/p, in Pb-Pb collisions are found to be in agreement with a common chemical freeze-out temperature of Tchem≈156 MeV. These ratios do not vary with centrality which is in agreement with the thermal-statistical model. In a coalescence approach, it excludes models in which nucleus production is proportional to the particle multiplicity and favors those in which it is proportional to the particle density instead. In addition, the observation of 31 anti-tritons in Pb-Pb collisions is reported. For comparison, the deuteron spectrum in p p collisions at √{s }=7 TeV is also presented. While the p /π ratio is similar in p p and Pb-Pb collisions, the d /p ratio in p p collisions is found to be lower by a factor of 2.2 than in Pb-Pb collisions.
Zhukotskiĭ, A V; Shchegolev, A I; Butusova, N N; Nemirovskiĭ, L E; Kogan, E M
1985-06-01
Geometric and optical parameters of chromatin of hepatocyte nuclei have been examined before (UV, lambda = 265 nm) and after gallocyanine staining. Quantitative parameters of the chromatin structure in the same nuclei measured in situ by a scanning microscope-photometer (step size 0.125 micron) before and after staining were equal. Tinctorial properties of chromatin granules (condensed part of the nuclear material) and its diffuse part were different. It is suggested that the difference between granules and the nongranular part of chromatin is not only of optical but also of chemical nature. PMID:2410060
Giacomelli, Michael G.; Chalut, Kevin J.; Ostrander, Julie H.; Wax, Adam
2010-01-01
We demonstrate an inverse light-scattering analysis procedure based on using the T-matrix method as a light-scattering model. We measure light scattered by in vitro cell monolayers using angle-resolved low-coherence interferometry (a/LCI) and compare the data to predictions of the T-matrix theory. The comparison yields measurements of the equal volume diameter and aspect ratio of the spheroid cell nuclei with accuracy comparable to quantitative image analysis of fixed and stained samples. These improvements represent a significant upgrade for the a/LCI technique, expanding both the range of tissue in which it is applicable and potentially increasing its value as a diagnostic tool. PMID:18978884
Spectral similarity of unbound asteroid pairs
NASA Astrophysics Data System (ADS)
Wolters, Stephen D.; Weissman, Paul R.; Christou, Apostolis; Duddy, Samuel R.; Lowry, Stephen C.
2014-04-01
Infrared (IR) spectroscopy between 0.8 and 2.5 μ has been obtained for both components of three unbound asteroid pairs, using the NASA Infrared Telescope Facility with the SpeX instrument. Pair primary (2110) Moore-Sitterly is classified as an S-type following the Bus-DeMeo taxonomy; the classification for secondary (44612) 1999 RP27 is ambiguous: S/Sq/Q/K/L-type. Primary (10484) Hecht and secondary (44645) 1999 RC118 are classified as V-types. IR spectra for Moore-Sitterly and Hecht are each linked with available visual photometry. The classifications for primary (88604) 2001 QH293 and (60546) 2000 EE85 are ambiguous: S/Sq/Q/K/L-type. Subtle spectral differences between them suggest that the primary may have more weathered material on its surface. Dynamical integrations have constrained the ages of formation: 2110-44612 > 782 kyr; 10484-44645 = 348 (+823,-225) kyr; 88604-60546 = 925 (+842,-754) kyr. The spectral similarity of seven complete pairs is ranked in comparison with nearby background asteroids. Two pairs, 17198-229056 and 19289-278067, have significantly different spectra between the components, compared to the similarity of spectra in the background population. The other pairs are closer than typical, supporting an interpretation of each pair's formation from a common parent body.
Unbounded Violation of Tripartite Bell Inequalities
NASA Astrophysics Data System (ADS)
Pérez-García, D.; Wolf, M. M.; Palazuelos, C.; Villanueva, I.; Junge, M.
2008-04-01
We prove that there are tripartite quantum states (constructed from random unitaries) that can lead to arbitrarily large violations of Bell inequalities for dichotomic observables. As a consequence these states can withstand an arbitrary amount of white noise before they admit a description within a local hidden variable model. This is in sharp contrast with the bipartite case, where all violations are bounded by Grothendieck’s constant. We will discuss the possibility of determining the Hilbert space dimension from the obtained violation and comment on implications for communication complexity theory. Moreover, we show that the violation obtained from generalized Greenberger-Horne-Zeilinger (GHZ) states is always bounded so that, in contrast to many other contexts, GHZ states do not lead to extremal quantum correlations in this case. In order to derive all these physical consequences, we will have to obtain new mathematical results in the theories of operator spaces and tensor norms. In particular, we will prove the existence of bounded but not completely bounded trilinear forms from commutative C*-algebras. Finally, we will relate the existence of diagonal states leading to unbounded violations with a long-standing open problem in the context of Banach algebras.
Alt, E.O.; Irgaziev, B.F.; Muminov, A.T.
1995-11-01
The quasielastic breakup of light nuclei into two charged fragments in the Coulomb field of a heavy multiply charged ion are studied. For fragments diverging with extremely low energies an asymptotic estimate is obtained for the ratio of the differential cross section in which three-body Coulomb effects are taken into account to that in which these effects are disregarded. It is shown that effects due to the acceleration of breakup fragments in the field of the heavy ion are significant. 13 refs., 2 figs.
NASA Astrophysics Data System (ADS)
Petrov, G. A.; Gagarskii, A. M.; Guseva, I. S.; Kopatch, Yu. N.; Gönnenwein, F.; Mutterer, M.
2008-07-01
Prospects for further studies of TRI and ROT effects of T-odd asymmetry in the emission of light particles in the ternary and binary fission of heavy nuclei that is induced by slow polarized neutrons are considered with a view to studying the mechanism for the formation of these effects and using them to get new information about fission dynamics. It is planned to investigate the dependence of the corresponding T-odd-asymmetry coefficients on the main characteristics of the fission reaction.
NASA Astrophysics Data System (ADS)
Nakamura, T.; Kondo, Y.
2016-06-01
Large acceptance spectrometers at in-flight RI separators have played significant roles in investigating the structure of exotic nuclei. Such spectrometers are in particular useful for probing unbound states of exotic nuclei, using invariant mass spectroscopy with reactions at intermediate and high energies. We discuss here the key characteristic features of such spectrometers, by introducing the recently commissioned SAMURAI facility at the RIBF, RIKEN. We also investigate the issue of cross talk in the detection of multiple neutrons, which has become crucial for exploring further unbound states and nuclei beyond the neutron drip line. Finally we discuss future perspectives for large acceptance spectrometers at the new-generation RI-beam facilities.
Isospin Mixing and the Continuum Coupling in Weakly Bound Nuclei
Michel, N.; Nazarewicz, Witold; Ploszajczak, M.
2010-01-01
We investigate the near-threshold behavior of one-nucleon spectroscopic factors in mirror nuclei using the Gamow Shell Model, which simultaneously takes into account many-body correlations and continuum effects. We demonstrate that for weakly bound or unbound systems, the mirror symmetry-breaking effects are appreciable, and they manifest in large differences of spectroscopic factors in a mirror pair.
Emergent properties of nuclei from ab initio coupled-cluster calculations
NASA Astrophysics Data System (ADS)
Hagen, G.; Hjorth-Jensen, M.; Jansen, G. R.; Papenbrock, T.
2016-06-01
Emergent properties such as nuclear saturation and deformation, and the effects on shell structure due to the proximity of the scattering continuum and particle decay channels are fascinating phenomena in atomic nuclei. In recent years, ab initio approaches to nuclei have taken the first steps towards tackling the computational challenge of describing these phenomena from Hamiltonians with microscopic degrees of freedom. This endeavor is now possible due to ideas from effective field theories, novel optimization strategies for nuclear interactions, ab initio methods exhibiting a soft scaling with mass number, and ever-increasing computational power. This paper reviews some of the recent accomplishments. We also present new results. The recently optimized chiral interaction NNLO{}{{sat}} is shown to provide an accurate description of both charge radii and binding energies in selected light- and medium-mass nuclei up to 56Ni. We derive an efficient scheme for including continuum effects in coupled-cluster computations of nuclei based on chiral nucleon–nucleon and three-nucleon forces, and present new results for unbound states in the neutron-rich isotopes of oxygen and calcium. The coupling to the continuum impacts the energies of the {J}π =1/{2}-,3/{2}-,7/{2}-,3/{2}+ states in {}{17,23,25}O, and—contrary to naive shell-model expectations—the level ordering of the {J}π =3/{2}+,5/{2}+,9/{2}+ states in {}{53,55,61}Ca. ).
Morelli, L. D’Agostino, M.; Bruno, M.; Baiocco, G.; Gulminelli, F.; Cinausero, M.; Gramegna, F.; Marchi, T.; Degerlier, M.; Fabris, D.; Barlini, S.; Bini, M.; Casini, G.; Gelli, N.; Olmi, A.; Pasquali, G.; Piantelli, S.
2015-10-15
In the recent years, cluster structures have been evidenced in many ground and excited states of light nuclei [1, 2]. Within the currently ongoing experimental campaign by the NUCL-EX collaboration we have measured the {sup 12}C+{sup 12}C and {sup 14}N+{sup 10}B reactions at 95 MeV and 80 MeV respectively, and compared experimental data corresponding to complete fusion of target and projectile into an excited {sup 24}Mg nucleus to the results of a pure statistical model[3, 4]. We found clear deviations from the statstical model in the decay pattern: emission channels involving multiple α particles are more probable than expected from a purely statistical behavior. To continue the investigation on light systems, we have recentely measured the {sup 16}O+{sup 12}C reaction at three different beam energies, namely E{sub beam} = 90, 110 and 130 MeV.
NASA Technical Reports Server (NTRS)
Pinsky, L. S.; Osborne, W. Z.; Bailey, J. V.
1975-01-01
A nuclear emulsion detector known as the Apollo Light Flash Moving Emulsion Detector (ALFMED) was designed: (1) to record tracks of primary cosmic rays; (2) to provide time-of-passage information via a relative plate translation technique; (3) to provide particle trajectory information; and (4) to fit into a masklike device that could be located about the head and eyes of an astronaut. An ALFMED device was worn by an astronaut observing light flashes for 60 minutes on each of the last two Apollo missions. During the Apollo 17 experiment seventeen separate flashes were reported by the observer. With one-third of the total plate area completely analyzed, two definite correlations have been found between Z greater than 8 cosmic ray nuclei traversing an eye and the reports of visual sensations.
Zhang, J H; Sampogna, S; Morales, F R; Chase, M H
1998-06-29
In the present study, we examined the age-related intra-axonal accumulation of neurofilaments in the dorsal column nuclei of the cat by using immunohistochemical techniques combined with light and electron microscopy. Light microscopic analysis revealed oval or circular immunostained structures in the dorsal column nuclei of old cats. These immunostained structures were not observed in the material obtained from adult controls. Under the electron microscope, it was discovered that the immunostained structures were greatly enlarged axons with disrupted myelin sheaths. These enlarged axons contained massive accumulations of neurofilaments, some mitochondria, vacuoles and dense granules. The abnormalities of the myelin sheaths included the breaking of myelin at several locations, a splitting and ballooning in the myelin lamellae of the sheath and a distended periaxonal space between the axon and myelin sheaths. These ultrastructural changes resembled the degenerative alterations that have been observed in the axons of human and animals suffering from a number of pathological conditions, including giant axonal neuropathy and toxic neuropathy. Therefore, severely altered axons with intra-axonal accumulation of neurofilaments appear to reflect chronic degenerative changes that are a component of the aging process. PMID:9666164
Differences in local genomic context of bound and unbound motifs
Hansen, Loren; Mariño-Ramírez, Leonardo; Landsman, David
2012-01-01
Understanding gene regulation is a major objective in molecular biology research. Frequently, transcription is driven by transcription factors (TFs) that bind to specific DNA sequences. These motifs are usually short and degenerate, rendering the likelihood of multiple copies occurring throughout the genome due to random chance as high. Despite this, TFs only bind to a small subset of sites, thus prompting our investigation into the differences between motifs that are bound by TFs and those that remain unbound. Here we constructed vectors representing various chromatin- and sequence-based features for a published set of bound and unbound motifs representing nine TFs in the budding yeast Saccharomyces cerevisiae. Using a machine learning approach, we identified a set of features that can be used to discriminate between bound and unbound motifs. We also discovered that some TFs bind most or all of their strong motifs in intergenic regions. Our data demonstrate that local sequence context can be strikingly different around motifs that are bound compared to motifs that are unbound. We concluded that there are multiple combinations of genomic features that characterize bound or unbound motifs. PMID:22692006
MMT HYPERVELOCITY STAR SURVEY. II. FIVE NEW UNBOUND STARS
Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J. E-mail: mgeller@cfa.harvard.edu
2012-05-20
We present the discovery of five new unbound hypervelocity stars (HVSs) in the outer Milky Way halo. Using a conservative estimate of Galactic escape velocity, our targeted spectroscopic survey has now identified 16 unbound HVSs as well as a comparable number of HVSs ejected on bound trajectories. A Galactic center origin for the HVSs is supported by their unbound velocities, the observed number of unbound stars, their stellar nature, their ejection time distribution, and their Galactic latitude and longitude distribution. Other proposed origins for the unbound HVSs, such as runaway ejections from the disk or dwarf galaxy tidal debris, cannot be reconciled with the observations. An intriguing result is the spatial anisotropy of HVSs on the sky, which possibly reflects an anisotropic potential in the central 10-100 pc region of the Galaxy. Further progress requires measurement of the spatial distribution of HVSs over the southern sky. Our survey also identifies seven B supergiants associated with known star-forming galaxies; the absence of B supergiants elsewhere in the survey implies there are no new star-forming galaxies in our survey footprint to a depth of 1-2 Mpc.
NASA Astrophysics Data System (ADS)
Al-Rubaiee, A. A.; Hashim, U.; Al-Douri, Y.
2015-11-01
The lateral distribution function (LDF) of Cherenkov radiation in extensive air showers (EAS) was simulated by CORSIKA program for the conditions of Yakutsk Cherenkov array at the high energy range (1013-1016) eV for two primary particles (p and Fe) for different zenith angles. By depending on Breit-Wigner function for analyzing of Cherenkov light LDF, a parameterization of Cherenkov light LDF was reconstructed by depending on CORSIKA simulation as a function of primary energy. The comparison between the estimated Cherenkov light LDF with the LDF that measured on the Yakutsk EAS array gives the ability of particle identification that initiated the shower and determination of particle's energy around the knee region. The extrapolation of approximated Cherenkov light LDF for energies 20 and 30 PeV was obtained for primary particles (p and Fe).
Blinov, A. V. Chadeyeva, M. V.
2006-09-15
The invariant cross sections for the cumulative production of protons, neutrons, and extremely light nuclei (d, {sup 3}H, and {sup 3}He) are determined on the basis of experimental data obtained by exposing the 2-m liquid-hydrogen bubble chamber of the Institute of Theoretical and Experimental Physics (ITEP, Moscow) to a 5-GeV/c {alpha}-particle beam, the kinetic energy of primary protons in the rest frame of the nucleus involved being T{sub p} = 620 MeV. The results obtained in this way are compared with the predictions of the Frankfurt-Strikman model, which takes into account short-range few-nucleon correlations, and with the predictions of the nuclear coalescence model.
Weischet, W O; Glotov, B O; Schnell, H; Zachau, H G
1982-01-01
In mouse myeloma T the productive kappa light chain gene differs from its aberrantly rearranged allele in the patterns of DNAase I hypersensitive sites. In the region of the alleles where they are identical in sequence they have one site in common which lies 0.8 kb downstream of the coding region; but two sites upstream of and within the C gene segment (2) are found only on the non-productive allele. Within the region of different sequences both alleles have analogously located DNAase I hypersensitive sites; they lie 0.15 kb upstream of the respective leader segments and cover putative promoter sequences. Only one of the six DNAase I hypersensitive sites is also very sensitive towards micrococcal nuclease due to its particular DNA sequence. The non-rearranged gene studied in liver nuclei has no DNAase I hypersensitive sites but is preferentially cleaved in A/T rich regions. Images PMID:6287416
Jia, Hong-Ge; Yamuy, Jack; Sampogna, Sharon; Morales, Francisco R; Chase, Michael H
2003-12-01
Cholinergic and gamma-aminobutyric acid (GABA) mechanisms in the dorsolateral pontomesencephalic tegmentum have been implicated in the control of active (REM) sleep and wakefulness. To determine the relationships between neurons that contain these neurotransmitters in this region of the brainstem in adult cats, combined light and electron microscopic immunocytochemical procedures were employed. Light microscopic analyses revealed that choline acetyltransferase (ChAT) and GABA immunoreactive neurons were distributed throughout the laterodorsal and pedunculopontine tegmental nuclei (LDT and PPT). Surprisingly, approximately 50% of the ChAT immunoreactive neurons in these nuclei also contained GABA. Using electron microscopic pre-embedding immunocytochemistry, GABA immunoreactivity was observed in somas, dendrites and axon terminals in both the LDT and PPT. Most of the GABA immunoreactive terminals formed symmetrical synapses with non-immunolabeled dendrites. Electron microscopic double-immunolabeling techniques revealed that ChAT and GABA were colocalized in axon terminals in the LDT/PPT. Approximately 30% of the ChAT immunoreactive terminals were also GABA immunoreactive, whereas only 6-8% of the GABA immunoreactive terminals were ChAT immunoreactive. Most of the ChAT/GABA immunoreactive terminals formed symmetrical synapses with non-immunolabeled dendrites; however, ChAT/GABA immunoreactive terminals were also observed that contacted ChAT immunoreactive dendrites. With respect to ChAT immunoreactive postsynaptic profiles, approximately 40% of the somas and 50% of the dendrites received synaptic contact from GABA immunoreactive terminals in both the LDT and PPT. These findings (a) indicate that there are fundamental interactions between cholinergic and GABAergic neurons within the LDT/PPT that play an important role in the control of active sleep and wakefulness and (b) provide an anatomical basis for the intriguing possibility that a mechanism of acetylcholine and
Verifying Multi-Agent Systems via Unbounded Model Checking
NASA Technical Reports Server (NTRS)
Kacprzak, M.; Lomuscio, A.; Lasica, T.; Penczek, W.; Szreter, M.
2004-01-01
We present an approach to the problem of verification of epistemic properties in multi-agent systems by means of symbolic model checking. In particular, it is shown how to extend the technique of unbounded model checking from a purely temporal setting to a temporal-epistemic one. In order to achieve this, we base our discussion on interpreted systems semantics, a popular semantics used in multi-agent systems literature. We give details of the technique and show how it can be applied to the well known train, gate and controller problem. Keywords: model checking, unbounded model checking, multi-agent systems
Sundaralingam, N.
1993-06-08
We study multiple muon events (muon bundles) recorded underground at a depth of 2090 mwe. To penetrate to this depth, the muons must have energies above 0.8 TeV at the Earth`s surface; the primary cosmic ray nuclei which give rise to the observed muon bundles have energies at incidence upon the upper atmosphere of 10 to 10{sup 5}TeV. The events are detected using the Soudan 2 experiment`s fine grained tracking calorimeter which is surrounded by a 14 m {times}10 m {times} 31 m proportional tube array (the ``active shield``). Muon bundles which have at least one muon traversing the calorimeter, are reconstructed using tracks in the calorimeter together with hit patterns in the proportional tube shield. All ionization pulses are required to be coincident within 3 microseconds. A goal of this study is to investigate the relative nuclear abundances in the primary cosmic radiation around the ``knee`` region (10{sup 3} {minus} 10{sup 4} TeV) of the incident energy spectrum. Four models for the nuclear composition of cosmic rays are considered: The Linsley model, the Constant Mass Composition model (CMC), the Maryland model and the Proton-poor model. A Monte Carlo which incorporates one model at a time is used to simulate events which are then reconstructed using the same computer algorithms that are used for the data. Identical cuts and selections are applied to the data and to the simulated events.
Studies of light exotic nuclei in the vicinity of neutron and proton drip lines at FLNR JINR
NASA Astrophysics Data System (ADS)
Grigorenko, L. V.; Golovkov, M. S.; Krupko, S. A.; Sidorchuk, S. I.; Ter-Akopian, G. M.; Fomichev, A. S.; Chudoba, V.
2016-04-01
Defining the limits of the existence of the nuclear structure is one of fundamental problems of natural science, requiring the advancement of studies towards the sites of maximum neutron- and proton-excess nuclei, to the borders of nuclear stability, and further, to the regions of nuclear instability. In such regions, nuclear systems exist only as resonant states in continuous spectra with characteristic 'nuclear' lifetimes. This work is done most effectively with experimental setups providing radioactive ion beams (RIBs). This review discusses the approaches in this field of research developed during the last 20 years at the ACCULINNA fragment separator in the Flerov Laboratory of Nuclear Reactions (FLNR) of the Joint Institute for Nuclear Research (JINR). The methodology developed is based on the comprehensive study of correlations among the reaction fragments emitted in the decays of nuclear-unstable systems which are populated in direct reactions induced by RIBs with intermediate (20 – 60 MeV per nucleon) energies. This allows us to acquire detailed knowledge about exotic nuclear systems close to and beyond nuclear drip lines. We discuss exotic forms of nuclear dynamics appearing in the vicinity of nuclear drip lines and relevant results of their theoretical analysis. Also discussed are existing facilities and prospective projects aimed at nuclear structure studies with RIBs at JINR.
NASA Astrophysics Data System (ADS)
Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Bracco, A.; Kravchuk, V. L.; Casini, G.; Barlini, S.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Brambilla, S.; Bruno, M.; Camera, F.; Carboni, S.; Cinausero, M.; Chbihi, A.; Chiari, M.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fornal, B.; Giaz, A.; Gramegna, F.; Krzysiek, M.; Leoni, S.; Marchi, T.; Matejska-Minda, M.; Mazumdar, I.; Meczyński, W.; Million, B.; Montanari, D.; Morelli, L.; Myalski, S.; Nannini, A.; Nicolini, R.; Pasquali, G.; Piantelli, S.; Prete, G.; Roberts, O. J.; Schmitt, Ch.; Styczeń, J.; Szpak, B.; Valdré, S.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; Ziebliński, M.; Dudek, J.; Dinh Dang, N.
2015-05-01
High-energy giant dipole resonance (GDR) γ rays were measured following the decay of the hot, rotating compound nucleus of 88Mo, produced at excitation energies of 124 and 261 MeV. The reaction 48Ti + 40Ca at 300 and 600 MeV bombarding energies has been used. The data were analyzed using the statistical model Monte Carlo code gemini++. It allowed extracting the giant dipole resonance parameters by fitting the high-energy γ -ray spectra. The extracted GDR widths were compared with the available data at lower excitation energy and with theoretical predictions based on (i) The Lublin-Strasbourg drop macroscopic model, supplemented with thermal shape fluctuations analysis, and (ii) The phonon damping model. The theoretical predictions were convoluted with the population matrices of evaporated nuclei from the statistical model gemini++. Also a comparison with the results of a phenomenological expression based on the existing systematics, mainly for lower temperature data, is presented and discussed. A possible onset of a saturation of the GDR width was observed around T =3 MeV.
Litvinova, E. V.; Afanasjev, A. V.
2011-07-15
The impact of particle-vibration coupling and polarization effects due to deformation and time-odd mean fields on single-particle spectra is studied systematically in doubly magic nuclei from low-mass {sup 56}Ni up to superheavy ones. Particle-vibration coupling is treated fully self-consistently within the framework of the relativistic particle-vibration coupling model. Polarization effects due to deformation and time-odd mean field induced by odd particle are computed within covariant density functional theory. It has been found that among these contributions the coupling to vibrations makes a major impact on the single-particle structure. The impact of particle-vibration coupling and polarization effects on calculated single-particle spectra, the size of the shell gaps, the spin-orbit splittings and the energy splittings in pseudospin doublets is discussed in detail; these physical observables are compared with experiment. Particle-vibration coupling has to be taken into account when model calculations are compared with experiment since this coupling is responsible for observed fragmentation of experimental levels; experimental spectroscopic factors are reasonably well described in model calculations.
"University Unbound" Rebounds: Can MOOCs "Educate" as Well as Train?
ERIC Educational Resources Information Center
McCully, George
2012-01-01
In the days since NEBHE convened hundreds of educators and opinion leaders in Boston for the "University Unbound" conference, people have received a surge of reactions including the one from George McCully, founder of the "Catalogue for Philanthropy." NEBHE has begun focusing the attention of New England institutions on the MOOC movement, which…
Infinite Factorial Unbounded-State Hidden Markov Model.
Valera, Isabel; Ruiz, Francisco J R; Perez-Cruz, Fernando
2016-09-01
There are many scenarios in artificial intelligence, signal processing or medicine, in which a temporal sequence consists of several unknown overlapping independent causes, and we are interested in accurately recovering those canonical causes. Factorial hidden Markov models (FHMMs) present the versatility to provide a good fit to these scenarios. However, in some scenarios, the number of causes or the number of states of the FHMM cannot be known or limited a priori. In this paper, we propose an infinite factorial unbounded-state hidden Markov model (IFUHMM), in which the number of parallel hidden Markovmodels (HMMs) and states in each HMM are potentially unbounded. We rely on a Bayesian nonparametric (BNP) prior over integer-valued matrices, in which the columns represent the Markov chains, the rows the time indexes, and the integers the state for each chain and time instant. First, we extend the existent infinite factorial binary-state HMM to allow for any number of states. Then, we modify this model to allow for an unbounded number of states and derive an MCMC-based inference algorithm that properly deals with the trade-off between the unbounded number of states and chains. We illustrate the performance of our proposed models in the power disaggregation problem. PMID:26571511
Gagarskii, A. M.; Guseva, I. S.; Goennenwein, F.; Kopach, Yu. N.; Mutterer, M.; Kuz'mina, T. E.; Petrov, G. A.; Tyurin, G.; Nesvizhevsky, V.
2011-12-15
The new physical effects of T-odd asymmetry of the emission of light charged particles (LCPs) during the ternary fission of some heavy nuclei by cold polarized neutrons have been experimentally studied. The coefficients of triple scalar and vector correlation of the pulses of light particles and fission fragments (TRI effect) and the fivefold correlation of the same vectors (ROT effect) have been measured. These effects are believed to be caused by the rotation of polarized fissioning system around its polarization direction. The treatment of the experimental data for LCPs in the framework of this hypothesis leads to a good agreement between the calculation results and experimental data. The calculated value of the angle of rotation of the fission axis in the ternary fission of the polarized fissioning {sup 236}U* compound nucleus was used to process the results of measuring the ROT effect for {gamma} photons from binary-fission fragments of the same nucleus. A satisfactory description of these experimental data is obtained which serves a convincing confirmation of the rotation hypothesis.
NASA Astrophysics Data System (ADS)
Morelli, L.; Bruno, M.; D'Agostino, M.; Baiocco, G.; Gulminelli, F.; Cinausero, M.; Degerlier, M.; Fabris, D.; Gramegna, F.; Marchi, T.; Barlini, S.; Bini, M.; Casini, G.; Gelli, N.; Pasquali, G.; Piantelli, S.; Valdrè, S.
2016-06-01
In the recent years, cluster structures have been evidenced in many ground and excited states of light nuclei [1, 2]. The decay of highly excited states of 24Mg is studied in fusion evaporation events completely detected in charge in the reactions 12C+12C and 14N+10B at 95 and 80 MeV incident energy, respectively, and compared to the results of a pure statistical model [3, 4]. Inclusive variables are in general well reproduced by the model. We found clear deviations from the statistical model if we select emission channels involving multiple α particles which are more probable than expected from a purely statistical behavior. Data from 12C+12C reaction have been analyzed in order to study the decay of the Hoyle state of 12C* with two different selections: peripheral binary collisions and 6α decay channel in central events. To continue the investigation on light systems, we have recently measured the 16O+12C reaction at three different beam energies, namely Ebeam = 90, 110 and 130 MeV. Preliminary results are presented.
NASA Astrophysics Data System (ADS)
Akram, W.; Schönbächler, M.; Sprung, P.; Vogel, N.
2013-11-01
Recent work based on analyses of meteorite and terrestrial whole-rock samples showed that the r- and s- process isotopes of Hf were homogeneously distributed throughout the inner solar system. We report new Hf isotope data for Calcium-Aluminum-rich inclusions (CAIs) of the CV3 carbonaceous chondrite Allende, and novel high-precision Zr isotope data for these CAIs and three carbonaceous chondrites (CM, CO, CK). Our Zr data reveal enrichments in the neutron-rich isotope 96Zr (<=1ɛ in 96Zr/90Zr) for bulk chondrites and CAIs (~2ɛ). Potential isotope effects due to incomplete sample dissolution, galactic and cosmic ray spallation, and the nuclear field shift are assessed and excluded, leading to the conclusion that the 96Zr isotope variations are of nucleosynthetic origin. The 96Zr enrichments are coupled with 50Ti excesses suggesting that both nuclides were produced in the same astrophysical environment. The same CAIs also exhibit deficits in r-process Hf isotopes, which provides strong evidence for a decoupling between the nucleosynthetic processes that produce the light (A <= 130) and heavy (A > 130) neutron-rich isotopes. We propose that the light neutron-capture isotopes largely formed in Type II supernovae (SNeII) with higher mass progenitors than the supernovae that produced the heavy r-process isotopes. In the context of our model, the light isotopes (e.g. 96Zr) are predominantly synthesized via charged-particle reactions in a high entropy wind environment, in which Hf isotopes are not produced. Collectively, our data indicates that CAIs sampled an excess of materials produced in a normal mass (12-25 M ⊙) SNII.
Akram, W.; Schönbächler, M.; Sprung, P.; Vogel, N.
2013-11-10
Recent work based on analyses of meteorite and terrestrial whole-rock samples showed that the r- and s- process isotopes of Hf were homogeneously distributed throughout the inner solar system. We report new Hf isotope data for Calcium-Aluminum-rich inclusions (CAIs) of the CV3 carbonaceous chondrite Allende, and novel high-precision Zr isotope data for these CAIs and three carbonaceous chondrites (CM, CO, CK). Our Zr data reveal enrichments in the neutron-rich isotope {sup 96}Zr (≤1ε in {sup 96}Zr/{sup 90}Zr) for bulk chondrites and CAIs (∼2ε). Potential isotope effects due to incomplete sample dissolution, galactic and cosmic ray spallation, and the nuclear field shift are assessed and excluded, leading to the conclusion that the {sup 96}Zr isotope variations are of nucleosynthetic origin. The {sup 96}Zr enrichments are coupled with {sup 50}Ti excesses suggesting that both nuclides were produced in the same astrophysical environment. The same CAIs also exhibit deficits in r-process Hf isotopes, which provides strong evidence for a decoupling between the nucleosynthetic processes that produce the light (A ≤ 130) and heavy (A > 130) neutron-rich isotopes. We propose that the light neutron-capture isotopes largely formed in Type II supernovae (SNeII) with higher mass progenitors than the supernovae that produced the heavy r-process isotopes. In the context of our model, the light isotopes (e.g. {sup 96}Zr) are predominantly synthesized via charged-particle reactions in a high entropy wind environment, in which Hf isotopes are not produced. Collectively, our data indicates that CAIs sampled an excess of materials produced in a normal mass (12-25 M{sub ☉}) SNII.
NASA Astrophysics Data System (ADS)
Holt, Roy J.
2016-03-01
Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.
Assessment of nuclear-reaction codes for proton-induced reactions on light nuclei below 250 MeV
NASA Astrophysics Data System (ADS)
Braunn, Benjamin; Boudard, Alain; David, Jean-Christophe; Koning, Arjan J.; Leprince, Anne; Leray, Sylvie; Mancusi, Davide
2015-07-01
We assess the suitability of nuclear-reaction codes for the generation of accurate cross-section libraries targeted at the simulation of the transport of high-energy protons (up to 250 MeV) in the human body, or in any material containing light nuclides. To this end we present an extensive study of elastic, reaction and fragmentation cross sections for proton-induced reactions on several nuclides. We compare TALYS evaluations against experimental data and, wherever applicable, against the predictions of the INCL/ABLA07 nuclear-reaction model. The TALYS evaluations have been cast in the form of a new cross-section library, which also includes evaluated proton-proton cross sections based on the NN-OnLine tool.
An exponentially fitted quadrature rule over unbounded intervals
NASA Astrophysics Data System (ADS)
Conte, D.; Paternoster, B.; Santomauro, G.
2012-09-01
A new class of quadrature formulae for the computation of integrals over unbounded intervals with oscillating integrand is illustrated. Such formulae are a generalization of the gaussian quadrature formulae by exploiting the Exponential Fitting theory. The coefficients depend on the frequency of oscillation, in order to improve the accuracy of the solution. The construction of the methods with 1, 2 and 3 nodes is described, together with the comparison of the order of accuracy with respect to classical formulae.
Spinor fields with zero mass in unbounded isotropic media
Hillion, P.
1988-01-01
The Dirac equation for massless fields in unbounded media has solutions similar to the focus wave mode solutions of Maxwell's equations leading to infinite dynamical invariants. We define the splash wave mode solutions as a weighted superposition of the focus wave modes, and discuss the conditions to be fulfilled by the weight functions to make the dynamical invariants bounded. We leave open the physical interpretation of these solutions.
Dynamical semigroup for unbounded repeated perturbation of an open system
NASA Astrophysics Data System (ADS)
Tamura, Hiroshi; Zagrebnov, Valentin A.
2016-02-01
We consider a dynamical semigroup for unbounded Kossakowski-Lindblad-Davies generator corresponding to evolution of an open system for a tuned repeated harmonic perturbation. For this evolution, we prove the existence of uniquely determined minimal trace-preserving strongly continuous dynamical semigroups on the space of states. The corresponding dual W∗-dynamical system is shown to be unital quasi-free and completely positive automorphisms of the canonical commutation relation-algebra.
Unbounded dynamics in dissipative flows: Rössler model
Barrio, Roberto Serrano, Sergio; Blesa, Fernando
2014-06-15
Transient chaos and unbounded dynamics are two outstanding phenomena that dominate in chaotic systems with large regions of positive and negative divergences. Here, we investigate the mechanism that leads the unbounded dynamics to be the dominant behavior in a dissipative flow. We describe in detail the particular case of boundary crisis related to the generation of unbounded dynamics. The mechanism of the creation of this crisis in flows is related to the existence of an unstable focus-node (or a saddle-focus) equilibrium point and the crossing of a chaotic invariant set of the system with the weak-(un)stable manifold of the equilibrium point. This behavior is illustrated in the well-known Rössler model. The numerical analysis of the system combines different techniques as chaos indicators, the numerical computation of the bounded regions, and bifurcation analysis. For large values of the parameters, the system is studied by means of Fenichel's theory, providing formulas for computing the slow manifold which influences the evolution of the first stages of the orbit.
Stochastic Homogenization of Nonconvex Unbounded Integral Functionals with Convex Growth
NASA Astrophysics Data System (ADS)
Duerinckx, Mitia; Gloria, Antoine
2016-03-01
We consider the well-trodden ground of the problem of the homogenization of random integral functionals. When the integrand has standard growth conditions, the qualitative theory is well-understood. When it comes to unbounded functionals, that is, when the domain of the integrand is not the whole space and may depend on the space-variable, there is no satisfactory theory. In this contribution we develop a complete qualitative stochastic homogenization theory for nonconvex unbounded functionals with convex growth. We first prove that if the integrand is convex and has p-growth from below (with p > d, the dimension), then it admits homogenization regardless of growth conditions from above. This result, that crucially relies on the existence and sublinearity at infinity of correctors, is also new in the periodic case. In the case of nonconvex integrands, we prove that a similar homogenization result holds provided that the nonconvex integrand admits a two-sided estimate by a convex integrand (the domain of which may depend on the space variable) that itself admits homogenization. This result is of interest to the rigorous derivation of rubber elasticity from polymer physics, which involves the stochastic homogenization of such unbounded functionals.
Stochastic Homogenization of Nonconvex Unbounded Integral Functionals with Convex Growth
NASA Astrophysics Data System (ADS)
Duerinckx, Mitia; Gloria, Antoine
2016-09-01
We consider the well-trodden ground of the problem of the homogenization of random integral functionals. When the integrand has standard growth conditions, the qualitative theory is well-understood. When it comes to unbounded functionals, that is, when the domain of the integrand is not the whole space and may depend on the space-variable, there is no satisfactory theory. In this contribution we develop a complete qualitative stochastic homogenization theory for nonconvex unbounded functionals with convex growth. We first prove that if the integrand is convex and has p-growth from below (with p > d, the dimension), then it admits homogenization regardless of growth conditions from above. This result, that crucially relies on the existence and sublinearity at infinity of correctors, is also new in the periodic case. In the case of nonconvex integrands, we prove that a similar homogenization result holds provided that the nonconvex integrand admits a two-sided estimate by a convex integrand (the domain of which may depend on the space variable) that itself admits homogenization. This result is of interest to the rigorous derivation of rubber elasticity from polymer physics, which involves the stochastic homogenization of such unbounded functionals.
NASA Technical Reports Server (NTRS)
Raisbeck, G. M.
1986-01-01
Cosmogenic nuclei, nuclides formed by nuclear interactions of galactic and solar cosmic rays with extraterrestrial or terrestrial matter are discussed. Long lived radioactive cosmogenic isotopes are focused upon. Their uses in dating, as tracers of the interactions of cosmic rays with matter, and in obtaining information on the variation of primary cosmic ray flux in the past are discussed.
Emergent properties of nuclei from ab initio coupled-cluster calculations
Hagen, G.; Hjorth-Jensen, M.; Jansen, G. R.; Papenbrock, T.
2016-05-17
Emergent properties such as nuclear saturation and deformation, and the effects on shell structure due to the proximity of the scattering continuum and particle decay channels are fascinating phenomena in atomic nuclei. In recent years, ab initio approaches to nuclei have taken the first steps towards tackling the computational challenge of describing these phenomena from Hamiltonians with microscopic degrees of freedom. Our endeavor is now possible due to ideas from effective field theories, novel optimization strategies for nuclear interactions, ab initio methods exhibiting a soft scaling with mass number, and ever-increasing computational power. We review some of the recent accomplishments. We also present new results. The recently optimized chiral interaction NNLOmore » $${}_{{\\rm{sat}}}$$ is shown to provide an accurate description of both charge radii and binding energies in selected light- and medium-mass nuclei up to 56Ni. We derive an efficient scheme for including continuum effects in coupled-cluster computations of nuclei based on chiral nucleon–nucleon and three-nucleon forces, and present new results for unbound states in the neutron-rich isotopes of oxygen and calcium. Finally, the coupling to the continuum impacts the energies of the $${J}^{\\pi }=1/{2}^{-},3/{2}^{-},7/{2}^{-},3/{2}^{+}$$ states in $${}^{\\mathrm{17,23,25}}$$O, and—contrary to naive shell-model expectations—the level ordering of the $${J}^{\\pi }=3/{2}^{+},5/{2}^{+},9/{2}^{+}$$ states in $${}^{\\mathrm{53,55,61}}$$Ca.« less
NASA Astrophysics Data System (ADS)
Khoa, Dao Tien; Egelhof, Peter; Gales, Sydney; Giai, Nguyen Van; Motobayashi, Tohru
2008-04-01
. -- Thermal pairing in nuclei / N. D. Dang -- Molecular-orbital and di-nuclei states in Ne and F isotopes / M. Kimura -- Low-momentum interactions for nuclei / A. Schwenk -- Nonrelativistic nuclear energy functionals including the tensor force / G. Colo et al. -- New aspects on dynamics in nuclei described by covariant density functional theory / P. Ring, D. Pena -- Theoretical studies on ground-state properties of superheavy nuclei / Z. Z. Ren et al. -- New results in the study of superfluid nuclei: many-body effects, spectroscopic factors / P. F. Bortignon et al. -- New Effective nucleon-nucleon interaction for the mean-field approximation / V. K. Au et al. -- Linear response calculations with the time-dependent Skyrme density functional / T. Nakatsukasa et al. -- Dissipative dynamics with exotic beams / M. Di Toro et al. -- Exploring the symmetry energy of asymmetric nuclear matter with heavy ion reactions / M. B. Tsang -- Invariant mass spectroscopy of halo nuclei / T. Nakamura et al. -- Core [symbol] structures in [symbol]C, [symbol]C and [symbol]C up to high excitation energies / H. G. Bohlen et al. -- Light neutron-rich nuclei studied by alpha-induced reactions / S. Shimoura -- Fusion and direct reactions around the Coulomb barrier for the system [symbol]He + [symbol]Zn / V. Scuderi et al. -- Analyzing power measurement for proton elastic scattering on [symbol]He / S. Sakaguchi et al. -- Knockout reaction spectroscopy of exotic nuclei / J. A. Tostevin -- Exotic nuclei, quantum phase transitions, and the evolution of structure / R. F. Casten -- Structure of exotic nuclei in the medium mass region / T. Otsuka -- Pairing correlations in halo nuclei / H. Sagawa, K. Hagino -- Experimental approach to high-temperature Stellar reactions with low-energy RI beams / S. Kubono et al. -- Transition to quark matter in neutron stars / G. X. Peng et al. -- Research at VATLY: main themes and recent results / P. N. Diep et al. -- Study of the astrophysical reaction [symbol
Selective population of unbound states in 10Li
NASA Astrophysics Data System (ADS)
Smith, J. K.; Baumann, T.; Brown, J.; DeYoung, P. A.; Frank, N.; Hinnefeld, J.; Kohley, Z.; Luther, B.; Marks, B.; Spyrou, A.; Stephenson, S. L.; Thoennessen, M.; Williams, S. J.
2015-08-01
Unbound positive-parity states in 10Li have been populated with a two-proton removal reaction from a 71 MeV/u 12B beam. The 9Li fragments and emitted neutrons were measured with the MoNA-LISA-Sweeper setup. The measured decay energy spectrum was best fit with three states at 110 ± 40, 500 ± 100, and 1100 ± 100 keV decay energy. This is the second observation of a resonance below 200 keV. The lower two states likely belong to the expected 1+, 2+ doublet.
Erosive Hit-and-Run Impact Events: Debris Unbound
NASA Astrophysics Data System (ADS)
Sarid, Gal; Stewart, Sarah T.; Leinhardt, Zoë M.
2016-01-01
Erosive collisions among planetary embryos in the inner solar system can lead to multiple remnant bodies, varied in mass, composition and residual velocity. Some of the smaller, unbound debris may become available to seed the main asteroid belt. The makeup of these collisionally produced bodies is different from the canonical chondritic composition, in terms of rock/iron ratio and may contain further shock-processed material. Having some of the material in the asteroid belt owe its origin from collisions of larger planetary bodies may help in explaining some of the diversity and oddities in composition of different asteroid groups.
Solution of the stochastic control problem in unbounded domains.
NASA Technical Reports Server (NTRS)
Robinson, P.; Moore, J.
1973-01-01
Bellman's dynamic programming equation for the optimal index and control law for stochastic control problems is a parabolic or elliptic partial differential equation frequently defined in an unbounded domain. Existing methods of solution require bounded domain approximations, the application of singular perturbation techniques or Monte Carlo simulation procedures. In this paper, using the fact that Poisson impulse noise tends to a Gaussian process under certain limiting conditions, a method which achieves an arbitrarily good approximate solution to the stochastic control problem is given. The method uses the two iterative techniques of successive approximation and quasi-linearization and is inherently more efficient than existing methods of solution.
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2012 CFR
2012-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system....
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2011 CFR
2011-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system....
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2010 CFR
2010-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system....
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2014 CFR
2014-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system....
21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.
Code of Federal Regulations, 2013 CFR
2013-04-01
... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system....