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Nuclear Theory·nucl-th

Monday·April 18, 2016

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    -meson production at forward/backward rapidity in high-energy nuclear collisions from a multiphase transport model

    Y. J. Ye🇨🇳 · J. H. Chen🇨🇳 · Y. G. Ma🇨🇳 · S. Zhang🇨🇳 · C. Zhong🇨🇳

    Within the framework of a multiphase transport model (AMPT), the -meson production is studied in d+Au collisions at \srt = {200} GeV in the forward (d-going, ) and backward (Au-going, ) direction. The AMPT model with string melting version (parton cascade turning-on) describes the experimental data well, while the pure hadronic transport scenario of the AMPT model underestimates the -meson production rate in comparison with the data. Detailed investigations including the rapidity, transverse momentum and collision system size dependencies of -meson nuclear modification factor indicate that a combination of the initial state effect and a follow-up parton cascade is required in the AMPT model to describe the data. Similar calculations are also present in p+Pb collisions at \srt = {5.02} TeV and p+p collisions at \srt = {2.76} TeV. The findings from a comparison of AMPT model study with the data are consistent with that at RHIC energy.

    nucl-thhep-phnucl-exPRC(2016)·4 citations
  2. 02

    On the possibility of generating a 4-neutron resonance with a {\boldmath } isospin 3-neutron force

    E. Hiyama · R. Lazauskas🇫🇷 · J. Carbonell🇫🇷 · M. Kamimura🇯🇵

    We consider the theoretical possibility to generate a narrow resonance in the four neutron system as suggested by a recent experimental result. To that end, a phenomenological three neutron force is introduced, in addition to a realistic interaction. We inquire what should be the strength of the force in order to generate such a resonance. The reliability of the three-neutron force in the channel is exmined, by analyzing its consistency with the low-lying states of H, He and Li and the scattering. The {\it ab initio} solution of the Schrödinger equation is obtained using the complex scaling method with boundary conditions appropiate to the four-body resonances. We find that in order to generate narrow resonant states a remarkably attractive force in the channel is required.

    nucl-thnucl-exPRC(2016)·86 citations
  3. 03

    Magnetic hexadecapole gamma transitions and neutrino-nuclear responses in medium heavy nuclei

    Lotta Jokiniemi🇫🇮 · Jouni Suhonen🇫🇮 · Hiroyasu Ejiri🇯🇵

    Neutrino-nuclear responses in the form of squares of nuclear matrix elements,NMEs, are crucial for studies of neutrino-induced processes in nuclei. In this work we investigate magnetic hexadecapole (M4) NMEs in medium-heavy nuclei. The experimentally derived NMEs, (M4), deduced from observed M4 transition half-lives are compared with the single-quasiparticle (QP) NMEs, (M4), and the microscopic quasiparticle-phonon model (MQPM) NMEs (M4). The experimentally driven M4 NMEs are found to be reduced by a coefficient with respect to (M4) and by with respect to (M4). The M4 NMEs are reduced a little by the quasiparticle-phonon correlations of the MQPM wave functions but mainly by other nucleonic and non-nucleonic correlations which are not explicitly included in the MQPM. The found reduction rates are of the same order of magnitude as those for magnetic quadrupole transitions and Gamow-Teller (GT) and spin-dipole (SD) transitions. The impact of the found reduction coefficients on the magnitudes of the NMEs involved in astroneutrino interactions and neutrinoless double beta decays are discussed.

    nucl-thAdv.High Energy Phys.(2016)·9 citations
  4. 04

    Ultra-relativistic nuclear collisions: where the spectators flow?

    Sergei A. Voloshin🇺🇸 · Takafumi Niida🇺🇸

    In high energy heavy ion collisions, the directed flow of particles is conventionally measured with respect to that of the projectile spectators, which is defined as positive direction. But it is not known if the spectators deflect in the "outward" direction or "inward" -- toward the center line of the collision. In this Letter we discuss how the measurements of the directed flow at mid-rapidity, especially in asymmetric collision such as Cu+Au, can be used to answer this question. We show that the existing data strongly favor the case that the spectators, in the ultrarelativistic collisions, on average deflect outwards.

    nucl-thnucl-exPRC(2016)·26 citations

Affiliations

first authorsco-authorsvia INSPIRE