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Nuclear Theory·nucl-th

Monday·September 14, 2015

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 01

    [Submitted on 10 Sept 2015]

    Contact-interaction Faddeev equation and, inter alia, proton tensor charges

    Shu-Sheng Xu🇨🇳 · Chen Chen🇨🇳 · Ian C.Cloet🇺🇸 · Craig D. Roberts🇺🇸 · Jorge Segovia🇪🇸 · Hong-Shi Zong🇨🇳

    A confining, symmetry-preserving, Dyson-Schwinger equation treatment of a vector-vector contact interaction is used to formulate Faddeev equations for the nucleon and Delta-baryon in which the kernel involves dynamical dressed-quark exchange and whose solutions therefore provide momentum-dependent Faddeev amplitudes. These solutions are compared with those obtained in the static approximation and with a QCD-kindred formulation of the Faddeev kernel. They are also used to compute a range of nucleon properties, amongst them: the proton's sigma-term; the large Bjorken-x values of separate ratios of unpolarised and longitudinally-polarised valence u- and d-quark parton distribution functions; and the proton's tensor charges, which enable one to directly determine the effect of dressed-quark electric dipole moments (EDMs) on neutron and proton EDMs.

    Comments:
    19 pages, 5 figures, 5 tables. Includes estimate of s-quark contribution to proton tensor charge. Phys. Rev. D (in press)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1509.03311 [pdf]
    PRD(2015)·60 citations
  2. 02

    [Submitted on 11 Sept 2015]

    Dynamical and statistical description of multifragmentation in heavy-ion collisions

    Lihua Mao · Ning Wang · Li Ou

    To explore the roles of dynamical model and statistical model in the description of multifragmentation in heavy-ion collisions at intermediate energies, the fragments charge distributions of Au+Au at 35 MeV/u are analyzed by using the hybrid model of improved quantum molecular dynamics (ImQMD) model plus the statistical model GEMINI. We find that, the ImQMD model can well describe the charge distributions of fragments produced in central and semi-central collisions. But for the peripheral collisions of Au+Au at 35 MeV/u, the statistical model is required at the end of the ImQMD simulations for the better description of the charge distribution of fragments. By using the hybrid model of ImQMD+GEMINI, the fragment charge distribution of Au+Au at 35 MeV/u can be reproduced reasonably well. The time evolution of the excitation energies of primary fragments is simultaneously investigated.

    Comments:
    6 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.03404 [pdf]
    PRC(2015)·7 citations
  3. 03

    [Submitted on 11 Sept 2015]

    Further study on mechanism of production of light complex particles in nucleon-induced reactions

    Dexian Wei · Lihua Mao · Ning Wang · Min Liu · Li Ou

    The Improved Quantum Molecular Dynamics (ImQMD) model incorporated with the statistical decay model is used to investigate the intermediate energy nucleon-induced reactions. In our last work, the description on light complex particle emission has been great improved with a phenomenological mechanism called surface coalescence and emission introduced into ImQMD model. In this work, taking account of different specific binding energies and separation energies for various light complex particles, the phase space parameters in surface coalescence model are readjusted. By using the new phase space parameters set with better physical fundament, the double differential cross sections of emitted light complex particles are found to be in better agreement with experimental data.

    Comments:
    11 pages, 4 figures. arXiv admin note: substantial text overlap with arXiv:1309.7534
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.03412 [pdf]
    NPA(2015)·3 citations
  4. 04

    [Submitted on 11 Sept 2015]

    Chemical and thermal freeze-out of identified hadrons at the LHC

    Xiangrong Zhu🇨🇳 · Huichao Song (Peking U.)🇨🇳

    This proceeding briefly summarizes our recent VISHNU hybrid model investigations on the chemical and thermal freeze-out of various hadrons species in 2.76 A TeV Pb+Pb collisions. Detailed analysis on the evolution of particle yields and the last elastic collisions distributions during the hadronic evolution reveals that the two multi-strange hadrons, and , experience early chemical and thermal freeze-out when compared with other hadron species.

    Comments:
    4 pages, 3 figures, SQM2015 proceeding
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.03450 [pdf]
    J.Phys.Conf.Ser.(2016)·0 citations
  5. 05

    [Submitted on 11 Sept 2015]

    Chiral Three-Nucleon Interactions in Light Nuclei, Neutron- Scattering, and Neutron Matter

    J. E. Lynn · I. Tews · J. Carlson · S. Gandolfi · A. Gezerlis · K. E. Schmidt · A. Schwenk

    We present quantum Monte Carlo calculations of light nuclei, neutron- scattering, and neutron matter using local two- and three-nucleon () interactions derived from chiral effective field theory up to next-to-next-to-leading order (NLO). The two undetermined low-energy couplings are fit to the He binding energy and, for the first time, to the spin-orbit splitting in the neutron- -wave phase shifts. Furthermore, we investigate different choices of local -operator structures and find that chiral interactions at NLO are able to simultaneously reproduce the properties of systems and of neutron matter, in contrast to commonly used phenomenological interactions.

    Comments:
    5 pages, 3 figures, 1 table - updated version: small wording changes, one reference change
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1509.03470 [pdf]
    PRL(2016)·323 citations
  6. 06

    [Submitted on 11 Sept 2015]

    Hyperons in Neutron Stars

    Isaac Vidana🇵🇹

    In this work I briefly review some of the effects of hyperons on the properties of neutron and proto-neutron stars. In particular, I revise the problem of the strong softening of the EoS, and the consequent reduction of the maximum mass, induced by the presence of hyperons, a puzzle which has become more intringuing and difficult to solve due the recent measurements of the unusually high masses of the millisecond pulsars PSR J1903+0327 (), PSR J1614-2230 (), and PSR J0348+0432 (). Some of the solutions proposed to tackle this problem are discussed. Finally, I re-examine also the role of hyperons on the cooling properties of newly born neutron stars and on the so-called r-mode instability.

    Comments:
    8 pages, 3 figures. Plenary talk at the 15th International Conference on Strangeness in Quark Matter (SQM2015), 6-11 July 2015, JINR, Dubna, Russia. To be published in Journal of Physics: Conference Series (JPCS)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    1509.03587 [pdf]
    J.Phys.Conf.Ser.(2016)·36 citations

Affiliations

first authorsco-authorsvia INSPIRE