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Nuclear Theory·nucl-th

Tuesday·September 13, 2022

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 08

    [Submitted on 30 Apr 2022] (cross-list from hep-th)

    Holographic Schwinger-Keldysh field theory of SU(2) diffusion

    Yanyan Bu🇨🇳 · Xiyang Sun🇨🇳 · Biye Zhang🇨🇳

    We construct effective field theory for SU(2) isospin charge diffusion, based on holographic Schwinger-Keldysh contour arXiv:2008.01269. The holographic model consists of a probe SU(2) gauge field in a doubled Schwarzschild-AdS geometry. Accurate to first order in derivative expansion, we analytically compute the effective action up to quartic order in hydrodynamical fields. The effective theory contains both non-Gaussianity for noises and nonlinear interactions between noises and dynamical variables. Moreover, the effective theory captures both thermal and quantum fluctuations, which perfectly satisfy dynamical Kubo-Martin-Schwinger (KMS) symmetry at quantum level. Interestingly, the dynamical KMS symmetry, which is crucial in formulating non-equilibrium effective field theory for a quantum many-body system, is found to have a nice holographic interpretation.

    Comments:
    published version ,32 pages, 2 figures
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2205.00195 [pdf]
    JHEP(2022)·14 citations
  2. 09

    [Submitted on 10 Sept 2022] (cross-list from astro-ph.HE)

    Bulk Viscosity of Relativistic Matter in Neutron-Star Mergers

    Mark Alford · Arus Harutyunyan · Armen Sedrakian

    We discuss the bulk viscosity of hot and dense matter arising from weak-interaction direct Urca processes. We consider two regimes of interest: (a) the neutrino-transparent regime with ( MeV is the neutrino-trapping temperature); and (b) the neutrino-trapped regime with . Nuclear matter is modeled in relativistic density functional approach with density-dependent parametrization DDME2. The maximum of the bulk viscosity is achieved at temperatures MeV in the neutrino-transparent regime, then it drops rapidly at higher temperatures where neutrino-trapping occurs. As an astrophysical application, we estimate the damping timescales of density oscillations by the bulk viscosity in neutron star mergers and find that, e.g., at the oscillation frequency kHz, the damping will be very efficient at temperatures MeV where the bulk viscosity might affect the evolution of the post-merger object.

    Comments:
    16 pages, 9 figures, matches published version
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2209.04717 [pdf]
    Particles(2022)·38 citations
  3. 10

    [Submitted on 12 Sept 2022] (cross-list from hep-ph)

    Exploration of trace anomaly contribution to proton mass based on light vector meson photoproduction

    Chen Dong🇨🇳 · Jiyuan Zhang🇨🇳 · Jingxuan Bu🇨🇳 · Huifang Zhou🇨🇳 · Xiao-Yun Wang🇨🇳

    In the quantum chromodynamics, the mass source of the proton is decomposed into four parts by the energy momentum tensor : quark energy term, gluon energy term, quark mass term and trace anomaly term. And the trace anomaly term is the most crucial contribution for studying the internal structure of the proton. In this work, under the definition of the vector meson dominant model, the trace anomaly contribution of the proton is extracted from the experimental datas of light vector mesons , and photoproduction at the near-threshold, which are (), () and (), respectively. Eventually, the average trace anomaly contribution of the proton is () , which only account for a small fraction of the total proton mass. The result of this work will provide theoretical information support for further study of proton internal structure.

    Comments:
    7 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2209.04979 [pdf]
    EPJC(2023)·4 citations
  4. 11

    [Submitted on 12 Sept 2022] (cross-list from nucl-ex)

    QCD Phase Structure and Interactions at High Baryon Density: Continuation of BES Physics Program with CBM at FAIR

    D. Almaalol🇺🇸 · M. Hippert🇺🇸 · J. Noronha-Hostler🇺🇸 · J. Noronha🇺🇸 · E. Speranza🇺🇸 · G. Basar🇺🇸 · S. Bass🇺🇸 · D. Cebra🇺🇸 · V. Dexheimer🇺🇸 · D. Keane🇺🇸 · S. Radhakrishnan🇺🇸 · A.I. Sheikh🇺🇸 and 32 other authors

    We advocate for an active US participation in the international collaboration of the CBM experiment that will allow the US nuclear physics program to build on its successful exploration of the QCD phase diagram, use the expertise gained at RHIC to make complementary measurements at FAIR, and contribute to achieving the scientific goals of the beam energy scan (BES) program.

    Comments:
    30 pages, 7 figures
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2209.05009 [pdf]
    38 citations
  5. 12

    [Submitted on 12 Sept 2022] (cross-list from physics.atom-ph)

    Empirical determination of the Bohr-Weisskopf effect in cesium and improved tests of precision atomic theory in searches for new physics

    G. Sanamyan🇦🇺 · B. M. Roberts🇦🇺 · J. S. M. Ginges🇦🇺

    The finite distribution of the nuclear magnetic moment across the nucleus gives a contribution to the hyperfine structure known as the Bohr-Weisskopf (BW) effect. We have obtained an empirical value of -0.24(18)% for this effect in the ground and excited s states of atomic Cs-133. This value is found from historical muonic-atom measurements in combination with our muonic-atom and atomic many-body calculations. The effect differs by 0.5% in the hyperfine structure from the value found using the uniform magnetization distribution, which has been commonly employed in the precision heavy-atom community over the last several decades. We also deduce accurate values for the BW effect in other isotopes and states of cesium. These results enable cesium atomic wave functions to be tested in the nuclear region at an unprecedented 0.2% level, and are needed for the development of precision atomic many-body methods. This is important for increasing the discovery potential of precision atomic searches for new physics, in particular for atomic parity violation in cesium.

    Subjects:
    Atomic Physics (physics.atom-ph); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2209.05099 [pdf]
    PRL(2023)·17 citations
  6. 13

    [Submitted on 12 Sept 2022] (cross-list from hep-ph)

    Accessing GPDs through the exclusive photoproduction of a -meson pair

    Goran Duplančić🇭🇷 · Saad Nabeebaccus🇫🇷 · Kornelija Passek-Kumerički🇭🇷 · Bernard Pire🇫🇷 · Lech Szymanowski🇵🇱 · Samuel Wallon🇫🇷

    We consider the exclusive photo-production of a photon-meson pair with a large invariant mass, working in the QCD factorisation framework. Explicitly, we consider a -meson or a charged in the final state. This process gives access both to chiral-even GPDs and chiral-odd GPDs, which are not well-known experimentally, especially the latter ones. The computation is performed at leading order and leading twist. We discuss the prospects of measuring them in experiments, focusing on the kinematics at the JLab 12-GeV experiment, and pPb ultra-peripheral collisions at LHC. In particular, the latter gives access to the small regime of GPDs.

    Comments:
    6 pages, 3 figures. Presented by S. Nabeebaccus at DIS2022: XXIX International Workshop on Deep-Inelastic Scattering and Related Subjects, Santiago de Compostela, Spain, May 2-6 2022
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2209.05380 [pdf]
    2 citations
  7. 14

    [Submitted on 12 Sept 2022] (cross-list from hep-ph)

    Gluon Transverse-Momentum-Dependent Distributions from Large-Momentum Effective Theory

    Ruilin Zhu🇨🇳 · Yao Ji🇩🇪 · Jian-Hui Zhang🇨🇳 · Shuai Zhao🇺🇸

    We demonstrate that gluon transverse-momentum-dependent parton distribution functions (TMDPDFs) can be extracted from lattice calculations of appropriate Euclidean correlations in large-momentum effective theory (LaMET). Based on perturbative calculations of gluon unpolarized and helicity TMDPDFs, we present a matching formula connecting them and their LaMET counterparts, where the latter are renormalized in a scheme facilitating lattice calculations and converted to the scheme. The hard matching kernel is given up to one-loop level. We also show that the perturbative result is independent of the prescription used for the pinch-pole singularity in the relevant correlations. Our results offer a guidance for the extraction of gluon TMDPDFs from lattice simulations, and have the potential to greatly facilitate perturbative calculations of the hard matching kernel.

    Comments:
    22 pages, 5 figures. Corrected a few typos. Accepted for publication in JHEP
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2209.05443 [pdf]
    JHEP(2023)·26 citations

Affiliations

first authorsco-authorsvia INSPIRE