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Nuclear Theory·nucl-th

Tuesday·April 17, 2018

17 papers—12 primary·5 cross-listed

All17Primary12Cross-lists5
  1. 13

    [Submitted on 8 Apr 2018] (cross-list from hep-ph)

    Charm quarks are more hydrodynamic than light quarks in final-state elliptic flow

    Hanlin Li🇨🇳 · Zi-Wei Lin🇨🇳 · Fuqiang Wang🇨🇳

    We study the charm quark elliptic flow () in heavy ion as well as small system collisions by tracking the evolution history of quarks of different flavors within a multi-phase transport model. The charm quark is studied as a function of the number of collisions the charm quark suffers with other quarks and then compared to the of lighter quarks. We find that the common escape mechanism is at work for both the charm and light quark . However, contrary to the naive expectation, the hydrodynamics-type flow is found to contribute more to the final state charm than light quark . This could be explained by the smaller average deflection angle the heavier charm quark undergoes in each collision, so that heavy quarks need more scatterings to accumulate a significant , while lighter quarks can more easily change directions with scatterings with their coming more from the escape mechanism. Our finding thus suggests that the charm is a better probe for studying the hydrodynamic properties of the quark-gluon plasma.

    Comments:
    10 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1804.02681 [pdf]
    PRC(2019)·25 citations
  2. 14

    [Submitted on 15 Apr 2018] (cross-list from hep-ph)

    In depth analysis of the combined HERA data in the dipole models with and without saturation

    Heikki Mäntysaari🇫🇮 · Pia Zurita🇺🇸

    We present an updated impact parameter dependent saturation model (IPsat) determined trough a fit to the combined HERA I and I+II reduced cross section data. The same HERA data are used to fit the linearized (IPnonsat) version of the applied dipole amplitude, which makes it possible to estimate the magnitude of the saturation effects in various experiments. We find that both parametrizations provide comparable descriptions of the considered data when an effective confinement scale dynamics is incorporated with quark masses. Moreover, it is possible to consistently determine the light and charm quark masses. The role of potentially non-perturbatively large dipoles is examined in detail, with the result that, especially in case of the structure function , their contribution is numerically significant. Potential to discriminate between the two models in future and experiments is also illustrated.

    Comments:
    17 pages, 23 figures. v2: version published in PRD
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1804.05311 [pdf]
    PRD(2018)·92 citations
  3. 15

    [Submitted on 16 Apr 2018] (cross-list from physics.atom-ph)

    Enhanced nuclear spin dependent parity violation effects using the 199HgH molecule

    A. J. Geddes🇦🇺 · L. V. Skripnikov🇷🇺 · A. Borschevsky🇳🇱 · J. C. Berengut🇦🇺 · V. V. Flambaum🇦🇺 · T. P. Rakitzis🇬🇷

    Electron interactions with the nuclear-spin-dependent (NSD) parity non-conserving (PNC) anapole moment are strongly enhanced within heteronuclear diatomic molecules. A novel, low-energy optical rotation experiment is being proposed with the aim of observing NSD PNC interactions in HgH. Based on the relativistic coupled cluster method we present a complete calculation of the circular polarization parameter for the optical transition of HgH, where is a dimensionless constant determined by the nuclear anapole moment. This provides an improvement in sensitivity to NSD PNC by 2 -- 3 orders of magnitude over the leading atomic Xe, Hg, Tl, Pb and Bi optical rotation experiments, and shows that the proposed measurement will be sensitive enough to extract the Hg anapole moment and shed light on the underlying theory of hadronic parity violation.

    Subjects:
    Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th)
    arXiv:
    1804.05475 [pdf]
    PRA(2018)·12 citations
  4. 16

    [Submitted on 16 Apr 2018] (cross-list from astro-ph.HE)

    Effective Stellar -Decay Rates of Nuclei with Long-lived Isomers: Al and Cl

    Projjwal Banerjee · G. Wendell Misch · Surja K. Ghorui · Yang Sun

    Isotopes with low-lying long-lived isomers can behave very differently from other isotopes in astrophysical environments. In particular, the assumption of thermal equilibrium in computing the temperature-dependent -decay rates of such isotopes can fail below certain temperatures. We focus on the -decay of Al since it is one of the most important isotopes in observational astrophysics and has a low-lying isomeric state; we compare and contrast these results with Cl. We rule out recently reported Al effective -decay rates that showed large differences from previous calculations, finding that we agree with the earlier results. We conclude that in general, effective -decay rates should be defined separately for the ground and isomeric states at temperatures where thermal equilibrium cannot be achieved.

    Comments:
    9 pages, 7 figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1804.05657 [pdf]
    PRC(2018)·15 citations
  5. 17

    [Submitted on 13 Apr 2018] (cross-list from hep-ph)

    Centrality dependence of freeze-out temperature fluctuations in Pb-Pb collisions at the LHC

    Dariusz Prorok🇵🇱

    Many data in the High Energy Physics are, in fact, sample means. It is shown that when this exact meaning of the data is taken into account and the most weakly bound states are removed from the hadron resonance gas, the whole spectra of pions, kaons and protons measured at midrapidity in Pb-Pb collisions at TeV can be fitted simultaneously. The invariant distributions are predicted with the help of the single-freeze-out model in the chemical equilibrium framework. The method is applied to the measurements in centrality bins of Pb-Pb collisions and gives acceptable fits for all but peripheral bins. The comparison with the results obtained in the framework of the original single-freeze-out model is also presented. Some more general, possible implications of this approach are pointed out.

    Comments:
    7 pages, 7 figures. arXiv admin note: substantial text overlap with arXiv:1508.07922, matches the published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1804.05691 [pdf]
    EPJA(2019)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE