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Nuclear Theory·nucl-th

Tuesday·August 24, 2021

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 05

    [Submitted on 20 Aug 2021] (cross-list from nucl-ex)

    The Physics of Neutrinoless Double Beta Decay: A Primer

    B.J.P. Jones🇺🇸

    Neutrinoless double beta decay is a hypothetical radioactive process which, if observed, would prove the neutrino to be a Majorana fermion: a particle that is its own antiparticle. In this lecture mini-series I discuss the physics of Majorana fermions and the connection between the nature of neutrino mass and neutrinoless double beta decay. We review Dirac and Majorana spinors, discuss methods of distinguishing between Majorana and Dirac fermions, and derive in outline the connection between neutrino mass and double beta decay rates. We conclude by briefly summarizing the experimental landscape and the challenges associated with searches for this elusive process.

    Comments:
    A write-up of a lecture series given at the Theoretical Advanced Study Institute: The Obscure Universe: Neutrinos and Other Dark Matters - TASI2020 summer school v2: Fix some typos from v1
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2108.09364 [pdf]
    35 citations
  2. 06

    [Submitted on 21 Aug 2021] (cross-list from hep-ph)

    3-dimensional QCD phase diagram with pion condensate in the NJL model

    Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Guang-Xiong Peng🇨🇳

    With the isovector coupling constants adjusted to reproduce the physical pion mass and lattice QCD results in baryon-free quark matter, we have carried out rigourous calculations for the pion condensate in the 3-flavor Nambu-Jona-Lasinio model, and studied the 3-dimensional QCD phase diagram. With the increasing isospin chemical potential , we have observed two nonzero solutions of the pion condensate at finite baryon chemical potentials , representing respectively the pion superfluid phase and the Sarma phase, and their appearance and disappearance correspond to a second-order (first-order) phase transition at higher (lower) temperatures and lower (higher) . Calculations by assuming equal constituent mass of and quarks would lead to large errors of the QCD phase diagram within MeV, and affect the position of the critical end point.

    Comments:
    14 pages, 10 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2108.09477 [pdf]
    PRD(2021)·17 citations
  3. 07

    [Submitted on 22 Aug 2021] (cross-list from hep-ph)

    Chiral vortical catalysis

    Yin Jiang🇨🇳

    Gluon interaction introduces remarkable corrections to the magnetic polarization effects on the chiral fermions, which is known as the inverse magnetic catalysis. It is a natural speculation that the vorticity, which has many similar properties as magnetic field, would bring non-negligible contribution to the chiral rotational suppression. Using the intuitive semi-classical background field method we studied the rotation dependence of the effective strong interaction coupling. Contrary to the magnetic field case the rotation increases the effective coupling which leads to slowing down the condensate melting procedure with temperature. This could be named as the chiral vortical catalysis or inverse rotation suppression. Imposing such dependence to the coupling in the NJL model, we numerically checked this analysis qualitatively. The pseudo critical temperature is shown to rise with the rotation and approach saturation eventually which may be induced by the model cutoff.

    Comments:
    6 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2108.09622 [pdf]
    EPJC(2022)·20 citations
  4. 08

    [Submitted on 22 Aug 2021] (cross-list from hep-ph)

    Femtoscopic study of coupled-channel and interactions

    Y. Kamiya🇨🇳 · K. Sasaki🇯🇵 · T. Fukui🇯🇵 · T. Hyodo🇯🇵 · K. Morita🇯🇵 · K. Ogata🇯🇵 · A. Ohnishi🇯🇵 · T. Hatsuda🇯🇵

    The momentum correlation functions of S = -2 baryon pairs (p Xi^- and Lambda Lambda) produced in high-energy pp and pA collisions are investigated on the basis of the coupled-channel formalism. The strong interaction is described by the coupled-channel HAL QCD potential obtained by the lattice QCD simulations near physical quark masses, while the hadronic source function is taken to be a static Gaussian form. The coupled-channel effect, the threshold difference, the realistic strong interaction, and the Coulomb interaction are fully taken into account for the first time in the femtoscopic analysis of baryon-baryon correlations. The characteristic features of the experimental data for the p Xi^- and Lambda Lambda pairs at LHC are reproduced quantitatively with a suitable choice of non-femtoscopic parameters and the source size. The agreement between theory and experiment indicates that the N Xi (Lambda Lambda) interaction is moderately (weakly) attractive without having a quasi-bound (bound) state.

    Comments:
    13 pages, 10 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2108.09644 [pdf]
    PRC(2022)·68 citations
  5. 09

    [Submitted on 23 Aug 2021] (cross-list from physics.data-an)

    Pileup Correction on Higher-order Cumulants with Unfolding Approach

    Yu Zhang🇨🇳 · Yige Huang🇨🇳 · Toshihiro Nonaka🇯🇵 · Xiaofeng Luo🇨🇳

    Higher-order cumulants of conserved charge distributions are sensitive observables to probe the critical fluctuations near QCD critical point in heavy-ion collisions. Due to high interaction rate, pileup event can be one of the major sources of background in the measurements of higher-order cumulants. In this paper, we studied the effects of pileup events on higher-order cumulants of proton multiplicity distributions using UrQMD model. It is found that the proposed pileup correction fails if the correction parameters are determined by the Glauber fitting of charged particle multiplicities, which is usually done in the real heavy-ion experiment. To address this, we propose a model independent unfolding approach to determine the parameters in the pileup correction. This approach can be applied in the pileup correction for the future measurement of higher-order cumulants in heavy-ion collision experiment.

    Comments:
    14 pages, 6 figures
    Subjects:
    Data Analysis, Statistics and Probability (physics.data-an); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2108.10134 [pdf]
    Nucl.Instrum.Meth.A(2022)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE