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Nuclear Theory·nucl-th

Monday·February 21, 2022

6 papers—1 primary·5 cross-listed

All6Primary1Cross-lists5
  1. 01

    [Submitted on 18 Feb 2022]

    Bjorken flow revisited: analytic and numerical solutions in flat space-time coordinates

    Daniele Simeoni🇮🇹 · Alessandro Gabbana🇳🇱 · Sauro Succi🇮🇹

    In this work we provide analytic and numerical solutions for the Bjorken flow, a standard benchmark in relativistic hydrodynamics providing a simple model for the bulk evolution of matter created in collisions between heavy nuclei. We consider relativistic gases of both massive and massless particles, working in a ( 2 + 1 ) and ( 3 + 1 ) Minkowski space-time coordinate system. The numerical results from a recently developed lattice kinetic scheme show excellent agreement with the analytic solutions.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); Computational Physics (physics.comp-ph)
    arXiv:
    2202.09133 [pdf]
    Commun.Comput.Phys.(2023)·4 citations
  2. 02

    [Submitted on 17 Feb 2022] (cross-list from hep-ph)

    Jet broadening in dense inhomogeneous matter

    João Barata🇪🇸 · Andrey V. Sadofyev🇪🇸 · Carlos A. Salgado🇪🇸

    In this work, we study the jet momentum broadening in an inhomogeneous dense QCD medium. The transverse profile of this nuclear matter is described within a gradient expansion, and we focus on the leading gradient contributions. The leading parton is allowed to interact multiple times with the background through the soft gluon exchanges. We derive the associated final particle distribution using both the GLV opacity series and the BDMPS-Z formalism. We further discuss the modified factorization of the initial and final state effects and its consequences for phenomenological applications in the context of heavy-ion collisions and deep inelastic scattering. Finally, we present the broadening probability (describing the final state effects) in several limiting regimes, and give its numerical estimates for phenomenologically motivated sets of parameters.

    Comments:
    42 pages, 4 figures, published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2202.08847 [pdf]
    PRD(2022)·61 citations
  3. 03

    [Submitted on 16 Feb 2022] (cross-list from physics.ins-det)

    Status and initial physics performance studies of the MPD experiment at NICA

    MPD Collaboration: V. Abgaryan · R. Acevedo Kado · S.V. Afanasyev · G.N. Agakishiev · E. Alpatov · G. Altsybeev · M. Alvarado Hernández · S.V. Andreeva · T.V. Andreeva · E.V. Andronov · N.V. Anfimov · A.A. Aparin and 466 other authors

    The Nuclotron-base Ion Collider fAcility (NICA) is under construction at the Joint Institute for Nuclear Research (JINR), with commissioning of the facility expected in late 2022. The Multi-Purpose Detector (MPD) has been designed to operate at NICA and its components are currently in production. The detector is expected to be ready for data taking with the first beams from NICA. This document provides an overview of the landscape of the investigation of the QCD phase diagram in the region of maximum baryonic density, where NICA and MPD will be able to provide significant and unique input. It also provides a detailed description of the MPD set-up, including its various subsystems as well as its support and computing infrastructures. Selected performance studies for particular physics measurements at MPD are presented and discussed in the context of existing data and theoretical expectations.

    Comments:
    53 pages, 68 figures, submitted as a Review article to EPJA
    Subjects:
    Instrumentation and Detectors (physics.ins-det); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2202.08970 [pdf]
    EPJA(2022)·125 citations
  4. 04

    [Submitted on 18 Feb 2022] (cross-list from hep-ph)

    Real-time observables from Euclidean thermal correlation functions

    Peter Lowdon🇩🇪 · Ralf-Arno Tripolt🇩🇪

    In this work we apply a local quantum field theory approach in order to analyse the connection between real-time observables and Euclidean thermal correlation functions. In particular, using data generated from the functional renormalisation group in the quark-meson model, we demonstrate that in-medium effects can be directly extracted from the spatial momentum dependence of the Euclidean propagators, in contrast to conventional approaches, which rely on the reconstruction from different Matsubara frequencies. As an application, we determine the analytic features that arise from the discrete spectral contribution to the pion correlation function, and calculate the non-perturbative shear viscosity arising from these states.

    Comments:
    13 pages, 5 figures; v2: additional discussion added, matches published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2202.09142 [pdf]
    PRD(2022)·7 citations
  5. 05

    [Submitted on 18 Feb 2022] (cross-list from hep-lat)

    Taylor expansions and Padé approximants for cumulants of conserved charge fluctuations at non-vanishing chemical potentials

    D. Bollweg🇺🇸 · J. Goswami🇩🇪 · O. Kaczmarek🇩🇪 · F. Karsch🇩🇪 · Swagato Mukherjee🇺🇸 · P. Petreczky🇺🇸 · C. Schmidt🇩🇪 · P. Scior🇺🇸

    Using high statistics datasets generated in (2+1)-flavor QCD calculations at finite temperature we present results for low order cumulants of net baryon-number fluctuations at non-zero values of the baryon chemical potential. We calculate Taylor expansions for the pressure (zeroth order cumulant), net baryon-number density (first order cumulant) and the variance of the distribution on net-baryon number fluctuations (second order cumulant). We obtain series expansions from an eighth order expansion of the pressure and compare these to diagonal Padé approximants. This allows us to estimate the range of values for the baryon chemical potential in which these expansions are reliable. We find , and for the zeroth, first and second order cumulants, respectively. We furthermore, construct estimators for the radius of convergence of the Taylor series of the pressure. In the vicinity of the pseudo-critical temperature, MeV, we find at vanishing strangeness chemical potential and somewhat larger values for strangeness neutral matter. These estimates are temperature dependent and range from at MeV to at MeV. The estimated radius of convergences is the same for any higher order cumulant.

    Comments:
    15 pages
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2202.09184 [pdf]
    PRD(2022)·115 citations
  6. 06

    [Submitted on 18 Feb 2022] (cross-list from astro-ph.HE)

    Chiral plasma instability and inverse cascade from nonequilibrium left-handed neutrinos in core-collapse supernovae

    Jin Matsumoto🇯🇵 · Naoki Yamamoto🇯🇵 · Di-Lun Yang🇹🇼

    We show that the backreaction of left-handed neutrinos out of equilibrium on the matter sector induces an electric current proportional to a magnetic field even without a chiral imbalance for electrons in core-collapse supernovae. We derive the transport coefficient of this effect based on the recently formulated chiral radiation transport theory for neutrinos. This chiral electric current generates a strong magnetic field via the so-called chiral plasma instability, which could provide a new mechanism for the strong and stable magnetic field of magnetars. We also numerically study the physical origin of the inverse cascade of the magnetic energy in the magnetohydrodynamics including this current. Our results indicate that incorporating the chiral effects of neutrinos would drastically modify the hydrodynamic evolutions of supernovae, which may also be relevant to the explosion dynamics.

    Comments:
    8 pages, 6 figures; v2: added figure 2 on the time evolution of magnetic helicity, minor revisions, published version
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2202.09205 [pdf]
    PRD(2022)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE