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Nuclear Theory·nucl-th

Wednesday·November 16, 2016

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 14 Nov 2016]

    Quantifying Chiral Magnetic Effect from Anomalous-Viscous Fluid Dynamics

    Yin Jiang🇩🇪 · Shuzhe Shi🇺🇸 · Yi Yin🇺🇸 · Jinfeng Liao🇺🇸

    The Chiral Magnetic Effect (CME) is a macroscopic manifestation of fundamental chiral anomaly in a many-body system of chiral fermions, and emerges as anomalous transport current in the fluid dynamics framework. Experimental observation of CME is of great interest and has been reported in Dirac and Weyl semimetals. Significant efforts have also been made to look for CME in heavy ion collisions. Critically needed for such search, is the theoretical prediction for CME signal. In this paper we report a first quantitative modeling framework, the Anomalous Viscous Fluid Dynamics (AVFD), which computes the evolution of fermion currents on top of realistic bulk evolution in heavy ion collisions and simultaneously accounts for both anomalous and normal viscous transport effects. The AVFD allows a quantitative understanding of the generation and evolution of CME-induced charge separation during hydrodynamic stage as well as its dependence on theoretical ingredients. With reasonable estimates of key parameters, the AVFD simulations provide the first phenomenologically successful explanation of the measured signal in 200AGeV AuAu collisions.

    Comments:
    5 pages, 6 figures; published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1611.04586 [pdf]
    CPC(2018)·110 citations
  2. 02

    [Submitted on 15 Nov 2016]

    Pseudoscalar condensation induced by chiral anomaly and vorticity for massive fermions

    Ren-hong Fang🇨🇳 · Jin-yi Pang🇩🇪 · Qun Wang🇨🇳 · Xin-nian Wang🇨🇳

    We derive the pseudoscalar condensate induced by anomaly and vorticity from the Wigner function for massive fermions in homogeneous electromagnetic fields. It has an anomaly term and a force-vorticity coupling term. As a mass effect, the pseudoscalar condensate is linearly proportional to the fermion mass in small mass expansion. By a generalization to two-flavor and three-flavor cases, the neutral pion and eta meson condensates are calculated from the Wigner function and have anomaly parts as well as force-vorticity parts, in which the anomaly part of the neutral pion condensate is consistent to the previous result. We also discuss about possible observables of the condensates in heavy ion collisions such as collective flows of neutral pions and eta mesons which may be influenced by the electromagnetic field and vorticity profiles.

    Comments:
    RevTex 4, 14 pages, 2 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1611.04670 [pdf]
    PRD(2017)·40 citations
  3. 03

    [Submitted on 15 Nov 2016]

    Overview of electromagnetic probes in ultra-relativistic heavy-ion collisions

    Jean-François Paquet🇺🇸

    An introductory overview of electromagnetic probes in ultra-relativistic heavy-ion collisions is provided. Experimental evidence supporting the production of thermal photons and dileptons in heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) are reviewed. Thermal electromagnetic emission evaluated from hydrodynamical models of collisions is discussed.

    Comments:
    Contribution to Hot Quarks 2016 proceedings. 6 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1611.05020 [pdf]
    J.Phys.Conf.Ser.(2017)·13 citations
  4. 04

    [Submitted on 11 Nov 2016] (cross-list from hep-lat)

    Euclidean relativistic quantum mechanics - scattering asymptotic conditions

    W. N. Polyzou🇺🇸 · Gordon Aiello🇺🇸

    We discuss the formulation of the scattering asymptotic condition in a relativistic quantum theory formulated in terms of reflection positive Euclidean Green functions.

    Comments:
    8 pages, proceedings of light cone 2016, Lisbon Portugal
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1611.04631 [pdf]
    Few Body Syst.(2017)·0 citations
  5. 05

    [Submitted on 15 Nov 2016] (cross-list from hep-ph)

    Relativistic effects in model calculations of double parton distribution function

    Matteo Rinaldi🇪🇸 · Federico Alberto Ceccopieri🇮🇹

    In this paper we consider double parton distribution functions (dPDFs) which are the main non perturbative ingredients appearing in the double parton scattering cross section formula in hadronic collisions. By using recent calculation of dPDFs by means of constituent quark models within the so called Light-Front approach, we investigate the role of relativistic effects on dPDFs. We find, in particular, that the so called Melosh operators, which allow to properly convert the LF spin into the canonical one and incorporate a proper treatment of boosts, produce sizeable effects on dPDFs. We discuss specific partonic correlations induced by these operators in transverse plane which are relevant to the proton structure and study under which conditions these results are stable against variations in the choice of the proton wave function.

    Comments:
    8 Figures, 9 pages and 1 table
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1611.04793 [pdf]
    PRD(2017)·35 citations
  6. 06

    [Submitted on 15 Nov 2016] (cross-list from hep-ph)

    Analytic Solutions of Transverse Magneto-hydrodynamics under Bjorken Expansion

    Shi Pu🇩🇪 · Di-Lun Yang🇯🇵

    We review the recent developments of analytic solutions in transverse magneto-hydrodynamics under Bjorken expansion. It is found that the time dependence of magnetic fields can either increase or reduce the energy density depending on the decay exponent of magnetic fields. Moreover, perturbative solutions under weak magnetic fields with spatial inhomogeneity results in transverse flow, where the directions of flow also depend on the decay exponent of magnetic fields in time.

    Comments:
    6 pages, 2 figures, proceeding of XII Confinement and the hadron spectrum
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1611.04840 [pdf]
    EPJ Web Conf.(2017)·16 citations
  7. 07

    [Submitted on 15 Nov 2016] (cross-list from hep-ph)

    Direct-Photon Spectra and Anisotropic Flow in Heavy Ion Collisions from Holography

    Ioannis Iatrakis🇳🇱 · Elias Kiritsis🇬🇷 · Chun Shen🇨🇦 · Di-Lun Yang🇯🇵

    The thermal-photon emission from strongly coupled gauge theories at finite temperature is calculated by using holographic models for QCD in the Veneziano limit (V-QCD). These emission rates are then embedded in hydrodynamic simulations combined with prompt photons from hard scattering and the thermal photons from hadron gas to analyze the spectra and anisotropic flow of direct photons at RHIC and LHC. The results from different sources responsible for the thermal photons in the quark gluon plasma (QGP) including the weakly coupled QGP (wQGP) from perturbative calculations, strongly coupled =4 super Yang-Mills (SYM) plasma (as a benchmark for reference), and Gubser's phenomenological model mimicking the strongly coupled QGP (sQGP) are then compared. It is found that the direct-photon spectra are enhanced in the strongly coupled scenario compared with the ones in the wQGP, especially at intermediate and high momenta, which improve the agreements with data. Moreover, by using IP-glassma initial states, both the elliptic flow and triangular flow of direct photons are amplified at high momenta (>2.5 GeV) for V-QCD, while they are suppressed at low momenta compared to wQGP. The distinct results in holography stem from the blue-shift of emission rates in strong coupling. In addition, the spectra and flow in small collision systems were evaluated for future comparisons. It is found that thermal photons from the deconfined phase are substantial to reconcile the spectra and flow at high momenta.

    Comments:
    10 pages, 7 figures, proceeding of XII Confinement and the hadron spectrum
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1611.04848 [pdf]
    EPJ Web Conf.(2017)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE