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Nuclear Theory·nucl-th

Friday·April 8, 2022

6 papers—2 primary·4 cross-listed

All6Primary2Cross-lists4
  1. 01

    [Submitted on 6 Apr 2022]

    Radiative hadronization: Photon emission at hadronization from quark-gluon plasma

    Hirotsugu Fujii🇯🇵 · Kazunori Itakura🇯🇵 · Katsunori Miyachi🇯🇵 · Chiho Nonaka🇯🇵

    We investigate photon emission at the hadronization stage from a quark-gluon plasma created in relativistic heavy-ion collisions. A recombination-model picture suggests that a quark and an antiquark bind into a meson state in hadronization, which would apparently violate the energy conservation if there is nothing else involved. We consider here a hadronization process where the recombination accompanies a photon emission. This is an analog of the "{\it radiative recombination}" known in plasma physics, such as , which occurs when an electromagnetic plasma goes back to a neutral atomic gas. The "radiative hadronization" picture will bring about (i) an enhancement of the photon yield, (ii) significant flow of photons similar to that of hadrons, and (iii) the photon transverse momentum () distribution with a thermal profile whose effective temperature is given by blue-shifted temperature of quarks. Here as a simplest and phenomenological realization of the radiative hadronization, we modify the recombination model to involve a photon emission and evaluate the photon yield with this modified model. Adding this contribution to the direct photon yield along with thermal photon contribution calculated with a hydrodynamic model and a parametrized contribution of prompt photons, we study the spectrum and elliptic flow of the photons produced in heavy-ion collisions at RHIC and LHC energies.

    Comments:
    25 pages, 15 figures (Appendix C with Fig.15 is added)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2204.03116 [pdf]
    PRC(2022)·15 citations
  2. 02

    [Submitted on 7 Apr 2022]

    Density functional approach to quark matter with confinement and color superconductivity

    Oleksii Ivanytskyi🇵🇱 · David Blaschke🇵🇱

    We present a novel relativistic density-functional approach to modeling quark matter with a mechanism to mimic confinement. The quasiparticle treatment of quarks provides their suppression due to a large quark selfenergy already at the mean-field level. We demonstrate that our approach is equivalent to a chiral quark model with medium-dependent couplings. The dynamical restoration of the chiral symmetry is ensured by construction of the density functional. Supplemented with the vector repulsion and diquark pairing the model is applied to construct a hybrid quark-hadron EoS of cold compact-star matter. We study the connection of such a hybrid EoS with the stellar mass-radius relation and tidal deformability. The model results are compared to various observational constraints including the NICER radius measurement of PSR J0740+6620 and the tidal deformability constraint from GW170817. The model is shown to be consistent with the constraints, still allowing for further improvement by adjusting the vector repulsion and diquark pairing couplings.

    Comments:
    Version accepted for publication in Physical Review D, 16 pages, 16 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2204.03611 [pdf]
    PRD(2022)·63 citations

Affiliations

first authorsco-authorsvia INSPIRE