Nuclear Theory·nucl-th

Monday·August 15, 2022

6 papers—4 primary·2 cross-listed

01
[Submitted on 11 Aug 2022]
The shear viscosity of parton matter under anisotropic scatterings
Noah M. MacKay🇺🇸 · Zi-Wei Lin🇺🇸
The shear viscosity $η$ of a quark-gluon plasma in equilibrium can be calculated analytically using multiple methods or numerically using the Green-Kubo relation. It has been realized, which we confirm here, that the Chapman-Enskog method agrees well with the Green-Kubo result for both isotropic and anisotropic two-body scatterings. We then apply the Chapman-Enskog method to study the shear viscosity of the parton matter from a multi-phase transport model. In particular, we study the parton matter in the center cell of central and midcentral Au+Au collisions at $200 A$ GeV and Pb+Pb collisions at $2760 A$ GeV, which is assumed to be a plasma in thermal equilibrium but partial chemical equilibrium. As a result of using a constant Debye mass or cross section $σ$ for parton scatterings, the $η / s$ ratio increases with time (as the effective temperature decreases), contrary to the trend preferred by Bayesian analysis of the experimental data or pQCD results that use temperature-dependent Debye masses. At $σ = 3$ mb that enables the transport model to approximately reproduce the elliptic flow data of the bulk matter, the average $η / s$ of the parton matter in partial equilibrium is found to be very small, between one to two times $1/ (4 π)$ .
Comments:
Added subsection on the Green-Kubo relation to better match published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2208.06027 [pdf]
EPJC(2022)·20 citations
02
[Submitted on 11 Aug 2022]
Dark matter effects on tidal deformabilities and moment of inertia in a hadronic model with short-range correlations
O. Lourenço🇧🇷 · C. H. Lenzi🇧🇷 · T. Frederico🇧🇷 · M. Dutra🇧🇷
In this work we study the outcomes related to dimensionless tidal deformability $(Λ)$ obtained through a relativistic mean-field (RMF) hadronic model including short-range correlations (SRC) and dark matter (DM) content [Phys. Rev. D 105, 023008 (2022)]. As a dark particle candidate, we use the lightest neutralino interacting with nucleons through the Higgs boson exchange. In particular, we test the model against the constraints regarding the observation of gravitational waves from the binary neutron star merger GW170817 event provided by LIGO and Virgo collaboration (LVC). We show that $Λ$ decreases as the dark particle Fermi momentum ( $k_{F}^{D M}$ ) increases. This feature favors the RMF-SRC-DM model used here to satisfy the limits of $Λ_{1.4} = 19 0_{- 120}^{+ 390}$ ( $Λ$ of a $1.4 M_{⊙}$ neutron star), and $Λ ~ = 30 0_{- 230}^{+ 420}$ given by the LVC. We also show that as $k_{F}^{D M}$ increases, $Λ_{1}$ and $Λ_{2}$ , namely, tidal deformabilities of the binary system, are also moved to the direction of the GW170817 observational data. Finally, we verify that the inclusion of DM in the system does not destroy the \mbox{ $I$ -Love} relation (correlation between $Λ$ and dimensionless moment of inertia, $I ˉ$ ). The observation data for $I ˉ_{⋆} \equiv I ˉ (M_{⋆}) = 11.1 0_{- 2.28}^{+ 3.68}$ , with $M_{⋆} = 1.338 M_{⊙}$ , is attained by the RMF-SRC-DM model.
Comments:
8 pages, 4 figures. Published in Phys. Rev. D
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2208.06067 [pdf]
PRD(2022)·47 citations
03
[Submitted on 12 Aug 2022]
Photon Production in High-Energy Heavy-Ion Collisions: Thermal Photons and Radiative Recombination
Hirotsugu Fujii🇯🇵 · Kazunori Itakura🇯🇵 · Katsunori Miyachi🇯🇵 · Chiho Nonaka🇯🇵
We present a comprehensive analysis of photon production at RHIC and the LHC, proposing radiative hadronization as an additional photon source in high-energy heavy-ion collisions. For thermal photon, we perform relativistic viscous hydrodynamic calculation with event-by-event fluctuations.
Comments:
6 pages, 4 figures, contribution to XXIXth International Conference on Ultra-relativistic Nucleus-Nucleus Collisions (QM2022)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2208.06168 [pdf]
Acta Phys.Polon.Supp.(2023)·2 citations
04
[Submitted on 12 Aug 2022]
Two-proton radioactivity within Coulomb and proximity potential model
De-Xing Zhu · Hong-Ming Liu · Yang-Yang Xu · You-Tian Zou · Xi-Jun Wu · Peng-Cheng Chu · Xiao-Hua Li
Considering the preformation probability of the two emitted protons in the parent nucleus, we extend the Coulomb and proximity potential model (CPPM) to systematically study two-proton (2p) radioactivity half-lives of the nuclei close to proton drip line. The proximity potential chosen is Prox. 81 proposed by Blocki et al. in 1981. Furthermore, we apply this model to predict the half-lives of possible 2p radioactive candidates whose 2p radioactivity is energetically allowed or observed but not yet quantified in the evaluated nuclear properties table NUBASE2016. The predicted results are in good agreement with those from other theoretical models and empirical formulas, namely the effective liquid drop model (ELDM), generalized liquid drop model (GLDM), Gamow-like model, Sreeja formula and Liu formula.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2208.06250 [pdf]
CPC(2022)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE

The shear viscosity of parton matter under anisotropic scatterings

Dark matter effects on tidal deformabilities and moment of inertia in a hadronic model with short-range correlations

Photon Production in High-Energy Heavy-Ion Collisions: Thermal Photons and Radiative Recombination

Two-proton radioactivity within Coulomb and proximity potential model

Affiliations