Nuclear Theory·nucl-th

Monday·August 10, 2020

12 papers—4 primary·8 cross-listed

01
Structure Factors of Neutron Matter at Finite Temperature
Andrei Alexandru🇺🇸 · Paulo Bedaque🇺🇸 · Evan Berkowitz🇺🇸 · Neill C. Warrington🇺🇸
We compute continuum and infinite volume limit extrapolations of the structure factors of neutron matter at finite temperature and density. Using a lattice formulation of leading-order pionless effective field theory, we compute the momentum dependence of the structure factors at finite temperature and at densities beyond the reach of the virial expansion. The Tan contact parameter is computed and the result agrees with the high momentum tail of the vector structure factor. All errors, statistical and systematic, are controlled for. This calculation is a first step towards a model-independent understanding of the linear response of neutron matter at finite temperature, a realm until now little explored.
nucl-thastro-ph.HEcond-mat.quant-gashep-latPRL(2021)·13 citations
02
Constraining the nuclear symmetry energy and properties of neutron star from GW170817 by Bayesian analysis
Yuxi Li · Houyuan Chen · Dehua Wen · Jing Zhang
Based on the distribution of tidal deformabilities and component masses of binary neutron star merger GW170817, the parametric equation of states (EOS) are employed to probe the nuclear symmetry energy and the properties of neutron star. To obtain a proper distribution of the parameters of the EOS that is consistent with the observation, Bayesian analysis is used and the constraints of causality and maximum mass are considered. From this analysis, it is found that the symmetry energy at twice the saturation density of nuclear matter can be constrained within $E_{sy m} (2 ρ_{0})$ = $34. 5_{- 2.3}^{+ 20.5}$ MeV at 90\% credible level. Moreover, the constraints on the radii and dimensionless tidal deformabilities of canonical neutron stars are also demonstrated through this analysis, and the corresponding constraints are 10.80 km $< R_{1.4} <$ 13.20 km and $133 < Λ_{1.4} < 686$ at 90\% credible level, with the most probable value of $R ˉ_{1.4}$ = 12.60 km and $Λ ˉ_{1.4}$ = 500, respectively. With respect to the prior, our result (posterior result) prefers a softer EOS, corresponding to a lower expected value of symmetry energy, a smaller radius and a smaller tidal deformability.
nucl-thastro-ph.HEEPJA(2021)·33 citations
03
Elliptic flow of hadrons in equal-velocity quark combination mechanism in relativistic heavy-ion collisions
Jun Song🇨🇳 · Hai-hong Li🇨🇳 · Feng-lan Shao🇨🇳
We apply a quark combination model with equal-velocity combination (EVC) approximation to study the elliptic flow ( $v_{2}$ ) of hadrons in heavy-ion collisions in a wide collision energy range ( $s_{N N} =$ 27 - 5020 GeV). Utilizing the simple relationship between $v_{2}$ of hadrons and those of quarks under EVC, we find that $v_{2}$ of up/down quarks obtained by experimental data of proton is consistent with that obtained by data of $Λ$ and $Ξ$ . $v_{2}$ of strange quarks obtained by data of $Ω$ is consistent with that obtained by data of $Λ$ and $Ξ$ , and at RHIC energies it is also consistent with that obtained by data of $ϕ$ . This means that $v_{2}$ of these hadrons have a common quark-level source. Using data of $D^{0}$ , we obtain $v_{2}$ of charm quarks with $p_{T} ≲ 6$ GeV/c. We find that under EVC charm quark dominates $v_{2}$ of $D$ mesons at low $p_{T}$ but light-flavor quarks significantly contribute to $v_{2}$ of $D$ mesons in the range $3 ≲ p_{T} ≲ 8$ GeV/c. We predict $v_{2}$ of charmed baryons $Λ_{c}^{+}$ and $Ξ_{c}^{0}$ which show a significant enhancement at intermediate $p_{T}$ due to the double contribution of light-flavor quarks. The properties of the obtained quark $v_{2}$ under EVC are studied and a regularity for $v_{2}$ of quarks as the function of $p_{T} / m$ is found.
nucl-thEPJC(2021)·16 citations
04
Extracting $σ_{π N}$ from pionic atoms
Eliahu Friedman · Avraham Gal
We discuss a recent extraction of the $π N$ $σ$ term $σ_{π N}$ from a large-scale fit of pionic-atom strong-interaction data across the periodic table. The value thus derived, $σ_{π N}^{FG} = 57 \pm 7$ MeV, is directly connected via the Gell-Mann--Oakes--Renner expression to the medium-renormalized $π N$ isovector scattering amplitude near threshold. It compares well with the value derived recently by the Bern-Bonn-Jülich group, $σ_{π N}^{RS} = 58 \pm 5$ MeV, using the Roy-Steiner equations to control the extrapolation of the vanishingly small near threshold $π N$ isoscalar scattering amplitude to zero pion mass.
nucl-thhep-phActa Phys. Pol. B 51 (2020) 45 and AIP Co…

Affiliations

first authorsco-authorsvia INSPIRE

Structure Factors of Neutron Matter at Finite Temperature

Constraining the nuclear symmetry energy and properties of neutron star from GW170817 by Bayesian analysis

Elliptic flow of hadrons in equal-velocity quark combination mechanism in relativistic heavy-ion collisions

Extracting σπN​ from pionic atoms

Affiliations

Extracting $σ_{π N}$ from pionic atoms