Nuclear Theory·nucl-th

Tuesday·February 7, 2023

8 papers—4 primary·4 cross-listed

01
[Submitted on 4 Feb 2023]
Shedding light on the pion production in heavy-ion collisions and application into the neutron star matter properties
Heng-Jin Liu🇨🇳 · Ban Zhang · Yuan-Qing Guo🇨🇳 · Hui-Gan Cheng🇨🇳 · Si-Na Wei🇨🇳 · Zhao-Qing Feng🇨🇳
Within the framework of the quantum molecular dynamics transport model, the pion production and constraint of the high-density symmetry energy in heavy-ion collisions near threshold energy have been thoroughly investigated. The energy conservation in the decay of resonances and reabsorption of pions as well as in the inelastic nucleon-nucleon and nucleon-resonance collisions are taken into account. The isospin diffusion in the low-density region (0.2 $ρ_{0}$ - 0.8 $ρ_{0}$ ) and high-density region (1.2 $ρ_{0}$ - 1.8 $ρ_{0}$ ) is investigated by analyzing the spectra of neutron/proton and $π^{-} / π^{+}$ ratios in the isotopic reactions of $^{132}$ Sn + $^{124}$ Sn and $^{108}$ Sn + $^{112}$ Sn at the incident energy of 270 MeV/nucleon, in which the symmetry energy manifests the opposite effect in the different density domain. The controversial conclusion of the $π^{-} / π^{+}$ ratio for constraining the high-density symmetry energy by different transport models with the FOPI data has been clarified. A soft symmetry energy with the slope parameter of $L (ρ_{0}) = 42 \pm 25$ MeV by using the standard error analysis within the range of $1 σ$ is obtained by analyzing the experimental data from the S $π$ RIT collaboration. The neutron stars with the maximal mass of 2 $M_{⊙}$ and radius of 11-13 km are obtained with the constrained symmetry energy.
Comments:
10 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2302.02131 [pdf]
1 citation
02
[Submitted on 5 Feb 2023]
Probing the jet transport coefficient of cold nuclear matter in electron-ion collisions
Peng Ru🇨🇳 · Zhong-Bo Kang🇺🇸 · Enke Wang🇨🇳 · Hongxi Xing🇨🇳 · Ben-Wei Zhang🇨🇳
We present a study of the nuclear-medium induced transverse momentum broadening of particle production in future electron-ion-collision~(EIC) experiments. By considering the multiple scattering between hard partons and cold nuclear medium within the higher-twist factorization framework in perturbative QCD, we calculate the transverse momentum broadening of single hadron production in semi-inclusive measurements, as well as the nuclear enhancement of the transverse momentum imbalance for di-hadron and heavy-meson pair productions. In particular, a kinematics dependent non-perturbative jet transport coefficient $q^= q^(x, Q^{2})$ extracted in a global analysis of the current data, together with its uncertainty determined with a Hessian method, are input into our calculations and are available for the community. Significant kinematic and color-state dependences of the nuclear induced broadening/imbalance are predicted. Our results indicate that the future EIC measurements are able to provide powerful constraints on the kinematic dependence of the transport coefficient $q^$ and thus greatly facilitate the jet tomography of cold nuclear medium.
Comments:
16 pages, 15 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2302.02329 [pdf]
6 citations
03
[Submitted on 6 Feb 2023]
Three- $α$ configurations of the second $J^{π} = 2^{+}$ state in $^{12}$ C
H. Moriya · W. Horiuchi · J. Casal · L. Fortunato
We investigate geometric configurations of $α$ ( $^{4}$ He nucleus) clusters in the second $J^{π} = 2^{+}$ state of $^{12}$ C, which has been discussed as a rotational band member of the second $0^{+}$ state, the Hoyle state. The ground and excited $0^{+}$ and $2^{+}$ states are described by a three- $α$ cluster model. The three-body Schrödinger equation with orthogonality conditions is accurately solved by the stochastic variational method with correlated Gaussian basis functions. To analyse the structure of these resonant states in a convenient form, we introduce a confining potential. The two-body density distributions together with the spectroscopic information clarify the structure of these states. We find that main configurations of both the second $0^{+}$ and $2^{+}$ states are acute-angled triangle shapes originating from the $^{8}$ Be( $0^{+}$ ) $+ α$ configuration. However, the $^{8}$ Be $+ α$ components in the second $2^{+}$ state become approximately 2/3 because the 8Be subsystem is hard to excite, indicating that the state is not an ideal rigid rotational band member of the Hoyle state.
Comments:
7 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2302.02539 [pdf]
EPJA(2023)·3 citations
04
[Submitted on 6 Feb 2023]
Nuclear and Hybrid Equations of State in Light of the Low-Mass Compact Star in HESS J1731-347
Liam Brodie🇺🇸 · Alexander Haber🇺🇸
We sample over $500$ relativistic mean-field theories constrained by chiral effective field theory and properties of isospin-symmetric nuclear matter and test them against known stellar structure constraints. This includes a recent mass and radius measurement of a compact object in supernova remnant HESS J1731-347, with an unusually low mass of $M = 0.7 7_{- 0.17}^{+ 0.20} M_{⊙}$ and a compact radius of $R = 10. 4_{- 0.78}^{+ 0.86}$ km. We show that none of the sampled nuclear models meet all constraints at the $68 %$ credibility level, but that hybrid equations of state with a quark matter inner core and nuclear outer core easily can. This indicates a tension between astrophysical constraints and low-energy nuclear theory.
Comments:
7 pages, 3 figures, version to appear in PRC, minor changes
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2302.02989 [pdf]
PRC(2023)·40 citations

Affiliations

first authorsco-authorsvia INSPIRE

Shedding light on the pion production in heavy-ion collisions and application into the neutron star matter properties

Probing the jet transport coefficient of cold nuclear matter in electron-ion collisions

Three-α configurations of the second Jπ=2+ state in 12C

Nuclear and Hybrid Equations of State in Light of the Low-Mass Compact Star in HESS J1731-347

Affiliations

Three- $α$ configurations of the second $J^{π} = 2^{+}$ state in $^{12}$ C