nucl-th digest · May 5, 2020

[Submitted on 4 May 2020]

Second virial coefficients of light nuclear clusters and their chemical freeze-out in nuclear collisions

K. A. Bugaev🇺🇦 · O. V. Vitiuk🇺🇦 · B. E. Grinyuk🇺🇦 · V. V. Sagun🇺🇦 · N. S. Yakovenko🇺🇦 · O. I. Ivanytskyi🇺🇦 · G. M. Zinovjev🇺🇦 · D. B. Blaschke🇵🇱 · E. G. Nikonov🇷🇺 · L. V. Bravina🇳🇴 · E. E. Zabrodin🇳🇴 · S. Kabana🇨🇱 and 4 other authors

Here we develop a new strategy to analyze the chemical freeze-out of light (anti)nuclei produced in high energy collisions of heavy atomic nuclei within an advanced version of the hadron resonance gas model. It is based on two different, but complementary approaches to model the hard-core repulsion between the light nuclei and hadrons. The first approach is based on an approximate treatment of the equivalent hard-core radius of a roomy nuclear cluster and pions, while the second approach is rigorously derived here using a self-consistent treatment of classical excluded volumes of light (anti)nuclei and hadrons. By construction, in a hadronic medium dominated by pions, both approaches should give the same results. Employing this strategy to the analysis of hadronic and light (anti)nuclei multiplicities measured by ALICE at $s_{N N} = 2.76$ TeV and by STAR at $s_{N N} = 200$ GeV, we got rid of the existing ambiguity in the description of light (anti)nuclei data and determined the chemical freeze-out parameters of nuclei with high accuracy and confidence. At ALICE energy the nuclei are frozen prior to the hadrons at the temperature $T = 175. 1_{- 3.9}^{+ 2.3}$ MeV, while at STAR energy there is a single freeze-out of hadrons and nuclei at the temperature $T = 167.2 \pm 3.9$ MeV. We argue that the found chemical freeze-out volumes of nuclei can be considered as the volumes of quark-gluon bags that produce the nuclei at the moment of hadronization.

Comments:: 15 pages, 4 figures, 3 tables
Subjects:: Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:: 2005.01555 [pdf]

EPJA(2020)·19 citations

Extracing the number of short-range corerlated nucleon pairs from inclusive electron scattering data

The extraction of the relative abundances of short-range correlated (SRC) nucleon pairs from inclusive electron scattering is studied using the generalized contact formalism (GCF) with several nuclear interaction models. GCF calculations can reproduce the observed scaling of the cross-section ratios for nuclei relative to deuterium at high-

x_{B}

and large-

Q^{2}

a_{2} = (σ_{A} / A) / (σ_{d} /2)

. In the non-relativistic instant-form formulation, the calculation is very sensitive to the model parameters and only reproduces the data using parameters that are inconsistent with ab-initio many-body calculations. Using a light-cone GCF formulation significantly decreases this sensitivity and improves the agreement with ab-initio calculations. The ratio of similar mass isotopes, such as

^{40}

Ca and

^{48}

Ca, should be sensitive to the nuclear asymmetry dependence of SRCs, but is found to also be sensitive to low-energy nuclear structure. Thus the empirical association of SRC pair abundances with the measured

a_{2}

values is only accurate to about

20%

. Improving this will require cross-section calculations that reproduce the data while properly accounting for both nuclear structure and relativistic effects.

Comments:: Accepted for publication in Phys. Rev. C (Lett). 6 pages, 4 figures, and online supplementary materials
Subjects:: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:: 2005.01621 [pdf]

PRC(2021)·33 citations

Tuesday·May 5, 2020

Second virial coefficients of light nuclear clusters and their chemical freeze-out in nuclear collisions

Extracing the number of short-range corerlated nucleon pairs from inclusive electron scattering data

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