Nuclear Theory·nucl-th

Monday·June 6, 2022

11 papers—5 primary·6 cross-listed

01
[Submitted on 2 Jun 2022]
A new Microscopic Model for $J / ψ$ Production in Heavy Ion Collisions
Denys Yen Arrebato Villar🇫🇷 · Jiaxing Zhao🇫🇷 · Joerg Aichelin🇫🇷 · Pol Bernard Gossiaux🇫🇷
We present a new model for the creation of \J mesons in ultrarelativistic heavy ion collisions, which allows to follow the individual heavy quarks from their creation until the detector through the Quark Gluon Plasma (QGP), which is formed in these collisions and described by the EPOS2 event generator. The \cc quarks interact via a potential, based on results of lattice gauge calculations. The annihilation and creation of \J is described by a density matrix approach whose time evolution is studied in the expanding system. The comparison with PbPb data at $s$ =5.02 TeV shows that this model can describe simultaneously the nuclear modification factor $R_{AA}$ and the elliptic flow $v_{2}$ of the \J at low transverse momen
Comments:
Computational error corrected. final version accepted by PRC
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2206.01308 [pdf]
PRC(2023)·26 citations
02
[Submitted on 3 Jun 2022]
Single-particle properties of the near-threshold proton-emitting resonance in $^{11}$ B
Le-Anh Nguyen · Minh-Loc Bui · Naftali Auerbach · Vladimir Zelevinsky
The excitation function of proton elastic scattering from $^{10}$ Be at keV energy is calculated using the self-consistent Skyrme Hartree-Fock in the continuum method. The calculation successfully reproduces the narrow near-threshold proton-emitting resonance ( $E_{x} = 11.4$ MeV, $Γ = 6$ keV, and quantum number $J^{π} = 1/ 2^{+}$ ) in $^{11}$ B relevant to the $β$ -delayed proton emission of $^{11}$ Be. This supports the recent experimental result of Y. Ayyad \textit{et al.} at the ReA3 re-accelerator facility of the National Superconducting Cyclotron Laboratory (NSCL) at the Michigan State University. The resonance is interpreted as the $s_{1/2}$ single-proton resonance state in the Skyrme Hartree-Fock mean-field theory.
Comments:
4 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2206.01350 [pdf]
PRC(2022)·11 citations
03
[Submitted on 3 Jun 2022]
Radiative proton capture on $^{15} N$ within effective field theory
Sangyeong Son · Shung-Ichi Ando · Yongseok Oh
The astrophysical $S$ factor for the radiative proton capture process on the $^{15} N$ nucleus, i.e., $^{15} N (p, γ)^{16} O$ , at stellar energies are studied within the framework of the cluster effective field theory. The thermonuclear $^{15} N (p, γ)^{16} O$ reaction links the type-I to type-II cycles of the carbon-nitrogen-oxygen cycle and affects the abundances of elements in the univere. For investigating this reaction in the effective field theory formalism, we first construct an effective Lagrangian that is appropriate for this reaction at low-energies. Since the intermediate excited states of the $^{16} O$ nucleus have a crucial role in this reaction, we include these resonances in the formalism. The corresponding radiative capture amplitudes and cross section are calculated, which lead to the astrophysical $S$ factor. The low energy constants introduced in the effective Lagrangian are determined by fitting the theoretical results to the observed $S$ factors in the range of $130 keV < E_{p} < 2500 keV$ using three different experimental data sets. Considering the recent data sets, we obtain $S (0) = 29.8 \mbox - 34.1 keV b$ , which is in a good agreement with the estimates from $R$ -matrix approaches in the literature. The values of $S$ at the Gamow energy are found to be larger than $S (0)$ values by about $10%$ .
Comments:
12 pages, 6 figures, 3 tables, to be published in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2206.01407 [pdf]
PRC(2022)·5 citations
04
[Submitted on 3 Jun 2022]
New insights into the oscillation of the nucleon electromagnetic form factors
Qin-He Yang🇨🇳 · Ling-Yun Dai🇨🇳 · Di Guo🇨🇳 · Johann Haidenbauer🇩🇪 · Xian-Wei Kang🇨🇳 · Ulf-G. Meißner🇩🇪
The electromagnetic form factors of the proton and the neutron in the timelike region are investigated. Electron-positron annihilation into antinucleon-nucleon ( $N ˉ N$ ) pairs is treated in distorted wave Born approximation, including the final-state interaction in the $N ˉ N$ system. The latter is obtained by a Lippmann-Schwinger equation for $N ˉ N$ potentials derived within SU(3) chiral effective field theory. By fitting to the phase shifts and (differential) cross section data, a high quality description is achieved. With these amplitudes, the oscillations of the electromagnetic form factors of the proton and the neutron are studied. It is found that each of them can be described by two fractional oscillators. One is characterized as \lq overdamped' and dominates near the threshold, while the other is \lq underdamped' and plays an important role in the high-energy region. These two oscillators are essential to understand the distributions of polarized electric charges induced by hard photons for the nucleons.
Comments:
11 pages, 8 figures, to be the same as the published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2206.01494 [pdf]
Sci.Bull.(2023)·28 citations
05
[Submitted on 3 Jun 2022]
Correcting the $B_{A}$ coalescence factor at GSI-HADES and RHIC-BES energies
Apiwit Kittiratpattana🇩🇪 · Tom Reichert🇩🇪 · Jan Steinheimer🇩🇪 · Christoph Herold🇹🇭 · Ayut Limphirat🇹🇭 · Yupeng Yan🇹🇭 · Marcus Bleicher🇩🇪
We investigate the coalescence factors $B_{2}$ and $B_{3}$ at low collision energies ( $s_{NN} < 6$ GeV) with special focus on the HADES and RHIC-BES experiments. It is shown that, in order to properly interpret the coalescence factors $B_{A}$ , two important corrections are necessary: I) $B_{2}$ has to be calculated using the proton $\times$ neutron yields in the denominator, instead of the square of the proton yield, and II) the primordial proton (neutron) densities have to be used for the normalization and not the final state (free) protons (neutrons). Both effects lead to a drastic reduction of $B_{2}$ and $B_{3}$ at low energies. This reduction decreases the discrepancy between the volumes extracted from HBT measurements and the volumes extracted from the coalescence factor ( $V \propto 1/ B_{2}$ ). While at HADES and low RHIC-BES energies these corrections are substantial, they become irrelevant above $s_{NN} > 6$ GeV. The proposed correction method is model independent and is only based on the measurement of protons, clusters and charged pions.
Comments:
10 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2206.01625 [pdf]
PRC(2022)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE

A new Microscopic Model for J/ψ Production in Heavy Ion Collisions

Single-particle properties of the near-threshold proton-emitting resonance in 11B

Radiative proton capture on 15N within effective field theory

New insights into the oscillation of the nucleon electromagnetic form factors

Correcting the BA​ coalescence factor at GSI-HADES and RHIC-BES energies

Affiliations

A new Microscopic Model for $J / ψ$ Production in Heavy Ion Collisions

Single-particle properties of the near-threshold proton-emitting resonance in $^{11}$ B

Radiative proton capture on $^{15} N$ within effective field theory

Correcting the $B_{A}$ coalescence factor at GSI-HADES and RHIC-BES energies