Nuclear Theory·nucl-th

Wednesday·September 22, 2021

8 papers—4 primary·4 cross-listed

01
[Submitted on 21 Sept 2021]
$α$ -clustering effect on flows of direct photons in heavy-ion collisions
Chen-Zhong Shi · Yu-Gang Ma
In this work, we reconstruct the $γ$ -photon energy spectrum which is in good agreement with the experimental data of $^{86}$ Kr + $^{12}$ C at $E / A$ = 44 MeV in the framework of our modified EQMD model. The directed flow and elliptic flow of free protons and direct photons have been investigated by taking $α$ -clustering structure of $^{12}$ C into account. Comparing with the free proton, the direct photon flows give a clearer information about early stage of nuclear reaction. Difference of collective flows between different configurations of $^{12}$ C is observed in this work. This indicates that collective flows of direct photons are sensitive to the initial configuration, therefore the $γ$ bremsstrahlung process might be taken as an alternative probe to investigate $α$ -clustering structure in light nucleus from heavy ion collisions at Fermi-energy region.
Comments:
10 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2109.09938 [pdf]
Nucl.Sci.Tech.(2021)·48 citations
02
[Submitted on 21 Sept 2021]
Lambda polarization in $^{108}$ Ag + $^{108}$ Ag and $^{197}$ Au + $^{197}$ Au collisions around a few GeV
Xian-Gai Deng🇨🇳 · Xu-Guang Huang🇨🇳 · Yu-Gang Ma🇨🇳
Within the framework of Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model, we extract the global spin polarization of $Λ$ hyperon in $^{108}$ Ag + $^{108}$ Ag and $^{197}$ Au + $^{197}$ Au collisions at $s_{NN} = 2.42 - 62.4$ GeV. We use two different approaches to calculate the $Λ$ polarization $P_{y}$ : approach I is based on equilibrium assumption so that $P_{y}$ is determined by thermal vorticity and approach II assumes a proportional relation between $P_{y}$ and the system's angular momentum in $Λ$ 's rest frame. We find that both approaches can describe the experimental data at low energies around a few GeV but only approach I describes well also higher-energy data. This suggests that at higher energies the relativistic effect plays an important role. After taking into such effect properly, the relativity-improved approach II can describe the higher-energy data as well.
Comments:
V3: 6 pages, 5 figures. Published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2109.09956 [pdf]
PLB(2022)·48 citations
03
[Submitted on 21 Sept 2021]
Persistence of cluster structure in the ground state of $^{11}$ B
Naoyuki Itagaki · Tomoya Naito · Yuichi Hirata
The persistence of $α + α + t$ cluster configuration in the ground state of $^{11}$ B is discussed. The $α$ particles emitted from excited states of $^{12}$ C could be utilized for cancer treatment, where the cluster states are created by a clinical proton beam on the $^{11}$ B target. Although the cross section has been already available, for the nuclear structure side, whether the ground state of $^{11}$ B contains the seeds of the cluster states is a crucial question, since the cluster structure may be washed out by the spin-orbit interaction, which has been known as a driving force to break the $α$ clusters. For this purpose, in addition to the basis states with cluster configurations, we include their breaking effects by employing the antisymmetrized quasi cluster model (AQCM). The inclusion of the breaking effect of $α + α + t$ cluster structure is found to contribute to the lowering of the ground-state energy by about 2 MeV. Assuming the typical three- $α$ cluster state of $^{12}$ C as an equilateral triangular configuration with the relative distances of $\approx 4$ fm, the ground state of $^{11}$ B is found to have a certain squared overlap with such state when a proton approaches. The third $3/ 2^{-}$ state has been suggested as a cluster state both theoretically and experimentally, and we confirmed the well-developed clustering.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2109.09957 [pdf]
PRC(2022)·4 citations
04
[Submitted on 21 Sept 2021]
Skyrmions and Fractional Quantum Hall Droplets Unified by Hidden Symmetries in Dense Matter
Mannque Rho🇫🇷
A chain of connections in compressed baryonic matter, up-to-date glaringly missing in nuclear effective field theory, between intrinsic or emergent symmetries of QCD, mesons-gluons dualities, vector meson dominance and Chern-Simons fields has recently been revealed, presaging a possible new paradigm in nuclear theory. It indicates a ubiquitous role, thus far unexplored, of hidden symmetries -- flavor-local and scale -- permeating from dilute baryonic systems to normal nuclear matter and then to compact-star matter. Here I give a brief account of the possibly "indispensable" relevance of the $η^{'}$ singular ring, a.k.a. fractional quantum Hall (FQH) droplet, to the properties of the lowest-lying vector mesons $ω$ and $ρ$ , relevant to dilepton production processes, argued to be Seiberg-dual to the gluons near the chiral restoration.
Comments:
9 pages, no figures, typos corrected
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2109.10059 [pdf]
2 citations

Affiliations

first authorsco-authorsvia INSPIRE

α-clustering effect on flows of direct photons in heavy-ion collisions

Lambda polarization in 108Ag +108Ag and 197Au +197Au collisions around a few GeV

Persistence of cluster structure in the ground state of 11B

Skyrmions and Fractional Quantum Hall Droplets Unified by Hidden Symmetries in Dense Matter

Affiliations

$α$ -clustering effect on flows of direct photons in heavy-ion collisions

Lambda polarization in $^{108}$ Ag + $^{108}$ Ag and $^{197}$ Au + $^{197}$ Au collisions around a few GeV

Persistence of cluster structure in the ground state of $^{11}$ B