Nuclear Theory·nucl-th

Wednesday·January 3, 2018

14 papers—5 primary·9 cross-listed

01
Chiral symmetry breaking in a semi-localized magnetic field
Gaoqing Cao🇨🇳
In this work, I'm going to explore the pattern of chiral symmetry breaking and restoration in a solvable magnetic distribution within Nambu--Jona-Lasinio model. The special semi-localized static magnetic field can roughly simulate the realistic situation in peripheral heavy ion collisions, thus the study is important for the dynamical evolution of quark matter. I find that the magnetic field dependent contribution from discrete spectra usually dominates over that from continuum ones and chiral symmetry breaking is locally catalyzed by both the magnitude and scale of the magnetic field.
nucl-thPRD(2018)·6 citations
02
Hydrodynamic Collectivity in Proton--Proton Collisions at 13 TeV
Wenbin Zhao🇨🇳 · You Zhou🇩🇰 · Hao-jie Xu🇨🇳 · Weitian Deng🇨🇳 · Huichao Song🇨🇳
In this paper, we investigate the hydrodynamic collectivity in proton--proton (pp) collisions at 13 TeV, using iEBE-VISHNU hybrid model with HIJING initial conditions. With properly tuned parameters, our model simulations can remarkably describe all the measured 2-particle correlations, including integrated and differential elliptic flow coefficients for all charged and identified hadrons ( $K_{S}^{0}$ , $Λ$ ). However, our model calculations show positive 4-particle cumulant $c_{2} {4}$ in high multiplicity pp collisions, and can not reproduce the negative $c_{2} {4}$ measured in experiment. Further investigations on the HIJING initial conditions show that the fluctuations of the second order anisotropy coefficient $ε_{2}$ increases with the increase of its mean value, which leads to a similar trend of the flow fluctuations. For a simultaneous description of the 2- and 4- particle cumulants within the hydrodynamic framework, it is required to have significant improvements on initial condition for pp collisions, which is still lacking of knowledge at the moment.
nucl-thhep-phnucl-exPLB(2018)·96 citations
03
Hoyle-analogue state in 13C studied with Antisymmetrized Molecular Dynamics
Y. Chiba · M. Kimura
The cluster states in $^{13} C$ are investigated by antisymmetrized molecular dynamics. By investigating the spectroscopic factors, the cluster configurations of the excited states are discussed. It is found that the $1/ 2_{2}^{+}$ state is dominantly composed of the $^{12} C (0_{2}^{+}) \otimes s_{1/2}$ configuration and can be regarded as a Hoyle analogue state. On the other hand, the p-wave states ( $3/ 2^{-}$ and $1/ 2^{-}$ ) do not have such structure, because of the coupling with other configurations. The isoscalar monopole and dipole transition strengths from the ground to the excited states are also studied. It is shown that the excited $1/ 2^{-}$ states have strong isoscalar monopole transition strengths consistent with the observation. On the other hand, the excited $1/ 2^{+}$ states unexpectedly have weak isoscalar dipole transitions except for the $1/ 2_{1}^{+}$ state. It is discussed that the suppression of the dipole transition is attributed to the property of the dipole operator.
nucl-thnucl-exPRC(2020)·22 citations
04
Shape coexistence close to $N = 50$ in the neutron-rich isotope $^{80}$ Ge investigated by IBM-2
Dali Zhang · Chengfu Mu
The properties of the low-lying states, especially the relevant shape coexistence in $^{80}$ Ge close to one of most neutron-rich doubly magic nuclei at $N = 50$ and $Z = 28$ have been investigated within the framework of the proton-neutron interacting model (IBM-2). Based on the fact that the relative energy of the $d$ neutron boson is different from proton bosons', the calculated energy levels of low-lying states, $E 2$ transition strengths can reproduce the experimental data very well. Particularly, the first excited state 0 $_{2}^{+}$ is reproduced quite nicely, which is intimately related with the shape coexistence phenomenon. And the $ρ^{2} (E 0, 0_{2}^{+} \to 0_{1}^{+})$ transition strength has been predicted. The experimental data and theoretical results indicate that both collective spherical and $γ$ -soft vibration structures coexist in $^{80}$ Ge. Key words: $^{80}$ Ge, low-lying states, $E 0$ transition strengths, shape coexistence, IBM-2.
nucl-thCPC(2018)·6 citations
05
Radiative heavy quark energy loss in an expanding viscous QCD plasma
Sreemoyee Sarkar🇮🇳 · Chandrodoy Chattopadhyay🇮🇳 · Subrata Pal🇮🇳
We study viscous effects on heavy quark radiative energy loss in a dynamically screened medium with boost-invariant longitudinal expansion. We calculate, to first order in opacity, the energy loss by incorporating viscous corrections in the single-particle phase-space distribution function within relativistic dissipative hydrodynamics. We consider the Grad's 14-moment and the Chapman-Enskog-like methods for the nonequilibrium distribution functions. Our numerical results for the charm quark radiative energy loss show that, as compared to static fluid, an expanding ideal (nonviscous) fluid causes a much smaller energy loss. Viscosity in the evolution lead to somewhat enhanced energy loss which is insensitive to the underlying viscous hydrodynamic models used. Further inclusion of viscous correction induces larger energy loss, the magnitude and pattern of this enhancement crucially depend on the form of viscous corrections used.
nucl-thPRC(2018)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE

Chiral symmetry breaking in a semi-localized magnetic field

Hydrodynamic Collectivity in Proton--Proton Collisions at 13 TeV

Hoyle-analogue state in 13C studied with Antisymmetrized Molecular Dynamics

Shape coexistence close to N=50 in the neutron-rich isotope 80Ge investigated by IBM-2

Radiative heavy quark energy loss in an expanding viscous QCD plasma

Affiliations

Shape coexistence close to $N = 50$ in the neutron-rich isotope $^{80}$ Ge investigated by IBM-2