Nuclear Theory·nucl-th

Tuesday·June 7, 2022

11 papers—6 primary·5 cross-listed

01
Ratios of collective flow observables in high-energy isobar collisions are insensitive to final state interactions
Chunjian Zhang🇺🇸 · Somadutta Bhatta🇺🇸 · Jiangyong Jia🇺🇸
The ratios of bulk observables, such as harmonic flow $v_{2}$ and $v_{3}$ , between high-energy $^{96}$ Ru+ $^{96}$ Ru and $^{96}$ Zr+ $^{96}$ Zr collisions were recently argued to be a clean probe of the nuclear structure differences between $^{96}$ Ru and $^{96}$ Zr. Using a transport model simulation of isobar collisions, we quantify this claim from the dependence of the ratios $v_{2, Ru} / v_{2, Zr}$ and $v_{3, Ru} / v_{3, Zr}$ on various final state effects, such as the shear viscosity, hadronization and hadronic cascade. Although the $v_{2}$ and $v_{3}$ change by more than 50% when varying the final state effects, the ratios are unchanged. In addition, these ratios are independent of the transverse momentum $p_{T}$ and hadron species, despite of up to a factor of two change in $v_{n}$ . The ratio of mean transverse momentum $⟨ p_{T} ⟩$ is found to be controlled by the nuclear skin and nuclear radius, but is only slightly impacted by the final state effects. Therefore, these isobar ratios serve as a clean probe of the initial condition of the quark-gluon plasma, which in turn is controlled by the collective structure of the colliding nuclei.
nucl-thhep-exhep-phnucl-exPRC(2022)·42 citations
02
Extended optimal Fermi averaging for near-recoilless $Λ$ production in the ( $K^{-}$ , $π^{-}$ ) reaction on nuclei
Toru Harada🇯🇵 · Yoshiharu Hirabayashi🇯🇵
We propose to extend the optimal Fermi averaging procedure theoretically in order to calculate an in-medium $K^{-} n \to π^{-} Λ$ amplitude for the exothermic ( $K^{-}$ , $π^{-}$ ) reaction on nuclei in the framework of a distorted-wave impulse approximation, taking into account the local momentum transfer generated by semiclassical distorted waves for $K^{-}$ and $π^{-}$ mesons. Angular distributions for the $^{12}$ C( $K^{-}$ , $π^{-}$ ) $_{Λ}^{12}$ C reaction in which a momentum transfer is $q ≲$ 80 MeV/ $c$ at $p_{K} =$ 800 MeV/ $c$ in the $π^{-}$ forward direction, are estimated by applying the extended procedure. The result shows that the calculated angular distributions are in good agreement with those of the data, and this extension is a successful prescription making it possible to describe the reaction cross sections in near-recoilless reactions such as ( $K^{-}$ , $π^{-}$ ) in our framework.
nucl-thnucl-exPRC(2022)·4 citations
03
Relativistic Mean Field Study of Neutron Stars and Hyperon Stars
Ishfaq Ahmad Rather🇮🇳
This thesis focuses on a variety of active research topics, such as nuclear matter, neutron stars, and phase transition within the framework of the RMF model. We use the previously successful effective field theory-driven Relativistic Mean Field (RMF) and density-dependent RMF (DD-RMF)formalisms for analyzing hadron matter to examine the infinite nuclear matter and neutron stars. The presence of exotic phases such as quarks has been investigated using the MIT Bag model and its variants, such as the vBag model, at various bag constants. The other exotic phases, such as hyperons, have also been studied under the influence of a strong magnetic field.
nucl-thastro-ph.HEgr-qc2 citations
04
Deep learning assisted jet tomography for the study of Mach cones in QGP
Zhong Yang🇨🇳 · Yayun He🇨🇳 · Wei Chen🇨🇳 · Wei-Yao Ke🇺🇸 · Long-Gang Pang🇨🇳 · Xin-Nian Wang🇨🇳
Mach cones are expected to form in the expanding quark-gluon plasma (QGP) when energetic quarks and gluons (called jets) traverse the hot medium at a velocity faster than the speed of sound in high-energy heavy-ion collisions. The shape of the Mach cone and the associated diffusion wake are sensitive to the initial jet production location and the jet propagation direction relative to the radial flow because of the distortion by the collective expansion of the QGP and large density gradient. The shape of jet-induced Mach cones and their distortions in heavy-ion collisions provide a unique and direct probe of the dynamical evolution and the equation of state of QGP. However, it is difficult to identify the Mach cone and the diffusion wake in current experimental measurements of final hadron distributions because they are averaged over all possible initial jet production locations and propagation directions. To overcome this difficulty, we develop a deep learning assisted jet tomography which uses the full information of the final hadrons from jets to localize the initial jet production positions. This method can help to constrain the initial regions of jet production in heavy-ion collisions and enable a differential study of Mach-cones with different jet path length and orientation relative to the radial flow of the QGP in heavy-ion collisions.
nucl-thEPJC(2023)·34 citations
05
Comprehensive simulation of heavy-ion collisions at non-zero baryon chemical potential
A. De🇺🇸 · J. I. Kapusta🇺🇸 · M. Singh🇺🇸 · T. Welle🇺🇸
We present results of hydrodynamic modelling of Au-Au collisions from $s_{N N}$ = 7.7 to 200 GeV. Our simulations have three novel components. Firstly, we use a Linear EXtrapolation of Ultrarelativistic nucleon-nucleon Scattering to nucleus-nucleus collisions (LEXUS) inspired Monte-Carlo initial state model. Secondly, we use a crossover equation of state at finite baryon densities without a critical point. Finally, we use departure functions derived from the quasiparticle theory of transport coefficients for hadronic matter at non-zero baryon densities.
nucl-thhep-phPRC(2022)·17 citations
06
Relation to a property of the angular momentum zero space of states of four fermions in an angular momentum $j = 9/2$ shell unexpectedly found to be stationary for any rotationally invariant two-body interaction
K. Neergård
The existence of states with angular momenta $I = 4$ and~6 of four fermions in an angular momentum $j = 9/2$ shell that are stationary for any rotationally invariant two-body interaction despite the presence of other states with the same angular momentum, the Escuderos-Zamick states, is shown to be equivalent to the invariance to any such interaction of the span of states generated from $I = 0$ states by one-body operators. This invariance is verified by exact calculation independently of previous verifications of the equivalent statement. It explains the occurrence of the Escuderos-Zamick states for just $I = 4$ and 6. The action of an arbitrary interaction on the invariant space and its orthogonal complement is analyzed, leading to a relation of the Escuderos-Zamick energy levels to levels with $I = 10$ and 12. Parts of the observed spectra of $^{72}$ Ni, $^{74}$ Ni, $^{94}$ Ru, $^{96}$ Pd, $^{212}$ Rn, and $^{214}$ Ra are discussed in the light of this relation.
nucl-thnucl-exPRC(2022)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE

Ratios of collective flow observables in high-energy isobar collisions are insensitive to final state interactions

Extended optimal Fermi averaging for near-recoilless Λ production in the (K−, π−) reaction on nuclei

Relativistic Mean Field Study of Neutron Stars and Hyperon Stars

Deep learning assisted jet tomography for the study of Mach cones in QGP

Comprehensive simulation of heavy-ion collisions at non-zero baryon chemical potential

Relation to a property of the angular momentum zero space of states of four fermions in an angular momentum j=9/2 shell unexpectedly found to be stationary for any rotationally invariant two-body interaction

Affiliations

Extended optimal Fermi averaging for near-recoilless $Λ$ production in the ( $K^{-}$ , $π^{-}$ ) reaction on nuclei

Relation to a property of the angular momentum zero space of states of four fermions in an angular momentum $j = 9/2$ shell unexpectedly found to be stationary for any rotationally invariant two-body interaction