Nuclear Theory·nucl-th

Tuesday·September 8, 2020

16 papers—5 primary·11 cross-listed

01
[Submitted on 4 Sept 2020]
Constraints on jet quenching from a multi-stage energy-loss approach
C. Park🇨🇦 · A. Angerami · S. A. Bass · S. Cao · Y. Chen · J. Coleman · L. Cunqueiro · T. Dai · L. Du · R. Ehlers · H. Elfner · D. Everett and 38 other authors
We present a multi-stage model for jet evolution through a quark-gluon plasma within the JETSCAPE framework. The multi-stage approach in JETSCAPE provides a unified description of distinct phases in jet shower contingent on the virtuality. We demonstrate a simultaneous description of leading hadron and integrated jet observables as well as jet $v_{n}$ using tuned parameters. Medium response to the jet quenching is implemented based on a weakly-coupled recoil prescription. We also explore the cone-size dependence of jet energy loss inside the plasma.
Comments:
4 pages, 4 figures, Proceedings of Hard Probes 2020, 1-6 June 2020, Austin, Texas
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2009.02410 [pdf]
PoS(2021)·3 citations
02
[Submitted on 5 Sept 2020]
Directed flow induced by electromagnetic fields in heavy ion collisions
Yifeng Sun🇮🇹 · Salvatore Plumari🇮🇹 · Vincenzo Greco🇮🇹
Strong electromagnetic fields are expected to be generated in off-central relativistic heavy ion collisions, which can induce a splitting of the directed flow of charged particles and anti-particles ( $Δ v_{1}$ ). Such a splitting manifests even for neutral charmed mesons pairs ( $D^{0}, D ˉ^{0}$ ), hence being a direct probe of the formation of deconfined phase with charm quarks as degree of freedom. In the limit of large $p_{T}$ and weak interaction with the QGP, a formula of $Δ v_{1} (p_{T}, y_{z})$ of charged particles and anti-particles as a function of $p_{T}$ and rapidity $y_{z}$ can be obtained, which is found to be related to the spectra of charged particles and the integrated effect of the Lorentz force. This formula is expected to be valid to heavy quarks and leptons at high $p_{T}$ , where the modification to their equations of motion due to the interaction with both QGP and electromagnetic fields is small, and should have a general application. We also proposed a measurement of $Δ v_{1} (p_{T}, y_{z})$ of leptons from $Z^{0}$ decay and its correlation to that of $D$ mesons, which would be a strong probe determining whether the large splitting measured in experiments has the electromagnetic origin.
Comments:
5 pages, 1 figure, Proceedings to Hard Probes 2020
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2009.02574 [pdf]
PoS(2021)·2 citations
03
[Submitted on 6 Sept 2020]
Pion production and absorption in heavy-ion collisions
Yuan Gao · Lei Zhang · Gao-Chan Yong · Zi-Yu Liu · Wei Zuo
Based on the isospin dependent transport model IBUU, the pion production and its absorption are thoroughly studied in the central collision of $A u + A u$ at a beam energy of 400 MeV/nucleon. It is found that the pions are firstly produced by the hard $Δ$ decay at the average density around $1.75 ρ_{0}$ , whereas about 18\% of them are absorbed absolutely in the subsequent inelastic collisions. For the free pions observed, more than half of them have been scattered for one or more times before they are free from matter. And the more scattering numbers of pions, the higher the momentum they possess. These pions, due to longer time of their existence in high density nuclear matter, carry more information about the symmetry energy of the nuclear matter at high densities.
Comments:
6 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2009.02674 [pdf]
PRC(2021)·5 citations
04
[Submitted on 7 Sept 2020]
Identifying the nature of the QCD transition in heavy-ion collisions with deep learning
Yi-Lun Du🇩🇪 · Kai Zhou🇩🇪 · Jan Steinheimer🇩🇪 · Long-Gang Pang🇺🇸 · Anton Motornenko🇩🇪 · Hong-Shi Zong🇨🇳 · Xin-Nian Wang🇺🇸 · Horst Stoecker🇩🇪
In this proceeding, we review our recent work using deep convolutional neural network (CNN) to identify the nature of the QCD transition in a hybrid modeling of heavy-ion collisions. Within this hybrid model, a viscous hydrodynamic model is coupled with a hadronic cascade "after-burner". As a binary classification setup, we employ two different types of equations of state (EoS) of the hot medium in the hydrodynamic evolution. The resulting final-state pion spectra in the transverse momentum and azimuthal angle plane are fed to the neural network as the input data in order to distinguish different EoS. To probe the effects of the fluctuations in the event-by-event spectra, we explore different scenarios for the input data and make a comparison in a systematic way. We observe a clear hierarchy in the predictive power when the network is fed with the event-by-event, cascade-coarse-grained and event-fine-averaged spectra. The carefully-trained neural network can extract high-level features from pion spectra to identify the nature of the QCD transition in a realistic simulation scenario.
Comments:
4 pages, 4 figures, Quark Matter 2019, will be published in Nucl. Phys. A
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2009.03059 [pdf]
NPA(2021)·5 citations
05
[Submitted on 7 Sept 2020]
The alternating-parity bands of \element{236,238}{U} and \element{238,240}{Pu} in a particle-number conserving method based on cranked shell model
Xiao-Tao He · Yu-Chun Li
The particle-number conserving (PNC) method in the framework of cranked shell model (CSM) is developed to deal with the reflection-asymmetric nuclear system by applying the $S_{x}$ symmetry. Based on an octupole-deformed Nilsson potential, the alternating-parity bands in \element{236,238}{U} and \element{238,240}{Pu} are investigated. The experimental kinematic moments of inertia (MoI) and the angular momentum alignments of all studied bands are reproduced well in the PNC-CSM calculations. The striking difference of rotational behaviors between U and Pu isotopes can be linked to the strength of octupole correlations. The upbendings of the alternating-parity bands in\element{236,238}{U} are due to the alignments of pairs of nucleons occupying $ν g_{9/2}$ , $π f_{7/2}$ orbitals and $ν j_{15/2}$ , $π i_{13/2}$ high- $j$ intruder orbitals. Particularly, the interference terms of nucleon occupying the octupole-correlation pairs of $ν^{2} j_{15/2} g_{9/2}$ and of $π^{2} i_{13/2} f_{7/2}$ give a very important contribution to the suddenly gained alignments.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2009.03198 [pdf]
PRC(2020)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE

Constraints on jet quenching from a multi-stage energy-loss approach

Directed flow induced by electromagnetic fields in heavy ion collisions

Pion production and absorption in heavy-ion collisions

Identifying the nature of the QCD transition in heavy-ion collisions with deep learning

The alternating-parity bands of \element{236,238}{U} and \element{238,240}{Pu} in a particle-number conserving method based on cranked shell model

Affiliations