Nuclear Theory·nucl-th

Wednesday·January 22, 2020

18 papers—12 primary·6 cross-listed

13
Effective (kinetic freeze-out) temperature, transverse flow velocity and kinetic freeze-out volume in high energy collisions
Muhammad Waqas🇨🇳 · Fu-Hu Liu🇨🇳 · Li-Li Li🇨🇳 · Haidar Mas'ud Alfanda🇨🇳
The transverse momentum spectra of different types of particles produced in central and peripheral gold-gold (Au-Au) and (inelastic) proton-proton ( $pp$ ) collisions at the Relativistic Heavy Ion Collider (RHIC), as well as in central and peripheral lead-lead (Pb-Pb) and $pp$ collisions at the Large Hadron Collider (LHC) are analyzed by the standard distribution in terms of multi-component. The obtained results from the standard distribution give an approximate agreement with the measured experimental data by the STAR, PHENIX and ALICE Collaborations. The methodical behavior of the effective (kinetic freeze-out) temperature, transverse flow velocity and kinetic freeze-out volume with the mass dependence for different particles is obtained, which observes the early kinetic freeze-out of heavier particles as compared to the lighter particles. The parameters for emissions of different particles are observed to be different, which reveals a direct signature of the mass dependent differential kinetic freeze-out. It is also observed that the peripheral nucleus-nucleus ( $AA$ ) and $pp$ collisions at the same center-of-mass energy per nucleon pair are close in terms of the extracted parameters.
↳ hep-phhep-exnucl-exnucl-thNucl.Sci.Tech.(2020)·33 citations
14
First implementation of transverse spherocity analysis for heavy-ion collisions at the Large Hadron Collider energies
Neelkamal Mallick🇮🇳 · Sushanta Tripathy🇮🇳 · Raghunath Sahoo🇮🇳 · Antonio Ortiz🇲🇽
Transverse spherocity, an event shape observable, has a very unique capability to separate the events based on their geometrical shape, i.e. jetty and isotropic. In this work, we use transverse spherocity for the first time in heavy-ion collisions using A Multi-Phase Transport Model (AMPT). We obtain the transverse momentum spectra, integrated yield, mean transverse momentum and azimuthal anisotropy for identified particles in Xe-Xe collisions at $s_{NN} = 5.44$ TeV and Pb-Pb collisions at $s_{NN} = 5.02$ TeV. The indication of collectivity in heavy-ion collisions can be clearly seen while comparing the transverse momentum spectra from jetty and isotropic events. The elliptic flow as a function of transverse spherocity shows that the isotropic events have nearly zero elliptic flow and the elliptic flow is mostly dominated by the jetty events. This study will pave a way to focus on jetty events in heavy-ion collisions in order to investigate jet medium modification and jet hadro-chemistry in a sophisticated manner.
↳ hep-phhep-exnucl-exnucl-th7 citations
15
Phenomenological implications of asymmetric $A d S_{5}$ shockwave collision studies for heavy ion physics
Berndt Müller🇺🇸 · Andreas Rabenstein🇩🇪 · Andreas Schäfer🇩🇪 · Sebastian Waeber🇩🇪 · Laurence G. Yaffe🇺🇸
This paper discusses possible phenomenological implications for p+A and A+A collisions of the results of recent numerical AdS/CFT calculations examining asymmetric collisions of planar shocks. In view of the extreme Lorentz contraction, we model highly relativistic heavy ion collisions (HICs) as a superposition of collisions between many near-independent transverse "pixels" with differing incident longitudinal momenta. It was found that also for asymmetric collisions the hydrodynamization time is in good approximation a proper time, just like for symmetric collisions, depending on the geometric mean of the longitudinally integrated energy densities of the incident projectiles. For realistic collisions with fluctuations in the initial energy densities, these results imply a substantial increase in the hydrodynamization time for highly asymmetric pixels. However, even in this case the local hydrodynamization time still is significantly smaller than perturbative results for the thermalization time.
↳ hep-phhep-thnucl-thPRD(2020)·17 citations
16
Differential two-particle number and momentum correlations with the AMPT, UrQMD, and EPOS models in Pb-Pb collisions at $s_{_{NN}}$ = 2.76 TeV
Sumit Basu🇺🇸 · Victor Gonzalez🇪🇸 · Jinjin Pan🇺🇸 · Anders Knospe🇺🇸 · Ana Marin🇩🇪 · Christina Markert🇺🇸 · Claude Pruneau🇺🇸
We report studies of charge-independent (CI) and charge-dependent (CD) two-particle differential number correlation functions, $R_{2} (Δ η, Δ φ)$ , and transverse momentum correlation functions, $P_{2} (Δ η, Δ φ)$ of charged particles produced in \PbPb\ collisions at the LHC centre-of-mass energy $s_{NN} =$ 2.76 TeV with the UrQMD, AMPT and EPOS models. Model predictions for $R_{2}$ and $P_{2}$ correlation functions are presented for inclusive charged hadrons ( $h^{\pm}$ ) in selected transverse momentum ranges and with full azimuthal coverage in the pseudorapidity range $∣ η ∣ < 1.0$ . We compare these predictions for the strength, shape, and particularly the width of the correlation functions with recent measurements of these observables by the ALICE collaboration. Our analysis indicate that comparative studies of $R_{2}$ and $P_{2}$ correlation functions provide valuable insight towards the understanding of particle production in Pb--Pb collisions. We find, in particular, that these models have quantitatively different predictions for these three observables but none reproduce the measured correlation functions reported by the ALICE collaboration. Accounting for quantum number conservation in models, particularly charge conservation, is mandatory to reproduce the detailed measurements of number and transverse momentum correlation functions.
↳ nucl-exnucl-thPRC(2021)·20 citations
17
Probing few-body nuclear dynamics via 3H and 3He (e,e'p)pn cross-section measurements
R. Cruz-Torres · D. Nguyen · F. Hauenstein · A. Schmidt · S. Li · D. Abrams · H. Albataineh · S. Alsalmi · D. Androic · K. Aniol · W. Armstrong · J. Arrington and 116 other authors
We report the first measurement of the \eep three-body breakup reaction cross sections in helium-3 ( $^{3}$ He) and tritium ( $^{3}$ H) at large momentum transfer ( $⟨ Q^{2} ⟩ \approx 1.9$ (GeV/c) $^{2}$ ) and $x_{B} > 1$ kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta $40 \leq p_{mi ss} \leq 500$ MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab-initio calculations. Overall good agreement, within $\pm 20%$ , is observed between data and calculations for the full $p_{mi ss}$ range for $^{3}$ H and for $100 \leq p_{mi ss} \leq 350$ MeV/c for $^{3}$ He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at $p_{mi ss} > 250$ MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of $^{3}$ He plus $^{3}$ H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire $p_{mi ss}$ range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of $500$ MeV/c.
↳ nucl-exnucl-thPRL(2020)·29 citations
18
Tensor supercurrent in QCD
Alexander S. Gorsky🇷🇺 · Dmitri E. Kharzeev🇺🇸
An external Abelian magnetic field excites in the QCD vacuum a tensor supercurrent that represents the tensor polarization of the chiral condensate. This tensor supercurrent can be deduced from the chiral lagrangian in the presence of anomalies; a similar tensor supercurrent emerges in rotating systems at finite chemical potential. We discuss the microscopic origin of this supercurrent and argue that it screens the instanton--anti-instanton $I I ˉ$ molecules in the QCD vacuum, similarly to the vector supercurrent screening Abrikosov vortices in a superconductor. A number of possible experimental manifestations of the tensor supercurrent are discussed: {\it i}) spin alignment of axial-vector and vector mesons in heavy ion collisions; {\it ii}) tensor charge of the nucleon; {\it iii}) transversity of quark distributions in polarized nucleons.
↳ hep-thhep-phnucl-thPRD(2020)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Effective (kinetic freeze-out) temperature, transverse flow velocity and kinetic freeze-out volume in high energy collisions

First implementation of transverse spherocity analysis for heavy-ion collisions at the Large Hadron Collider energies

Phenomenological implications of asymmetric AdS5​ shockwave collision studies for heavy ion physics

Differential two-particle number and momentum correlations with the AMPT, UrQMD, and EPOS models in Pb-Pb collisions at sNN​​​= 2.76 TeV

Probing few-body nuclear dynamics via 3H and 3He (e,e'p)pn cross-section measurements

Tensor supercurrent in QCD

Affiliations

Phenomenological implications of asymmetric $A d S_{5}$ shockwave collision studies for heavy ion physics

Differential two-particle number and momentum correlations with the AMPT, UrQMD, and EPOS models in Pb-Pb collisions at $s_{_{NN}}$ = 2.76 TeV