The influence of initial state fluctuations on heavy quark energy loss in relativistic heavy-ion collisions

The transverse momentum distributions for inclusive ηc,b meson described by gluon-gluon interactions from photoproduction processes in relativistic heavy ion collisions are calculated. We considered the color-singlet (CS) and color-octet (CO) components within the framework of Nonrelativistic Quantum Chromodynamics (NRQCD) in the production of heavy quarkonium. The phenomenological values of the matrix elements for the color-singlet and color-octet components give the main contribution to the production of heavy quarkonium from the gluon-gluon interaction caused by the emission of additional gluon in the initial state. The numerical results indicate that the contribution of photoproduction processes cannot be negligible for midrapidity in p-p and Pb-Pb collisions at the Large Hadron Collider (LHC) energies.

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Highlights from PHENIX at RHIC

EPJ Web of Conferences ◽

10.1051/epjconf/201817101003 ◽

2018 ◽

Vol 171 ◽

pp. 01003

Author(s):

Rachid Nouicer

Keyword(s):

Heavy Quark ◽

Heavy Ion Collisions ◽

Meson Production ◽

Heavy Ion ◽

Relativistic Heavy Ion Collisions ◽

Dense Medium ◽

Heavy Flavor ◽

Theoretical Understanding ◽

Rapidity Region ◽

Ion Collisions

Hadrons conveying strange quarks or heavy quarks are essential probes of the hot and dense medium created in relativistic heavy-ion collisions. With hidden strangeness, ϕ meson production and its transport in the nuclear medium have attracted high interest since its discovery. Heavy quark-antiquark pairs, like charmonium and bottomonium mesons, are mainly produced in initial hard scattering processes of partons. While some of the produced pairs form bound quarkonia, the vast majority hadronize into particles carrying open heavy flavor. In this context, the PHENIX collaboration carries out a comprehensive physics program which studies the ϕ meson production, and heavy flavor production in relativistic heavy-ion collisions at RHIC. In recent years, the PHENIX experiment upgraded the detector in installing silicon vertex tracker (VTX) at mid-rapidity region and forward silicon vertex tracker (FVTX) at the forward rapidity region. With these new upgrades, the experiment has collected large data samples, and enhanced the capability of heavy flavor measurements via precision tracking. This paper summarizes the latest PHENIX results concerning ϕ meson, open and closed charm and beauty heavy quark production in relativistic heavy-ion collisions. These results are presented as a function of rapidity, energy and system size, and their interpretation with respect to the current theoretical understanding.

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The global geometrical property of jet events in high-energy nuclear collisions

The European Physical Journal C ◽

10.1140/epjc/s10052-020-08452-3 ◽

2020 ◽

Vol 80 (9) ◽

Author(s):

Shi-Yong Chen ◽

Wei Dai ◽

Shan-Liang Zhang ◽

Qing Zhang ◽

Ben-Wei Zhang

Keyword(s):

Energy Loss ◽

Heavy Ion Collisions ◽

Heavy Ion ◽

High Energy ◽

Jet Quenching ◽

Relativistic Heavy Ion Collisions ◽

Parton Energy Loss ◽

Boltzmann Transport ◽

Ion Collisions ◽

Medium Modifications

AbstractWe present the first theoretical study of medium modifications of the global geometrical pattern, i.e., transverse sphericity ($$S_{\perp }$$ S ⊥ ) distribution of jet events with parton energy loss in relativistic heavy-ion collisions. In our investigation, POWHEG + PYTHIA is employed to make an accurate description of transverse sphericity in the p + p baseline, which combines the next-to-leading order (NLO) pQCD calculations with the matched parton shower (PS). The Linear Boltzmann Transport (LBT) model of the parton energy loss is implemented to simulate the in-medium evolution of jets. We calculate the event normalized transverse sphericity distribution in central Pb + Pb collisions at the LHC, and give its medium modifications. An enhancement of transverse sphericity distribution at small $$S_{\perp }$$ S ⊥ region but a suppression at large $$S_{\perp }$$ S ⊥ region are observed in A + A collisions as compared to their p + p references, which indicates that in overall the geometry of jet events in Pb + Pb becomes more pencil-like. We demonstrate that for events with 2 jets in the final-state of heavy-ion collisions, the jet quenching makes the geometry more sphere-like with medium-induced gluon radiation. However, for events with $$\ge 3$$ ≥ 3 jets, parton energy loss in the QCD medium leads to the events more pencil-like due to jet number reduction, where less energetic jets may lose their energies and then fall off the jet selection kinematic cut. These two effects offset each other and in the end result in more jetty events in heavy-ion collisions relative to that in p + p.

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Heavy flavour production at RHIC and LHC

EPJ Web of Conferences ◽

10.1051/epjconf/201817104001 ◽

2018 ◽

Vol 171 ◽

pp. 04001 ◽

Cited By ~ 1

Author(s):

Gian Michele Innocenti

Keyword(s):

Energy Loss ◽

Quark Matter ◽

Heavy Ion Collisions ◽

Heavy Ion ◽

Experimental Results ◽

Relativistic Heavy Ion Collisions ◽

Dense Medium ◽

Medium Energy ◽

Ion Collisions ◽

Flavour Physics

In this proceedings, I present selected experimental results on heavy-flavour production at RHIC and at the LHC, which were presented at the Strangeness in Quark Matter 2017 conference. I will present a brief introduction to the heavy-flavour physics in heavy ion collisions and I will focus on recents measurements of in-medium energy loss and and collective properties of heavy-flavour particles, which provided important information on the mechanisms of heavy flavour interaction with the hot and dense medium created in ultra-relativistic heavy-ion collisions.

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