scholarly journals On transverse momentum broadening in real-time lattice simulations of the glasma and in the weak-field limit

2022 ◽  
Vol 258 ◽  
pp. 05002
Author(s):  
Andreas Ipp ◽  
David I. Müller ◽  
Daniel Schuh
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Field Approximation ◽  
Weak Field ◽  
Initial State ◽  
Flux Tubes ◽  
Ion Collisions ◽  
Weak Field Limit ◽  
Magnetic Flux Tubes

In these proceedings, we report on our numerical lattice simulations of partons traversing the boost-invariant, non-perturbative glasma as created at the early stages of collisions at RHIC and LHC. Since these highly energetic partons are produced from hard scatterings during heavy-ion collisions, they are already affected by the first stage of the medium's time evolution, the glasma, which is the pre-equilibrium precursor state of the quark-gluon plasma. We find that partons quickly accumulate transverse momentum up to the saturation momentum during the glasma stage. Moreover, we observe an interesting anisotropy in transverse momentum broadening of partons with larger broadening in the rapidity than in the azimuthal direction. Its origin can be related to correlations among the longitudinal color-electric and color-magnetic flux tubes in the initial state of the glasma. We compare these observations to the semi-analytic results obtained by a weak-field approximation, where we also find such an anisotropy in a parton's transverse momentum broadening.

JET CONVERSIONS IN QGP AND SUPPRESSION OF IDENTIFIED HADRONS

2007 ◽  
Vol 16 (07n08) ◽  
pp. 1930-1936 ◽  
Author(s):  
WEI LIU ◽  
CHE MING KO ◽  
BEN-WEI ZHANG
Keyword(s):  
Transverse Momentum ◽  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collisions ◽  
High Transverse Momentum ◽  
Ion Collisions ◽  
Conversion Rates ◽  
Gluon Jets

A gluon or quark jet traversing through a quark-gluon plasma can be converted into a quark or gluon jet through scatterings with thermal partons. Their conversion rates due to two-body elastic and inelastic scattering as well as scatterings involving gluon radiation are evaluated in the lowest order in Quantum Chromodynamics (QCD). Including both energy loss and conversions of quark and gluon jets in the expanding quark-gluon plasma produced in relativistic heavy ion collisions, we find a net conversion of quark jets to gluon jets. This reduces the difference between the nuclear modification factors for quark and gluon jets in central heavy ion collisions and thus enhances the p/π+ and [Formula: see text] ratios at high transverse momentum. Using the larger QCD coupling constant from lattice QCD calculations than that given by the perturbative QCD further enhances the net quark to gluon jet conversion rate, leading to a closer similarity between these ratios at high transverse momentum in central Au + Au collisions at [Formula: see text] and in p + p collisions at same energy as observed in experiments.

scholarly journals Anisotropic flow of identified particles in Pb–Pb collisions at √SNN = 5.02 TeV

2018 ◽  
Vol 171 ◽  
pp. 17002
Author(s):  
Redmer Alexander Bertens
Keyword(s):  
Initial Conditions ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Mass Energy ◽  
Initial State ◽  
Anisotropic Flow ◽  
Center Of Mass Energy ◽  
Ion Collisions ◽  
Hydrodynamic Calculations

Anisotropic flow is sensitive to the shear (η/s) and bulk (ζ/s) viscosity of the quark-gluon plasma created in heavy-ion collisions, as well as the initial state of such collisions and hadronization mechanisms. In these proceedings, elliptic (υ2) and higher harmonic (υ3, υ4) flow coefficients of π±, K±, p(p) and the ϕ-meson, are presented for Pb—Pb collisions at the highest-ever center-of-mass energy of [see formula in PDF] = 5.02 TeV. Comparisons to hydrodynamic calculations (IP-Glasma, MUSIC, UrQMD) are shown to constrain the initial conditions and viscosity of the medium.

scholarly journals DECONFINEMENT, MONOPOLES AND NEW PHENOMENA IN HEAVY ION COLLISIONS

2010 ◽  
Vol 25 (02n03) ◽  
pp. 532-542 ◽  
Author(s):  
EDWARD SHURYAK
Keyword(s):  
Electric Fields ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Flux Tubes ◽  
Influence Propagation ◽  
Ion Collisions ◽  
Magnetic Screening ◽  
Small Density ◽  
Deconfinement Phase Transition ◽  
New Phenomena

We discuss various manifestations of the "magnetic scenario" for the quark-gluon plasma viewed as a mixture of two plasmas, of electrically (quark and gluons) as well as magnetically charged quasiparticles. Near the deconfinement phase transition, T ≈ Tc very small density of free quarks should lead to negligible screening of electric field while magnetic screening remains strong. The consequence of this should be existence of a "corona" of the QGP, in a way similar to that of the Sun, in which electric fields influence propagation of perturbations and even form metastable flux tubes. The natural tool for its description is (dual) magnetohydrodynamics: among observable consequences is splitting of sound into two modes, with larger and smaller velocity. The latter can be zero, hinting for formation of pressure-stabilized flux tubes. Remarkably, recent experimental discoveries at RHIC show effects similar to expected for "corona structures". In dihadron correlation function with large-pt trigger there are a "cone" and a "hard ridge", while the so called "soft ridge" is a similar structure seen without hard trigger. They seem to be remnants of flux tubes, which – contrary to naive expectations – seem to break less often in near-Tc matter than do confining strings in vacuum.

scholarly journals COLOR GLASS CONDENSATE AND GLASMA

2013 ◽  
Vol 28 (01) ◽  
pp. 1330001 ◽  
Author(s):  
FRANÇOIS GELIS
Keyword(s):  
Quark Gluon Plasma ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Effective Theory ◽  
Color Glass ◽  
Color Glass Condensate ◽  
Saturation Regime ◽  
Initial State ◽  
Ion Collisions

We review the color glass condensate effective theory, that describes the gluon content of a high energy hadron or nucleus, in the saturation regime. The emphasis is put on applications to high energy heavy ion collisions. After describing initial state factorization, we discuss the glasma phase, that precedes the formation of an equilibrated quark–gluon plasma. We end this review with a presentation of recent developments in the study of the isotropization and thermalization of the quark–gluon plasma.

scholarly journals Jets in Heavy Ion Collisions with the ATLAS Detector

2018 ◽  
Vol 46 ◽  
pp. 1860020
Author(s):  
Helena Santos
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Statistical Significance ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Dense Medium ◽  
Momentum Balance ◽  
Ion Collisions ◽  
High Statistical Significance ◽  
Wide Range

Jets constitute a golden probe to study the quark gluon plasma produced in heavy ion collisions at the LHC. Being produced at the early stages of the collisions, they are expected to be modified as propagating through the hot and dense medium. A signature of the modification is the energy loss lowering the jet yields at a given transverse momentum. A factor of two suppression is observed in central Pb+Pb collisions with respect to [Formula: see text] collisions. Other signatures are the modification of the dijet momentum balance and the modification of fragmentation functions. These proceedings describe results on these observables from ATLAS in Runs 1 and 2. The high statistical significance of these data samples collected by ATLAS allows precision measurements of these observables in a wide range of transverse momentum and centrality.

scholarly journals Vector boson tagged jets and jet substructure

2018 ◽  
Vol 172 ◽  
pp. 05006
Author(s):  
Ivan Vitev
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Vector Boson ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Jet Substructure ◽  
Proton Proton ◽  
Jet Production ◽  
Ion Collisions ◽  
Jet Shapes

In these proceedings, we report on recent results related to vector boson-tagged jet production in heavy ion collisions and the related modification of jet substructure, such as jet shapes and jet momentum sharing distributions. Z0-tagging and γ-tagging of jets provides new opportunities to study parton shower formation and propagation in the quark-gluon plasma and has been argued to provide tight constrains on the energy loss of reconstructed jets. We present theoretical predictions for isolated photon-tagged and electroweak boson-tagged jet production in Pb+Pb collisions at √sNN = 5.02 TeV at the LHC, addressing the modification of their transverse momentum and transverse momentum imbalance distributions. Comparison to recent ATLAS and CMS experimental measurements is performed that can shed light on the medium-induced radiative corrections and energy dissipation due to collisional processes of predominantly quark-initiated jets. The modification of parton splitting functions in the QGP further implies that the substructure of jets in heavy ion collisions may differ significantly from the corresponding substructure in proton-proton collisions. Two such observables and the implication of tagging on their evaluation is also discussed.

scholarly journals The Rapidity Distributions and the Thermalization Induced Transverse Momentum Distributions in Au-Au Collisions at RHIC Energies

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Zhi-Jin Jiang ◽  
Jia-Qi Hui ◽  
Yu Zhang
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Good Description ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Ion Collisions ◽  
Hadronic State ◽  
Momentum Distributions ◽  
Rapidity Distributions ◽  
Made In

It is widely believed that the quark-gluon plasma (QGP) might be formed in the current heavy ion collisions. It is also widely recognized that the relativistic hydrodynamics is one of the best tools for describing the process of expansion and hadronization of QGP. In this paper, by taking into account the effects of thermalization, a hydrodynamic model including phase transition from QGP state to hadronic state is used to analyze the rapidity and transverse momentum distributions of identified charged particles produced in heavy ion collisions. A comparison is made between the theoretical results and experimental data. The theoretical model gives a good description of the corresponding measurements made in Au-Au collisions at RHIC energies.

scholarly journals Extraction of the specific shear viscosity of quark-gluon plasma from two-particle transverse momentum correlations

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Victor Gonzalez ◽  
Sumit Basu ◽  
Ana Marin ◽  
Jinjin Pan ◽  
Pedro Ladron de Guevara ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Shear Viscosity ◽  
Quark Gluon Plasma ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Collision Centrality ◽  
Ion Collisions ◽  
Linear Fit ◽  
Pseudorapidity Density ◽  
Freeze Out

AbstractThe specific shear viscosity, $$\eta /s$$ η / s , of the quark-gluon plasma formed in ultrarelativistic heavy-ion collisions at RHIC and LHC is estimated based on the progressive longitudinal broadening of transverse momentum two-particle correlators, $$G_2$$ G 2 , reported as a function of collision centrality by the STAR and ALICE experiments. Estimates are computed as a function of collision centrality using the Gavin ansatz which relates the $$G_2$$ G 2 longitudinal broadening to the specific shear viscosity. Freeze out times required for the use of the ansatz are computed using a linear fit of freeze out times reported as a function of the cubic root of the charged particle pseudorapidity density ($${\mathrm{d}}N_{\mathrm{ch}}$$ d N ch /d$$\eta )^{1/3}$$ η ) 1 / 3 . Estimates of $$\eta /s$$ η / s based on ALICE data exhibit little to no dependence on collision centrality at LHC energy, while estimates obtained from STAR data hint that $$\eta /s$$ η / s might be a function of collision centrality at top RHIC energy.

scholarly journals Azimuthal dependence of two-particle transverse momentum current correlations

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
Niseem Magdy ◽  
Sumit Basu ◽  
Victor Gonzalez ◽  
Ana Marin ◽  
Olga Evdokimov ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Theoretical Models ◽  
Energy System ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Entropy Density ◽  
Relativistic Heavy Ion Collisions ◽  
Azimuthal Dependence ◽  
Ion Collisions

AbstractTwo-particle transverse momentum correlation functions are a powerful technique for understanding the dynamics of relativistic heavy-ion collisions. Among these, the transverse momentum correlator $$G_{2}\left( \varDelta \eta ,\varDelta \varphi \right) $$ G 2 Δ η , Δ φ is of particular interest for its potential sensitivity to the shear viscosity per unit of entropy density $$\eta /s$$ η / s of the quark-gluon plasma formed in heavy-ion collisions. We use the UrQMD, AMPT, and EPOS models for Au–Au at $$\sqrt{s_\mathrm{NN}}$$ s NN = 200 GeV and Pb–Pb at $$\sqrt{s_\mathrm{NN}}$$ s NN = 2760 GeV to investigate the long range azimuthal dependence of $$G_{2}\left( \varDelta \eta ,\varDelta \varphi \right) $$ G 2 Δ η , Δ φ , and explore its utility to constrain $$\eta /s$$ η / s based on charged particle correlations. We find that the three models yield quantitatively distinct transverse momentum Fourier harmonics coefficients $$a^{p_\mathrm{T}}_{n}$$ a n p T . We also observe these coefficients exhibit a significant dependence on $$\eta /s$$ η / s in the context of the AMPT model. These observations suggest that exhaustive measurements of the dependence of $$G_{2}\left( \varDelta \varphi \right) $$ G 2 Δ φ with collision energy, system size, collision centrality, in particular, offer the potential to distinguish between different theoretical models and their underlying assumptions. Exhaustive analyses of $$G_{2}\left( \varDelta \varphi \right) $$ G 2 Δ φ obtained in large and small systems should also be instrumental in establishing new constraints for precise extraction of $$\eta /s$$ η / s .

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