scholarly journals Measurements of jets in heavy ion collisions

2018 ◽  
Vol 172 ◽  
pp. 05010 ◽  
Author(s):  
Christine Nattrass
Keyword(s):  
Energy Loss ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Relativistic Heavy Ion Collider ◽  
Ion Collisions

The Quark Gluon Plasma (QGP) is created in high energy heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). This medium is transparent to electromagnetic probes but nearly opaque to colored probes. Hard partons produced early in the collision fragment and hadronize into a collimated spray of particles called a jet. The partons lose energy as they traverse the medium, a process called jet quenching. Most of the lost energy is still correlated with the parent parton, contributing to particle production at larger angles and lower momenta relative to the parent parton than in proton-proton collisions. This partonic energy loss can be measured through several observables, each of which give different insights into the degree and mechanism of energy loss. The measurements to date are summarized and the path forward is discussed.

scholarly journals Jet quenching in high-energy heavy-ion collisions

2015 ◽  
Vol 24 (11) ◽  
pp. 1530014 ◽  
Author(s):  
Guang-You Qin ◽  
Xin-Nian Wang
Keyword(s):  
Energy Loss ◽  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Parton Energy Loss ◽  
Ion Collisions ◽  
Phenomenological Studies

Jet quenching in high-energy heavy-ion collisions can be used to probe properties of hot and dense quark–gluon plasma. We provide a brief introduction to the concept and framework for the study of jet quenching. Different approaches and implementation of multiple scattering and parton energy loss are discussed. Recent progresses in the theoretical and phenomenological studies of jet quenching in heavy-ion collisions at RHIC and LHC are reviewed.

RELATIVISTIC HEAVY-ION COLLISIONS: RECENT RESULTS FROM RHIC

2004 ◽  
Vol 19 (07) ◽  
pp. 1111-1118
Author(s):  
D. HARDTKE
Keyword(s):  
Energy Loss ◽  
Nuclear Matter ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
High Energy ◽  
Jet Quenching ◽  
Relativistic Heavy Ion Collisions ◽  
Dense Medium ◽  
Relativistic Heavy Ion Collider ◽  
Ion Collisions

High energy collisions of heavy nuclei at the Relativistic Heavy-Ion Collider permit the study of nuclear matter at extreme densities and temperatures. Selected experimental highlights from the early RHIC program are presented. Measurements of the total multiplicity in heavy-ion collisions show a surprising similarity to measurements in e+e- collisions after nuclear geometry is taken into account. RHIC has sufficient center-of-mass energy to use large transverse momentum particles and jets as a probe of the nuclear medium. Signatures of "jet quenching" due to radiative gluon energy loss of fast partons in a dense medium are observed for the first time at RHIC. In order to account for this energy loss, initial energy densities of 30-100 times normal nuclear matter density are required.

scholarly journals Signatures of QGP at RHIC and the LHC

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
T. Niida ◽  
Y. Miake
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Theoretical Studies ◽  
Debye Screening ◽  
Direct Photons ◽  
Ion Collisions ◽  
Experimental And Theoretical Studies

AbstractThe progress over the 30 years since the first high-energy heavy-ion collisions at the BNL-AGS and CERN-SPS has been truly remarkable. Rigorous experimental and theoretical studies have revealed a new state of the matter in heavy-ion collisions, the quark-gluon plasma (QGP). Many signatures supporting the formation of the QGP have been reported. Among them are jet quenching, the non-viscous flow, direct photons, and Debye screening effects. In this article, selected signatures of the QGP observed at RHIC and the LHC are reviewed.

scholarly journals On Pseudorapidity Distribution and Speed of Sound in High Energy Heavy Ion Collisions Based on a New Revised Landau Hydrodynamic Model

2015 ◽  
Vol 2015 ◽  
pp. 1-23 ◽  
Author(s):  
Li-Na Gao ◽  
Fu-Hu Liu
Keyword(s):  
Speed Of Sound ◽  
Hydrodynamic Model ◽  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Relativistic Heavy Ion Collider ◽  
Central Source ◽  
Ion Collisions

We propose a new revised Landau hydrodynamic model to study systematically the pseudorapidity distributions of charged particles produced in heavy ion collisions over an energy range from a few GeV to a few TeV per nucleon pair. The interacting system is divided into three sources, namely, the central, target, and projectile sources, respectively. The large central source is described by the Landau hydrodynamic model and further revised by the contributions of the small target/projectile sources. The modeling results are in agreement with the available experimental data at relativistic heavy ion collider, large hadron collider, and other energies for different centralities. The value of square speed of sound parameter in different collisions has been extracted by us from the widths of rapidity distributions. Our results show that, in heavy ion collisions at energies of the two colliders, the central source undergoes a phase transition from hadronic gas to quark-gluon plasma liquid phase; meanwhile, the target/projectile sources remain in the state of hadronic gas. The present work confirms that the quark-gluon plasma is of liquid type rather than being of a gas type.

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

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.

Collective flow and correlation with higher harmonic event planes

Open Physics ◽  
2012 ◽  
Vol 10 (6) ◽  
Author(s):  
ShinIchi Esumi
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
System Response ◽  
Azimuthal Correlation ◽  
Particle Correlation ◽  
Ion Collisions ◽  
Higher Harmonic

AbstractAzimuthal event anisotropy and particle correlation have been used to analyze the collectivity of the system created in the high-energy heavy-ion collisions in order to study the properties of Quark Gluon Plasma (QGP). Higher harmonic event anisotropy is recently recognized to carry the information of initial participant geometrical fluctuation because of the finite number of participating nucleons in heavy-ion collisions. The system response after the collective expansion can be observed as higher harmonic event anisotropy, the n-th harmonic order dependence can be used to further constrain the hydro-dynamical properties of the system. The multi-particle azimuthal correlation with respect to the higher harmonic event plane can be used as a tool to understand the origin of the higher harmonic event anisotropy and its relation to the medium response from the jet-quenching as soft-hard interplay. Recent results on the higher harmonic event anisotropy measurements and an attempt of two-particle correlation analysis with respect to the higher harmonic event planes are discussed.

scholarly journals Quarkonia disintegration due to time dependence of the qq̄ potential in relativistic heavy-ion collisions

2015 ◽  
Vol 30 (32) ◽  
pp. 1550162 ◽  
Author(s):  
Partha Bagchi ◽  
Ajit M. Srivastava
Keyword(s):  
Survival Probability ◽  
Heavy Ion Collisions ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collisions ◽  
Relativistic Heavy Ion Collider ◽  
Ion Collisions ◽  
Quarkonium State ◽  
Short Time

Rapid thermalization in ultra-relativistic heavy-ion collisions leads to fast changing potential between a heavy quark and antiquark from zero temperature potential to the finite temperature one. Time-dependent perturbation theory can then be used to calculate the survival probability of the initial quarkonium state. In view of very short time scales of thermalization at relativistic heavy-ion collider (RHIC) and large hadron collider (LHC) energies, we calculate the survival probability of [Formula: see text] and [Formula: see text] using sudden approximation. Our results show that quarkonium decay may be significant even when temperature of quark–gluon plasma (QGP) remains low enough so that the conventional quarkonium melting due to Debye screening is ineffective.

scholarly journals Comparative analysis of strange meson production in heavy ion collisions

2021 ◽  
Vol 2103 (1) ◽  
pp. 012134
Author(s):  
V S Borisov ◽  
A Ya Berdnikov ◽  
Ya A Berdnikov ◽  
D O Kotov ◽  
Iu M Mitrankov
Keyword(s):  
Experimental Data ◽  
Heavy Ion Collisions ◽  
Particle Production ◽  
High Energy Physics ◽  
Heavy Ion ◽  
High Energy ◽  
Jet Quenching ◽  
Model Calculations ◽  
Quenching Effect ◽  
Ion Collisions

Abstract The study of deconfinement state of nuclear matter called quark-gluon plasma (QGP) and phase transition of QGP to hadronic gas is the main goal of high energy physics. Some of the important signatures of QGP formation in heavy-ion collisions include strangeness enhancement at intermediate values of the transverse momentum (ρT ) and a jet quenching effect at high ρT values. Nuclear modification factors (RAB ) for light hadrons are used to quantify these effects. The K *0 and φ mesons can serve as a good probes to investigate QGP properties, because these mesons contain (anti)strange quark and its yields can be measured in a wide ρT range. Comparison of experimental data with theoretical model calculations is important for understanding the evolution of heavy-ion collision. One of the most commonly used event generators to describe experimental results of collider experiments is Pythia8. This paper shows, that Pythia8 predicts RAB values of K *0 and φ less than RAB values in experimental data. Consequently, additional (hidden)strange particle production mechanisms are involved.

scholarly journals Time reclustering for jet quenching studies

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
Liliana Apolinário ◽  
André Cordeiro ◽  
Korinna Zapp
Keyword(s):  
Hadron Collider ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Jet Quenching ◽  
Time Structure ◽  
Relativistic Heavy Ion Collisions ◽  
Relativistic Heavy Ion Collider ◽  
Ion Collisions ◽  
Physics Program ◽  
Unique Potential

AbstractThe physics program of ultra-relativistic heavy-ion collisions at the Large Hadron Collider (LHC) and Relativistic Heavy-Ion Collider (RHIC) has brought a unique insight into the hot and dense QCD matter created in such collisions, the Quark-Gluon Plasma (QGP). Jet quenching, a collection of medium-induced modifications of the jets’ internal structure that occur through their development in dense QCD matter, has a unique potential to assess the time structure of the produced medium. In this work, we perform an exploratory study to identify jet reclustering tools that can potentiate future QGP tomographic measurements with jets at current energies. Our results show that by using the inverse of formation time to obtain the jet clustering history, one can identify more accurately the time structure of QCD emissions inside jets, even in the presence of jet quenching.

Exploring sQGP and small systems

2021 ◽  
pp. 2130014
Author(s):  
Debasish Das
Keyword(s):  
Heavy Ions ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Relativistic Heavy Ion Collider ◽  
Small Systems ◽  
Strongly Coupled ◽  
Ion Collisions ◽  
Low Viscosity

A strongly coupled Quark–Gluon Plasma (sQGP) is created in the high-energy heavy-ion collisions at Relativistic Heavy-Ion Collider (RHIC) and Large Hadron Collider (LHC). Our present understanding of sQGP as a very good liquid with astonishingly low viscosity is reviewed. With the arrival of the interesting results from LHC in high-energy [Formula: see text] and [Formula: see text], a new endeavor to characterize the transition from these small systems to heavy ions [Formula: see text] is now in place, since even the small systems showed prominent similarities to heavy ions in the rising multiplicity domains. An outlook of future possibilities for better measurements is also made at the end of this brief review.

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