AZIMUTHAL ANISOTROPY MEASUREMENT OF DIRECT PHOTON IN $\sqrt{^SNN} = 200\ {\rm GeV}$Au + Au COLLISIONS AT RHIC-PHENIX

2007 ◽  
Vol 16 (07n08) ◽  
pp. 2160-2165
Author(s):  
◽  
KENTARO MIKI
Keyword(s):  
Heavy Ion ◽  
Azimuthal Anisotropy ◽  
Dense Medium ◽  
High Transverse Momentum ◽  
Initial State ◽  
Direct Photons ◽  
Ion Collisions ◽  
Hadron Decay ◽  
Decay Photon ◽  
Anisotropy Measurement

Azimuthal anisotropy of direct photons is measured in [Formula: see text] Au + Au collisions by the PHENIX experiment at RHIC. Direct photons are one of the most effective probes to study properties of hot dense medium at initial state (also QGP state) of heavy ion collisions because photons do not interact strongly with medium once produced. They keep their conditions when they are created. Within statistical and systematic errors, the elliptic flow parameter (v2) of direct photons is consistent with zero. Direct photons v2 is measured by the hadron decay photon background v2 from inclusive photon v2 in intermediate to high transverse momentum (pT) region (0 to 10 GeV/c) for 3 centrality selections (20% steps) and minimum bias.

scholarly journals An Experimental Review on Heavy-Flavorv2in Heavy-Ion Collision

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Md. Nasim ◽  
Roli Esha ◽  
Huan Zhong Huang
Keyword(s):  
Hadron Collider ◽  
Large Mass ◽  
Heavy Ion ◽  
Azimuthal Anisotropy ◽  
Relativistic Heavy Ion Collisions ◽  
Dense Medium ◽  
Heavy Flavor ◽  
Relativistic Heavy Ion Collider ◽  
Ion Collisions ◽  
Ion Collision

For over a decade now, the primary purpose of relativistic heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC) has been to study the properties of QCD matter under extreme conditions—high temperature and high density. The heavy-ion experiments at both RHIC and LHC have recorded a wealth of data in p+p, p+Pb, d+Au, Cu+Cu, Cu+Au, Au+Au, Pb+Pb, and U+U collisions at energies ranging fromsNN=7.7 GeV to 7 TeV. Heavy quarks are considered good probe to study the QCD matter created in relativistic collisions due to their very large mass and other unique properties. A precise measurement of various properties of heavy-flavor hadrons provides an insight into the fundamental properties of the hot and dense medium created in these nucleus-nucleus collisions, such as transport coefficient and thermalization and hadronization mechanisms. The main focus of this paper is to present a review on the measurements of azimuthal anisotropy of heavy-flavor hadrons and to outline the scientific opportunities in this sector due to future detector upgrade. We will mainly discuss the elliptic flow of open charmed meson (D-meson),J/ψ, and leptons from heavy-flavor decay at RHIC and LHC energy.

scholarly journals Reconstruction of neutral-triggered charged recoil jets in √s = 200 GeV p+p collisions at the STAR experiment

2020 ◽  
Vol 235 ◽  
pp. 05005
Author(s):  
Derek Anderson
Keyword(s):  
Energy Loss ◽  
Path Length ◽  
Heavy Ion ◽  
Particle Dynamics ◽  
Dense Medium ◽  
Direct Photons ◽  
Ion Collisions ◽  
200 Gev ◽  
Star Experiment ◽  
Shed Light

Jets — collimated sprays of hadrons — are produced by hard-scattered partons during the early stages of heavy ion collisions. Hence, they provide a valuable probe of the complex multi-particle dynamics within the hot, dense medium produced in such collisions. In particular, the study of jets recoiling from direct photons (γdir+jet) and those recoiling from energetic π0 (π0+jet) may shed light on the path-length and initial flavor (quark vs. gluon) dependence of the energy-loss experienced by a parton as it traverses the medium. We present here measurements of the yields of charged recoil jets tagged by γdir and π0 in p+p collisions at √S = 200 GeV. These measurements will serve as a vacuum fragmentation reference for an upcoming measurement in Au + Au collisions.

A NLO ANALYSIS ON AZIMUTHAL ANISOTROPY OF HIGH pT HADRON IN HEAVY-ION COLLISIONS

2007 ◽  
Vol 16 (10) ◽  
pp. 3185-3192 ◽  
Author(s):  
HANZHONG ZHANG ◽  
ENKE WANG
Keyword(s):  
Parton Model ◽  
Heavy Ion ◽  
High Energy ◽  
Azimuthal Anisotropy ◽  
Jet Quenching ◽  
Dense Medium ◽  
Quenching Effect ◽  
Ion Collisions ◽  
Jet Fragmentation ◽  
Fragmentation Functions

The azimuthal anisotropy of high pT hadron in high energy A + A collisions is studied within the next-to-leading order (NLO) perturbative QCD parton model. The effect of jet quenching is incorporated via a model for modified jet fragmentation functions due to radiative parton energy loss in dense medium. Because NLO contributions behave with stronger quenching effect than LO contributions, the NLO elliptic flow parameter is found to be larger than the LO in the medium pT region.

scholarly journals JET MEASUREMENTS IN p+p AND D+Au COLLISIONS WITH STAR AT RHIC

2011 ◽  
Vol 20 (07) ◽  
pp. 1651-1655
Author(s):  
◽  
JAN KAPITÁN
Keyword(s):  
Quantitative Study ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Jet Quenching ◽  
Dense Medium ◽  
Initial State ◽  
Ion Collisions ◽  
Promising Tool ◽  
200 Gev ◽  
Nuclear Effects

Full jet reconstruction in heavy-ion collisions is a promising tool for the quantitative study of properties of the dense medium produced at RHIC. In addition to baseline measurements in p + p , results from d + Au collisions are needed to disentangle initial state nuclear effects from medium-induced k T broadening and jet quenching. We present mid-rapidity inclusive jet p T spectra and di-jet correlations (k T ) in 200 GeV p + p and d + Au collisions from the 2007-2008 RHIC run.

scholarly journals Thermal photons at PHENIX experiment

2020 ◽  
Vol 235 ◽  
pp. 02001
Author(s):  
Veronica Canoa Roman
Keyword(s):  
Particle Production ◽  
Heavy Ion ◽  
Azimuthal Anisotropy ◽  
Direct Photon ◽  
Direct Photons ◽  
Small Systems ◽  
Ion Collisions ◽  
Large Yield ◽  
Charged Particle Production ◽  
Thermal Origin

Direct photons are a unique probe to study the properties of the medium created in heavy ion collisions. In particular low pT direct photons are of great importance since one expects that they are predominantly of thermal origin. In A+A systems PHENIX has observed a large yield of low pT direct photon that are emitted with a significant azimuthal anisotropy with respect to the reaction plane (v2). The mechanism responsible for the large yield and large v2 is not understood yet. Following recent evidence for collective behavior of charged particle production from small systems like p+A, d+Au, and 3He+Au, PHENIX has made systematic measurements of direct pho- tons with different collision energies and system configurations. It has been found that the low pT direct photon yield dNγ/dη is proportional to (dNch/dη)α. This behavior holds for beam energies measured both at RHIC and at the LHC in large-on-large systems, while data from small systems suggest an onset of QGP formation at low dNch/dα. In this talk, I will report recent measurements of thermal photon and related observables.

scholarly journals Direct Photons at the PHENIX Experiment: From Large to Small Systems

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 32 ◽  
Author(s):  
Veronica Roman
Keyword(s):  
Heavy Ion ◽  
Azimuthal Anisotropy ◽  
Direct Photon ◽  
Particle Multiplicity ◽  
Photon Yield ◽  
Direct Photons ◽  
Ion Collisions ◽  
200 Gev ◽  
Charge Particle Multiplicity ◽  
System Configurations

Direct photons are a unique probe to study the properties of the medium created in heavy ion collisions. Low transverse momentum ( p T ) direct photons are of special interest since thermal photons are supposed to be dominant, while at high p T direct photons come from initial hard scattering (pQCD). PHENIX has observed a large excess of direct photon yield as well as large azimuthal anisotropy at low p T in Au+Au collisions at the c.m.s energy per nucleon pair s N N = 200 GeV. The mechanism to produce a large direct photon yield with a large elliptic anisotropy ( v 2 ) is not well understood yet. PHENIX has made systematic measurements of direct photons with different collision energies and system configurations. It has been found that direct photon yield d N γ / d η is proportional to charge particle multiplicity ( d N c h / d η ) 1 . 25 . This behavior holds for beam energies measured both at RHIC and at the LHC in large systems. This scaling suggests that there is a transition from p+p to A+A system which could be understood with the analysis of smaller systems like p+Au and d+Au.

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 The First Moment of Azimuthal Anisotropy in Nuclear Collisions from AGS to LHC Energies

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Subhash Singha ◽  
Prashanth Shanmuganathan ◽  
Declan Keane
Keyword(s):  
Quark Gluon Plasma ◽  
Charged Particles ◽  
Theoretical Work ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Azimuthal Anisotropy ◽  
Flow Focusing ◽  
Nuclear Collisions ◽  
Ion Collisions ◽  
First Moment

We review topics related to the first moment of azimuthal anisotropy (v1), commonly known as directed flow, focusing on both charged particles and identified particles from heavy-ion collisions. Beam energies from the highest available, at the CERN LHC, down to projectile kinetic energies per nucleon of a few GeV per nucleon, as studied in experiments at the Brookhaven AGS, fall within our scope. We focus on experimental measurements and on theoretical work where direct comparisons with experiment have been emphasized. The physics addressed or potentially addressed by this review topic includes the study of Quark Gluon Plasma and, more generally, investigation of the Quantum Chromodynamics phase diagram and the equation of state describing the accessible phases.

scholarly journals 3D glasma initial state for relativistic heavy ion collisions

2016 ◽  
Vol 94 (4) ◽  
Author(s):  
Björn Schenke ◽  
Sören Schlichting
Keyword(s):  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Initial State ◽  
Ion Collisions
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