scholarly journals An estimate of the thermodynamic pressure in high-energy collisions

2015 ◽  
Vol 30 (07) ◽  
pp. 1550027 ◽  
Author(s):  
Abdel Nasser Tawfik
Keyword(s):  
Energy Density ◽  
Chemical Potential ◽  
Lattice Energy ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Order Moment ◽  
Particle Multiplicity ◽  
The Mean ◽  
Thermodynamic Pressure

We introduce a novel approach to estimate the thermodynamic pressure from heavy-ion collisions based on recently measured higher-order moments of particle multiplicities by the STAR experiment. We start with fitting the experimental results in the most-central collisions. Then, we integrate them back to lower ones. For example, we find that the first-order moment, the mean multiplicity, is exactly reproduced from the integral of variance, the second-order moment. Therefore, the zeroth-order moment, the thermodynamic pressure, can be estimated from the integral of the mean multiplicity. The possible comparison between such a kind of pressure (deduced from the integral of particle multiplicity) and the lattice pressure and the relating of Bjorken energy density to the lattice energy density are depending on lattice QCD at finite baryon chemical potential and first-principle estimation of the formation time of the quark–gluon plasma (QGP).

Phenomenological modeling of the photon production rate from the QGP at finite quark chemical potential

2015 ◽  
Vol 30 (33) ◽  
pp. 1550196 ◽  
Author(s):  
Yogesh Kumar ◽  
Poonam Jain
Keyword(s):  
Significant Contribution ◽  
Chemical Potential ◽  
Emission Rate ◽  
Photon Emission ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Photon Production ◽  
Phenomenological Parameter ◽  
Ion Collisions

We show the extended calculation of leading order process for photon production from Quark–Gluon Plasma (QGP) using a finite quark mass incorporating phenomenological parameter of quarks and gluons with the effect of quark chemical potential. The photon emission rate is observed in the range of low and intermediate transverse momentum. Our modified results of photon production give significant contribution in the range of quark phenomenological parameter, i.e. [Formula: see text] of high-energy heavy-ion collisions. The results obtained are compared with other results.

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 High energy density physics research at IMP, Lanzhou, China

2014 ◽  
Vol 2 ◽  
Author(s):  
Yongtao Zhao ◽  
Rui Cheng ◽  
Yuyu Wang ◽  
Xianming Zhou ◽  
Yu Lei ◽  
...  
Keyword(s):  
Energy Density ◽  
Ion Beam ◽  
Heavy Ion ◽  
High Energy ◽  
High Energy Density ◽  
Accelerator Facility ◽  
High Energy Density Physics ◽  
Research Activities ◽  
Modern Physics ◽  
Heavy Ion Beam

Abstract Recent research activities relevant to high energy density physics (HEDP) driven by the heavy ion beam at the Institute of Modern Physics, Chinese Academy of Sciences are presented. Radiography of static objects with the fast extracted high energy carbon ion beam from the Cooling Storage Ring is discussed. Investigation of the low energy heavy ion beam and plasma interaction is reported. With HEDP research as one of the main goals, the project HIAF (High Intensity heavy-ion Accelerator Facility), proposed by the Institute of Modern Physics as the 12th five-year-plan of China, is introduced.

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 Probing jet medium interactions via Z(H) + jet momentum imbalances

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Lin Chen ◽  
Shu-Yi Wei ◽  
Han-Zhong Zhang
Keyword(s):  
Transport Coefficient ◽  
Good Description ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Jet Quenching ◽  
Quenching Effect ◽  
Nuclear Collisions ◽  
Ion Collisions ◽  
Pqcd Approach

AbstractDifferent types of high energy hard probes are used to extract the jet transport properties of the Quark-Gluon Plasma created in heavy-ion collisions, of which the heavy boson tagged jets are undoubtedly the most sophisticated due to its clean decay signature and production mechanism. In this study, we used the resummation improved pQCD approach with high order correction in the hard factor to calculate the momentum ratio $$x_J$$ x J distributions of Z and Higgs (H) tagged jets. We found that the formalism can provide a good description of the 5.02 TeV pp data. Using the BDMPS energy loss formalism, along with the OSU 2 + 1D hydro to simulate the effect of the medium, we extracted the value of the jet transport coefficient to be around $${\hat{q}}_0=4\sim 8~\text {GeV}^2/\text {fm}$$ q ^ 0 = 4 ∼ 8 GeV 2 / fm by comparing with the Z + jet PbPb experimental data. The H + jet $$x_J$$ x J distribution were calculated in a similar manner in contrast and found to have a stronger Sudakov effect as compared with the Z + jet distribution. This study uses a clean color-neutral boson as trigger to study the jet quenching effect and serves as a complimentary method in the extraction of the QGP’s transport coefficient in high energy nuclear collisions.

scholarly journals QCD PHASE TRANSITION IN DGP BRANE COSMOLOGY

2012 ◽  
Vol 21 (08) ◽  
pp. 1250069 ◽  
Author(s):  
K. ATAZADEH ◽  
A. M. GHEZELBASH ◽  
H. R. SEPANGI
Keyword(s):  
Phase Transition ◽  
Energy Density ◽  
Early Universe ◽  
Effective Temperature ◽  
Quark Gluon Plasma ◽  
Friedmann Equation ◽  
Gluon Plasma ◽  
High Energy ◽  
Brane World ◽  
High Energy Density

In the standard picture of cosmology it is predicted that a phase transition, associated with chiral symmetry breaking after the electroweak transition, has occurred at approximately 10μ seconds after the Big Bang to convert a plasma of free quarks and gluons into hadrons. We consider the quark-hadron phase transition in a Dvali, Gabadadze and Porrati (DGP) brane world scenario within an effective model of QCD. We study the evolution of the physical quantities useful for the study of the early universe, namely, the energy density, temperature and the scale factor before, during and after the phase transition. Also, due to the high energy density in the early universe, we consider the quadratic energy density term that appears in the Friedmann equation. In DGP brane models such a term corresponds to the negative branch (ϵ = -1) of the Friedmann equation when the Hubble radius is much smaller than the crossover length in 4D and 5D regimes. We show that for different values of the cosmological constant on a brane, λ, phase transition occurs and results in decreasing the effective temperature of the quark-gluon plasma and of the hadronic fluid. We then consider the quark-hadron transition in the smooth crossover regime at high and low temperatures and show that such a transition occurs along with decreasing the effective temperature of the quark-gluon plasma during the process of the phase transition.

Sudden increase in the degrees of freedom in dense QCD matter

2021 ◽  
Author(s):  
Aditya Nath Mishra ◽  
Guy Paić ◽  
C. Pajares ◽  
R. P. Scharenberg ◽  
B. K. Srivastava
Keyword(s):  
Charged Particle ◽  
Energy Density ◽  
Heavy Ion Collisions ◽  
Degrees Of Freedom ◽  
Initial Temperature ◽  
Heavy Ion ◽  
Particle Multiplicity ◽  
Sudden Increase ◽  
Alice Experiment ◽  
Ion Collisions

In this paper, we analyzed charged particle transverse momentum spectra in high multiplicity events in proton–proton and nucleus–nucleus collisions at LHC energies from the ALICE experiment using the color string percolation model (CSPM). The color reduction factor and associated string density parameters are extracted for various multiplicity classes in [Formula: see text] collisions and centrality classes for heavy-ion collisions at various LHC energies to study the effect of collision geometry and collision energy. These parameters are used to extract the thermodynamical quantities temperature and the energy density of the hot nuclear matter. A universal scaling is observed in initial temperature when studied as a function of charged particle multiplicity scaled by transverse overlap area. From the measured initial energy density [Formula: see text] and the initial temperature T, a dimensionless quantity [Formula: see text] is constructed which is used to obtain the degrees of freedom (DOF) of the deconfined phase. A two-step behavior and a sudden increase in DOF of [Formula: see text]47 for the ideal gas, above the hadronization temperature (T [Formula: see text] 210[Formula: see text]MeV), are observed in case of heavy-ion collisions at LHC energies.

scholarly journals PROBING THE STATES OF MATTER IN QCD

2013 ◽  
Vol 28 (27) ◽  
pp. 1330043 ◽  
Author(s):  
HELMUT SATZ
Keyword(s):  
Critical Temperature ◽  
Quark Gluon Plasma ◽  
Heavy Ion Collisions ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
High Energy ◽  
Ideal Resonance ◽  
Ion Collisions ◽  
Quantum Numbers ◽  
Quark Deconfinement

The ultimate aim of high energy heavy ion collisions is to study quark deconfinement and the quark–gluon plasma predicted by quantum chromodynamics. This requires the identification of observables calculable in QCD and measurable in heavy ion collisions. I concentrate on three such phenomena, related to specific features of strongly interacting matter. The observed pattern of hadrosynthesis corresponds to that of an ideal resonance gas in equilibrium at the pseudo-critical temperature determined in QCD. The critical behavior of QCD is encoded in the fluctuation patterns of conserved quantum numbers, which are presently being measured. The temperature of the quark–gluon plasma can be determined by the dissociation patterns of the different quarkonium states, now under study at the LHC for both charmonia and bottomonia.

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