Photon production in high energy nuclear collision of quark–gluon plasma

2014 ◽  
Vol 29 (22) ◽  
pp. 1450110 ◽  
Author(s):  
S. Somorendro Singh ◽  
Yogesh Kumar

We extend to investigate photon production through annihilation with scattering (AWS), and Compton and annihilation processes from a stabilized high energy nuclear collision of quark–gluon plasma (QGP) incorporating finite value of quark mass obtained through a strong coupling value. The production rate is represented in the region of low and intermediate photon energy and it is observed to be a decreasing function with temperature. The calculation is extended to the case of photon spectra with the photon transverse momentum. The current observation shows little enhancement in both processes at the temperature T = 0.25 GeV and it is in conformity with the recent direct photon production of other works at temperature T = 0.30 GeV .

2015 ◽  
Vol 30 (13) ◽  
pp. 1550067
Author(s):  
Carlos Hidalgo-Duque ◽  
Felipe J. Llanes-Estrada

We study the collisional aspects of jet quenching in a high-energy nuclear collision, especially in the final state pion gas. The jet has a large energy, and acquires momentum transverse to its axis more effectively by multiple soft collisions than by few hard scatterings (as known from analogous systems such as J/ψ production at Hera). Such regime of large E and small momentum transfer corresponds to Regge kinematics and is characteristically dominated by the pomeron. From this insight we estimate the jet quenching parameter in the hadron medium (largely a pion gas) at the end of the collision, which is naturally small and increases with temperature in line with the gas density and compare it to the jet quenching parameter obtained within the quark–gluon plasma (QGP) phase in widely known perturbative approximations. The physics in the quark–gluon plasma/liquid phase is less obvious, and here we revisit a couple of simple estimates that suggest indeed that the pomeron-mediated interactions are very relevant and should be included in analysis of the jet quenching parameter. Finally, since the occasional hard collisions produce features characteristic of a Lèvy flight in the [Formula: see text] plane perpendicular to the jet axis, we suggest one- and two-particle q⊥correlations as interesting experimental probes sensitive to the nature (softness versus hardness) of the interactions of a jet inside the QGP.


2015 ◽  
Vol 30 (03) ◽  
pp. 1550020 ◽  
Author(s):  
S. Somorendro Singh ◽  
Yogesh Kumar

We extend to calculate the direct photon production from quark–gluon plasma (QGP) considering finite chemical potential. The calculation is done from a system of strongly interacting QGP and the result is found to be increasing function of chemical potential in all the channels of photon production. It also shows enhancement of photon production from photon production without chemical potential and other theoretical calculation of direct photon productions.


1993 ◽  
Vol 08 (40) ◽  
pp. 3853-3859 ◽  
Author(s):  
D. K. MAITY ◽  
P. K. BANERJEE ◽  
B. B. DAS ◽  
D. RAVINDRAN ◽  
D. K. BHATTACHARJEE

A study of intermittency in hadron-nucleus and the comparison with nucleus-nucleus interactions is presented. The power law behavior of the factorial moments and the variation of intermittency index with the center-of-mass energy are shown. Results favor the formation of quark-gluon plasma in preference to a cascade mechanism.


2015 ◽  
Vol 2015 ◽  
pp. 1-23 ◽  
Author(s):  
Li-Na Gao ◽  
Fu-Hu Liu

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.


2016 ◽  
Vol 93 (6) ◽  
Author(s):  
Lusaka Bhattacharya ◽  
Radoslaw Ryblewski ◽  
Michael Strickland

2020 ◽  
Vol 2 ◽  
pp. 1
Author(s):  
N. G. Antoniou

Incorporating fractal geometry in the Regge-Mueller approach to strong interaction dynamics one may formulate a model for the one-dimensional critical sector of the hadronic 5-matrix in a high energy collision. A non conventional component of the correlation functions in rapidity space is obtained, the phenomenological implications of which are related with the intermittency effects in quark-gluon plasma physics.


2012 ◽  
Vol 21 (08) ◽  
pp. 1250069 ◽  
Author(s):  
K. ATAZADEH ◽  
A. M. GHEZELBASH ◽  
H. R. SEPANGI

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.


2018 ◽  
Vol 172 ◽  
pp. 05005
Author(s):  
Sandra S. Padula

The quark-gluon plasma created in high energy collisions of large nuclei exhibits strong anisotropic collective behavior as a nearly perfect fluid, flowing with little frictional resistance or viscosity. It has been investigated extensively over the past years employing two or more particle correlations. An overview of collective flow and particle correlation measurements at CMS as a function of transverse momentum, pseudorapidity, event multiplicity, for both charged hadrons or identified particles will be presented. These results are compared among pp, pPb and PbPb systems and several aspects of their intriguing similarities are discussed.


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