Medium effects of charged particles in Xe+Xe collisions at s NN = 5.44 TeV using modified Tsallis distribution

2021 ◽  
Vol 36 (07) ◽  
pp. 2150059
Author(s):  
Pramod Kumar ◽  
P. K. Khandai ◽  
Kapil Saraswat ◽  
V. Singh
Keyword(s):  
Good Description ◽  
Charged Particles ◽  
Heavy Ion ◽  
Transverse Flow ◽  
Original Form ◽  
Published Data ◽  
Medium Effects ◽  
Final State ◽  
Particle Spectra ◽  
Tsallis Distribution

We present a systematic study of transverse momentum [Formula: see text] spectra of charged particles in [Formula: see text] and Xe[Formula: see text]Xe collisions at [Formula: see text] TeV. The published data of invariant yields of charged particles as a function of [Formula: see text] is taken from ALICE at LHC in the mid-pseudorapidity region [Formula: see text]. The modified form of Tsallis distribution is used here to analyze the [Formula: see text] spectra of charged particles. The power law of Tsallis/Hagedorn form gives very good description of the charged particle spectra in [Formula: see text] collisions within a [Formula: see text] range of 0.15 GeV/[Formula: see text] to 50 GeV/[Formula: see text]. When we go from [Formula: see text] collisions to heavy-ion (Xe[Formula: see text]Xe) collisions, the original form of Tsallis/Hagedorn distribution is not able to describe the [Formula: see text] spectra of charged particles properly. This may be occurred due to the medium effects or the final state effects. Here we discuss two types of medium effects of charged particles in Xe[Formula: see text]Xe collisions, one is the transverse flow in the low to intermediate [Formula: see text] region ([Formula: see text] GeV/[Formula: see text]) and the other is the energy loss in the high [Formula: see text] region ([Formula: see text] GeV/[Formula: see text]), using the modified Tsallis distribution.

Combined analysis of midrapidity transverse momentum spectra of the charged pions and kaons, protons and antiprotons in p+p and Pb+Pb collisions at (snn)1/2 = 2.76 and 5.02 TeV at the LHC

2020 ◽  
Vol 35 (29) ◽  
pp. 2050237
Author(s):  
Khusniddin K. Olimov ◽  
Shakhnoza Z. Kanokova ◽  
Alisher K. Olimov ◽  
Kobil I. Umarov ◽  
Boburbek J. Tukhtaev ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Transverse Flow ◽  
Alice Collaboration ◽  
Momentum Spectra ◽  
Charged Pions ◽  
Transverse Momentum Spectra ◽  
Tsallis Distribution ◽  
Freeze Out

The experimental transverse momentum spectra of the charged pions and kaons, protons and antiprotons, produced at midrapidity in [Formula: see text] collisions at [Formula: see text] and 5.02 TeV, central (0–5%) and peripheral (60–80%) Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] TeV, central (0–5%), semicentral (40–50%) and peripheral (80–90%) Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] TeV, measured by ALICE collaboration, were analyzed using the Tsallis distribution function as well as Hagedorn formula with the embedded transverse flow. To exclude the influence (on the results) of different available fitting [Formula: see text] ranges in the analyzed collisions, we compare the results obtained from combined (simultaneous) fits of midrapidity spectra of the charged pions and kaons, protons and antiprotons with the above theoretical model functions using the identical fitting [Formula: see text] ranges in [Formula: see text] as well as Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] and 5.02 TeV. Using the combined fits with the thermodynamically consistent Tsallis distribution as well as the simple Tsallis distribution without thermodynamical description, it is obtained that the global temperature [Formula: see text] and non-extensivity parameter [Formula: see text] slightly increase (consistently for all the particle types) with an increase in center-of-mass (c.m.) energy [Formula: see text] of [Formula: see text] collisions from 2.76 TeV to 5.02 TeV, indicating that the more violent and faster [Formula: see text] collisions at [Formula: see text] TeV result in a smaller degree of thermalization (higher degree of non-equilibrium) compared to that in [Formula: see text] collisions at [Formula: see text] TeV. The [Formula: see text] values for pions and kaons proved to be very close to each other, whereas [Formula: see text] for protons and antiprotons proved to be significantly lower than that for pions and kaons, that is [Formula: see text]. The results of the combined fits using Hagedorn formula with the embedded transverse flow are consistent with practically no (zero) transverse (radial) flow in [Formula: see text] collisions at [Formula: see text] and 5.02 TeV. Using Hagedorn formula with the embedded transverse flow, it is obtained that the value of the (average) transverse flow velocity increases and the temperature [Formula: see text] decreases with an increase in collision centrality in Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] and 5.02 TeV, which is in good agreement with the results of the combined Boltzmann–Gibbs blast-wave fits to the particle spectra in Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] and 5.02 TeV in recent works of ALICE collaboration. The temperature [Formula: see text] parameter, which approximates the kinetic freeze-out temperature, was shown to coincide in central (0–5%) Pb[Formula: see text]+[Formula: see text]Pb collisions at [Formula: see text] and 5.02 TeV, which implies, taking into account the results of our previous analysis, that kinetic freeze-out temperature stays practically constant in central heavy-ion collisions in [Formula: see text] GeV energy range.

MESON PRODUCTION AT SPS ENERGIES

2007 ◽  
Vol 22 (02n03) ◽  
pp. 659-662 ◽  
Author(s):  
ANDRZEJ RYBICKI
Keyword(s):  
Production Process ◽  
Comparative Studies ◽  
Initial Conditions ◽  
Meson Production ◽  
Heavy Ion ◽  
Coulomb Interactions ◽  
Final State ◽  
Ion Collisions ◽  
New Information ◽  
Particle Spectra

Comparative studies of hadron-induced interactions and heavy ion collisions have been performed at beam energies of 158 GeV/nucleon, corresponding to [Formula: see text]. They indicate that the heavy ion reaction is a mixture of various processes, including multiple nucleon collisions, isospin effects, and final state Coulomb interactions. The latter interactions result in surprising phenomena, like the presence of large and strongly varying structures in the shape of double-differential particle spectra. These phenomena depend on the initial conditions of the reaction and therefore can provide new information on the space and time evolution of the non-perturbative meson production process.

scholarly journals Centrality, transverse momentum and collision energy dependence of the Tsallis parameters in relativistic heavy-ion collisions

2021 ◽  
Vol 136 (6) ◽  
Author(s):  
Rajendra Nath Patra ◽  
Bedangadas Mohanty ◽  
Tapan K. Nayak
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Collision Energy ◽  
Charged Particles ◽  
Heavy Ion ◽  
High Energy ◽  
Relativistic Heavy Ion Collisions ◽  
Central Collisions ◽  
Ion Collisions ◽  
Tsallis Distribution

AbstractThe thermodynamic properties of matter created in high-energy heavy-ion collisions have been studied in the framework of the non-extensive Tsallis statistics. The transverse momentum ($$p_\mathrm{T}$$ p T ) spectra of identified charged particles (pions, kaons, protons) and all charged particles from the available experimental data of Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC) energies and Pb-Pb collisions at the Large Hadron Collider (LHC) energies are fitted by the Tsallis distribution. The fit parameters, q and T, measure the degree of deviation from an equilibrium state and the effective temperature of the thermalized system, respectively. The $$p_\mathrm{T}$$ p T  spectra are well described by the Tsallis distribution function from peripheral to central collisions for the wide range of collision energies, from $$\sqrt{s_\mathrm{NN}}$$ s NN = 7.7 GeV to 5.02 TeV. The extracted Tsallis parameters are found to be dependent on the particle species, collision energy, centrality, and fitting ranges in $$p_\mathrm{T}$$ p T . For central collisions, both q and T depend strongly on the fit ranges in $$p_\mathrm{T}$$ p T . For most of the collision energies, q remains almost constant as a function of centrality, whereas T increases from peripheral to central collisions. For a given centrality, q systematically increases as a function of collision energy, whereas T has a decreasing trend. A profile plot of q and T with respect to collision energy and centrality shows an anti-correlation between the two parameters.

Some Results on Angular Characteristics of Relativistic Charged Particles Produced in 12C-emulsion Interactions at 4.5 A GeV/c

1998 ◽  
Vol 07 (06) ◽  
pp. 659-667 ◽  
Author(s):  
Prithipal Singh ◽  
H. Khushnood
Keyword(s):  
Charged Particles ◽  
Heavy Ion ◽  
Angular Distributions ◽  
Final State ◽  
Angular Characteristic ◽  
Ion Interactions ◽  
Singly Charged ◽  
Relativistic Particles

An attempt has been made to study the angular characteristic of relativistic charged particles produced in 4.5 A GeV/c 12C-emulsion collisions. The dependence of these characteristics on the multiplicity of the relativistic particles, Ns, has also been investigated. The results reveal that the angular distributions of relativistic particles do not depend on Ns, except at small angles where contribution of singly charged particles fragments enhances the number of relativistic charged particles. It is also observed that the maximum of pseudorapidity, η and <η> distributions, shifts towards the lower value of η with increasing multiplicity of Ns. The study of the rapidity dispersion of relativistic charged particles reveals that the clusterization effect occurs significantly among the final state relativistic particles produced in heavy ion interactions.

CHARACTERISTICS OF RELATIVISTIC CHARGED PARTICLES PRODUCED IN 24Mg–EMULSION INTERACTIONS AT 4.5A GeV/C

2001 ◽  
Vol 10 (01) ◽  
pp. 55-68 ◽  
Author(s):  
N. N. ABD ALLAH ◽  
S. A. H. ABOU-STEIT ◽  
M. MOHERY ◽  
S. S. ABDEL-AZIZ
Keyword(s):  
Charged Particles ◽  
Heavy Ion ◽  
Scaling Behavior ◽  
Final State ◽  
Azimuthal Correlations ◽  
Ion Interactions ◽  
Multiplicity Distributions ◽  
Pseudorapidity Distributions ◽  
Relativistic Particles

The interactions of 4.5A GeV/c 24 Mg nuclei with emulsion have been studied. The multiplicity distributions of all the produced target protons from 24 Mg –emulsion interactions has been found to obey the KNO scaling behavior. The angular characteristics of the relativistic charged particles have been investigated and their dependence on the multiplicity of the relativistic shower particles has been studied. The results reveal that increasing the multiplicity of the shower particles, leads to a shift of the peak of the pseudorapidity distributions towards the lower values of the pseudorapidity and also to a decrease of the average pseudorapidity. The study of the rapidity dispersion of the relativistic charged particles shows that the clusterization effect is significant among the final state of the relativistic particles produced in the heavy-ion interactions. Azimuthal correlations in the angles of the relativistic charged particles have been investigated.

scholarly journals Can Tsallis Distribution Fit All the Particle Spectra Produced at RHIC and LHC?

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
H. Zheng ◽  
Lilin Zhu
Keyword(s):  
Degree Of Freedom ◽  
Medium Effects ◽  
Particle Spectra ◽  
Tsallis Distribution ◽  
New Formula ◽  
Distribution Fit

The Tsallis distribution has been tested to fit all the particle spectra at mid-rapidity from central events produced in d + Au, Cu + Cu, and Au + Au collisions at RHIC and p + Pb, Pb + Pb collisions at LHC. Even though there are strong medium effects in Cu + Cu and Au + Au collisions, the results show that the Tsallis distribution can be used to fit most of particle spectra in the collisions studied except in Au + Au collisions where some deviations are seen for proton andΛat lowpT. In addition, as the Tsallis distribution can only fit part of the particle spectra produced in Pb + Pb collisions wherepTis up to 20 GeV/c, a new formula with one more fitting degree of freedom is proposed in order to reproduce the entirepTregion.

scholarly journals A Description of the Transverse Momentum Distributions of Charged Particles Produced in Heavy Ion Collisions at RHIC and LHC Energies

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Jia-Qi Hui ◽  
Zhi-Jin Jiang ◽  
Dong-Fang Xu
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion Collisions ◽  
Good Description ◽  
Charged Particles ◽  
Heavy Ion ◽  
Ion Collisions ◽  
Nonextensive Statistics ◽  
Long Range Interactions ◽  
Momentum Distributions ◽  
Momentum Region

By assuming the existence of memory effects and long-range interactions, nonextensive statistics together with relativistic hydrodynamics including phase transition are used to discuss the transverse momentum distributions of charged particles produced in heavy ion collisions. It is shown that the combined contributions from nonextensive statistics and hydrodynamics can give a good description of the experimental data in Au+Au collisions at sNN=200 GeV and in Pb+Pb collisions at sNN=2.76 TeV for π± and K± in the whole measured transverse momentum region and for pp- in the region of pT≤2.0 GeV/c. This is different from our previous work using the conventional statistics plus hydrodynamics, where the describable region is only limited in pT≤1.1 GeV/c.

scholarly journals Characterising Charm Jet Properties with Azimuthal Correlations of D Mesons and Charged Particles with ALICE at the LHC

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 35
Author(s):  
Shyam Kumar for the ALICE Collaboration
Keyword(s):  
Heavy Ion Collisions ◽  
Charm Quark ◽  
Charged Particles ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collisions ◽  
Pp Collisions ◽  
Final State ◽  
Essential Information ◽  
Ion Collisions

Charm quarks are produced via hard parton scattering in ultra-relativistic heavy-ion collisions, hence are ideal probes to study a possible de-confined state of matter, known as Quark Gluon Plasma (QGP). The angular correlation of a meson containing a charm quark with other charged particles in heavy-ion collisions can help in studying the properties of QGP. Similar studies in pp collisions can give insight about the charm production mechanism while in p-Pb collisions could provide essential information to disentangle final-state QGP-induced modifications from effects caused by cold nuclear matter. In this proceedings, the results are presented for p-Pb collisions at s NN = 5.02 TeV and pp collisions at s = 13 TeV, so far the highest available energy at the LHC. The results are compared with Monte Carlo (MC) simulations using PYTHIA and POWHEG event generators and with pp collision results at s = 7 TeV.

scholarly journals Identifying QCD Transition Using Deep Learning

2018 ◽  
Vol 171 ◽  
pp. 16005 ◽  
Author(s):  
Kai Zhou ◽  
Long-gang Pang ◽  
Nan Su ◽  
Hannah Petersen ◽  
Horst Stoecker ◽  
...  
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Equation Of State ◽  
Convolutional Neural Network ◽  
Phase Structure ◽  
Heavy Ion ◽  
Final State ◽  
Ion Collisions ◽  
Particle Spectra ◽  
Dynamical Information

In this proceeding we review our recent work using supervised learning with a deep convolutional neural network (CNN) to identify the QCD equation of state (EoS) employed in hydrodynamic modeling of heavy-ion collisions given only final-state particle spectra ρ(pT, Ф). We showed that there is a traceable encoder of the dynamical information from phase structure (EoS) that survives the evolution and exists in the final snapshot, which enables the trained CNN to act as an effective “EoS-meter” in detecting the nature of the QCD transition.

scholarly journals Prehydrodynamic evolution and its signatures in final-state heavy-ion observables

2021 ◽  
Vol 103 (5) ◽  
Author(s):  
T. Nunes da Silva ◽  
D. Chinellato ◽  
G. S. Denicol ◽  
M. Hippert ◽  
M. Luzum ◽  
...  
Keyword(s):  
Heavy Ion ◽  
Final State
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