scholarly journals Tsallis Statistical Interpretation of Transverse Momentum Spectra in High-EnergypA Collisions

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Bao-Chun Li ◽  
Zhao Zhang ◽  
Jun-Hui Kang ◽  
Guo-Xing Zhang ◽  
Fu-Hu Liu
Keyword(s):  
Transverse Momentum ◽  
Charged Pion ◽  
Statistical Interpretation ◽  
Incident Momentum ◽  
Proton Production ◽  
Momentum Spectra ◽  
Angular Interval ◽  
Transverse Momentum Spectra ◽  
Tsallis Distribution ◽  
The Difference

In Tsallis statistics, we investigate charged pion and proton production forpCu andpPb interactions at 3, 8, and 15 GeV/c. Two versions of Tsallis distribution are implemented in a multisource thermal model. A comparison with experimental data of the HARP-CDP group shows that they both can reproduce the transverse momentum spectra, but the improved form gives a better description. It is also found that the difference betweenqandq′is small when the temperatureT = T′for the same incident momentum and angular interval, and the value ofqis greater thanq′in most cases.

scholarly journals Emission of Protons and Charged Pions inp+ Cu andp+ Pb Collisions at 3, 8, and 15 GeV/c

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
J. H. Kang ◽  
Y. C. Qian ◽  
B. C. Li ◽  
S. W. Wu
Keyword(s):  
Experimental Data ◽  
Transverse Momentum ◽  
Thermal Model ◽  
Charged Pion ◽  
Incident Momentum ◽  
Particle Distributions ◽  
Momentum Spectra ◽  
Charged Pions ◽  
Transverse Momentum Spectra

We present an analysis of proton and charged pion transverse momentum spectra ofp+Cuandp+Pbreactions at 3, 8, and 15 GeV/cin the framework of a multisource thermal model. The spectra are compared closely with the experimental data of HARP-CDP at all angular intervals. The result shows that the widths of the particle distributions in bothp+Cuandp+Pbcollisions decrease with increasing the angle for the same incident momentum.

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.

scholarly journals Comparing the Tsallis Distribution with and without Thermodynamical Description inp+pCollisions

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
H. Zheng ◽  
Lilin Zhu
Keyword(s):  
Experimental Data ◽  
Transverse Momentum ◽  
Transverse Energy ◽  
Transverse Mass ◽  
Heavy Particles ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Extra Factor ◽  
Particle Spectra ◽  
Tsallis Distribution

We compare two types of Tsallis distribution, that is, with and without thermodynamical description, using the experimental data from the STAR, PHENIX, ALICE, and CMS Collaborations on the rapidity and energy dependence of the transverse momentum spectra inp+pcollisions. Both of them can fit the particle spectra well. We show that the Tsallis distribution with thermodynamical description gives lower temperatures than the ones without it. The extra factormT(transverse mass) in the Tsallis distribution with thermodynamical description plays an important role in the discrepancies between the two types of Tsallis distribution. But for the heavy particles, the choice to usemTorET(transverse energy) in the Tsallis distribution becomes more crucial.

scholarly journals Coulomb Interaction Effects on Pion Production in Au+Au Collisions at Relativistic Energies

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Catalin Ristea ◽  
Oana Ristea ◽  
Alexandru Jipa
Keyword(s):  
Transverse Momentum ◽  
Coulomb Interaction ◽  
Beam Energy ◽  
Pion Production ◽  
Charged Pion ◽  
Centrality Dependence ◽  
Central Collisions ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Coulomb Effects

Coulomb effects on charged pion transverse momentum spectra measured in Au+Au collisions at RHIC-BES energies are investigated. From these spectra the π-/π+ ratios as a function of transverse momentum are obtained and used to extract the “Coulomb kick”, pc (a momentum change due to the Coulomb interaction), and initial pion ratio for three different collision energies and various centrality classes. The Coulomb kick shows a decrease with the increase of beam energy and a clear centrality dependence, with larger values for the most central collisions. The results are connected with the kinetic freeze-out dynamics.

scholarly journals Kinetic Freeze-Out Properties from Transverse Momentum Spectra of Pions in High Energy Proton-Proton Collisions

Physics ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 277-308
Author(s):  
Li-Li Li ◽  
Fu-Hu Liu
Keyword(s):  
Transverse Momentum ◽  
Blast Wave ◽  
Complex Structure ◽  
Excitation Functions ◽  
Proton Proton ◽  
Proton Collisions ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Tsallis Distribution ◽  
Proton Proton Collisions

Transverse momentum spectra of negative and positive pions produced at mid-(pseudo)rapidity in inelastic or non-single-diffractive proton-proton collisions over a center-of-mass energy, s , range from a few GeV to above 10 TeV are analyzed by the blast-wave fit with Boltzmann (Tsallis) distribution. The blast-wave fit results are well fitting to the experimental data measured by several collaborations. In a particular superposition with Hagedorn function, both the excitation functions of kinetic freeze-out temperature ( T 0 ) of emission source and transverse flow velocity ( β T ) of produced particles obtained from a given selection in the blast-wave fit with Boltzmann distribution have a hill at s ≈ 10 GeV, a drop at dozens of GeV, and then an increase from dozens of GeV to above 10 TeV. However, both the excitation functions of T 0 and β T obtained in the blast-wave fit with Tsallis distribution do not show such a complex structure, but a very low hill. In another selection for the parameters or in the superposition with the usual step function, T 0 and β T increase generally quickly from a few GeV to about 10 GeV and then slightly at above 10 GeV, there is no such the complex structure, when also studying nucleus-nucleus collisions.

scholarly journals Squeezed spectra of bosons and antibosons with different in-medium masses

2021 ◽  
pp. 2150043
Author(s):  
Yong Zhang ◽  
Hui-Qiang Ding ◽  
Shi-Yao Wang
Keyword(s):  
Transverse Momentum ◽  
Mass Difference ◽  
Mass Region ◽  
Transverse Mass ◽  
Medium Mass ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
The Difference ◽  
Increasing Temperature ◽  
Freeze Out

In this paper, we study the influence of the in-medium mass difference between boson and antiboson on their spectra. The in-medium mass difference may lead to a difference between the transverse momentum spectra of boson and antiboson. This effect increases with the increasing in-medium mass difference between boson and antiboson. The difference between the transverse momentum spectra of boson and antiboson increases with the increasing expanding velocity of the source and decreases with the increasing transverse momentum in large transverse mass region ([Formula: see text][Formula: see text]GeV). The interactions between the hadron and the medium may increase with the increasing temperature of the medium and the higher freeze-out temperature may lead to a larger mass difference between boson and antiboson, and may give rise to a larger difference between the transverse momentum spectra of boson and antiboson for higher freeze-out temperature.

Systematic analysis of midrapidity transverse momentum spectra of identified charged particles in p + p collisions at (snn)1/2 = 2.76, 5.02, and 7 TeV at the LHC

2020 ◽  
Vol 35 (27) ◽  
pp. 2050167
Author(s):  
Khusniddin K. Olimov ◽  
Akhtar Iqbal ◽  
Samina Masood
Keyword(s):  
Transverse Momentum ◽  
Collision Energy ◽  
Radial Flow ◽  
Transverse Flow ◽  
Systematic Analysis ◽  
Limiting Behavior ◽  
Momentum Spectra ◽  
Charged Pions ◽  
Transverse Momentum Spectra ◽  
Tsallis Distribution

The experimental transverse momentum spectra of the charged pions and kaons, protons and antiprotons, produced at midrapidity in inelastic [Formula: see text] collisions at [Formula: see text], 5.02, and 7 TeV, measured by ALICE collaboration, are analyzed systematically using the thermodynamically consistent Tsallis distribution function as well as Hagedorn function with the embedded transverse flow. To compare directly the results obtained from combined (simultaneous) fits with the above theoretical model functions of midrapidity spectra of the charged pions and kaons, protons and antiprotons in [Formula: see text] collisions at [Formula: see text], 5.02, and 7 TeV, we use the optimal identical fitting [Formula: see text] ranges [Formula: see text] in [Formula: see text] collisions at [Formula: see text], 5.02, and 7 TeV. The parameter [Formula: see text] increases consistently for all the particle species with increasing [Formula: see text] of [Formula: see text] collisions from 2.76 to 5.02 TeV, remaining practically constant within fit errors in the collision energy range [Formula: see text] TeV, suggesting probably a saturation and limiting behavior of the [Formula: see text] value in [Formula: see text] collisions at [Formula: see text] TeV. Approximate equality of the extracted nonextensivity parameter [Formula: see text] for the pions and kaons ([Formula: see text]) and relation [Formula: see text] are obtained in [Formula: see text] collisions at [Formula: see text], 5.02, and 7 TeV. Very negligible transverse (radial) flow velocity (consistent with zero value within the fit errors) is obtained in [Formula: see text] collisions at [Formula: see text], 5.02, and 7 TeV from fitting the [Formula: see text] distributions of the charged pions and kaons, protons and antiprotons with the Hagedorn formula with the embedded transverse flow in the selected optimal identical [Formula: see text] ranges as well as in the full measured [Formula: see text] ranges.

scholarly journals Inferring freeze-out parameters from pion measurements at RHIC and LHC

2015 ◽  
Vol 24 (06) ◽  
pp. 1550046 ◽  
Author(s):  
Priyanka Sett ◽  
Prashant Shukla
Keyword(s):  
Transverse Momentum ◽  
System Size ◽  
Transverse Flow ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Momentum Range ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Tsallis Distribution ◽  
Freeze Out

We analyze the transverse momentum spectra of charged pions measured in Au + Au collisions at [Formula: see text] and in Pb + Pb collisions at [Formula: see text] using the Tsallis distribution modified to include transverse flow. All the spectra are well described by the modified Tsallis distribution in an extended transverse momentum range upto 6 GeV/c. The kinetic freeze-out temperature (T), average transverse flow (β) and degree of nonthermalization (q) are obtained as a function of system size for both the energies. With increasing system size β shows increasing trend whereas T remains constant. While the systems at RHIC and LHC energies show similar β and q, the parameter T is higher at LHC as compared to RHIC. The kinetic freeze-out temperature is also extracted using the measured charged particle multiplicity and HBT volume of the system as a function of system size and collision energies.

scholarly journals Study of Production of (Anti-)deuteron Observed in Au+Au Collisions at s NN = 14.5 , 62.4, and 200 GeV

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ying Yuan
Keyword(s):  
Transverse Momentum ◽  
Thermal Model ◽  
Event Centrality ◽  
Transverse Excitation ◽  
Momentum Distributions ◽  
Momentum Spectra ◽  
200 Gev ◽  
Transverse Momentum Spectra ◽  
Tsallis Distribution ◽  
Number Of Particles

Transverse momentum distributions of deuterons and antideuterons in Au + Au collisions at s NN = 14.5 , 62.4, and 200 GeV with different centrality are studied in the framework of the multisource thermal model. Transverse momentum spectra are conformably and approximately described by the Tsallis distribution. The dependence of parameters (average transverse momenta, effective temperature, and entropy index) on event centrality is obtained. It is found that the parameters T increase and q decrease with increase of the average number of particles involved in collisions, which reveals the transverse excitation degree increases with collision centrality.

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