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 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.

On centrality and rapidity dependences of transverse momentum spectra of negative pions in 12C + 12C collisions at 4.2 GeV/c per nucleon

2014 ◽  
Vol 23 (09) ◽  
pp. 1450047 ◽  
Author(s):  
Akhtar Iqbal ◽  
Khusniddin K. Olimov ◽  
Imran Khan ◽  
B. S. Yuldashev ◽  
Mahnaz Q. Haseeb
Keyword(s):  
Transverse Momentum ◽  
Projectile Fragmentation ◽  
Exponential Functions ◽  
Rapidity Range ◽  
Gaussian Functions ◽  
Collision Centrality ◽  
Central Collisions ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Fitting In

The dependences of the experimental transverse momentum spectra of the negative pions, produced in minimum bias 12 C + 12 C collisions at a momentum of 4.2A GeV/c, on the collision centrality and the pion rapidity range were studied. To analyze quantitatively the change in the pt spectra of π- mesons with the changes of collision centrality and pion rapidity range, the extracted pt spectra were fitted by Hagedorn, Boltzmann, Simple Exponential and Gaussian functions. The values of the extracted spectral temperatures T1 and T2 were consistently larger for the pt spectra of π- mesons coming from midrapidity range as compared to those of the negative pions generated in the target and projectile fragmentation regions. The spectral temperatures T1 and T2 extracted from fitting the pt spectra of π- mesons in range pt = 0.1–1.2 GeV/c practically coincided with each other in peripheral, semicentral and central 12 C + 12 C collision events, and thus did not show any collision centrality dependence. However, the values of T1 and T2 extracted from fitting in range pt = 0.1–0.7 GeV/c were consistently and noticeably larger in case of central collisions as compared to peripheral and semicentral 12 C + 12 C collisions. Hagedorn and Boltzmann functions provided significantly better fits of the transverse momentum spectra of the negative pions with the physically acceptable values of the extracted temperatures as compared to Gaussian and Simple Exponential functions.

scholarly journals Centrality Dependence of Deuteron Production in PbPb Collisions at 2.76 TeV via Hydrodynamics and Hadronic Afterburner +

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Dmytro Oliinychenko ◽  
Long-Gang Pang ◽  
Hannah Elfner ◽  
Volker Koch
Keyword(s):  
Transverse Momentum ◽  
Good Description ◽  
Hybrid Approach ◽  
Heavy Ion ◽  
High Energy ◽  
Central Collisions ◽  
Ion Collisions ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Deuteron Production

The deuteron binding energy is only 2.2 MeV. At the same time, its yield in Pb+Pb collisionsatpsNN = 2.76 TeV corresponds to a thermal yield at the temperature around 155 MeV, which is toohot to keep deuterons bound. This puzzle is not completely resolved yet. In general, the mechanism oflight nuclei production in ultra-high energy heavy ion collisions remains under debate. In a previouswork we suggest a microscopic explanation of the deuteron production in central ultra-relativisticPb+Pb collisions, the main mechanism being ppn $ pd reactions in the hadronic phase of thecollision. We use a state-of-the-art hybrid approach, combining relativistic hydrodynamics for the hotand dense stage and hadronic transport for a later, more dilute stage. Deuteron rescattering in thehadronic stage is implemented explicitly, using its experimentally measured vacuum cross-sections.In these proceedings we extend our previous work to non-central collisions, keeping exactly thesame methodology and parameters. We find that our approach leads to a good description of themeasured deuteron transverse momentum spectra at centralities up to 40%, and underestimatesthe amount of deuterons at low transverse momentum at higher centralities. Nevertheless, thecoalescence parameter B2, measured by ALICE collaboration, is reproduced well in our approacheven for peripheral collisions.

scholarly journals THE CENTRALITY DEPENDENCE OF STRANGE BARYON AND MESON PRODUCTION IN CU+CU AND AU+AU FOR $\sqrt{^SNN} = 200 {\rm GEV}$ COLLISIONS

2007 ◽  
Vol 16 (07n08) ◽  
pp. 2055-2060 ◽  
Author(s):  
◽  
ANTHONY R. TIMMINS
Keyword(s):  
Transverse Momentum ◽  
Meson Production ◽  
Strangeness Production ◽  
Centrality Dependence ◽  
Strange Baryon ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra

Transverse momentum spectra of Λ and [Formula: see text] particles are presented for Cu + Cu at [Formula: see text] collisions observed at STAR, and compared to Au + Au measurements at the same energy. For both systems, a number of observables are shown to increase at mid-rapidity (|y| < 0.5) with increasing centrality. These are the integrated Λ and [Formula: see text] yields, the integrated ? and [Formula: see text] yields per participating nucleon, and mid-pT(1 GeV /c → 4.5 GeV /c)[Formula: see text] ratios. The RCP ratio is found to be higher for the Λ yields at mid-pT compared to the [Formula: see text] yields for both the Cu + Cu and Au + Au data. In contrast, when similar numbers of participating nucleons are considered for the Cu + Cu and Au + Au data, an indication of increased bulk strangeness production and a higher mid-pT(1 GeV /c → 4.5 GeV /c)[Formula: see text] ratio are found, for Cu + Cu .

scholarly journals Out-Of-Equilibrium Transverse Momentum Spectra of Pions at LHC Energies

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Abdel Nasser Tawfik
Keyword(s):  
Transverse Momentum ◽  
Entire Range ◽  
Pion Production ◽  
Ad Hoc ◽  
Chemical Potential ◽  
Alice Experiment ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Bose Einstein

In order to characterize the transverse momentum spectra (pT) of positive pions measured in the ALICE experiment, two thermal approaches are utilized; one is based on degeneracy of nonperfect Bose-Einstein gas and the other imposes an ad hoc finite pion chemical potential. The inclusion of missing hadron states and the out-of-equilibrium contribute greatly to the excellent characterization of pion production. An excellent reproduction of these pT-spectra is achieved at μπ=0.12 GeV and this covers the entire range of pT. The excellent agreement with the experimental results can be understood as a manifestation of not-yet-regarded anomalous pion production, which likely contributes to the long-standing debate on “anomalous” proton-to-pion ratios at top RHIC and LHC energies.

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.

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