scholarly journals Analyzing Transverse Momentum Spectra by a New Method in High-Energy Collisions

Universe ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 31
Author(s):  
Li-Li Li ◽  
Fu-Hu Liu ◽  
Muhammad Waqas ◽  
Muhammad Ajaz
Keyword(s):  
Transverse Momentum ◽  
Energy Range ◽  
Momentum Distribution ◽  
Effective Temperature ◽  
Center Of Mass ◽  
High Energy ◽  
Transverse Momentum Distribution ◽  
Central Nucleus ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra

We analyzed the transverse momentum spectra of positively and negatively charged pions (π+ and π−), positively and negatively charged kaons (K+ and K−), protons and antiprotons (p and p¯), as well as ϕ produced in mid-(pseudo)rapidity region in central nucleus–nucleus (AA) collisions over a center-of-mass energy range from 2.16 to 2760 GeV per nucleon pair. The transverse momentum of the considered particle is regarded as the joint contribution of two participant partons which obey the modified Tsallis-like transverse momentum distribution and have random azimuths in superposition. The calculation of transverse momentum distribution of particles is performed by the Monte Carlo method and compared with the experimental data measured by international collaborations. The excitation functions of effective temperature and other parameters are obtained in the considered energy range. With the increase of collision energy, the effective temperature parameter increases quickly and then slowly. The boundary appears at around 5 GeV, which means the change of reaction mechanism and/or generated matter.

scholarly journals An Analysis of Transverse Momentum Spectra of Various Jets Produced in High Energy Collisions

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yang-Ming Tai ◽  
Pei-Pin Yang ◽  
Fu-Hu Liu
Keyword(s):  
Transverse Momentum ◽  
Momentum Distribution ◽  
Thermal Model ◽  
High Energy ◽  
Transverse Momentum Distribution ◽  
High Energies ◽  
Model Distribution ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
High Energy Collisions

With the framework of the multisource thermal model, we analyze the experimental transverse momentum spectra of various jets produced in different collisions at high energies. Two energy sources, a projectile participant quark and a target participant quark, are considered. Each energy source (each participant quark) is assumed to contribute to the transverse momentum distribution to be the TP-like function, i.e., a revised Tsallis–Pareto-type function. The contribution of the two participant quarks to the transverse momentum distribution is then the convolution of two TP-like functions. The model distribution can be used to fit the experimental spectra measured by different collaborations. The related parameters such as the entropy index-related, effective temperature, and revised index are then obtained. The trends of these parameters are useful to understand the characteristic of high energy collisions.

scholarly journals The transverse momentum spectrum of low mass Drell–Yan production at next-to-leading order in the parton branching method

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
A. Bermudez Martinez ◽  
P. L. S. Connor ◽  
D. Dominguez Damiani ◽  
L. I. Estevez Banos ◽  
F. Hautmann ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Hadron Collider ◽  
Center Of Mass ◽  
High Energy ◽  
Leading Order ◽  
Collinear Factorization ◽  
Transverse Momentum Dependent ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Low Mass

Abstract It has been observed in the literature that measurements of low-mass Drell–Yan (DY) transverse momentum spectra at low center-of-mass energies $$\sqrt{s}$$s are not well described by perturbative QCD calculations in collinear factorization in the region where transverse momenta are comparable with the DY mass. We examine this issue from the standpoint of the Parton Branching (PB) method, combining next-to-leading-order (NLO) calculations of the hard process with the evolution of transverse momentum dependent (TMD) parton distributions. We compare our predictions with experimental measurements at low DY mass, and find very good agreement. In addition we use the low mass DY measurements at low $$\sqrt{s}$$s to determine the width $$q_s$$qs of the intrinsic Gauss distribution of the PB-TMDs at low evolution scales. We find values close to what has earlier been used in applications of PB-TMDs to high-energy processes at the Large Hadron Collider (LHC) and HERA. We find that at low DY mass and low $$\sqrt{s}$$s even in the region of $$p_\mathrm{T}/m_\mathrm{DY}\sim 1$$pT/mDY∼1 the contribution of multiple soft gluon emissions (included in the PB-TMDs) is essential to describe the measurements, while at larger masses ($$m_\mathrm{DY}\sim m_{{\mathrm{Z}}}$$mDY∼mZ) and LHC energies the contribution from soft gluons in the region of $$p_\mathrm{T}/m_\mathrm{DY}\sim 1$$pT/mDY∼1 is small.

scholarly journals Excitation Functions of Tsallis-Like Parameters in High-Energy Nucleus–Nucleus Collisions

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 478
Author(s):  
Li-Li Li ◽  
Fu-Hu Liu ◽  
Khusniddin K. Olimov
Keyword(s):  
Transverse Momentum ◽  
High Energy ◽  
Central Nucleus ◽  
Excitation Functions ◽  
Momentum Spectra ◽  
Charged Pions ◽  
Transverse Momentum Spectra ◽  
Two Parameters ◽  
Freeze Out ◽  
Aa Collisions

The transverse momentum spectra of charged pions, kaons, and protons produced at mid-rapidity in central nucleus–nucleus (AA) collisions at high energies are analyzed by considering particles to be created from two participant partons, which are assumed to be contributors from the collision system. Each participant (contributor) parton is assumed to contribute to the transverse momentum by a Tsallis-like function. The contributions of the two participant partons are regarded as the two components of transverse momentum of the identified particle. The experimental data measured in high-energy AA collisions by international collaborations are studied. The excitation functions of kinetic freeze-out temperature and transverse flow velocity are extracted. The two parameters increase quickly from ≈3 to ≈10 GeV (exactly from 2.7 to 7.7 GeV) and then slowly at above 10 GeV with the increase of collision energy. In particular, there is a plateau from near 10 GeV to 200 GeV in the excitation function of kinetic freeze-out temperature.

scholarly journals A New Description of Transverse Momentum Spectra of Identified Particles Produced in Proton-Proton Collisions at High Energies

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Pei-Pin Yang ◽  
Fu-Hu Liu ◽  
Raghunath Sahoo
Keyword(s):  
Transverse Momentum ◽  
Center Of Mass ◽  
High Energy ◽  
Momentum Spectrum ◽  
Transverse Momentum Spectrum ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Momentum Spectra ◽  
Quark Level ◽  
Transverse Momentum Spectra

The transverse momentum spectra of identified particles produced in high energy proton-proton p + p collisions are empirically described by a new method with the framework of the participant quark model or the multisource model at the quark level, in which the source itself is exactly the participant quark. Each participant (constituent) quark contributes to the transverse momentum spectrum, which is described by the TP-like function, a revised Tsallis–Pareto-type function. The transverse momentum spectrum of the hadron is the convolution of two or more TP-like functions. For a lepton, the transverse momentum spectrum is the convolution of two TP-like functions due to two participant quarks, e.g., projectile and target quarks, taking part in the collisions. A discussed theoretical approach seems to describe the p + p collisions data at center-of-mass energy s = 200     GeV , 2.76 TeV, and 13 TeV very well.

scholarly journals Study of Dependence of Kinetic Freezeout Temperature on the Production Cross-Section of Particles in Various Centrality Intervals in Au–Au and Pb–Pb Collisions at High Energies

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 488
Author(s):  
Muhammad Waqas ◽  
Guang-Xiong Peng
Keyword(s):  
Transverse Momentum ◽  
Flow Velocity ◽  
Production Cross ◽  
Center Of Mass ◽  
Wave Model ◽  
Transverse Flow ◽  
Peripheral Collisions ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Transverse Flow Velocity

Transverse momentum spectra of π+, p, Λ, Ξ or Ξ¯+, Ω or Ω¯+ and deuteron (d) in different centrality intervals in nucleus–nucleus collisions at the center of mass energy are analyzed by the blast wave model with Boltzmann Gibbs statistics. We extracted the kinetic freezeout temperature, transverse flow velocity and kinetic freezeout volume from the transverse momentum spectra of the particles. It is observed that the non-strange and strange (multi-strange) particles freezeout separately due to different reaction cross-sections. While the freezeout volume and transverse flow velocity are mass dependent, they decrease with the resting mass of the particles. The present work reveals the scenario of a double kinetic freezeout in nucleus–nucleus collisions. Furthermore, the kinetic freezeout temperature and freezeout volume are larger in central collisions than peripheral collisions. However, the transverse flow velocity remains almost unchanged from central to peripheral collisions.

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.

Production cross-section of heavy flavored hadrons in pp collision at s = 7 TeV

2019 ◽  
Vol 34 (19) ◽  
pp. 1950150 ◽  
Author(s):  
Muhammad Ajaz ◽  
Irfan Khan ◽  
M. K. Suleymanov
Keyword(s):  
Experimental Data ◽  
Transverse Momentum ◽  
Differential Cross Section ◽  
Cross Section ◽  
Momentum Distribution ◽  
Cross Sections ◽  
Production Cross ◽  
Center Of Mass ◽  
Transverse Momentum Distribution ◽  
Mass Frame

The transverse momentum distribution of the differential production cross-sections of heavy flavored charm hadrons [Formula: see text], [Formula: see text] in pp collisions at 7 TeV are simulated. Predictions of DPMJETIII.17-1, HIJING1.383 and Sibyll2.3c are compared to the differential cross-section measurements of the LHCb experimental data presented in the region of [Formula: see text] and [Formula: see text], where the pp center of mass frame is used to measure the transverse momentum and rapidity. The models reproduce only some regions of [Formula: see text] and/or bins of [Formula: see text] but none of them predict completely all the [Formula: see text] bins over the entire [Formula: see text] range.

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