scholarly journals Meson Production in High Energy p+p Collisions at the RHIC Energies

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Bao-Chun Li ◽  
Ya-Zhou Wang ◽  
Er-Qin Wang
Keyword(s):  
Transverse Momentum ◽  
Meson Production ◽  
High Energy ◽  
Maximum Energy ◽  
High Transverse Momentum ◽  
Component Distribution ◽  
Tail Part ◽  
Cylinder Model ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra

Transverse momentum spectra of mesons produced in p+p collisions are studied in the framework of a thermalized cylinder model. In the region of high transverse momentum, the considered distributions have a tail part at the maximum energy of RHIC. A two-component distribution based upon the improved cylinder model is used to fit the experimental data of the PHENIX Collaboration. It is found that the improved approach can describe the meson production in the wider range of transverse momenta.

scholarly journals Dependence of Temperatures and Kinetic Freeze-Out Volume on Centrality in Au-Au and Pb-Pb Collisions at High Energy

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Muhammad Waqas ◽  
Fu-Hu Liu ◽  
Zafar Wazir
Keyword(s):  
Transverse Momentum ◽  
Hadron Collider ◽  
Heavy Ion ◽  
High Energy ◽  
Relativistic Heavy Ion Collider ◽  
Event Centrality ◽  
Momentum Spectra ◽  
Standard Distribution ◽  
Transverse Momentum Spectra ◽  
Freeze Out

Centrality-dependent double-differential transverse momentum spectra of negatively charged particles (π−, K−, and p¯) at the mid(pseudo)rapidity interval in nuclear collisions are analyzed by the standard distribution in terms of multicomponent. The experimental data measured in gold-gold (Au-Au) collisions by the PHENIX Collaboration at the Relativistic Heavy Ion Collider (RHIC) and in lead-lead (Pb-Pb) collisions by the ALICE Collaboration at the Large Hadron Collider (LHC) are studied. The effective temperature, initial temperature, kinetic freeze-out temperature, transverse flow velocity, and kinetic freeze-out volume are extracted from the fitting to transverse momentum spectra. We observed that the mentioned five quantities increase with the increase of event centrality due to the fact that the average transverse momentum increases with the increase of event centrality. This renders that larger momentum (energy) transfer and further multiple scattering had happened in central centrality.

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 The origin of thermal component in the transverse momentum spectra in high energy hadronic processes

2014 ◽  
Vol 23 (12) ◽  
pp. 1450083 ◽  
Author(s):  
Alexander A. Bylinkin ◽  
Dmitri E. Kharzeev ◽  
Andrei A. Rostovtsev
Keyword(s):  
Transverse Momentum ◽  
High Energy ◽  
Relative Strength ◽  
Unruh Effect ◽  
Hadron Spectrum ◽  
Thermal Component ◽  
Momentum Spectra ◽  
Rapidity Gap ◽  
Transverse Momentum Spectra ◽  
High Energy Collisions

The transverse momentum spectra of hadrons produced in high energy collisions can be decomposed into two components: the exponential ("thermal") and the power ("hard") ones. Recently, the H1 Collaboration has discovered that the relative strength of these two components in Deep Inelastic Scattering (DIS) depends drastically upon the global structure of the event — namely, the exponential component is absent in the diffractive events characterized by a rapidity gap. We discuss the possible origin of this effect and speculate that it is linked to confinement. Specifically, we argue that the thermal component is due to the effective event horizon introduced by the confining string, in analogy to the Hawking–Unruh effect. In diffractive events, the t-channel exchange is color-singlet and there is no fragmenting string — so the thermal component is absent. The slope of the soft component of the hadron spectrum in this picture is determined by the saturation momentum that drives the deceleration in the color field, and thus the Hawking–Unruh temperature. We analyze the data on nondiffractive pp collisions and find that the slope of the thermal component of the hadron spectrum is indeed proportional to the saturation momentum.

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 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 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.

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