scholarly journals Excitation Function of Initial Temperature of Heavy Flavor Quarkonium Emission Source in High Energy Collisions

2020 ◽  
Vol 2020 ◽  
pp. 1-31
Author(s):  
Qi Wang ◽  
Fu-Hu Liu
Keyword(s):  
Transverse Momentum ◽  
Initial Temperature ◽  
High Energy ◽  
Erlang Distribution ◽  
Wide Energy Range ◽  
Heavy Flavor ◽  
Inverse Power Law ◽  
Two Component ◽  
Transverse Momentum Spectra ◽  
The Mean

The transverse momentum spectra of J/ψ, ψ2S, and YnS,n=1,2,3 produced in proton-proton p+p, proton-antiproton p+p¯, proton-lead p+Pb, gold-gold Au+Au, and lead-lead (Pb+Pb) collisions over a wide energy range are analyzed by the (two-component) Erlang distribution, the Hagedorn function (the inverse power-law), and the Tsallis-Levy function. The initial temperature is obtained from the color string percolation model from the fit by the (two-component) Erlang distribution in the framework of a multisource thermal model. The excitation functions of several parameters such as the mean transverse momentum and initial temperature increase from 39 GeV to 13 TeV, which is considered in this work. The mean transverse momentum and initial temperature decrease (increase slightly or do not change significantly) with the increase of rapidity (centrality). Meanwhile, the mean transverse momentum of YnS,n=1,2,3 is larger than that of J/ψ and ψ2S, and the initial temperature for YnS,n=1,2,3 emission is higher than that for J/ψ and ψ2S emission, which shows a mass-dependent behavior.

scholarly journals Comparing Erlang Distribution and Schwinger Mechanism on Transverse Momentum Spectra in High Energy Collisions

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Li-Na Gao ◽  
Fu-Hu Liu
Keyword(s):  
Transverse Momentum ◽  
Hadron Collider ◽  
String Tension ◽  
High Energy ◽  
Erlang Distribution ◽  
Proton Proton ◽  
Two Component ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Schwinger Mechanism

We study the transverse momentum spectra ofJ/ψandΥmesons by using two methods: the two-component Erlang distribution and the two-component Schwinger mechanism. The results obtained by the two methods are compared and found to be in agreement with the experimental data of proton-proton (pp), proton-lead (p-Pb), and lead-lead (Pb-Pb) collisions measured by the LHCb and ALICE Collaborations at the large hadron collider (LHC). The related parameters such as the mean transverse momentum contributed by each parton in the first (second) component in the two-component Erlang distribution and the string tension between two partons in the first (second) component in the two-component Schwinger mechanism are extracted.

scholarly journals Initial-State Temperature of Light Meson Emission Source From Squared Momentum Transfer Spectra in High-Energy Collisions

2021 ◽  
Vol 9 ◽  
Author(s):  
Qi Wang ◽  
Fu-Hu Liu ◽  
Khusniddin K. Olimov
Keyword(s):  
Transverse Momentum ◽  
Momentum Transfer ◽  
High Energy ◽  
Emission Source ◽  
Erlang Distribution ◽  
Photon Virtuality ◽  
Initial State ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
High Energy Collisions

The squared momentum transfer spectra of light mesons, π0, π+, η, and ρ0, produced in high-energy virtual photon-proton (γ*p) → meson + nucleon process in electron-proton (ep) collisions measured by the CLAS Collaboration are analyzed by the Monte Carlo calculations, where the transfer undergoes from the incident γ* to emitted meson or equivalently from the target proton to emitted nucleon. In the calculations, the Erlang distribution from a multi-source thermal model is used to describe the transverse momentum spectra of emitted particles. Our results show that the average transverse momentum (⟨pT⟩) and the initial-state temperature (Ti) increase from lower squared photon virtuality (Q2) and Bjorken variable (xB) to higher one. This renders that the excitation degree of emission source, which is described by ⟨pT⟩ and Ti, increases with increasing of Q2 and xB.

scholarly journals Event Patterns Extracted from Transverse Momentum and Rapidity Spectra ofZBosons and Quarkonium States Produced in pp and Pb-Pb Collisions at LHC

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Ya-Hui Chen ◽  
Fu-Hu Liu ◽  
Roy A. Lacey
Keyword(s):  
Transverse Momentum ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Erlang Distribution ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Two Component ◽  
Scatter Plots ◽  
Parameter Values

Transverse momentum (pT) and rapidity (y) spectra ofZbosons and quarkonium states (some charmoniumcc¯mesons such asJ/ψandψ(2S)and some bottomoniumbb¯mesons such asΥ(1S),Υ(2S), andΥ(3S)) produced in proton-proton (pp) and lead-lead (Pb-Pb) collisions at the large hadron collider (LHC) are uniformly described by a hybrid model of two-component Erlang distribution forpTspectrum and two-component Gaussian distribution foryspectrum. The former distribution results from a multisource thermal model, and the latter one results from the revised Landau hydrodynamic model. The modelling results are in agreement with the experimental data measured in pp collisions at center-of-mass energiess=2.76and 7 TeV and in Pb-Pb collisions at center-of-mass energy per nucleon pairsNN=2.76 TeV. Based on the parameter values extracted frompTandyspectra, the event patterns (particle scatter plots) in two-dimensionalpT-yspace and in three-dimensional velocity space are obtained.

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.

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