scholarly journals Energy-Dependent Chemical Potentials of Light Hadrons and Quarks Based on Transverse Momentum Spectra and Yield Ratios of Negative to Positive Particles

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Xing-Wei He ◽  
Feng-Min Wu ◽  
Hua-Rong Wei ◽  
Bi-Hai Hong
Keyword(s):  
Transverse Momentum ◽  
Mass Spectra ◽  
High Energy ◽  
Collision System ◽  
Pp Collisions ◽  
Chemical Potentials ◽  
Momentum Spectra ◽  
Dominant State ◽  
Transverse Momentum Spectra ◽  
Energy Dependent

We describe the transverse momentum spectra or transverse mass spectra of π ± , K ± , p , and p ¯ produced in central gold-gold (Au-Au), central lead-lead (Pb-Pb), and inelastic proton-proton (pp) collisions at different collision energies range from the AGS to LHC by using a two-component (in most cases) Erlang distribution in the framework of multisource thermal model. The fitting results are consistent with the experimental data, and the final-state yield ratios of negative to positive particles are obtained based on the normalization constants from the above describing the transverse momentum (or mass) spectra. The energy-dependent chemical potentials of light hadrons ( π , K , and p ) and quarks ( u , d , and s ) in central Au-Au, central Pb-Pb, and inelastic (pp) collisions are then extracted from the modified yield ratios in which the contributions of strong decay from high-mass resonance and weak decay from heavy flavor hadrons are removed. The study shows that most types of energy-dependent chemical potentials decrease with increase of collision energy over a range from the AGS to LHC. The curves of all types of energy-dependent chemical potentials, obtained from the fits of yield ratios vs. energy, have the maximum at about 3.510 GeV, which possibly is the critical energy of phase transition from a liquid-like hadron state to a gas-like quark state in the collision system. At the top RHIC and LHC, all types of chemical potentials become small and tend to zero at very high energy, which confirms that the high energy collision system possibly changes completely from the liquid-like hadron-dominant state to the gas-like quark-dominant state and the partonic interactions possibly play a dominant role at the LHC.

scholarly journals On Extraction of Chemical Potentials of Quarks from Particle Transverse Momentum Spectra in High Energy Collisions

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Hong Zhao ◽  
Fu-Hu Liu
Keyword(s):  
Transverse Momentum ◽  
Charged Particles ◽  
High Energy ◽  
Nuclear Collisions ◽  
Chemical Potentials ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
High Energy Collisions ◽  
Positively Charged

We present two methods to extract the chemical potentials of quarks in high energy collisions. The first method is based on the ratios of negatively/positively charged particles, and the temperatures extracted from the transverse momentum spectra of related hadrons are needed. The second method is based on the chemical potentials of some particles, and we also need the transverse momentum spectra of related hadrons. To extract the quark chemical potentials, we would like to propose experimental collaborations to measure simultaneously not only the transverse momentum spectra ofp-,p,K-,K+,π-, andπ+, but also those ofD-,D+,B-, andB+(even those ofΔ++,Δ-, andΩ-) in high energy nuclear collisions.

scholarly journals Chemical Potentials of Light Flavor Quarks from Yield Ratios of Negative to Positive Particles in Au+Au Collisions at RHIC

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ya-Qin Gao ◽  
Hai-Ling Lao ◽  
Fu-Hu Liu
Keyword(s):  
Transverse Momentum ◽  
Collision Energy ◽  
Center Of Mass ◽  
Star Collaboration ◽  
Strange Quarks ◽  
Center Of Mass Energy ◽  
Chemical Potentials ◽  
Momentum Spectra ◽  
200 Gev ◽  
Transverse Momentum Spectra

The transverse momentum spectra of π-, π+, K-, K+, p¯, and p produced in Au+Au collisions at center-of-mass energy sNN=7.7, 11.5, 19.6, 27, 39, 62.4, 130, and 200 GeV are analyzed in the framework of a multisource thermal model. The experimental data measured at midrapidity by the STAR Collaboration are fitted by the (two-component) standard distribution. The effective temperature of emission source increases obviously with the increase of the particle mass and the collision energy. At different collision energies, the chemical potentials of up, down, and strange quarks are obtained from the antiparticle to particle yield ratios in given transverse momentum ranges available in experiments. With the increase of logarithmic collision energy, the chemical potentials of light flavor quarks decrease exponentially.

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 Charged particle transverse momentum spectra in pp collisions at $ \sqrt {s} = 0.9 $ and 7 TeV

2011 ◽  
Vol 2011 (8) ◽  
Author(s):  
S. Chatrchyan ◽  
◽  
V. Khachatryan ◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
...  
Keyword(s):  
Charged Particle ◽  
Transverse Momentum ◽  
Pp Collisions ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra
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