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 ◽  
...  
1997 ◽  
Vol 485 (1-2) ◽  
pp. 3-22 ◽  
Author(s):  
C. Adloff ◽  
S. Aid ◽  
M. Anderson ◽  
V. Andreev ◽  
B. Andrieu ◽  
...  

2020 ◽  
Vol 1643 (1) ◽  
pp. 012007
Author(s):  
Angela Badalà

Abstract The study of hadronic resonances plays an important role both in pp and in heavy-ion collisions. Since the lifetimes of short-lived resonances are comparable with the lifetime of the fireball formed in heavy-ion collisions, regeneration and re-scattering effects can modify the measured yields, especially at low transverse momentum. Measurements in pp collisions at different energies constitute a baseline for studies in heavy-ion collisions and provide constraints for tuning QCD-inspired event generators. Furthermore, high multiplicity pp collisions, where the density and the volume of the system are expected to be larger compared to minimum bias pp collisions, can help in the search for the onset of collective phenomena. Here we present recent results on short-lived hadronic resonances obtained by the ALICE experiment at LHC energies in different collision systems (pp, p–Pb and Pb–Pb) including new results obtained in Xe–Xe collisions. The ALICE results on transverse momentum spectra, yields and their ratios to long-lived particles will be discussed.


2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Xing-Wei He ◽  
Feng-Min Wu ◽  
Hua-Rong Wei ◽  
Bi-Hai Hong

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.


1988 ◽  
Vol 7 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Ames-Bologna-CERN-Dortmund-Heidelbu Collaboration ◽  
A Breakstone ◽  
R Campanini ◽  
H. B Crawley ◽  
M Cuffiani ◽  
...  

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 488
Author(s):  
Muhammad Waqas ◽  
Guang-Xiong Peng

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.


Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 803
Author(s):  
Hai-Ling Lao ◽  
Fu-Hu Liu ◽  
Bo-Qiang Ma

The transverse momentum spectra of different types of particles, π±, K±, p and p¯, produced at mid-(pseudo)rapidity in different centrality lead–lead (Pb–Pb) collisions at 2.76 TeV; proton–lead (p–Pb) collisions at 5.02 TeV; xenon–xenon (Xe–Xe) collisions at 5.44 TeV; and proton–proton (p–p) collisions at 0.9, 2.76, 5.02, 7 and 13 TeV, were analyzed by the blast-wave model with fluctuations. With the experimental data measured by the ALICE and CMS Collaborations at the Large Hadron Collider (LHC), the kinetic freeze-out temperature, transverse flow velocity and proper time were extracted from fitting the transverse momentum spectra. In nucleus–nucleus (A–A) and proton–nucleus (p–A) collisions, the three parameters decrease with the decrease of event centrality from central to peripheral, indicating higher degrees of excitation, quicker expansion velocities and longer evolution times for central collisions. In p–p collisions, the kinetic freeze-out temperature is nearly invariant with the increase of energy, though the transverse flow velocity and proper time increase slightly, in the considered energy range.


Sign in / Sign up

Export Citation Format

Share Document