The first measurements of skewness and kurtosis of mean transverse momentum (< p(T)>) fluctuations are reported in Pb-Pb collisions at root s(NN) = 5.02 TeV, Xe-Xe collisions at root s(NN) = 5.44 TeV and pp collisions at root s = 5.02 TeV using the ALICE detector. The measurements are carried out as a function of system size < dN(ch)/d eta >(1/3)(vertical bar eta vertical bar<0.5), using charged particles with transverse momentum (p(T)) and pseudorapidity (eta), in the range 0.2 < p(T) < 3.0 GeV/c and vertical bar eta vertical bar < 0.8, respectively. In Pb-Pb and Xe-Xe collisions, positive skewness is observed in the fluctuations of < p(T)> for all centralities, which is significantly larger than what would be expected in the scenario of independent particle emission. This positive skewness is considered a crucial consequence of the hydrodynamic evolution of the hot and dense nuclear matter created in heavy-ion collisions. Furthermore, similar observations of positive skewness for minimum bias pp collisions are also reported here. Kurtosis of < p(T)> fluctuations is found to be in good agreement with the kurtosis of Gaussian distribution, for most central Pb-Pb collisions. Hydrodynamic model calculations with MUSIC using Monte Carlo Glauber initial conditions are able to explain the measurements of both skewness and kurtosis qualitatively from semicentral to central collisions in Pb-Pb system. Color reconnection mechanism in PYTHIA8 model seems to play a pivotal role in capturing the qualitative behavior of the same measurements in pp collisions

Skewness and kurtosis of mean transverse momentum fluctuations at the LHC energies

Barbera, R.;La Rocca, P.;Rasa, M.;
2024-01-01

Abstract

The first measurements of skewness and kurtosis of mean transverse momentum (< p(T)>) fluctuations are reported in Pb-Pb collisions at root s(NN) = 5.02 TeV, Xe-Xe collisions at root s(NN) = 5.44 TeV and pp collisions at root s = 5.02 TeV using the ALICE detector. The measurements are carried out as a function of system size < dN(ch)/d eta >(1/3)(vertical bar eta vertical bar<0.5), using charged particles with transverse momentum (p(T)) and pseudorapidity (eta), in the range 0.2 < p(T) < 3.0 GeV/c and vertical bar eta vertical bar < 0.8, respectively. In Pb-Pb and Xe-Xe collisions, positive skewness is observed in the fluctuations of < p(T)> for all centralities, which is significantly larger than what would be expected in the scenario of independent particle emission. This positive skewness is considered a crucial consequence of the hydrodynamic evolution of the hot and dense nuclear matter created in heavy-ion collisions. Furthermore, similar observations of positive skewness for minimum bias pp collisions are also reported here. Kurtosis of < p(T)> fluctuations is found to be in good agreement with the kurtosis of Gaussian distribution, for most central Pb-Pb collisions. Hydrodynamic model calculations with MUSIC using Monte Carlo Glauber initial conditions are able to explain the measurements of both skewness and kurtosis qualitatively from semicentral to central collisions in Pb-Pb system. Color reconnection mechanism in PYTHIA8 model seems to play a pivotal role in capturing the qualitative behavior of the same measurements in pp collisions
2024
PROTON-PROTON COLLISIONS; QUARK-GLUON PLASMA; PB-PB COLLISIONS; XE-XE COLLISIONS; CHARGED-PARTICLES; PP COLLISIONS; MULTIPLICITY; DISTRIBUTIONS; ROOT-S=5.02; DEPENDENCE
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/642123
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