Understanding partonic energy loss from measured light charged particles and jets in PbPb collisions at LHC energies. (29th October 2020)

• Record Type: Journal Article
• Authors: Shukla, Prashant; Saraswat, Kapil
• Is Part Of: Journal of physics. Volume 47:Number 12(2020:Dec.)
• Publication Date: 2020-10-29
• Subjects: charged particle spectra -- jet spectra -- partonic energy loss -- quark gluon plasma; Nuclear physics -- Periodicals; Particles (Nuclear physics) -- Periodicals; Physique nucléaire -- Périodiques; Particules (Physique nucléaire) -- Périodiques; Kernfysica; Elementaire deeltjes; 539.7
• DOI: 10.1088/1361-6471/abb58a
• Languages: English
• ISSNs: 0954-3899

Abstract

Abstract: We perform a comprehensive study of partonic energy loss reflected in the nuclear modification factors of charged particles and jets measured in PbPb collisions at s NN = 2.76 and 5.02 TeV in wide transverse momentum ( p T ) and centrality range. The p T distributions in pp collisions are fitted with a modified power law and the nuclear modification factor in PbPb collisions can be obtained using effective shift (Δ p T ) in the spectrum measured at different centralities. Driven by physics consideration, the functional form of energy loss given by Δ p T can be assumed as power law with different power indices in three different p T regions. The power indices and the boundaries of three p T regions are obtained by fitting the measured nuclear modification factor as a function of p T in all collision centralities simultaneously. The energy loss in different collisions centralities are described in terms of fractional power of number of participants. It is demanded that the power law functions in three p T regions and their derivatives are continuous at the p T boundaries. The Δ p T for light charged particles is found to increase linearly with p T in low p T region below ∼5–6 GeV c −1 and approaches a constant value in high p T region above ∼22–29 GeV c −1 with an intermediate power law connecting the two regions. The method is also used for jets and it is found that for jets, the Δ p T increases approximately linearly even at very high p T .