The meaning behind observed pT regions at the LHC energies

Abstract

We argue that [Formula: see text] distribution data from the LHC on the invariant differential yield of the charged primary particles in [Formula: see text] collisions at [Formula: see text] and in Pb–Pb collisions at [Formula: see text]TeV with six centrality bins contains several [Formula: see text] regions with special properties. These distributions were analyzed by fitting the data with exponential functions. We conclude that the regions reflect features of fragmentation and hadronization of partons through the string dynamics. The nuclear transparency results in negligible influence of the medium in the III region ([Formula: see text]), which has highest [Formula: see text] values. The effects and changes by the medium start to appear weakly in the II region ([Formula: see text]) and become stronger in the I region ([Formula: see text]). It seems that the II region has highest number of strings. The increase in string density in this region could lead to fusion of strings, appearance of a new string and collective behavior of the partons in the most central collisions. These phenomena can explain anomalous behavior of the Nuclear Modification Factor in the II region. We propose the II region as a possible area of Quark Gluon Plasma formation through string fusion. The first [Formula: see text] regions are the ones with the maximum number of hadrons and minimum number of strings due to direct hadronization of the low energy strings into two quark systems–mesons.