Relativistic Hard-Scattering and Tsallis Fits to pT Spectra in pp Collisions at the LHC

TL;DR

This paper investigates the relativistic hard-scattering model to explain the power-law behavior of high-pT spectra in proton-proton collisions at the LHC, connecting pQCD predictions with Tsallis fits.

Contribution

It provides an approximate analytical expression for the differential cross section and links the power-law index to QCD predictions, enhancing understanding of high-pT spectra.

Findings

Power index n for jet production is 4.5-5.5, consistent with pQCD.

Hadron production power indices are slightly higher than jet indices.

Analytical expression aligns with Tsallis fits to experimental data.

Abstract

Motivated by the good Tsallis fits to the high-pT spectra in pp collisions at the LHC, we study the relativistic hard-scattering model and obtain an approximate analytical expression for the differential hard-scattering cross section at \eta ~ 0. The power-law behaviour of the transverse spectra, in the form of d\sigma/dpT^2 \propto 1/pT^n, gives a power index n in the range of 4.5-5.5 for jet production as predicted by pQCD, after the dependencies of the structure functions and the running coupling constant are properly taken into account. The power indices for hadron production n are slightly greater than those for jet production.