Applications of pT-xR Variables in Describing Inclusive Cross Sections at the LHC

TL;DR

This paper analyzes extensive LHC data on inclusive particle and jet cross sections using pT-xR variables, revealing power-law behaviors and relating observations to parton scattering physics, with applications to heavy ion collisions.

Contribution

It extends previous work by analyzing more data, introducing the F-function, and relating the A-function to parton scattering, providing new tools for understanding inclusive cross sections.

Findings

Power-law dependencies in sqrt(s), pT, and xR.

The A-function relates directly to parton scattering.

The F-function obeys radial scaling, testing parton physics.

Abstract

Invariant inclusive single particle/jet cross sections in p-p collisions can be factorized in terms of two separable pT dependences, a [pT - sqrt(s)] sector and an [xR - pT - sqrt(s)] sector, where xR = E/Emax is the radial scaling variable. Here, we extend our earlier work by analyzing more extensive data to explore various s-dependent attributes and other systematics of inclusive jet, photon and single particle inclusive reactions. Approximate power laws in sqrt(s), pT and xR are found. Physical arguments are given which relate observations to the underlying physics of parton - parton hard scattering and the parton distribution functions in the proton. We show that the A(sqrt(s), pT)-function, introduced in our earlier publication to describe the pT-dependence of the inclusive cross section, is directly related to the underlying hard parton-parton scattering for jet production with little influence from soft physics. In addition to the A-function, we introduce another function, the F(sqrt(s), xR)-function, which obeys radial scaling for inclusive jets that offers another test of the underlying parton physics. An application to heavy ion physics is given where we use our variables to determine the transparency of cold nuclear matter to penetrating heavy mesons through the lead nucleus.