On the relation between the soft and hard parts of the transverse momentum distribution

TL;DR

This paper introduces an analytical function based on a q-Gaussian distribution to describe the entire transverse momentum spectrum, linking soft and hard QCD processes through string tension fluctuations.

Contribution

It proposes a novel analytical model that unifies soft and hard transverse momentum distributions using a q-Gaussian approach, connecting fluctuation effects to spectrum features.

Findings

The model accurately describes the full transverse momentum spectrum.

The q parameter controls the transition between soft and hard regimes.

The ratio of soft to hard scales depends solely on the q parameter.

Abstract

Usually, the transverse momentum distribution is described by a sum of an exponential decay term plus a decreasing power like contribution representing the soft non-perturbative and hard perturbative QCD collisions, respectively. In this paper, we derive an analytical function that can describe the whole transverse momentum spectrum. This is obtained using a $q$-Gaussian distribution to describe the string tension fluctuations. The parameter $q$ determines the departure of the thermal distribution as well as the minimum length that can be explored at high transverse momentum. We also show that the ratio between both scales only depends on the $q$ parameter.