Significance of non-perturbative input to TMD gluon density for hard processes at LHC

TL;DR

This paper investigates the importance of non-perturbative inputs to the TMD gluon density for accurate predictions of hard processes at the LHC, deriving and extending the distribution using experimental data and QCD evolution equations.

Contribution

It introduces a method to derive the non-perturbative TMD gluon distribution from LHC data and extends it to higher scales with CCFM evolution, improving phenomenological predictions.

Findings

Derived TMD gluon distribution from low-momentum spectra

Matched TMD gluon with BFKL solution at low x

Extended TMD gluon to higher scales using CCFM evolution

Abstract

We study the role of the non-perturbative input to the transverse momentum dependent (TMD) gluon density in hard processes at the LHC. We derive the input TMD gluon distribution at low scale mu0^2 ~ 1 GeV^2 from the fit of the inclusive hadron spectra measured at low transverse momenta in pp collisions at the LHC and demonstrate that the best description of these spectra for larger hadron transverse momenta can be achieved by matching the derived TMD gluon distribution with the exact solution of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) equation obtained at low x and small gluon transverse momenta outside the saturation region. Then, we extend the input TMD gluon density to higher mu^2 numerically using the Catani-Ciafoloni-Fiorani-Marchesini (CCFM) gluon evolution equation. A special attention is put to the phenomenological applications of obtained TMD gluon density to some LHC processes, which are sensitive to the gluon content of a proton.