A Global Fit to Scattering Data with NLL BFKL Resummations

TL;DR

This paper presents a comprehensive global fit to scattering data incorporating NLL BFKL resummations, resulting in improved theoretical predictions and resolving issues present in standard NLO fits.

Contribution

It introduces a novel global fit method that includes NLL BFKL resummations, leading to more stable and physically consistent gluon distributions.

Findings

Positive definite gluon at input scale

Stable longitudinal structure function at small x

Turnover in reduced cross-section at high y

Abstract

We perform a global parton fit to DIS and related data, including next-to-leading logarithmic (NLL) BFKL resummations in both the massless and massive sectors. The resummed fit improves over a standard next-to-leading order (NLO) DGLAP fit, with a positive definite gluon at the input scale as opposed to the negative gluon seen at NLO. Furthermore, the predicted longitudinal structure function is free of perturbative instability at small x, and the reduced cross-section shows a turnover at high y (absent in the NLO fit) consistent with the HERA data.