The $\gamma^* \gamma^*$ total cross section in NLA BFKL

TL;DR

This paper investigates the gamma* gamma* total cross section using NLA BFKL formalism, incorporating recent NLO impact factor corrections, and compares different optimization methods against LEP2 experimental data.

Contribution

It introduces new NLO impact factor corrections into the NLA BFKL framework and compares multiple optimization techniques with experimental results.

Findings

Different representations of the cross section are equivalent within NLA.

Optimization methods show varying behavior with energy.

Comparison with LEP2 data provides insights into the model's accuracy.

Abstract

We study the $\gamma^* \gamma^*$ total cross section in the NLA BFKL approach. We have extracted the NLO corrections to the photon impact factor from two recent papers of Balitsky and Chirilli and Chirilli and Kovchegov and used them to build several representations of the total cross section, equivalent within the NLA. We have combined these different representations with two among the most common methods for the optimization of a perturbative series, namely PMS and BLM, and compared their behavior with the energy with the only available experimental data, those from the LEP2 collider.