Resummation of thrust distributions in DIS

TL;DR

This work extends perturbative resummation to DIS event shapes by deriving LL and NLL resummations for thrust in the Breit-frame current hemisphere, considering two normalizations ($T_Q$ and $T_E$). It accounts for space-like initial-state radiation and remnant-hemisphere recoil, introducing $\tau=1-T$ and the integrated cross section $\Sigma(\tau)$ to organize logarithms. The authors compare the second-order expansion of the resummed results with fixed-order Monte Carlo predictions (DISENT and DISASTER++) and present a matching prescription to combine resummed and fixed-order calculations. These developments provide more reliable perturbative predictions for DIS event shapes, enabling improved tests of QCD and more robust extractions of the strong coupling constant.

Abstract

We calculate the resummed distributions for the thrust in DIS in the limit T->1. Two variants of the thrust are considered: that normalised to Q/2, and that normalised to the energy in the current hemisphere. The results expanded to second order are compared to predictions from the Monte Carlo programs DISENT and DISASTER++. A prescription is given for matching the resummed expressions with the full fixed order calculation.