NNLL resummation for squark-antisquark pair production at the LHC

TL;DR

This paper develops NNLL threshold resummation for squark-antisquark production at the LHC within the MSSM, focusing on reducing theoretical uncertainties and improving cross-section predictions near threshold. The authors construct the NNLL cross section by combining soft-gluon resummation in Mellin space with one-loop matching coefficients and two-loop soft anomalous dimensions, and they implement a matching to the full NLO result to avoid double counting using the minimal prescription. They also compute Coulomb corrections and analyze their impact on the total cross section, reporting significant scale-stability improvements and notable cross-section increases (up to ~30% at 1.5 TeV squark masses for 7 TeV). Predictions are provided for √s = 7 and 14 TeV LHC, with an emphasis on the practical implications for SUSY searches and mass/exclusion limits.

Abstract

We consider the resummation of soft gluon emission for squark-antisquark pair-production at the LHC at next-to-next-to-leading-logarithmic (NNLL) accuracy in the framework of the minimal supersymmetric standard model. We present the analytical ingredients needed for the calculation and provide numerical predictions for the LHC at centre-of-mass energies of 7 and 14 TeV. We find a significant reduction in the scale uncertainty and a considerable increase in the prediction of the total cross section. Compared to the next-to-leading order prediction, the corrections increase the cross section by up to 30% for 1.5 TeV squarks at a centre-of-mass energy of 7 TeV.