Soft and Coulomb gluon resummation in squark-antisquark production at the LHC

TL;DR

The paper develops and applies a unified soft- and Coulomb-gluon resummation framework for squark-antisquark production at the LHC, using a factorised, RG-evolved description of hard, soft, and Coulomb dynamics in color space. It extends prior effective-theory results to this SUSY process, derives momentum-space resummation formulas, and implements NLL soft plus Coulomb resummation matched to NLO. The authors find total threshold corrections of about 5–14% across squark masses from 200 GeV to 2 TeV and observe reduced scale dependence, with significant contributions from soft-Coulomb interference and bound-state effects below threshold. These results provide more precise hadronic cross sections for squark searches and mass-limit interpretations at the LHC.

Abstract

We present results for a combined resummation of soft and Coloumb gluon corrections in squark-antisquark production at the LHC, including the non-trivial interference of the two effects and the contribution of squark-antisquark bound states below threshold. The total correction to the next-to-leading order approximation is found to be sizeable, and amounts to 5-14 % in the squark mass region 200 GeV-2 TeV. The scale dependence of the total cross section is also reduced.

Figures (3)

• Figure 1: Schematic representation of the resummation of threshold logarithms via RGEs.
• Figure 2: Corrections to the NLO squark-antisquark cross section from soft-Coulomb resummation as functions of the squark mass $m_{\tilde{q}}$.
• Figure 3: Scale dependence of the LO (solid red), NLO (dotted blue) and resummed cross section (green band) for different choices of $\mu_s$ and $\mu_h$. See the text for explanation.