Threshold Resummation Effects in the Associated Production of Chargino and Neutralino at Hadron Colliders

TL;DR

This paper studies the impact of threshold resummation on the production rates of charginos and neutralinos in the MSSM at Tevatron and LHC, showing increased cross sections and reduced scale dependence.

Contribution

It provides the first detailed analysis of threshold resummation effects on chargino-neutralino production at hadron colliders within the MSSM, including supersymmetric QCD corrections.

Findings

Resummation increases total cross sections by about 3.6-4.7%.

Resummation significantly affects large invariant mass distributions.

Resummation reduces scale dependence of predictions to 4-5%.

Abstract

We investigate the QCD effects in the associated production of the chargino and the neutralino, $\tilde\chi^\pm_{1}$ and $\tilde\chi^0_{2}$, in the Minimal Supersymmetric Standard Model (MSSM) at both the Fermilab Tevatron and the CERN Large Hadron Collider (LHC). We include the next-to-leading order (NLO) QCD corrections (including supersymmetric QCD) and the threshold resummation effects. Our results show that, compared to the NLO predictions, the threshold resummation effects can increase the total cross sections by 3.6% and 3.9% for the associated production of $\tilde\chi^+_{1}\tilde\chi^0_{2}$ and $\tilde\chi^-_{1}\tilde\chi^0_{2}$ at the LHC, respectively, and by 4.7% for those of $\tilde\chi^\pm_{1}\tilde\chi^0_{2}$ at the Tevatron. In the invariant mass distributions the resummation effects are significant for large invariant mass. The threshold resummation reduces the dependence of the total cross sections at the LHC (Tevatron) on the renormalization/factorization scales to 5% (4%) from up to 7% (11%) at NLO.