Next-to-Leading Order SUSY-QCD Predictions for Associated Production of Gauginos and Gluinos

TL;DR

This work delivers a complete next-to-leading order SUSY-QCD calculation for associated production of gluinos with gauginos at hadron colliders, including virtual loops and real emission with phase-space slicing to handle infrared and collinear divergences. It analyzes several SUSY-breaking scenarios (SUGRA, GMSB, AMSB, gaugino mediation, and a light gluino LSP) to predict total and differential cross sections at Tevatron and LHC energies. The NLO corrections are generally positive and significantly reduce renormalization/factorization scale dependence, with especially large enhancements from the qg initial state at the LHC. These results refine expectations for discovery reach and enable more precise probing of soft SUSY-breaking parameters through associated g̃ χ̃ production channels.

Abstract

We present complete results of a next-to-leading order calculation of the production of gaugino-like charginos ($\chargino$) and neutralinos ($\neutralino$) in association with gluinos ($\gluino$) at hadron colliders, including the strong corrections from the exchange of colored particles and sparticles. Adopting a variety of models for the sparticle mass spectrum, including typical supergravity (SUGRA) models and a light gluino model, we provide predictions for total and differential cross sections at the energies of the Fermilab Tevatron and CERN Large Hadron Collider (LHC).

Figures (26)

• Figure 1: Leading order Feynman diagrams for $q \bar{q} \rightarrow \tilde{g} {\tilde{\chi}}$.
• Figure 2: Generic virtual one-loop diagrams for the associated production of a gluino and a gaugino. The crossed regions denote self-energy and vertex corrections that are present only one at a time at next-to-leading order.
• Figure 3: Self-energy diagrams for external quarks ($q$) and gluinos ($\tilde{g}$) and internal squarks ($\tilde{q}$) including the full supersymmetric QCD particle spectrum. Contributions from the tadpole graphs vanish.
• Figure 4: Vertex corrections for the quark-squark-gluino ($q\tilde{q}\tilde{g}$) and quark-squark-gaugino ($q\tilde{q}\tilde{\chi}$) vertices including the full supersymmetric QCD particle spectrum.
• Figure 5: Box diagrams for associated production of a gluino and a gaugino. There are $u$-channel box diagrams in addition to the diagrams shown.