Single top-quark production by strong and electroweak supersymmetric flavor-changing interactions at the LHC

TL;DR

This paper investigates single top-quark production via supersymmetric flavor-changing neutral currents at the LHC, including both strong and electroweak effects within the MSSM, and assesses their potential observability under current constraints.

Contribution

It provides a comprehensive calculation of the full MSSM contributions to single top-quark production, including SUSY-QCD and SUSY-EW effects, under realistic experimental constraints.

Findings

SUSY-QCD can produce up to 10^5 events per 100 fb^{-1}

SUSY-EW effects can yield around 10^3 events under favorable conditions

Detection of such events could indicate supersymmetric new physics

Abstract

(Abridged) We report on a complete study of the single top-quark production by direct supersymmetric flavor-changing neutral-current (FCNC) processes at the LHC. The total cross section for pp(gg)->t\bar{c}+\bar{t}c is computed at the 1-loop order within the unconstrained Minimal Supersymmetric Standard Model (MSSM). The present study extends the results of the supersymmetric strong effects (SUSY-QCD), which were advanced by some of us in a previous work, and includes the computation of the full supersymmetric electroweak corrections (SUSY-EW). Our analysis of pp(gg)->t\bar{c}+\bar{t}c in the MSSM has been performed in correspondence with the stringent low-energy constraints from b->s gamma. In the most favorable scenarios, the SUSY-QCD contribution can give rise to production rates of around 10^5 events per 100 fb^{-1} of integrated luminosity. Furthermore, we show that there exist regions of the MSSM parameter space where the SUSY-EW correction becomes sizeable. In the SUSY-EW favored regions, one obtains lower, but still appreciable, event production rates that can reach the 10^3 level for the same range of integrated luminosity. We study also the possible reduction in the maximum event rate obtained from the full MSSM contribution if we additionally include the constraints from B^0_s-\bar{B}^0_s. In view of the fact that the FCNC production of heavy quark pairs of different flavors is extremely suppressed in the SM, the detection of a significant number of these events could lead to evidence of new physics -- of likely supersymmetric origin.