Squark Flavor Violation at the LHC

TL;DR

This paper explores the potential to detect squark flavor violation at the LHC through single top production signals, analyzing various decay patterns in R-symmetric supersymmetry and MSSM, with a focus on background reduction and event tagging.

Contribution

It introduces a detailed analysis of squark flavor violation signals at the LHC, considering multiple decay scenarios and identifying promising channels like the neutralino NLSP with photon signatures.

Findings

Case II with prompt NLSP decay offers the best signal with two hard photons.

Background can be effectively reduced with specific event selection cuts.

Flavor violation signals are challenging but potentially detectable in long-lived chargino scenarios.

Abstract

We consider the prospects for measuring squark flavor violation through the signal of single top production at the LHC. We study this signal in the context of R-symmetric supersymmetry, which allows for large flavor violation in the squark sector, however the results can also be generalized to the MSSM. The single top signal arises from squark pair production in which one squark decays to a top and gaugino, whereas the other squark decays to a non-top quark and gaugino. We study three decay patterns: (I) squark decay into a quark and neutralino LSP; (II) squark decay into a quark and neutralino NLSP, with subsequent decay of the NLSP to a photon and gravitino; (III) squark decay into a quark and chargino NLSP, with subsequent decay of the NLSP to a H^\pm/W^\pm and gravitino. Case II is the most promising, when the NLSP decay is prompt, since every event contains two hard photons that can be used to tag the events, reducing the background to a negligible level. Case I is promising if the neutralino LSP is bino-like. We carefully consider large SM backgrounds and identify a series of cuts to isolate the signal. Case III can occur in the MRSSM with Higgsino-like lightest gauginos. Due to the large Higgs coupling, squarks preferentially decay to top quarks, substantially reducing the potential flavor violating signal. Nevertheless, the flavor violating signal might still be identifiable if the chargino NLSP is long-lived.