Trilepton production at the CERN LHC: Standard model sources and beyond

TL;DR

This paper analyzes standard model sources of trilepton events at the LHC, highlighting heavy flavor decays as significant backgrounds, and proposes new cuts to improve the detection of supersymmetric signals.

Contribution

It identifies heavy flavor decays as major backgrounds in trilepton searches and introduces new cuts to enhance supersymmetry discovery potential.

Findings

Heavy flavor decays can dominate trilepton backgrounds after cuts.

New cuts can suppress backgrounds and improve SUSY signal detection.

Potential to observe a 4 sigma excess for specific SUSY parameters with 30 fb$^{-1}$.

Abstract

Events with three or more isolated leptons in the final state are known to be signatures of new physics phenomena at high energy collider physics facilities. Standard model sources of isolated trilepton final states include gauge boson pair production such as $WZ$ and $W\gamma^*$, and $t\bar{t}$ production. We demonstrate that leptons from heavy flavor decays, such as $b \to lX$ and $c \to lX$, provide sources of trileptons that can be orders-of-magnitude larger after cuts than other standard model backgrounds to new physics processes. We explain the physical reason heavy flavor backgrounds survive isolation cuts. We propose new cuts to control the backgrounds in the specific case of chargino plus neutralino pair production in supersymmetric models. After these cuts are imposed, we show that it should be possible to find at least a 4 sigma excess for supersymmetry parameter space point LM9 with 30 fb$^{-1}$ of integrated luminosity.