Rapidity Gap Events in Squark Pair Production at the LHC

TL;DR

This paper investigates the potential to detect rapidity gap events resulting from squark pair production via electroweak gaugino exchange at the LHC, using simulations to identify distinctive energy deposition patterns.

Contribution

It provides a detailed analysis of rapidity gap signatures in squark pair production, including parton-level and full event simulations with PYTHIA and Herwig++, highlighting the feasibility of detection.

Findings

Significant evidence for color singlet exchange at SPS1a point

Systematic differences between PYTHIA and Herwig++ are larger than the physical effect

Tuning Monte Carlo generators can reduce systematic uncertainties

Abstract

The exchange of electroweak gauginos in the $t-$ or $u-$channel allows squark pair production at hadron colliders without color exchange between the squarks. This can give rise to events where little or no energy is deposited in the detector between the squark decay products. We discuss the potential for detection of such rapidity gap events at the Large Hadron Collider (LHC). Our numerical analysis is divided into two parts. First, we evaluate in a simplified framework the rapidity gap signal at the parton level. The second part covers an analysis with full event simulation using PYTHIA as well as Herwig++, but without detector simulation. We analyze the transverse energy deposited between the jets from squark decay, as well as the probability of finding a third jet in between the two hardest jets. For the mSUGRA benchmark point SPS1a we find statistically significant evidence for a color singlet exchange contribution. The systematical differences between current versions of PYTHIA and HERWIG++ are larger than the physical effect from color singlet exchange; however, these systematic differences could be reduced by tuning both Monte Carlo generators on normal QCD di--jet data.