Searches for QCD instantons with forward proton tagging

TL;DR

This paper investigates the potential to detect heavy QCD instantons at the LHC using forward proton tagging, highlighting challenges from detector effects and pile-up, and proposing timing information as a possible solution.

Contribution

It provides a detailed simulation study of instanton detection prospects at the LHC and suggests new strategies to improve signal identification.

Findings

Single-tagged signals are significantly affected by detector and pile-up effects.

Double-tagged signals are overwhelmed by background at high pile-up.

Timing information could be crucial for enhancing instanton detection.

Abstract

We study the possibility to observe heavy ($M_{\rm inst}> 60$ GeV) QCD instantons at the LHC in events with one or two tagged leading protons including fast simulation of detector and pile-up effects. We show that the expected instanton signal in a single-tagged configuration is strongly affected by central detector and pile-up effects. For double-tagged approach, where larger integrated luminosities and hence larger pile-up contaminations need to be considered, the combinatorial background overwhelms the expected signal. We suggest that additional time information about tracks at central and forward rapidities would be crucial for potential improvements.