Tagging photon interactions at the LHC

TL;DR

This paper discusses methods for identifying photon interactions at the LHC, focusing on detector techniques, their performance, and challenges like beamline misalignment.

Contribution

It provides a detailed analysis of photon tagging techniques, including the characterization and performance of very forward detectors at the LHC.

Findings

Characterization of forward detectors for photon tagging

Assessment of detector acceptance and reconstruction performance

Discussion of beamline misalignment effects and solutions

Abstract

Photon interactions at the LHC result in striking final states with much lower hadronic activity in the central detectors than for pp interactions. In addition, the elastic exchange of a photon leads to a proton scattered at almost zero-degree angle. Tagging photon interactions relies on either the use of large rapidity gaps or on the detection of the scattered proton using very forward detectors. The studies related to such detectors are presented, including their characterization, their acceptance and reconstruction performance. Limitations due to the LHC beamline misalignment and possible solutions are also given.