High energy photon interactions at the LHC

TL;DR

The paper investigates high-energy photon interactions at the LHC, treating the collider as a platform for photon-photon and photon-proton physics at energies beyond the electroweak scale. Using the equivalent photon approximation (EPA) and tagging strategies with forward detectors and large rapidity gaps, it computes cross sections by folding photon fluxes $dN(x,Q^2)$ into process-dependent amplitudes, e.g. $d\sigma_{pp}=\sigma_{\gamma\gamma} dN_1 dN_2$ or $\sigma_{pp}=\int_{x_{\min}}^{1} f_{\gamma}(x)\,\sigma_{\gamma p}\,dx$. It assesses backgrounds, survival probabilities, and detector capabilities, presenting prospects for Higgs searches, supersymmetric particles, anomalous quartic gauge couplings, and top-quark physics. The work highlights how two-photon events yield clean final states with energy reconstruction from forward protons, enabling precision tests in a high-energy photon collider regime and informing detector design and analysis strategies.

Abstract

Experimental prospects for studying high-energy photon-photon and photon-proton interactions at the CERN Large Hadron Collider (LHC) are discussed. Cross sections are calculated for many electroweak and beyond the Standard Model processes. Selection strategies based on photon interaction tagging techniques are studied. Assuming a typical LHC multipurpose detector, various signals and their irreducible backgrounds are presented after applying acceptance cuts. Prospects are discussed for the Higgs boson search, detection of supersymmetric particles and of anomalous quartic gauge couplings, as well as for the top quark physics.

Figures (2)

• Figure 1: Elastic relative luminosity spectrum of photon-photon collisions at the lhc for the integration range $Q_{min}^2<Q^2<2~\textrm{GeV}^2$ (plain blue line). The dashed (green) line shows the corresponding luminosity if energy of each photon is restricted to the tagging range $20~\textrm{GeV}~<~E_{\gamma}~<~900~\textrm{GeV}$.
• Figure :