Searching for anomalous top quark interactions with proton tagging and timing detectors at the LHC

TL;DR

This paper investigates the LHC's ability to detect new broad neutral resonances and anomalous top quark interactions via proton tagging and timing detectors, achieving sensitivities to couplings and resonance masses.

Contribution

It introduces a novel approach combining proton tagging and timing detectors to enhance sensitivity to anomalous top interactions and broad resonances at the LHC.

Findings

Sensitivity to dimension-8 operators of 1.4e-11 GeV^{-4} at 95% CL

Improved sensitivity to couplings down to 7e-12 GeV^{-4} with 20 ps timing precision

Detection of broad neutral resonances up to 1500 GeV mass

Abstract

We study the LHC sensitivity to new broad neutral resonances produced in two-photon fusion and decaying to a top quark pair, $\gamma\gamma \to t\bar{t}$. This is probed in central exclusive $t\bar{t}$ production in proton-proton collisions, $pp \to p t\bar{t} p$. We use the tagging of the intact protons by PPS (CMS) and AFP (ATLAS) and consider the semi-leptonic $t\bar t$ channel. The sensitivity is also mapped onto a set of dimension-8 $\gamma\gamma t\bar{t}$ operators in the large mass limit. Using the kinematical correlations between the intact protons and the reconstructed $t\bar{t}$ system, we obtain a sensitivity to the couplings of the dimension-8 operators of $1.4 \cdot 10^{-11}~\mathrm{GeV}^{-4}$ at 95% CL. The sensitivity to the anomalous couplings is significantly improved down to about $7\cdot 10^{-12}~\mathrm{GeV}^{-4}$ if the proton time-of-flight is known with a precision of 20 ps in future measurements. The 95% CL sensitivity to broad neutral resonances reaches masses of order $ 1500~\mathrm{GeV} $ when using timing information.