Search for central exclusive production of top quark pairs with the CMS and TOTEM experiments

TL;DR

This paper reports a search for central exclusive production of top quark pairs using CMS and TOTEM data, introducing new background estimation and classification methods, and setting the first upper limits on this rare process.

Contribution

It presents the first search for exclusive top quark pair production at the LHC, employing a novel background estimation technique and a Boosted Decision Tree classifier.

Findings

First upper limits on exclusive t-tbar production cross section

Development of a data-driven background estimation method

Implementation of a Boosted Decision Tree classifier

Abstract

A search for central exclusive production of top quark pairs ($\mathrm{t}\bar{\mathrm{t}}$) is presented using collision data collected by CMS and the CMS-TOTEM Precision Proton Spectrometer in 2017. A data-driven method to estimate the background from coincidences of inclusive events and pileup protons is described, as well as the development of a Boosted Decision Tree classifier to separate the exclusive $\mathrm{t}\bar{\mathrm{t}}$ signal from the inclusive $\mathrm{t}\bar{\mathrm{t}}$ background. The first-ever upper limits on the cross section of exclusive $\mathrm{t}\bar{\mathrm{t}}$ are shown.