Running of the top quark mass from proton-proton collisions at $\sqrt{s} =$ 13 TeV

TL;DR

This paper presents the first experimental investigation of the running of the top quark mass in the $ mar{MS}$ scheme, using proton-proton collision data at 13 TeV to compare differential cross sections with theoretical predictions.

Contribution

It introduces a novel experimental method to measure the scale dependence of the top quark mass in the $ mar{MS}$ scheme from LHC data.

Findings

The measured running is consistent with the renormalization group equation predictions.

The analysis probes the top quark mass running up to about 1 TeV scale.

First experimental evidence of top quark mass running at high energy scales.

Abstract

The running of the top quark mass is experimentally investigated for the first time. The mass of the top quark in the modified minimal subtraction ($\mathrm{\overline{MS}}$) renormalization scheme is extracted from a comparison of the differential top quark-antiquark ($\mathrm{t\overline{t}}$) cross section as a function of the invariant mass of the $\mathrm{t\overline{t}}$ system to next-to-leading-order theoretical predictions. The differential cross section is determined at the parton level by means of a maximum-likelihood fit to distributions of final-state observables. The analysis is performed using $\mathrm{t\overline{t}}$ candidate events in the e$^\pm\mu^\mp$ channel in proton-proton collision data at a centre-of-mass energy of 13 TeV recorded by the CMS detector at the CERN LHC in 2016, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The extracted running is found to be compatible with the scale dependence predicted by the corresponding renormalization group equation. In this analysis, the running is probed up to a scale of the order of 1 TeV.