Measurement of the top quark mass in $\boldsymbol{\ppbar}$ collisions using events with two leptons

TL;DR

This paper measures the top quark mass in proton-antiproton collisions using dilepton events, employing novel techniques to reduce uncertainties and combining multiple datasets for a precise result.

Contribution

The study introduces a method to analyze dilepton events by integrating over neutrino rapidity and applies jet response corrections, improving the precision of top quark mass measurement.

Findings

Measured top quark mass as 173.7 GeV with 2.8 GeV statistical uncertainty.

Combined analysis yields a top quark mass of 173.9 GeV with 1.9 GeV statistical uncertainty.

Achieved a total uncertainty of approximately 2.5 GeV in the top quark mass measurement.

Abstract

We present a measurement of the top quark mass ($m_t$) in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV using $t\bar{t}$ events with two leptons ($ee$, $e\mu$, or $\mu\mu$) and accompanying jets in $4.3 fb^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron collider. We analyze the kinematically underconstrained dilepton events by integrating over their neutrino rapidity distributions. We reduce the dominant systematic uncertainties from the calibration of jet energy using a correction obtained from $t\bar{t}$ events with a final state of a single lepton plus jets. We also correct jets in simulated events to replicate the quark flavor dependence of the jet response in data. We measure $m_t = 173.7 \pm 2.8\thinspace(\rm stat) \pm 1.5\thinspace(\rm syst)$ GeV and combining with our analysis in 1 fb$^{-1}$ of preceding data we measure $m_t = 174.0 \pm 2.4\thinspace(\rm stat) \pm 1.4\thinspace(\rm syst)$ GeV. Taking into account statistical and systematic correlations, a combination with the D0 matrix element result from both data sets yields $m_t = 173.9 \pm 1.9\thinspace(\rm stat) \pm 1.6\thinspace(\rm syst)$ GeV.