Direct measurement of the mass difference between top and antitop quarks

TL;DR

This paper reports the first direct measurement of the mass difference between top and antitop quarks, using data from the Fermilab Tevatron Collider, finding results consistent with no difference.

Contribution

It provides the first direct measurement of a mass difference between a quark and its antiquark, using experimental data from top-antitop events.

Findings

Measured mass difference: 3.8±3.7 GeV

Result consistent with zero difference

First direct measurement of quark-antiquark mass difference

Abstract

We present a measurement of the mass difference between t and tbar quarks observed in lepton+jets final states of ttbar events in 1 fb-1 of data collected with the D0 detector at the Fermilab Tevatron Collider in ppbar collisions at sqrt(s)=1.96 TeV. The observed mass difference of 3.8+-3.7 GeV is consistent with the equality of t and tbar masses. This is the first direct measurement of a mass difference between a quark and its antiquark partner.