Spin Correlations in Top Quark Production and the Top Quark Mass

TL;DR

This paper discusses how spin correlations in top-antitop quark pairs influence decay product distributions and impact top mass measurements, favoring a lower mass estimate in dilepton events.

Contribution

It highlights the importance of including spin correlations in top mass analyses, revealing a bias towards lower mass values in dilepton channels.

Findings

Spin correlations significantly affect decay angular distributions.

Including correlations favors a lower top mass (~155 GeV).

Analysis of dilepton events supports a lower top mass estimate.

Abstract

Top-antitop quark pairs produced at the Tevatron have a sizeable spin correlation. That correlation feeds into the angular distribution of the decay products, particularly in the dilepton channel. Including the expected correlation in an overall analysis of a handful of actual dilepton events continues to favor a lower top mass (centered on 155 GeV) than the single lepton events.