Measurement of the forward-backward asymmetry in top quark-antiquark production in ppbar collisions using the lepton+jets channel

TL;DR

This paper measures the forward-backward asymmetry in top quark-antiquark production at the Tevatron, using advanced reconstruction algorithms, finding results consistent with the Standard Model predictions.

Contribution

Introduces new kinematic and partial reconstruction algorithms for analyzing top quark pairs in lepton+jets channels, improving measurement accuracy.

Findings

Asymmetry measured at 10.6% with 3.0% uncertainty

Results align with Standard Model predictions (5.0%-8.8%)

Analyzed asymmetry dependence on invariant mass and rapidity differences

Abstract

We present a measurement of the forward--backward asymmetry in top quark-antiquark production using the full Tevatron Run II dataset collected by the D0 experiment at Fermilab. The measurement is performed in lepton+jets final states using a new kinematic fitting algorithm for events with four or more jets and a new partial reconstruction algorithm for events with only three jets. Corrected for detector acceptance and resolution effects, the asymmetry is evaluated to be 10.6+-3.0 %. Results are consistent with the standard model predictions which range from 5.0% to 8.8%. We also present the dependence of the asymmetry on the invariant mass of the top quark--antiquark system and the difference in rapidities of top quark and antiquark.