Colored bosons on top FBA and angular cross section for $t \bar t$ production

TL;DR

This paper investigates how colored bosons, specifically color triplet scalars and color octet vectors, can explain the observed anomalies in top quark forward-backward asymmetry and angular distributions in $t\bar t$ production.

Contribution

It introduces models with colored bosons that significantly enhance the top FBA and angular moments, addressing experimental deviations from the Standard Model.

Findings

Top FBA can be increased to around 30% with triplet scalars.

First Legendre moment $a_1$ can reach 0.38 with triplet and 0.23 with octet models.

Models improve agreement with experimental asymmetry measurements.

Abstract

With full data set that corresponds to an integrated luminosity of 9.4 fb$^{-1}$, CDF has updated the top quark forward-backward asymmetry (FBA) as functions of rapidity difference $|\Delta y|$ and $t\bar t$ invariant mass $M_{t\bar t}$. Beside the sustained inconsistency between experiments and standard model (SM) predictions at large $|\Delta y|$ and $M_{t\bar t}$, an unexpected large first Legendre moment with $a_1= 0.39\pm 0.108 $ is found. In order to solve the large top FBA, we study the contributions of color triplet scalar and color octet vector boson. We find that the top FBA at $|\Delta y| >1$ and $M_{t\bar t} > 450$ GeV in triplet and octet model could be enhanced to be around 30% and 20%, whereas the first Legendre moment is $a^{\bf Di}_1= 0.38$ and $a^{\bf Axi}_1= 0.23$, respectively.