CP Violation via Top Quark Anomalous Interaction at the Fermilab Tevatron

TL;DR

This paper predicts a CP-violating polarization asymmetry in top quark pair production at Fermilab Tevatron, which could signal new physics beyond the Standard Model through anomalous gluon-top couplings.

Contribution

It introduces a method to detect CP violation via polarization asymmetry caused by anomalous chromomagnetic and chromoelectric couplings of the gluon to the top quark.

Findings

Asymmetry depends on Im(tilde{kappa}) and Im(kappa^* tilde{kappa})

Detectable CP violation possible when |Im(kappa^* tilde{kappa})|>0.5

Potential to observe new physics signals at Fermilab Tevatron

Abstract

Expecting the forthcoming experiment at the upgraded Fermilab Tevatron, we calculated CP-violating polarization asymmetry of t t-bar, A_{CP}= [sigma(p p-bar --> t(-) t-bar(-) X) - sigma(p p-bar --> t(+) t-bar(+) X)]/ sigma(p p-bar --> t t-bar X), due to possible anomalous chromomagnetic (kappa) and chromoelectric (tilde{kappa}) couplings of the gluon to the top quark. Since kappa and tilde{kappa} are sensitive to a contribution from new physics beyond standard model, this observable is useful to search for a signal of new physics. It was seen that the magnitude of A_{CP} depends only on Im(tilde{kappa) and Im(kappa^* tilde{kappa}). Futhermore, we found that when |Im(kappa^* tilde{kappa})|>0.5, one can possibly detect the CP-violation effect as a signal of new physics even if the magnitude of Im(tilde{kappa) is zero.