Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at $\sqrt{s}=$ 13 TeV

Abstract

The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (${\hat{d}}_{\mathrm{t}}$) and chromomagnetic (${\hat{\mu }}_{\mathrm{t}}$) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb${}^{-1}$. The linearized variable $A_{\mathrm{FB}}^{(1)}$ is used to approximate the asymmetry. Candidate $\mathrm{t}\bar{\mathrm{t}}$ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for $\mathrm{t}\bar{\mathrm{t}}$ final states. The values found for the parameters are $A_{\mathrm{FB}}^{(1)}=$ 0.048 ${}_{-0.087}^{+0.095}$ (stat) ${}_{-0.029}^{+0.020}$ (syst), ${\hat{\mu }}_{\mathrm{t}}=-$ 0.024 ${}_{-0.009}^{+0.013}$ (stat) ${}_{-0.011}^{+0.016}$ (syst), and a limit is placed on the magnitude of $|{\hat{d}}_{\mathrm{t}}|$ $<$ 0.03 at 95% confidence level.

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-15-018 (CMS Public Pages)