Search for CP violation in \ttbar events in the lepton+jets channel in proton-proton collisions at \sqrt{s}=13~\mathrm{TeV}$

Pu-Sheng Chen^1*

¹National Taiwan University, Taiwan

* Presenter:Pu-Sheng Chen, email:sam7k9621@gmail.com

The results of a search for CP violation in the production and decay of top quark-antiquark pairs using the lepton+jets decay channel are presented. The search uses data from proton-proton collisions at $\sqrt{s}=13~\mathrm{TeV}$, collected with the CMS detector, corresponding to an integrated luminosity of $137~\mathrm{fb}^{-1}$. Asymmetries that probe CP violating interactions are measured in observables constructed from linearly independent four-momentum vectors associated with the final-state particles. The CP violating effect is evaluated using the measured asymmetries in each observable. The measured dimensionless chromoelectric dipole moment obtained from the observed asymmetries in the combined lepton+jets channel is $0.04\pm0.10~(\text{stat})\pm0.07~(\text{syst})$. The measured effective asymmetries achieved a precision of $10^{-3}$ and exhibit no evidence for CP violating effects, consistent with the expectation from the standard model.

Keywords: top, CPV, asymmetry