Abstract
A search for new physics in top quark production is performed in proton-proton collisions at $$13\,\text {TeV} $$13TeV. The data set corresponds to an integrated luminosity of $$35.9{\,\text {fb}^{-1}} $$35.9fb-1 collected in 2016 with the CMS detector. Events with two opposite-sign isolated leptons (electrons or muons), and $$\mathrm{b}$$b quark jets in the final state are selected. The search is sensitive to new physics in top quark pair production and in single top quark production in association with a $$\mathrm{W}$$W boson. No significant deviation from the standard model expectation is observed. Results are interpreted in the framework of effective field theory and constraints on the relevant effective couplings are set, one at a time, using a dedicated multivariate analysis. This analysis differs from previous searches for new physics in the top quark sector by explicitly separating $$\mathrm{t}\mathrm{W}$$tW from $$\mathrm{t}{\bar{\mathrm{t}}}$$tt¯ events and exploiting the specific sensitivity of the $$\mathrm{t}\mathrm{W}$$tW process to new physics.
Evidence for single top-quark production in the s-channel in proton–proton collisions at s=8 TeV with the ATLAS detector using the Matrix Element Method
