Abstract
Abstract:
This Letter presents a normalized differential cross-section measurement in a fiducial phase-
space region where interference effects between top-quark pair production and associated production
of a single top quark with a W boson and a b-quark are significant. Events with exactly two leptons
(ee, µµ, or eµ) and two b-tagged jets that satisfy a multi-particle invariant mass requirement are
selected from 36.1 fb−1 of proton–proton collision data taken
at √s = 13 TeV with the ATLAS detector at the LHC in 2015 and 2016. The results are
compared with predictions from simulations using various strategies for the interference. The
standard prescriptions for interference modeling are significantly different from each other but
are within 2σ of the data. State-of-the-art predictions that naturally incorporate interference
effects provide the best description of the data in the measured region of phase space most
sensitive to these effects. These results provide an important constraint on interference models
and will guide future model development and tuning.