Speaker
Description
At the LHC, electroweak production of single top quarks in the $t$-channel
leads, in the standard model, to a high degree of top quark polarization.
Two subprocesses, $u b \rightarrow d t$ and $\bar{d} b \rightarrow \bar{u} t$
contribute to $t$-channel production of single top, while charge-conjugate
processes contribute to production of antitop. A high degree of top quark
polarization along the direction of the scattered light-quark (or
"spectator" quark) is expected for top production, and opposite to that
direction for antitop production. This analysis extracts the polarization
of samples of top and antitop quarks produced within a fiducial region of
acceptance, using an integrated luminosity 80.52 fb$^{-1}$ of proton-proton
collisions at 13 TeV, collected with the ATLAS detector. From the angular
distribution of top quark decay products, we obtain all three components of
the polarization of both top quarks and top antiquarks.
