Search for single production of vector-like quarks decaying into $Wb$ in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

Understand

A search for singly produced vector-like quarks $Q$, where $Q$ can be either a $T$ quark with charge $+2/3$ or a $Y$ quark with charge $-4/3$, is performed in proton-proton collision data at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of $36.1 \text{fb}^{-1}$, recorded with the ATLAS detector at the LHC in 2015 and 2016.

• The analysis targets $Q \to Wb$ decays where the $W$ boson decays leptonically.
• No significant deviation from the expected Standard Model background is observed.
• Upper limits are set on the $QWb$ coupling strength and the mixing between the Standard Model sector and a singlet $T$ quark or a $Y$ quark from a $(B,Y)$ doublet or a $(T,B,Y)$ triplet, taking into account the interference effects with the Standard Model background.