Measurement of the polarization of singly-produced top quarks in CDF

We present a measurement of the polarization of singly-produced top quarks in $p\bar p$ collisions using 3 $fb^{-1}$ of data collected with the CDF detector. Single top quarks are expected to be produced via virtual $W$ boson exchange in $t$-channel and $s$-channel processes. The standard model predicts a left-handed vector coupling at the $Wtb$ vertex, but extensions allow a right-handed vector coupling. We measure separately the left- and right-handed couplings, and thus the polarization, by measuring the angular distributions of the top quark's decay products.