Search for Single Top Quark Production at D\O

Protons and antiprotons are collided in Run~II at the Fermilab Tevatron at a center of mass energy of 1.96~TeV. We present results of an improved search for single top quark production in these collisions using a dataset of approximately 360~pb$^{-1}$ collected with the D\O detector. This analysis considers both production modes, $s$-channel $tb$ and $t$-channel $tqb$, and makes use of secondary-vertex tagging to identify jets originating from $b$~quarks as well as neural networks to separate the expected signals from backgrounds.