Search for single top quark production at DO using neural networks

We present a search for electroweak production of single top quarks in approximate to 90 pb(-1) of data collected with the D(null set) detector at the Fermilab Tevatron collider. Using arrays of neural networks to separate signals from backgrounds, we set upper limits on the cross sections of 17 pb for the s-channel process p (p) over bar --> tb + X, and 22 pb for the t-channel process p (p) over bar --> tqb + X, both at the 95% confidence level. (C) 2001 Elsevier Science B.V. All rights reserved.