Single Top Results from CDF

TL;DR

This paper reports on the search for single top quark production at the Tevatron using CDF data, employing multiple analysis techniques, and sets limits on new physics such as W' bosons, with a modest excess observed in one method.

Contribution

It introduces and compares three analysis techniques for single top detection and provides the first measurement of combined t-channel and s-channel cross section in this dataset.

Findings

Matrix element analysis observed a 2.3 sigma excess.

Upper limits set on W' boson production at 760-790 GeV/c^2.

Combined cross section measured as 2.7 +1.5-1.3 pb.

Abstract

The CDF Collaboration has analyzed 955/pb of CDF II data to search for electroweak single top quark production at the Tevatron. We employ three different analysis techniques to search for a single top signal: multivariate likelihood functions; neural networks; the matrix element analysis technique. The sensitivities to a single top signal at the rate predicted by the Standard Model are 2.1 - 2.6 sigma. The first two analyses observe a deficit of single top-like events and set upper limits on the production cross section. The matrix element analysis observes a 2.3 sigma single top excess and measures a combined t-channel and s-channel cross section of 2.7 +1.5-1.3 pb. Using the same dataset, we have searched for non-Standard Model production of single top quarks through a heavy W' boson resonance. No evidence for a signal is observed. We exclude at the 95 % C.L. W' boson production with masses of 760 GeV/c^2 (790 GeV/c^2) in case the right handed neutrino is smaller (larger) than the mass of the W' boson.