Observation of Single Top-Quark Production

TL;DR

This paper reports the first observation of single top-quark production via electroweak interactions in proton-antiproton collisions at Fermilab, confirming the Standard Model prediction with high statistical significance.

Contribution

It provides the first experimental evidence of electroweak single top-quark production at the Tevatron, measuring its cross section with high confidence.

Findings

Measured cross section: 3.94 ± 0.88 pb

Significance of observation: 5.0 standard deviations

Probability of background fluctuation: 2.5 x 10^-7

Abstract

We report observation of the electroweak production of single top quarks in ppbar collisions at sqrt(s) = 1.96 TeV based on 2.3 fb^-1 of data collected by the D0 detector at the Fermilab Tevatron Collider. Using events containing an isolated electron or muon and missing transverse energy, together with jets originating from the fragmentation of b quarks, we measure a cross section of sigma(ppbar -> tb + X, tqb + X) = 3.94 +- 0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.5 x 10^-7, corresponding to a 5.0 standard deviation significance for the observation.