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We present a review of searches for electroweak production of single top quarks at the Fermilab Tevatron proton–antiproton collider at . Searches for s-channel and t-channel single top quark production have been carried out using secondary-vertex b-quark tagging and advanced event analysis methods in order to maximize the sensitivity to single top quark production. So far, no evidence for a single top quark signal has been found. However, 95% confidence level upper limits on the production cross-section have been set that improve upon previous limits by factors of two to three and are approaching the cross-section region predicted by the standard model.

We have performed a search for the electroweak production of single top quarks in collisions at the Fermilab Tevatron at a center of mass energy of . The search was performed in the muon plus jets decay channel requiring at least one b-tagged jet. The data were collected using the DØ detector between August 2002 and September 2003 corresponding to an integrated luminosity of 158 pb^-1. The resulting 95% C.L. upper limits on the production cross sections are 27 pb in the s-channel, 41 pb in the t-channel, and 36 pb in the combined s + t channel using the secondary vertex tagger (SVT) algorithm. We also present results from the combined electron and muon channel search using the DØ detector.

The single top quark production has an electroweak nature and provides an additional support to the top pair production source of the top quarks. The processes involving single top have unique properties and are very interesting from both theoretical and experimental viewpoints. Short review of the single top quark production processes is given in the paper.

In particle physics, search for signals of new particles in the proton–proton collisions is an ongoing effort. The energies and luminosities have reached a level where new search techniques are becoming a necessity. In this work, we develop a search technique for light-charged Higgs boson (nearly degenerate with $W$-boson), which is extremely hard to do with the traditional cut-based methods. To this end, we employ a deep anomaly detection approach to extract the signal (light-charged Higgs particle) from the vast $W$-boson background. We construct a Deviation Network (DevNet) to directly obtain anomaly scores used to identify signal events using background data and few labeled signal data. Our results show that DevNet is able to find regions of high efficiency and gives better performance than the autoencoders, the classic semi-supervised anomaly detection method. It shows that employing Deviation Networks in particle physics can provide a distinct and powerful approach to search for new particles.