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Title: Looking for single top quarks in D0 data

Abstract

No abstract prepared.

Authors:
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
900362
Report Number(s):
FERMILAB-CONF-06-521-E
arXiv eprint number hep-ex/0702042; TRN: US0702269
DOE Contract Number:
AC02-07CH11359
Resource Type:
Conference
Resource Relation:
Conference: Presented at 34th International Meeting on Fundamental Physics: From HERA and the Tevatron to the LHC, El Escorial, Madrid, Spain, 2-7 Apr 2006
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; FERMILAB TEVATRON; PHYSICS; T QUARKS; Experiment-HEP

Citation Formats

Garcia-Bellido, Aran. Looking for single top quarks in D0 data. United States: N. p., 2007. Web.
Garcia-Bellido, Aran. Looking for single top quarks in D0 data. United States.
Garcia-Bellido, Aran. Thu . "Looking for single top quarks in D0 data". United States. doi:. https://www.osti.gov/servlets/purl/900362.
@article{osti_900362,
title = {Looking for single top quarks in D0 data},
author = {Garcia-Bellido, Aran},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}

Conference:
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  • The authors present a search for t {r_arrow} bH{sup +} in t{bar t} candidate events at D0 based on two methods. The first seeks a deficit in signal relative to expectations from the standard model (SM). Such a deficit would imply the presence of a non-SM decay of the top quark. This search involves the full data sample of {approx} 110 pb{sup {minus}1} of p{bar p} collisions at {radical}s = 1.8 TeV, collected with the D0 detector. The second method looks for charged Higgs decays to {tau} leptons (and associated neutrinos), and is based on a 62 pb{sup {minus}1} subsetmore » of the aforementioned data sample.« less
  • I present brief descriptions of two top quark analyses performed using D0 data from p{bar p} collisions at {radical}s = 1.96 TeV: the search for flavor-changing neutral-current couplings (FCNC) of the top quark with a charm or an up quark with the exchange of a gluon, and the search for the standard model production of single top quarks. The search for FCNC couplings of a gluon to the top quark is the first such analysis at hadron colliders. I describe the application of the Bayesian approach for comparing our physics models to the observed data in both analyses and, inmore » one of them, to separate small signals from large backgrounds.« less
  • The top quark has been discovered in 1995 by CDF and D0 collaborations in proton-antiproton collisions at the Tevatron. The amount of data recorded by both experiments makes it possible to accurately measure the properties of this very massive quark. This thesis is devoted to the measurement of the top pair production cross-section via the strong interaction, in a final state composed of two electrons, two particle jets and missing transverse energy. It is based on a 1 fb -1 data set collected by the D0 experiment between 2002 and 2006. The reconstruction and identification of electrons and jets ismore » of major importance in this analysis, and have been studied in events where a Z boson is produced together with one or more jets. The Z+jets process is indeed the dominant physics background to top pair production in the dielectron final state. The primary goal of this cross-section measurement is to verify Standard Model predictions. In this document, this result is also interpreted to indirectly extract the top quark mass. Moreover, the cross-section measurement is sensitive to new physics such as the existence of a charged Higgs boson. The selection established for the cross-section analysis has been used to search for a H + boson lighter than the top quark, where the latter can decay into a W + or H + boson and a b quark. The model that has been studied makes the assumption that the H + boson can only decay into a tau lepton and a neutrino.« less
  • The authors have performed a search for the electroweak production of single top quarks in p{bar p} collisions at the Fermilab Tevatron at a center of mass energy of {radical}s = 1.96 TeV. The search was performed in the muon plus jets decay channel requiring at least one b-tagged jet. The data were collected using the D0 detector between August 2002 and September 2003 corresponding to an integrated luminosity of 158 pb{sup -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 themore » combined s + t channel using the secondary vertex tagger (SVT) algorithm. They also present results from the combined electron and muon channel search using the D0 detector.« less
  • The results of the first analysis to show evidence for production of single top quarks are presented. Using 0.9 fb-1 of data collected with the D0 detector at the Fermilab Tevatron, the analysis is performed in the electron jets and muon jets decay modes, taking special care in modeling the large backgrounds, applying a new powerful b-quark tagging algorithm and using three multivariate techniques to extract the small signal in the data. The combined measured production cross section is 4.8 +- 1.3 pb. The probability to measure a cross section at this value or higher in the absence of amore » signal is 0.027%, corresponding to a 3.5 standard deviation significance.« less