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Title: Multivariate searches for single top quark production with the D0 detector

Abstract

We present a search for electroweak production of single top quarks in (p{bar p} {yields} t{bar b} + X) and t-channel (p{bar p} {yields} tq{bar b} + X) modes. We have analyzed 230 pb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider at a center-of-mass energy of {radical}s = 1.96 TeV. Two separate analysis methods are used: neural networks and a cut-based analysis. No evidence for a single top quark signal is found. We set 95% confidence level upper limits on the production cross sections using Bayesian statistics, based on event counts and binned likelihoods formed from the neural network output. The limits from the neural network (cut-based) analysis are 6.4 pb (10.6 pb) in the s-channel and 5.0 pb (11.3 pb) in the t-channel.

Authors:
; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
892398
Report Number(s):
FERMILAB-PUB-06-069-E
arXiv eprint number hep-ex/0604020; TRN: US200711%%451
DOE Contract Number:
AC02-76CH03000
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys.Rev.D75:092007,2007
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CROSS SECTIONS; FERMILAB TEVATRON; NEURAL NETWORKS; PRODUCTION; S CHANNEL; STATISTICS; T CHANNEL; T QUARKS; Experiment-HEP

Citation Formats

Abazov, V.M., Abbott, B., Abolins, M., Acharya, B.S., Adams, M., Adams, T., Agelou, M., Agram, J.-L., Ahn, S.H., Ahsan, M., Alexeev, G.D., and /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Beijing, Inst. High Energy Phys. /Hefei, CUST /Andes U., Bogota. Multivariate searches for single top quark production with the D0 detector. United States: N. p., 2006. Web.
Abazov, V.M., Abbott, B., Abolins, M., Acharya, B.S., Adams, M., Adams, T., Agelou, M., Agram, J.-L., Ahn, S.H., Ahsan, M., Alexeev, G.D., & /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Beijing, Inst. High Energy Phys. /Hefei, CUST /Andes U., Bogota. Multivariate searches for single top quark production with the D0 detector. United States.
Abazov, V.M., Abbott, B., Abolins, M., Acharya, B.S., Adams, M., Adams, T., Agelou, M., Agram, J.-L., Ahn, S.H., Ahsan, M., Alexeev, G.D., and /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Beijing, Inst. High Energy Phys. /Hefei, CUST /Andes U., Bogota. Sat . "Multivariate searches for single top quark production with the D0 detector". United States. doi:. https://www.osti.gov/servlets/purl/892398.
@article{osti_892398,
title = {Multivariate searches for single top quark production with the D0 detector},
author = {Abazov, V.M. and Abbott, B. and Abolins, M. and Acharya, B.S. and Adams, M. and Adams, T. and Agelou, M. and Agram, J.-L. and Ahn, S.H. and Ahsan, M. and Alexeev, G.D. and /Buenos Aires U. /Rio de Janeiro, CBPF /Rio de Janeiro State U. /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Beijing, Inst. High Energy Phys. /Hefei, CUST /Andes U., Bogota},
abstractNote = {We present a search for electroweak production of single top quarks in (p{bar p} {yields} t{bar b} + X) and t-channel (p{bar p} {yields} tq{bar b} + X) modes. We have analyzed 230 pb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider at a center-of-mass energy of {radical}s = 1.96 TeV. Two separate analysis methods are used: neural networks and a cut-based analysis. No evidence for a single top quark signal is found. We set 95% confidence level upper limits on the production cross sections using Bayesian statistics, based on event counts and binned likelihoods formed from the neural network output. The limits from the neural network (cut-based) analysis are 6.4 pb (10.6 pb) in the s-channel and 5.0 pb (11.3 pb) in the t-channel.},
doi = {},
journal = {Phys.Rev.D75:092007,2007},
number = ,
volume = ,
place = {United States},
year = {Sat Apr 01 00:00:00 EST 2006},
month = {Sat Apr 01 00:00:00 EST 2006}
}
  • We present a search for electroweak production of single top quarks in the s-channel (pp{yields}tb+X) and t-channel (pp{yields}tqb+X) modes. We have analyzed 230 pb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron Collider at a center-of-mass energy of {radical}(s)=1.96 TeV. No evidence for a single top quark signal is found. We set 95% confidence level upper limits on the production cross sections, based on binned likelihoods formed from a neural network output. The observed (expected) limits are 6.4 pb (4.5 pb) in the s-channel and 5.0 pb (5.8 pb) in the t-channel.
  • We report on the observation of single top quark production by the D0 collaboration using a dataset of 2.3 fb{sup -1} collected at the Fermilab Tevatron p{bar p} collider. Several multivariate techniques are combined to separate the single top signal from backgrounds. The measured single top cross section is {sigma}{sub tb+tqb} = 3.94 {+-} 0.88 pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.9 x 10{sup -7}, corresponding to a 5.0 standard deviation significance for the presence of signal. The lower limit at the 95% C.L. on the CKMmore » matrix element V{sub tb} is |V{sub tb}| > 0.78. A separate measurement of the t-channel cross section gives {sigma}{sub tqb} = 3.14{sub -0.80}{sup +0.94} pb.« less
  • The authors present the first simultaneous measurement of the ratio of branching fractions, R = {Beta}(t {yields} Wb)/{Beta}(t {yields} Wq), with q being a d, s, or b quark, and the top quark pair production cross section {sigma}{sub t{bar t}} in the lepton plus jets channel using 0.9 fb{sup -1} of p{bar p} collision data at {radical}s = 1.96 TeV collected with the D0 detector. they extract R and {sigma}{sub t{bar t}} by analyzing samples of events with 0, 1 and {ge} 2 identified b jets. They measure R = 0.97{sub -0.08}{sup +0.09} (stat+syst) and {sigma}{sub t{bar t}} = 8.18{submore » -0.84}{sup +0.90}(stat+syst) {+-} 0.50 (lumi) pb, in agreement with the standard model prediction.« less
  • We present the first simultaneous measurement of the ratio of branching fractions, R=B(t{yields}Wb)/B(t{yields}Wq), with q being a d, s, or b quark, and the top-quark pair production cross section {sigma}{sub tt} in the lepton plus jets channel using 0.9 fb{sup -1} of pp collision data at {radical}(s)=1.96 TeV collected with the D0 detector. We extract R and {sigma}{sub tt} by analyzing samples of events with 0, 1, and {>=}2 identified b jets. We measure R=0.97{sub -0.08}{sup +0.09}(stat+syst) and {sigma}{sub tt}=8.18{sub -0.84}{sup +0.90}(stat+syst){+-}0.50(lumi) pb, in agreement with the standard model prediction.
  • No abstract prepared.