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Title: Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector

Abstract

A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of {radical}s = 7 TeV, corresponding to an integrated luminosity of 2.05 fb{sup -1}, are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95% confidence level on the cross-section multiplied by the t {yields} Wb branching fraction is measured to be {sigma}{sub qg{yields}t} x {Beta}(t {yields} Wb) < 3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths {kappa}{sub ugt}/{Lambda} < 6.9 {center_dot} 10{sup -3} TeV{sup -1} and {kappa}{sub cgt}/{Lambda} < 1.6 {center_dot} 10{sup -2} TeV{sup -1}, where {Lambda} is the new physics scale, and on the branching fractions {Beta}(t {yields} ug) < 5.7 {center_dot} 10{sup -5} and {Beta}(t {yields} cg) < 2.7 {center_dot} 10{sup -4}.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
BROOKHAVEN NATIONAL LABORATORY (BNL)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1048770
Report Number(s):
BNL-98361-2012-JA
KA1101021; TRN: US1204292
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Physics Letters B
Additional Journal Information:
Journal Volume: 712; Journal Issue: 4-5
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DECAY; DISTRIBUTION; LUMINOSITY; NEURAL NETWORKS; NEUTRAL CURRENTS; PHYSICS; PRODUCTION; T QUARKS

Citation Formats

Aad G., Abbott, B., Abdallah, J., Abdelalim, A. A., Abdesselam, A., Abdinov, O., Abi, B., Abolins, M., AbouZeid, O. S., Abramowicz, H., Abreu, H., Acerbi, E., Acharya, B. S., Adamczyk, L., Adams, D. L., Addy, T. N., Adelman, J., Aderholz, M., Adomeit, S., and et al. Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector. United States: N. p., 2012. Web.
Aad G., Abbott, B., Abdallah, J., Abdelalim, A. A., Abdesselam, A., Abdinov, O., Abi, B., Abolins, M., AbouZeid, O. S., Abramowicz, H., Abreu, H., Acerbi, E., Acharya, B. S., Adamczyk, L., Adams, D. L., Addy, T. N., Adelman, J., Aderholz, M., Adomeit, S., & et al. Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector. United States.
Aad G., Abbott, B., Abdallah, J., Abdelalim, A. A., Abdesselam, A., Abdinov, O., Abi, B., Abolins, M., AbouZeid, O. S., Abramowicz, H., Abreu, H., Acerbi, E., Acharya, B. S., Adamczyk, L., Adams, D. L., Addy, T. N., Adelman, J., Aderholz, M., Adomeit, S., and et al. Tue . "Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector". United States.
@article{osti_1048770,
title = {Search for FCNC single top-quark production at root s=7 TeV with the ATLAS detector},
author = {Aad G. and Abbott, B. and Abdallah, J. and Abdelalim, A. A. and Abdesselam, A. and Abdinov, O. and Abi, B. and Abolins, M. and AbouZeid, O. S. and Abramowicz, H. and Abreu, H. and Acerbi, E. and Acharya, B. S. and Adamczyk, L. and Adams, D. L. and Addy, T. N. and Adelman, J. and Aderholz, M. and Adomeit, S. and et al.},
abstractNote = {A search for the production of single top-quarks via flavour-changing neutral-currents is presented. Data collected with the ATLAS detector at a centre-of-mass energy of {radical}s = 7 TeV, corresponding to an integrated luminosity of 2.05 fb{sup -1}, are used. Candidate events with a semileptonic top-quark decay signature are classified as signal- or background-like events by using several kinematic variables as input to a neural network. No signal is observed in the neural network output distribution and a Bayesian upper limit is placed on the production cross-section. The observed upper limit at 95% confidence level on the cross-section multiplied by the t {yields} Wb branching fraction is measured to be {sigma}{sub qg{yields}t} x {Beta}(t {yields} Wb) < 3.9 pb. This upper limit is converted using a model-independent approach into upper limits on the coupling strengths {kappa}{sub ugt}/{Lambda} < 6.9 {center_dot} 10{sup -3} TeV{sup -1} and {kappa}{sub cgt}/{Lambda} < 1.6 {center_dot} 10{sup -2} TeV{sup -1}, where {Lambda} is the new physics scale, and on the branching fractions {Beta}(t {yields} ug) < 5.7 {center_dot} 10{sup -5} and {Beta}(t {yields} cg) < 2.7 {center_dot} 10{sup -4}.},
doi = {},
journal = {Physics Letters B},
number = 4-5,
volume = 712,
place = {United States},
year = {2012},
month = {6}
}