Professor Claire Gwenlan: Publications

Measurement of the ZZ production cross section and limits on anomalous neutral triple gauge couplings in proton-proton collisions at √s=7TeV with the ATLAS detector

Physical Review Letters 108:4 (2012)

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, H Abramowicz, H Abreu, E Acerbi, BS Acharya, DL Adams, TN Addy, J Adelman, M Aderholz, S Adomeit, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, M Ahsan, G Aielli, T Akdogan, TPA Åkesson, G Akimoto, AV Akimov, A Akiyama, MS Alam, MA Alam, J Albert, S Albrand, M Aleksa, IN Aleksandrov, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, M Aliyev, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, B Alvarez Gonzalez, MG Alviggi, K Amako, P Amaral, C Amelung, VV Ammosov, A Amorim, G Amorós, N Amram, C Anastopoulos, LS Ancu, N Andari, T Andeen, CF Anders, G Anders, KJ Anderson, A Andreazza, V Andrei, ML Andrieux, XS Anduaga, A Angerami, F Anghinolfi, N Anjos, A Annovi, A Antonaki, M Antonelli, A Antonov, J Antos, F Anulli, S Aoun, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault, S Arfaoui, JF Arguin, E Arik, M Arik, AJ Armbruster, O Arnaez, A Artamonov, G Artoni, D Arutinov

Abstract:

A measurement of the ZZ production cross section in proton-proton collisions at √s=7TeV using data corresponding to an integrated luminosity of 1.02fb -1 recorded by the ATLAS experiment at the LHC is presented. Twelve events containing two Z boson candidates decaying to electrons and/or muons are observed, with an expected background of 0.3±0.3(stat)- 0.3+0.4(syst) events. The cross section measured in a phase-space region with good detector acceptance and for dilepton masses within the range 66 to 116 GeV is σZZ→" +" -" +" -fid=19.4-5.2+6.3(stat)-0.7+0. 9(syst)±0.7(lumi)fb. The resulting total cross section for on-shell ZZ production, σZZtot=8.5-2.3+2.7(stat)-0.3+0.4(syst)±0.3(lumi)pb, is consistent with the standard model expectation of 6.5-0.2+0.3pb calculated at the next-to-leading order in QCD. Limits on anomalous neutral triple gauge boson couplings are derived. © 2012 CERN. Published by the American Physical Society under the terms of the < uri xlink:href="http://creativecommons. org/licenses/by/3.0/" > Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Measurement of the cross-section for b-jets produced in association with a Z boson at s=7 TeV with the ATLAS detector

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 706:4-5 (2012) 295-313

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, H Abramowicz, H Abreu, E Acerbi, BS Acharya, DL Adams, TN Addy, J Adelman, M Aderholz, S Adomeit, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, M Ahsan, G Aielli, T Akdogan, TPA Åkesson, G Akimoto, AV Akimov, A Akiyama, MS Alam, MA Alam, J Albert, S Albrand, M Aleksa, IN Aleksandrov, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, M Aliyev, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, MG Alviggi, K Amako, P Amaral, C Amelung, VV Ammosov, A Amorim, G Amorós, N Amram, C Anastopoulos, LS Ancu, N Andari, T Andeen, CF Anders, G Anders, KJ Anderson, A Andreazza, V Andrei, ML Andrieux, XS Anduaga, A Angerami, F Anghinolfi, N Anjos, A Annovi, A Antonaki, M Antonelli, A Antonov, J Antos, F Anulli, S Aoun, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault, S Arfaoui, JF Arguin, E Arik, M Arik, AJ Armbruster, O Arnaez, C Arnault, A Artamonov, G Artoni, D Arutinov

Abstract:

A measurement is presented of the inclusive cross-section for b-jet production in association with a Z boson in pp collisions at a centre-of-mass energy of s=7 TeV. The analysis uses the data sample collected by the ATLAS experiment in 2010, corresponding to an integrated luminosity of approximately 36 pb-1. The event selection requires a Z boson decaying into high pT electrons or muons, and at least one b-jet, identified by its displaced vertex, with transverse momentum pT>25 GeV and rapidity |y|<2.1. After subtraction of background processes, the yield is extracted from the vertex mass distribution of the candidate b-jets. The ratio of this cross-section to the inclusive Z cross-section (the average number of b-jets per Z event) is also measured. Both results are found to be in good agreement with perturbative QCD predictions at next-to-leading order. © 2011 CERN.

ATLAS search for a heavy gauge boson decaying to a charged lepton and a neutrino in pp collisions at √s =7 TeV

European Physical Journal C 72:12 (2012)

Authors:

G Aad, T Abajyan, B Abbott, J Abdallah, S Abdel Khalek, AA Abdelalim, O Abdinov, R Aben, B Abi, M Abolins, OS Abouzeid, H Abramowicz, H Abreu, BS Acharya, L Adamczyk, DL Adams, TN Addy, J Adelman, S Adomeit, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Agustoni, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, M Ahsan, G Aielli, T Akdogan, TPA Åkesson, G Akimoto, AV Akimov, MS Alam, MA Alam, J Albert, S Albrand, M Aleksa, IN Aleksandrov, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, BMM Allbrooke, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, F Alonso, A Altheimer, B Alvarez Gonzalez, MG Alviggi, K Amako, C Amelung, VV Ammosov, SP Amor Dos Santos, A Amorim, N Amram, C Anastopoulos, LS Ancu, N Andari, T Andeen, CF Anders, G Anders, KJ Anderson, A Andreazza, V Andrei, ML Andrieux, XS Anduaga, P Anger, A Angerami, F Anghinolfi, A Anisenkov, N Anjos, A Annovi, A Antonaki, M Antonelli, A Antonov, J Antos, F Anulli, M Aoki, S Aoun, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, ATH Arce, S Arfaoui, JF Arguin, E Arik, M Arik

Abstract:

The ATLAS detector at the LHC is used to search for high-mass states, such as heavy charged gauge bosons (Wʹ), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.7 fb−1. No excess beyond Standard Model expectations is observed. AWʹ with Sequential Standard Model couplings is excluded at the 95% credibility level for masses up to 2.55 TeV. Excited chiral bosons (W*) with equivalent coupling strength are excluded for masses up to 2.42 TeV.

Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA

European Physical Journal C 72:10 (2012) 1-17

Authors:

FD Aaron, H Abramowicz, I Abt, L Adamczyk, M Adamus, R Aggarwal, C Alexa, V Andreev, S Antonelli, P Antonioli, A Antonov, M Arneodo, O Arslan, V Aushev, Y Aushev, O Bachynska, S Backovic, A Baghdasaryan, S Baghdasaryan, A Bamberger, AN Barakbaev, G Barbagli, G Bari, F Barreiro, E Barrelet, W Bartel, N Bartosik, D Bartsch, M Basile, K Begzsuren, O Behnke, J Behr, U Behrens, L Bellagamba, A Belousov, P Belov, A Bertolin, S Bhadra, M Bindi, JC Bizot, C Blohm, V Bokhonov, K Bondarenko, EG Boos, K Borras, D Boscherini, D Bot, V Boudry, I Bozovic-Jelisavcic, T Bołd, N Brümmer, J Bracinik, G Brandt, M Brinkmann, V Brisson, D Britzger, I Brock, E Brownson, R Brugnera, D Bruncko, A Bruni, G Bruni, B Brzozowska, A Bunyatyan, PJ Bussey, A Bylinkin, B Bylsma, L Bystritskaya, A Caldwell, AJ Campbell, KB Cantun Avila, M Capua, R Carlin, CD Catterall, F Ceccopieri, K Cerny, V Cerny, S Chekanov, V Chekelian, J Chwastowski, J Ciborowski, R Ciesielski, L Cifarelli, F Cindolo, A Contin, JG Contreras, AM Cooper-Sarkar, N Coppola, M Corradi, F Corriveau, M Costa, JA Coughlan, J Cvach, G D'Agostini, JB Dainton, F Dal Corso, K Daum, B Delcourt, J Delvax, RK Dementiev

Abstract:

A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy √s= 318 Gev where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q2 < 200 GeV2 in photon virtuality, 0.00035 < xP < 0.09 in proton fractional momentum loss, 0.09 <{pipe}t{pipe}< 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < β <0.816 in β=x/xP, where x is the Bjorken scaling variable. © 2012 The Author(s).

Measurement of the W boson polarization in top quark decays with the ATLAS detector

Journal of High Energy Physics 2012:6 (2012)

Authors:

G Aad, B Abbott, J Abdallah, S Abdel Khalek, AA Abdelalim, O Abdinov, B Abi, M Abolins, OS AbouZeid, H Abramowicz, H Abreu, E Acerbi, BS Acharya, L Adamczyk, DL Adams, TN Addy, J Adelman, S Adomeit, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Agustoni, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, M Ahsan, G Aielli, T Akdogan, TPA Åkesson, G Akimoto, AV Akimov, A Akiyama, MS Alam, MA Alam, J Albert, S Albrand, M Aleksa, IN Aleksandrov, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, BMM Allbrooke, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, B Alvarez Gonzalez, MG Alviggi, K Amako, C Amelung, VV Ammosov, A Amorim, N Amram, C Anastopoulos, LS Ancu, N Andari, T Andeen, CF Anders, G Anders, KJ Anderson, A Andreazza, V Andrei, XS Anduaga, P Anger, A Angerami, F Anghinolfi, A Anisenkov, N Anjos, A Annovi, A Antonaki, M Antonelli, A Antonov, J Antos, F Anulli, S Aoun, L Aperio Bella, R Apolle, G Arabidze, I Aracena, Y Arai, ATH Arce, S Arfaoui, JF Arguin, E Arik, M Arik, AJ Armbruster, O Arnaez, V Arnal, C Arnault, A Artamonov

Abstract:

This paper presents measurements of the polarization ofW bosons in top quark decays, derived from tt̄ events with missing transverse momentum, one charged lepton and at least four jets, or two charged leptons and at least two jets. Data from pp collisions at a centre-of-mass energy of 7 TeV were collected with the ATLAS experiment at the LHC and correspond to an integrated luminosity of 1.04 fb-1. The measured fractions of longitudinally, left- and right-handed polarization are F0 = 0.67 ± 0.07, FL = 0.32 ± 0.04 and FR = 0.01 ± 0.05, in agreement with the Standard Model predictions. As the polarization of the W bosons in top quark decays is sensitive to the Wtb vertex Lorentz structure and couplings, the measurements were used to set limits on anomalous contributions to the Wtb couplings. © CERN.

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