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Search for scalar bottom quark pair production with the ATLAS detector in pp collisions at √s=7TeV

Physical Review Letters 108:18 (2012)

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, OS Abouzeid, H Abramowicz, H Abreu, E Acerbi, BS Acharya, L Adamczyk, 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 Kesson, 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, 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, JP Archambault, S Arfaoui, JF Arguin, E Arik, M Arik, AJ Armbruster, O Arnaez

Abstract:

The results of a search for pair production of the scalar partners of bottom quarks in 2.05fb -1 of pp collisions at √s=7TeV using the ATLAS experiment are reported. Scalar bottom quarks are searched for in events with large missing transverse momentum and two jets in the final state, where both jets are identified as originating from a bottom quark. In an R-parity conserving minimal supersymmetric scenario, assuming that the scalar bottom quark decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits are obtained in the b 1-χ10 mass plane such that for neutralino masses below 60 GeV scalar bottom masses up to 390 GeV are excluded. © 2012 CERN.
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Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at √s =7 TeV with the ATLAS experiment

European Physical Journal C 72:5 (2012) 1-30

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, OS AbouZeid, H Abramowicz, H Abreu, E Acerbi, BS Acharya, L Adamczyk, 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, BMM Allbrooke, 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, 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

Abstract:

This paper describes an analysis of the angular distribution of W→eν and W→μν decays, using data from pp collisions at √s =7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb-1. Using the decay lepton transverse momentum and the missing transverse momentum, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (pWT): 35 < pWT < 50 GeV and pWT > 50 GeV. Good agreement is found with theoretical predictions. For pWT >50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be: f0=0. 127±0. 030±0. 108 and fL-fR=0. 252±0. 017±0. 030, where the first uncertainties are statistical, and the second include all systematic effects. © 2012 CERN for the benefit of the ATLAS collaboration.
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OBSERVATION AND SPECTRAL MEASUREMENTS OF THE CRAB NEBULA WITH MILAGRO

The Astrophysical Journal American Astronomical Society 750:1 (2012) 63

Authors:

AA Abdo, BT Allen, R Atkins, T Aune, W Benbow, D Berley, E Blaufuss, E Bonamente, J Bussons, C Chen, GE Christopher, DG Coyne, T DeYoung, BL Dingus, DE Dorfan, RW Ellsworth, A Falcone, L Fleysher, R Fleysher, J Galbraith-Frew, MM Gonzalez, JA Goodman, TJ Haines, E Hays, CM Hoffman, PH Hüntemeyer, LA Kelley, BE Kolterman, CP Lansdell, JT Linnemann, J McCullough, JE McEnery, T Morgan, AI Mincer, MF Morales, P Nemethy, D Noyes, J Pretz, JM Ryan, FW Samuelson, PM Saz Parkinson, A Shoup, G Sinnis, AJ Smith, GW Sullivan, V Vasileiou, GP Walker, M Wascko, DA Williams, S Westerhoff, GB Yodh
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Number crunch

Nature Physics Springer Nature 8:5 (2012) 359-360
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Search for excited leptons in proton-proton collisions at √s=7TeV with the ATLAS detector

Physical Review D - Particles, Fields, Gravitation and Cosmology 85:7 (2012)

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, OS Abouzeid, H Abramowicz, H Abreu, E Acerbi, BS Acharya, L Adamczyk, 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 Akesson, 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, BMM Allbrooke, 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, 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

Abstract:

The ATLAS detector is used to search for excited leptons in the electromagnetic radiative decay channel *→γ. 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 2.05fb-1. No evidence for excited leptons is found, and limits are set on the compositeness scale Λ as a function of the excited lepton mass m *. In the special case where Λ=m *, excited electron and muon masses below 1.87 TeV and 1.75 TeV are excluded at 95% C.L., respectively. © 2012 CERN.
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