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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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Search for heavy long-lived charged particles in pp collisions at sqrt(s) = 7 TeV

ArXiv 1205.0272 (2012)
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Search for large extra dimensions in dimuon and dielectron events in pp collisions at s=7 TeV

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 711:1 (2012) 15-34

Authors:

S Chatrchyan, V Khachatryan, AM Sirunyan, A Tumasyan, W Adam, T Bergauer, M Dragicevic, J Erö, C Fabjan, M Friedl, R Frühwirth, VM Ghete, J Hammer, M Hoch, N Hörmann, J Hrubec, M Jeitler, W Kiesenhofer, M Krammer, D Liko, I Mikulec, M Pernicka, B Rahbaran, C Rohringer, H Rohringer, R Schöfbeck, J Strauss, A Taurok, F Teischinger, P Wagner, W Waltenberger, G Walzel, E Widl, CE Wulz, V Mossolov, N Shumeiko, J Suarez Gonzalez, S Bansal, L Benucci, T Cornelis, EA De Wolf, X Janssen, S Luyckx, T Maes, L Mucibello, S Ochesanu, B Roland, R Rougny, M Selvaggi, H Van Haevermaet, P Van Mechelen, N Van Remortel, A Van Spilbeeck, F Blekman, S Blyweert, J D'Hondt, R Gonzalez Suarez, A Kalogeropoulos, M Maes, A Olbrechts, W Van Doninck, P Van Mulders, GP Van Onsem, I Villella, O Charaf, B Clerbaux, G De Lentdecker, V Dero, APR Gay, GH Hammad, T Hreus, A Léonard, PE Marage, L Thomas, C Vander Velde, P Vanlaer, J Wickens, V Adler, K Beernaert, A Cimmino, S Costantini, G Garcia, M Grunewald, B Klein, J Lellouch, A Marinov, J Mccartin, AA Ocampo Rios, D Ryckbosch, N Strobbe, F Thyssen, M Tytgat, L Vanelderen, P Verwilligen, S Walsh, E Yazgan, N Zaganidis, S Basegmez, G Bruno, J Caudron

Abstract:

Results are presented from a search for large, extra spatial dimensions in events with either two isolated muons or two isolated electrons. The data are from proton-proton interactions at s=7 TeV collected with the CMS detector at the LHC. The size of the data sample corresponds to an integrated luminosity of approximately 2 fb -1. The observed dimuon and dielectron mass spectra are found to be consistent with standard-model expectations. Depending on the number of extra dimensions, the 95% confidence level limits from the combined μμ and ee channels range from M s>2.4 TeV to M s>3.8 TeV, where M s characterizes the scale for the onset of quantum gravity. © 2012 CERN.
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Studies of jet quenching using isolated-photon + jet correlations in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV

ArXiv 1205.0206 (2012)
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The MICE Muon Beam on ISIS and the beam-line instrumentation of the Muon Ionization Cooling Experiment

Journal of Instrumentation 7:5 (2012)

Authors:

M Bogomilov, Y Karadzhov, D Kolev, I Russinov, R Tsenov, G Vankova-Kirilova, L Wang, FY Xu, SX Zheng, R Bertoni, M Bonesini, F Ferri, G Lucchini, R Mazza, F Paleari, F Strati, V Palladino, G Cecchet, A De Bari, M Capponi, A Cirillo, A Iaciofano, A Manfredini, M Parisi, D Orestano, F Pastore, A Tonazzo, L Tortora, Y Mori, Y Kuno, H Sakamoto, A Sato, T Yano, M Yoshida, S Ishimoto, S Suzuki, K Yoshimura, F Filthaut, R Garoby, S Gilardoni, P Gruber, K Hanke, H Haseroth, P Janot, A Lombardi, S Ramberger, M Vretenar, P Bene, A Blondel, F Cadoux, JS Graulich, V Grichine, E Gschwendtner, F Masciocchi, R Sandstrom, V Verguilov, H Wisting, C Petitjean, R Seviour, J Alexander, G Charnley, N Collomb, S Griffiths, B Martlew, A Moss, I Mullacrane, A Oates, P Owens, C White, S York, D Adams, R Apsimon, P Barclay, DE Baynham, TW Bradshaw, M Courthold, P Drumm, R Edgecock, T Hayler, M Hills, Y Ivaniouchenkov, A Jones, A Lintern, C MacWaters, C Nelson, A Nichols, R Preece, S Ricciardi, JH Rochford, C Rogers, W Spensley, J Tarrant, K Tilley, S Watson, A Wilson, D Forrest, FJP Soler, K Walaron, P Cooke, R Gamet

Abstract:

The international Muon Ionization Cooling Experiment (MICE), which is under construction at the Rutherford Appleton Laboratory (RAL), will demonstrate the principle of ionization cooling as a technique for the reduction of the phase-space volume occupied by a muon beam. Ionization cooling channels are required for the Neutrino Factory and the Muon Collider. MICE will evaluate in detail the performance of a single lattice cell of the Feasibility Study 2 cooling channel. The MICE Muon Beam has been constructed at the ISIS synchrotron at RAL, and in MICE Step I, it has been characterized using the MICE beam-instrumentation system. In this paper, the MICE Muon Beam and beam-line instrumentation are described. The muon rate is presented as a function of the beam loss generated by the MICE target dipping into the ISIS proton beam. For a 1 V signal from the ISIS beam-loss monitors downstream of our target we obtain a 30 KHz instantaneous muon rate, with a neglible pion contamination in the beam. © 2012 IOP Publishing Ltd and Sissa Medialab srl.
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