Accelerator Neutrinos

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Measurement of the masses and widths of the bottom baryons Σb± and Σb*±

Physical Review D - Particles, Fields, Gravitation and Cosmology 85:9 (2012)

Authors:

T Aaltonen, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, JA Appel, T Arisawa, A Artikov, J Asaadi, W Ashmanskas, B Auerbach, A Aurisano, F Azfar, W Badgett, T Bae, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Barria, P Bartos, M Bauce, F Bedeschi, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, A Bhatti, D Bisello, I Bizjak, KR Bland, B Blumenfeld, A Bocci, A Bodek, D Bortoletto, J Boudreau, A Boveia, L Brigliadori, C Bromberg, E Brucken, J Budagov, HS Budd, K Burkett, G Busetto, P Bussey, A Buzatu, A Calamba, C Calancha, S Camarda, M Campanelli, M Campbell, F Canelli, B Carls, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, M Cavalli-Sforza, A Cerri, L Cerrito, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, WH Chung, YS Chung, MA Ciocci, A Clark, C Clarke, G Compostella, ME Convery, J Conway, M Corbo, M Cordelli, CA Cox, DJ Cox, F Crescioli, J Cuevas, R Culbertson, D Dagenhart, N D'ascenzo, M Datta, P De Barbaro, M Dell'orso, L Demortier, M Deninno, F Devoto, M D'errico, A Di Canto

Abstract:

Using data from pp̄ collisions at √s=1.96TeV recorded by the CDF II detector at the Fermilab Tevatron, we present improved measurements of the masses and first measurements of natural widths of the four bottom baryon resonance states Σb+, Σb*+ and Σb-, Σb*-. These states are fully reconstructed in their decay modes to Λb0π ± where Λb0→Λc+π - with Λc+→pK -π +. The analysis is based on a data sample corresponding to an integrated luminosity of 6.0fb -1 collected by an online event selection based on tracks displaced from the pp̄ interaction point. © 2012 American Physical Society.
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Improved measurement of muon antineutrino disappearance in MINOS

Physical Review Letters 108:19 (2012)

Authors:

P Adamson, DS Ayres, C Backhouse, G Barr, M Bishai, A Blake, GJ Bock, DJ Boehnlein, D Bogert, SV Cao, S Childress, JAB Coelho, L Corwin, D Cronin-Hennessy, IZ Danko, JK De Jong, NE Devenish, MV Diwan, CO Escobar, JJ Evans, E Falk, GJ Feldman, MV Frohne, HR Gallagher, RA Gomes, MC Goodman, P Gouffon, N Graf, R Gran, K Grzelak, A Habig, J Hartnell, R Hatcher, A Himmel, A Holin, X Huang, J Hylen, GM Irwin, Z Isvan, DE Jaffe, C James, D Jensen, T Kafka, SMS Kasahara, G Koizumi, S Kopp, M Kordosky, A Kreymer, K Lang, J Ling, PJ Litchfield, L Loiacono, P Lucas, WA Mann, ML Marshak, M Mathis, N Mayer, R Mehdiyev, JR Meier, MD Messier, DG Michael, WH Miller, SR Mishra, J Mitchell, CD Moore, L Mualem, S Mufson, J Musser, D Naples, JK Nelson, HB Newman, RJ Nichol, JA Nowak, WP Oliver, M Orchanian, RB Pahlka, J Paley, RB Patterson, G Pawloski, S Phan-Budd, RK Plunkett, X Qiu, A Radovic, J Ratchford, B Rebel, C Rosenfeld, HA Rubin, MC Sanchez, J Schneps, A Schreckenberger, P Schreiner, R Sharma, A Sousa, M Strait, N Tagg, RL Talaga, J Thomas, MA Thomson, G Tinti, R Toner

Abstract:

We report an improved measurement of ν ̄μ disappearance over a distance of 735 km using the MINOS detectors and the Fermilab Main Injector neutrino beam in a ν ̄μ-enhanced configuration. From a total exposure of 2.95×1020 protons on target, of which 42% have not been previously analyzed, we make the most precise measurement of Δm ̄2=[2.62-0.28+0.31(stat)±0. 09(syst)]×10 -3eV2 and constrain the ν ̄μ mixing angle sin2(2θ̄)>0.75 (90% C.L.). These values are in agreement with Δm2 and sin2(2θ) measured for ν μ, removing the tension reported in. © 2012 American Physical Society.
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Study of substructure of high transverse momentum jets produced in proton-antiproton collisions at √s=1.96TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 85:9 (2012)

Authors:

T Aaltonen, R Alon, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, JA Appel, A Apresyan, T Arisawa, A Artikov, J Asaadi, W Ashmanskas, B Auerbach, A Aurisano, F Azfar, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Barria, P Bartos, M Bauce, G Bauer, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, A Bhatti, M Binkley, D Bisello, I Bizjak, KR Bland, B Blumenfeld, A Bocci, A Bodek, D Bortoletto, J Boudreau, A Boveia, L Brigliadori, A Brisuda, C Bromberg, E Brucken, M Bucciantonio, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, C Calancha, S Camarda, M Campanelli, M Campbell, F Canelli, B Carls, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, M Cavalli-Sforza, A Cerri, L Cerrito, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, A Clark, C Clarke, G Compostella, ME Convery, J Conway, M Corbo, M Cordelli, CA Cox, DJ Cox, F Crescioli, C Cuenca Almenar, J Cuevas, R Culbertson

Abstract:

A study of the substructure of jets with transverse momentum greater than 400GeV/c produced in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron Collider and recorded by the CDF II detector is presented. The distributions of the jet mass, angularity, and planar flow are measured for the first time in a sample with an integrated luminosity of 5.95fb -1. The observed substructure for high mass jets is consistent with predictions from perturbative quantum chromodynamics. © 2012 American Physical Society.
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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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