Accelerator Neutrinos

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Measurement of the top pair production cross section in the lepton+jets channel using a jet flavor discriminant

Physical Review D - Particles, Fields, Gravitation and Cosmology 84:3 (2011)

Authors:

T Aaltonen, 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, B Brau, 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, A Canepa, 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, G Compostella, ME Convery, J Conway, M Corbo, M Cordelli, CA Cox, DJ Cox, F Crescioli, C Cuenca Almenar, J Cuevas, R Culbertson

Abstract:

We present a new method to measure the top quark pair production cross section and the background rates with data corresponding to an integrated luminosity of 2.7fb-1 from pp̄ collisions at √s=1.96TeV collected with the CDF II Detector. We select events with a single electron or muon candidate, missing transverse energy, and at least one b-tagged jet. We perform a simultaneous fit to a jet flavor discriminant across nine samples defined by the number of jets and b tags. An advantage of this approach is that many systematic uncertainties are measured in situ and inversely scale with integrated luminosity. We measure a top cross section of σ tt̄=7.64±0.57(stat+syst)±0.45(luminosity)pb. © 2011 American Physical Society.
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The T2K near detector data acquisition systems

IEEE Transactions on Nuclear Science 58:4 PART 1 (2011) 1800-1806

Authors:

M Thorpe, C Angelsen, G Barr, C Metelko, T Nicholls, G Pearce, N West

Abstract:

T2K is a second generation long-baseline experiment in Japan, designed to perform precision studies of neutrino oscillations. A neutrino beam originating at the J-PARC facility is sampled by two near detectors, approximately 280 m distant from the source and directed towards the Kamioka underground facility, 295 km distant, where the Super-Kamiokande water Cerenkov detector is situated. Both the on-axis (INGRID) and off-axis (ND280) near detectors employ the MIDAS framework for their data acquisition systems. Events are selected via a flexible hardware trigger, which allows mixed operating modes incorporating beam spill, cosmic and calibration triggers. Data are acquired from the front-end electronics over optical Gigabit Ethernet links by custom MIDAS front-end applications distributed over a cluster of Linux computers. Event fragments from all sub-detectors are merged and logged on a central backend processor and then copied to remote storage for long-term archival. The system is also designed to allow flexible partitioning of sub-detectors for standalone diagnostics and calibration. We present the design of the DAQ system and report on experience gathered during early operation of the near detectors. © 2006 IEEE.
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Improved search for muon-neutrino to electron-neutrino oscillations in MINOS

(2011)

Authors:

MINOS Collaboration, P Adamson, DJ Auty, DS Ayres, C Backhouse, G Barr, M Betancourt, M Bishai, A Blake, GJ Bock, DJ Boehnlein, D Bogert, SV Cao, S Cavanaugh, D Cherdack, S Childress, JAB Coelho, L Corwin, D Cronin-Hennessy, IZ Danko, JK de Jong, NE Devenish, MV Diwan, M Dorman, 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, G Lefeuvre, J Ling, PJ Litchfield, L Loiacono, P Lucas, WA Mann, ML Marshak, M Mathis, N Mayer, AM McGowan, 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, JP Ochoa-Ricoux, WP Oliver, M Orchanian, J Paley, RB Patterson, G Pawloski, GF Pearce, S Phan-Budd, RK Plunkett, X Qiu, J Ratchford, B Rebel, C Rosenfeld, HA Rubin, MC Sanchez, J Schneps, A Schreckenberger, P Schreiner, P Shanahan, R Sharma, A Sousa, N Tagg, RL Talaga, J Thomas, MA Thomson, R Toner, D Torretta, G Tzanakos, J Urheim, P Vahle, B Viren, JJ Walding, A Weber, RC Webb, C White, L Whitehead, SG Wojcicki, T Yang, R Zwaska
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Limits on anomalous trilinear gauge couplings in Zγ events from pp̄ collisions at √s=1.96TeV

Physical Review Letters 107:5 (2011)

Authors:

T Aaltonen, B Lvarez 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, B Brau, 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, A Canepa, 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, G Compostella, ME Convery, J Conway, M Corbo, M Cordelli, CA Cox, DJ Cox, F Crescioli, C Cuenca Almenar, J Cuevas, R Culbertson

Abstract:

Using Zγ candidate events collected by the CDF detector at the Tevatron Collider, we search for potential anomalous (non-standard-model) couplings between the Z boson and the photon. Zγ couplings vanish at tree level and are heavily suppressed at higher orders; hence any evidence of couplings indicates new physics. Measurements are performed using data corresponding to an integrated luminosity of 4.9fb-1 in the Z→νν̄ decay channel and 5.1fb-1 in the Z→l +l- (l=μ, e) decay channels. The combination of these measurements provides the most stringent limits to date on Zγ trilinear gauge couplings. Using an energy scale of Λ=1.5TeV to allow for a direct comparison with previous measurements, we find limits on the CP-conserving parameters that describe Zγ couplings to be |h3γ,Z|<0.022 and |h4γ,Z|<0.0009. These results are consistent with standard model predictions. © 2011 American Physical Society.
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First search for multijet resonances in √s=1.96TeV pp̄ collisions

Physical Review Letters 107:4 (2011)

Authors:

T Aaltonen, 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, B Brau, 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, A Canepa, 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, G Compostella, ME Convery, J Conway, M Corbo, M Cordelli, CA Cox, DJ Cox, F Crescioli, C Cuenca Almenar, J Cuevas, R Culbertson

Abstract:

We present the first model independent search for three-jet hadronic resonances within multijet events in √s=1.96TeV pp̄ collisions at the Fermilab Tevatron using the CDF II detector. Pair production of supersymmetric gluinos and squarks with hadronic R-parity violating decays is employed as an example of a new physics benchmark for this signature. Selection criteria based on the kinematic properties of an ensemble of jet combinations within each event help to extract signal from copious QCD background. No significant excess outside the top quark mass window is observed in data with an integrated luminosity of 3.2fb⊃-1. We place 95% confidence level limits on the production cross section σ(pp̄→XX⊃′) ×BR(gg→3jet+3jet) where X, X⊃′=g, q, or q̄, with q, q̄→g+jet, as a function of gluino mass, in the range of 77GeV/c2 to 240GeV/c2. © 2011 American Physical Society.
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