Accelerator Neutrinos

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Search for new physics in the μμ+e/μ+E T channel with a low-pT lepton threshold at the Collider Detector at Fermilab

Physical Review D - Particles, Fields, Gravitation and Cosmology 79:5 (2009)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, BA González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzurri, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, S Burke, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, 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, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, T Chwalek, CI Ciobanu, MA Ciocci, A Clark

Abstract:

A search for new physics using three-lepton (trilepton) data collected with the CDF II detector and corresponding to an integrated luminosity of 976 pb-1 is presented. The standard model predicts a low rate of trilepton events, which makes some supersymmetric processes, such as chargino-neutralino production, measurable in this channel. The μμ+ signature is investigated, where ℓ is an electron or a muon, with the additional requirement of large missing transverse energy. In this analysis, the lepton transverse momenta with respect to the beam direction (pT) are as low as 5GeV/c, a selection that improves the sensitivity to particles that are light as well as to ones that result in leptonically decaying tau leptons. At the same time, this low-pT selection presents additional challenges due to the non-negligible heavy-quark background at low lepton momenta. This background is measured with an innovative technique using experimental data. Several dimuon and trilepton control regions are investigated, and good agreement between experimental results and standard-model predictions is observed. In the signal region, we observe one three-muon event and expect 0.4±0.1μμ+ events from standard-model processes. © 2009 The American Physical Society.
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Sudden stratospheric warmings seen in MINOS deep underground muon data

Geophysical Research Letters American Geophysical Union (AGU) 36:5 (2009)

Authors:

S Osprey, J Barnett, J Smith, P Adamson, C Andreopoulos, KE Arms, R Armstrong, DJ Auty, DS Ayres, B Baller, PD Barnes, GD Barr, WL Barrett, BR Becker, A Belias, RH Bernstein, D Bhattacharya, M Bishai, A Blake, GJ Bock, J Boehm, DJ Boehnlein, D Bogert, C Bower, E Buckley‐Geer, S Cavanaugh, JD Chapman, D Cherdack, S Childress, BC Choudhary, JH Cobb, SJ Coleman, AJ Culling, JK de Jong, M Dierckxsens, MV Diwan, M Dorman, SA Dytman, CO Escobar, JJ Evans, E Falk, GJ Feldman, MV Frohne, HR Gallagher, A Godley, MC Goodman, P Gouffon, R Gran, EW Grashorn, N Grossman, K Grzelak, A Habig, D Harris, PG Harris, J Hartnell, R Hatcher, A Himmel, A Holin, J Hylen, GM Irwin, M Ishitsuka, DE Jaffe, C James, D Jensen, T Kafka, SMS Kasahara, JJ Kim, G Koizumi, S Kopp, M Kordosky, DJ Koskinen, A Kreymer, S Kumaratunga, K Lang, J Ling, PJ Litchfield, RP Litchfield, L Loiacono, P Lucas, J Ma, WA Mann, ML Marshak, JS Marshall, N Mayer, AM McGowan, JR Meier, MD Messier, CJ Metelko, DG Michael, L Miller, WH Miller, SR Mishra, CD Moore, JG Morfin, L Mualem, S Mufson, J Musser, D Naples, JK Nelson, HB Newman, RJ Nichol, TC Nicholls, JP Ochoa‐Ricoux, WP Oliver, R Ospanov, J Paley, V Paolone, Z Pavlovic, G Pawloski, GF Pearce, CW Peck, DA Petyt, R Pittam, RK Plunkett, A Rahaman, RA Rameika, TM Raufer, B Rebel, J Reichenbacher, PA Rodrigues, C Rosenfeld, HA Rubin, K Ruddick, MC Sanchez, N Saoulidou, J Schneps, P Schreiner, SM Seun, P Shanahan, W Smart, C Smith, R Smith, A Sousa, B Speakman, P Stamoulis, M Strait, P Symes, N Tagg, RL Talaga, MA Tavera, J Thomas, J Thompson, MA Thomson, JL Thron, G Tinti, G Tzanakos, J Urheim, P Vahle, B Viren, M Watabe, A Weber, RC Webb, A Wehmann, N West, C White, SG Wojcicki, DM Wright, T Yang, K Zhang, R Zwaska
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Unexplained excess of electronlike events from a 1-GeV neutrino beam.

Physical review letters 102:10 (2009) 101802

Authors:

AA Aguilar-Arevalo, CE Anderson, AO Bazarko, SJ Brice, BC Brown, L Bugel, J Cao, L Coney, JM Conrad, DC Cox, A Curioni, Z Djurcic, DA Finley, BT Fleming, R Ford, FG Garcia, GT Garvey, C Green, JA Green, TL Hart, E Hawker, R Imlay, RA Johnson, G Karagiorgi, P Kasper, T Katori, T Kobilarcik, I Kourbanis, S Koutsoliotas, EM Laird, SK Linden, JM Link, Y Liu, Y Liu, WC Louis, KBM Mahn, W Marsh, G McGregor, W Metcalf, PD Meyers, F Mills, GB Mills, J Monroe, CD Moore, RH Nelson, VT Nguyen, P Nienaber, JA Nowak, S Ouedraogo, RB Patterson, D Perevalov, CC Polly, E Prebys, JL Raaf, H Ray, BP Roe, AD Russell, V Sandberg, R Schirato, D Schmitz, MH Shaevitz, FC Shoemaker, D Smith, M Sodeberg, M Sorel, P Spentzouris, I Stancu, RJ Stefanski, M Sung, HA Tanaka, R Tayloe, M Tzanov, R Van de Water, MO Wascko, DH White, MJ Wilking, HJ Yang, GP Zeller, ED Zimmerman, MiniBooNE Collaboration

Abstract:

The MiniBooNE Collaboration observes unexplained electronlike events in the reconstructed neutrino energy range from 200 to 475 MeV. With 6.46x10;{20} protons on target, 544 electronlike events are observed in this energy range, compared to an expectation of 415.2+/-43.4 events, corresponding to an excess of 128.8+/-20.4+/-38.3 events. The shape of the excess in several kinematic variables is consistent with being due to either nu_{e} and nu[over ]_{e} charged-current scattering or nu_{mu} neutral-current scattering with a photon in the final state. No significant excess of events is observed in the reconstructed neutrino energy range from 475 to 1250 MeV, where 408 events are observed compared to an expectation of 385.9+/-35.7 events.
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Measurement of the fraction of tt̄ production via gluon-gluon fusion in pp̄ collisions at s=1.96TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 79:3 (2009)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzurri, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, P Bednar, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, M Campanelli, M Campbell, F Canelli, A Canepa, 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, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, A Clark, D Clark, G Compostella

Abstract:

We present a measurement of the ratio of the tt̄ production cross section via gluon-gluon fusion to the total tt̄ production cross section in pp̄ collisions at s=1.96TeV at the Tevatron. Using a data sample with an integrated luminosity of 955pb-1 recorded by the CDF II detector at Fermilab, we select events based on the tt̄ decay to lepton+jets. Using an artificial neural network technique we discriminate between tt̄ events produced via qq̄ annihilation and gg fusion, and find Gf=σ(gg→tt̄)/ σ(pp̄→tt̄)<0.33 at the 68% confidence level. This result is combined with a previous measurement to obtain the most stringent measurement of this quantity by CDF to date, Gf=0.07-0.07+0.15. © 2009 The American Physical Society.
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Comparisons of the MINOS Near and Far Detector Readout Systems at a Test Beam

ArXiv 0902.1116 (2009)

Authors:

A Cabrera, P Adamson, M Barker, A Belias, S Boyd, G Crone, G Drake, E Falk, PG Harris, J Hartnell, L Jenner, M Kordosky, K Lang, RP Litchfield, D Michael, PS Miyagawa, R Morse, S Murgia, R Nichol, T Nicholls, GF Pearce, D Petyt, D Reyna, R Saakyan, P Shanahan, C Smith, P Symes, N Tagg, J Thomas, P Vahle, A Weber
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