Accelerator Neutrinos

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Search for Bs0→μ+μ- and B0→μ+μ- decays with CDF II

Physical Review Letters 107:19 (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, 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, D Dagenhart

Abstract:

A search has been performed for Bs0→μ+μ- and B0→μ+μ- decays using 7fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B0 candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of B(B0→μ+μ-)<6.0×10-9 at 95% confidence level. We observe an excess of Bs0 candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of Bs0→μ+μ- could produce such an excess or larger is 1.9%. These data are used to determine B(Bs0→μ+μ-)=(1.8-0.9+1.1)×10 -8 and provide an upper limit of B(Bs0→μ+μ -)<4.0×10-8 at 95% confidence level. © 2011 American Physical Society.

Search for new T′ particles in final states with large jet multiplicities and missing transverse energy in pp̄ collisions at √s=1.96TeV

Physical Review Letters 107:19 (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, M Bentivegna, 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

Abstract:

We present a search for a new particle T′ decaying to a top quark via T′→t+X, where X goes undetected. We use a data sample corresponding to 5.7fb-1 of integrated luminosity of pp̄ collisions with √s=1.96TeV, collected at Fermilab Tevatron by the CDF II detector. Our search for pair production of T′ is focused on the hadronic decay channel, pp̄→T′T ̄′→tt̄+XX̄→bqq̄b̄ qq̄+XX̄. We interpret our results in terms of a model where T ′ is an exotic fourth generation quark and X is a dark matter particle. The data are consistent with standard model expectations. We set a limit on the generic production of T′T̄′→tt̄+XX̄, excluding the fourth generation exotic quarks T′ at 95% confidence level up to m T′=400GeV/c2 for mX≤70GeV/c2. © 2011 American Physical Society.

Improved search for Muon-neutrino to electron-neutrino oscillations in MINOS.

Phys Rev Lett 107:18 (2011) 181802

Authors:

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, MINOS Collaboration

Abstract:

We report the results of a search for ν(e) appearance in a ν(μ) beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of 8.2 × 10(20) protons on the NuMI target at Fermilab, we find that 2 sin(2) (θ(23))sin(2)(2θ(13))<0.12(0.20) at 90% confidence level for δ = 0 and the normal (inverted) neutrino mass hierarchy, with a best-fit of 2sin(2) (θ(23))sin(2)(2θ(13)) = 0.041(-0.031)(+0.047) (0.079(-0.053) (+0.071)). The θ(13) = 0 hypothesis is disfavored by the MINOS data at the 89% confidence level.

Search for resonant production of tt̄ pairs in 4.8fb-1 of integrated luminosity of pp̄ collisions at √s=1.96TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 84:7 (2011)

Authors:

T Aaltonen, B Alvarez González, 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, 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, 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 Clark, 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

Abstract:

We search for resonant production of tt̄ pairs in 4.8fb-1 integrated luminosity of pp̄ collision data at √s=1.96TeV in the lepton+jets decay channel, where one top quark decays leptonically and the other hadronically. A matrix-element reconstruction technique is used; for each event a probability density function of the tt̄ candidate invariant mass is sampled. These probability density functions are used to construct a likelihood function, whereby the cross section for resonant tt̄ production is estimated, given a hypothetical resonance mass and width. The data indicate no evidence of resonant production of tt̄ pairs. A benchmark model of leptophobic Z′→tt̄ is excluded with m Z′<900GeV/c2 at 95% confidence level. © 2011 American Physical Society.

The 2010 Interim Report of the Long-Baseline Neutrino Experiment Collaboration Physics Working Groups

(2011)

Authors:

T Akiri, D Allspach, M Andrews, K Arisaka, E Arrieta-Diaz, M Artuso, X Bai, B Balantekin, B Baller, W Barletta, G Barr, M Bass, A Beck, B Becker, V Bellini, O Benhar, B Berger, M Bergevin, E Berman, H Berns, A Bernstein, F Beroz, V Bhatnagar, B Bhuyan, R Bionta, M Bishai, A Blake, E Blaufuss, B Bleakley, E Blucher, S Blusk, D Boehnlein, T Bolton, J Brack, R Bradford, R Breedon, C Bromberg, R Brown, N Buchanan, L Camilleri, M Campbell, R Carr, G Carminati, A Chen, H Chen, D Cherdack, C Chi, S Childress, B Choudhary

Abstract:

In early 2010, the Long-Baseline Neutrino Experiment (LBNE) science collaboration initiated a study to investigate the physics potential of the experiment with a broad set of different beam, near- and far-detector configurations. Nine initial topics were identified as scientific areas that motivate construction of a long-baseline neutrino experiment with a very large far detector. We summarize the scientific justification for each topic and the estimated performance for a set of far detector reference configurations. We report also on a study of optimized beam parameters and the physics capability of proposed Near Detector configurations. This document was presented to the collaboration in fall 2010 and updated with minor modifications in early 2011.