Accelerator Neutrinos

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Precision electroweak measurements on the Z resonance

Physics Reports 427:5-6 (2006) 257-454

Authors:

JA Bagger, M Grünewald, S Schael, R Barate, R Brunelière, D Buskulic, I De Bonis, D Decamp, P Ghez, C Goy, S Jézéquel, JP Lees, A Lucotte, F Martin, E Merle, MN Minard, JY Nief, P Odier, B Pietrzyk, B Trocmé, S Bravo, MP Casado, M Chmeissani, P Comas, JM Crespo, E Fernandez, M Fernandez-Bosman, L Garrido, E Grauges, A Juste, M Martinez, G Merino, R Miquel, LM Mir, S Orteu, A Pacheco, IC Park, J Perlas, I Riu, H Ruiz, F Sanchez, A Colaleo, D Creanza, N De Filippis, M De Palma, G Iaselli, G Maggi, M Maggi, S Nuzzo, A Ranieri, G Raso, F Ruggieri, G Selvaggi, L Silvestris, P Tempesta, A Tricomi, G Zito, X Huang, J Lin, Q Ouyang, T Wang, Y Xie, R Xu, S Xue, J Zhang, L Zhang, W Zhao, D Abbaneo, A Bazarko, U Becker, G Boix, F Bird, E Blucher, B Bonvicini, P Bright-Thomas, T Barklow, O Buchmüller, M Cattaneo, F Cerutti, V Ciulli, B Clerbaux, H Drevermann, RW Forty, M Frank, TC Greening, R Hagelberg, AW Halley, F Gianotti, M Girone, JB Hansen, J Harvey, R Jacobsen, DE Hutchcroft, P Janot, B Jost, J Knobloch, M Kado, I Lehraus, P Lazeyras, P Maley

Abstract:

We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLD experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, mZ and ΓZ, and its couplings to fermions, for example the ρ parameter and the effective electroweak mixing angle for leptons, are precisely measured: mZ = 91.1875 ± 0.0021 GeV, ΓZ = 2.4952 ± 0.0023 GeV, ρl = 1.0050 ± 0.0010, sin2 θlepteff = 0.23153 ± 0.00016. The number of light neutrino species is determined to be 2.9840 ± 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, mt = 173+13-10 GeV, and the mass of the W boson, mW = 80.363 ± 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of mt and mW, the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level.
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Search for charged Higgs bosons from top quark decays in pp̄ collisions at s=1.96TeV

Physical Review Letters 96:4 (2006)

Authors:

A Abulencia, D Acosta, J Adelman, T Affolder, T Akimoto, MG Albrow, D Ambrose, S Amerio, D Amidei, A Anastassov, K Anikeev, A Annovi, J Antos, M Aoki, G Apollinari, JF Arguin, T Arisawa, A Artikov, W Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, J Bellinger, A Belloni, E Ben-Haim, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, S Bourov, A Boveia, B Brau, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carron, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, J Chapman, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, JP Chou, PH Chu, SH Chuang, K Chung, WH Chung

Abstract:

We report the results of a search for a charged Higgs boson in the decays of top quarks produced in pp̄ collisions at a center-of-mass energy of 1.96 TeV. We use a data sample corresponding to an integrated luminosity of 193pb-1 collected by the upgraded Collider Detector at Fermilab. No evidence for charged Higgs production is found, allowing 95% C.L. upper limits to be placed on BR(t→H+b) for different charged Higgs decay scenarios. In addition, we present in the minimal supersymmetric standard model (mH±,tan β) plane the first exclusion regions with radiative and Yukawa coupling corrections. © 2006 The American Physical Society.
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Search for excited and exotic muons in the μy decay channel in pp - collisions at s=1.96 TeV

Physical Review Letters 97:19 (2006)

Authors:

A Abulencia, D Acosta, J Adelman, T Affolder, T Akimoto, MG Albrow, D Ambrose, S Amerio, D Amidei, A Anastassov, K Anikeev, A Annovi, J Antos, M Aoki, G Apollinari, JF Arguin, T Arisawa, A Artikov, W Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, J Bellinger, A Belloni, E Ben Haim, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, A Boveia, B Brau, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, J Chapman, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, JP Chou, PH Chu, SH Chuang, K Chung, WH Chung, YS Chung, M Ciljak

Abstract:

We search for excited and exotic muon states * using an integrated luminosity of 371pb-1 of pp collision data at s=1.96TeV. We search for associated production of * followed by the decay *. We compare the data to model predictions as a function of the mass of the excited muon M *, the compositeness energy scale , and the gauge coupling factor f. No signal above the standard model expectation is observed. We exclude 107
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Search for resonant second generation slepton production at the Fermilab tevatron

Physical Review Letters 97:11 (2006)

Authors:

VM Abazov, B Abbott, M Abolins, BS Acharya, M Adams, T Adams, M Agelou, JL Agram, SH Ahn, M Ahsan, GD Alexeev, G Alkhazov, A Alton, G Alverson, GA Alves, M Anastasoaie, T Andeen, S Anderson, B Andrieu, MS Anzelc, Y Arnoud, M Arov, A Askew, B Åsman, ACS Assis Jesus, O Atramentov, C Autermann, C Avila, C Ay, F Badaud, A Baden, L Bagby, B Baldin, DV Bandurin, P Banerjee, S Banerjee, E Barberis, P Bargassa, P Baringer, C Barnes, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, M Begalli, M Begel, C Belanger-Champagne, L Bellantoni, A Bellavance, JA Benitez, SB Beri, G Bernardi, R Bernhard, L Berntzon, I Bertram, M Besançon, R Beuselinck, VA Bezzubov, PC Bhat, V Bhatnagar, M Binder, C Biscarat, KM Black, I Blackler, G Blazey, F Blekman, S Blessing, D Bloch, K Bloom, U Blumenschein, A Boehnlein, O Boeriu, TA Bolton, F Borcherding, G Borissov, K Bos, T Bose, A Brandt, R Brock, G Brooijmans, A Bross, D Brown, NJ Buchanan, D Buchholz, M Buehler, V Buescher, S Burdin, S Burke, TH Burnett, E Busato, CP Buszello, JM Butler, P Calfayan, S Calvet, J Cammin, S Caron, W Carvalho, BCK Casey, NM Cason

Abstract:

We present a search for supersymmetry in the R-parity violating resonant production and decay of smuons and muon sneutrinos in the channels, 2,3,40. We analyzed 0.38fb-1 of integrated luminosity collected between April 2002 and August 2004 with the D0 detector at the Fermilab Tevatron Collider. The observed number of events is in agreement with the standard model expectation, and we calculate 95% C.L. limits on the slepton production cross section times branching fraction to gaugino plus muon, as a function of slepton and gaugino masses. In the framework of minimal supergravity, we set limits on the coupling parameter, extending significantly previous results obtained in Run I of the Tevatron and at the CERN LEP collider. © 2006 The American Physical Society.
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Low energy hadron production data and current status of CERN measurements

NUCL PHYS B-PROC SUP 151 (2006) 175-182

Authors:

G Barr, R Engel

Abstract:

Data on low-energy hadron production in collisions of nucleons, pions and kaons with light nuclei are needed for many astrophysical and accelerator applications. Modern simulations have reached a level of accuracy that the lack of detailed understanding of hadron production processes has become one of the most important limitations to further improvements. After giving some examples of hadro-production processes in astrophysics and neutrino experiments we briefly review existing fixed-target data on light nuclei. Preliminary results and prospects of current CERN measurements (HARP, NA49) are discussed.
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