Accelerator Neutrinos

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Search for 3- and 4-body decays of the scalar top quark in pp̄ collisions at √s=1.8 TeV

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 581:3-4 (2004) 147-155

Authors:

VM Abazov, B Abbott, A Abdesselam, M Abolins, V Abramov, BS Acharya, DL Adams, M Adams, SN Ahmed, GD Alexeev, A Alton, GA Alves, EW Anderson, Y Arnoud, C Avila, VV Babintsev, L Babukhadia, TC Bacon, A Baden, S Baffioni, B Baldin, PW Balm, S Banerjee, E Barberis, P Baringer, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, F Beaudette, M Begel, A Belyaev, SB Beri, G Bernardi, I Bertram, A Besson, R Beuselinck, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, G Blazey, F Blekman, S Blessing, A Boehnlein, NI Bojko, TA Bolton, F Borcherding, K Bos, T Bose, A Brandt, R Breedon, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, M Buehler, V Buescher, VS Burtovoi, JM Butler, F Canelli, W Carvalho, D Casey, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, DK Cho, S Choi, S Chopra, D Claes, AR Clark, L Coney, B Connolly, WE Cooper, D Coppage, S Crépé-Renaudin, MAC Cummings, D Cutts, H da Motta, GA Davis, K De, SJ de Jong, M Demarteau, R Demina, P Demine, D Denisov, SP Denisov, S Desai, HT Diehl, M Diesburg, S Doulas, LV Dudko, S Duensing, L Duflot, SR Dugad, A Duperrin, A Dyshkant

Abstract:

We have searched for the signature of 3- and 4-body decays of pair-produced scalar top quarks (stop) in the inclusive final state containing an electron, a muon, and significant missing transverse energy using a sample of pp̄ events corresponding to 108.3 pb-1 of data collected with the DØ detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the neutralino (χ̃10) is the lightest supersymmetric particle and is stable. No evidence for a signal is found and we derive cross-section upper limits as a function of stop (t̃) and neutralino masses in different decay scenarios leading to the bℓνχ̃10 final state. © 2004 Published by Elsevier B.V.
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First observation of the KS → π0γ γ decay

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 578:3-4 (2004) 276-284

Authors:

A Lai, D Marras, JR Batley, RS Dosanjh, TJ Gershon, GE Kalmus, C Lazzeroni, DJ Munday, E Olaiya, MA Parker, TO White, SA Wotton, R Arcidiacono, G Barr, G Bocquet, A Ceccucci, T Cuhadar-Dönszelmann, D Cundy, N Doble, V Falaleev, L Gatignon, A Gonidec, B Gorini, P Grafström, W Kubischta, A Lacourt, A Norton, B Panzer-Steindel, G Tatishvili, H Wahl, C Cheshkov, P Hristov, V Kekelidze, D Madigojine, N Molokanova, Y Potrebenikov, A Zinchenko, V Martin, P Rubin, R Sacco, A Walker, M Contalbrigo, P Dalpiaz, J Duclos, PL Frabetti, A Gianoli, M Martini, F Petrucci, M Savrié, A Bizzeti, M Calvetti, G Collazuol, G Graziani, E Iacopini, M Lenti, F Martelli, M Veltri, M Eppard, A Hirstius, K Holtz, K Kleinknecht, U Koch, L Köpke, P Lopes da Silva, P Marouelli, I Mestvirishvili, I Pellmann, A Peters, SA Schmidt, V Schönharting, Y Schué, R Wanke, A Winhart, M Wittgen, JC Chollet, L Fayard, L Iconomidou-Fayard, G Unal, I Wingerter-Seez, G Anzivino, P Cenci, E Imbergamo, P Lubrano, A Mestvirishvili, A Nappi, M Pepe, M Piccini, R Casali, C Cerri, M Cirilli, F Costantini, R Fantechi, L Fiorini, S Giudici, I Mannelli, G Pierazzini, M Sozzi, JB Cheze, M De Beer, P Debu

Abstract:

Using the NA48 detector at the CERN SPS, 31 KS → π 0γγ candidates with an estimated background of 13.7 ± 3.2 events have been observed. This first observation leads to a branching ratio of BR(KS → π0γγ) z>0.2 = (4.9 ± 1.6stat ± 0.9 syst) × 10-8 in agreement with Chiral Perturbation Theory predictions. © 2003 Elsevier B.V. All rights reserved.
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Combination of CDF and D0 results on the W boson mass and width

Physical Review D - Particles, Fields, Gravitation and Cosmology 70:9 (2004)

Authors:

VM Abazov, B Abbott, A Abdesselam, M Abolins, V Abramov, BS Acharya, D Acosta, DL Adams, M Adams, T Affolder, SN Ahmed, H Akimoto, A Akopian, MG Albrow, GD Alexeev, A Alton, GA Alves, P Amaral, D Ambrose, SR Amendolia, D Amidei, K Anikeev, J Antos, G Apollinari, Y Arnoud, T Arisawa, A Artikov, T Asakawa, C Avila, W Ashmanskas, M Atac, F Azfar, P Azzi-Bacchetta, VV Babintsev, L Babukhadia, N Bacchetta, H Bachacou, TC Bacon, A Baden, W Badgett, S Baffioni, MW Bailey, S Bailey, B Baldin, PW Balm, S Banerjee, P de Barbaro, A Barbaro-Galtieri, E Barberis, P Baringer, VE Barnes, BA Barnett, S Baroiant, M Barone, J Barreto, JF Bartlett, U Bassler, D Bauer, G Bauer, A Bean, F Beaudette, F Bedeschi, S Behari, M Begel, S Belforte, WH Bell, G Bellettini, J Bellinger, A Belyaev, D Benjamin, J Bensinger, A Beretvas, JP Berge, SB Beri, G Bernardi, I Bertram, J Berryhill, A Besson, R Beuselinck, B Bevensee, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, G Blazey, F Blekman, S Blessing, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, A Boehnlein, NI Bojko

Abstract:

The results based on 1992-95 data (Run 1) from the CDF and D0 experiments on the measurements of the W boson mass and width are presented, along with the combined results. We report a Tevatron collider average MW = 80.456 ± 0.059 GeV. We also report the Tevatron collider average of the directly measured W boson width TW = 2.115 ± 0.105 GeV. We describe a new joint analysis of the direct W mass and width measurements. Assuming the validity of the standard model, we combine the directly measured W boson width with the width extracted from the ratio of W and Z boson leptonic partial cross sections. This combined result for the Tevatron is TW = 2.135 ± 0.050 GeV. Finally, we use the measurements of the direct total W width and the leptonic branching ratio to extract the leptonic partial width Γ(W → eν) = 224 ± 13 MeV.
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Measurement of the average time-integrated mixing probability of b-flavored hadrons produced at the Fermilab Tevatron

Physical Review D - Particles, Fields, Gravitation and Cosmology 69:1 (2004)

Authors:

D Acosta, T Affolder, H Akimoto, MG Albrow, D Ambrose, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, W Badgett, S Bailey, P Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Behari, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, J Berryhill, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, G Bolla, A Bolshov, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, C Bromberg, M Brozovic, E Brubaker, N Bruner, J Budagov, HS Budd, K Burkett, G Busetto, KL Byrum, S Cabrera, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, W Caskey, A Castro, D Cauz, A Cerri, L Cerrito, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, M Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, JY Chung, W Chung, YS Chung, CI Ciobanu, AG Clark, M Coca, A Connolly, M Convery, J Conway, M Cordelli, J Cranshaw, R Culbertson, D Dagenhart

Abstract:

We have measured the number of like-sign (LS) and opposite-sign (OS) lepton pairs arising from double semileptonic decays of b and [Formula Presented] hadrons, pair produced at the Fermilab Tevatron collider. The data samples were collected with the Collider Detector at Fermilab during the 1992–1995 collider run by triggering on the existence of [Formula Presented] or [Formula Presented] candidates in an event. The observed ratio of LS to OS dileptons leads to a measurement of the average time-integrated mixing probability of all produced b-flavored hadrons which decay weakly, [Formula Presented] that is significantly larger than the world average [Formula Presented] © 2004 The American Physical Society.
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Search for new particles in the two-jet decay channel with the DØ detector

Physical Review D Particles Fields Gravitation and Cosmology 69:11 (2004)

Authors:

VM Abazov, B Abbott, A Abdesselam, M Abolins, V Abramov, BS Acharya, DL Adams, M Adams, SN Ahmed, GD Alexeev, A Alton, GA Alves, EW Anderson, Y Arnoud, C Avila, VV Babintsev, L Babukhadia, TC Bacon, A Baden, S Baffioni, B Baldin, PW Balm, S Banerjee, E Barberis, P Baringer, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, F Beaudette, M Begel, A Belyaev, SB Beri, G Bernardi, I Bertram, A Besson, R Beuselinck, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, G Blazey, F Blekman, S Blessing, A Boehnlein, NI Bojko, TA Bolton, F Borcherding, K Bos, T Bose, A Brandt, G Briskin, R Brock, G Brooijmans, A Bross, D Buchholz, M Buehler, V Buescher, VS Burtovoi, JM Butler, F Canelli, W Carvalho, D Casey, H Castilla-Valdez, D Chakraborty, KM Chan, SV Chekulaev, DK Cho, S Choi, S Chopra, D Claes, AR Clark, B Connolly, WE Cooper, D Coppage, S Crépé-Renaudin, M Cummings, D Cutts, H Motta, GA Davis, K De, SJ Jong, M Demarteau, R Demina, P Demine, D Denisov, SP Denisov, S Desai, HT Diehl, M Diesburg, S Doulas, LV Dudko, S Duensing, L Duflot, SR Dugad, A Duperrin, A Dyshkant, D Edmunds, J Ellison

Abstract:

We present the results of a search for the production of new particles decaying into two jets in [Formula Presented]collisions at [Formula Presented] using the DØ 1992–1995 data set corresponding to [Formula Presented] We exclude at the 95% confidence level the production of excited quarks [Formula Presented] with masses below 775 GeV/[Formula Presented] the most restrictive limit to date. We also exclude standard-model-like [Formula Presented][Formula Presented] bosons with masses between 300 and 800 GeV/[Formula Presented](400 and 640 GeV/[Formula Presented] A [Formula Presented]boson with mass [Formula Presented] has been excluded by previous measurements, and our lower limit is therefore the most stringent to date. © 2004 The American Physical Society.
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