Search for exclusive gammagamma production in Hadron-Hadron collisions.

Phys Rev Lett 99:24 (2007) 242002

Authors:

T Aaltonen, A Abulencia, J Adelman, T Affolder, T Akimoto, MG Albrow, S Amerio, D Amidei, A Anastassov, K Anikeev, A Annovi, J Antos, M Aoki, G Apollinari, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, P-H Beauchemin, F Bedeschi, S Behari, G Bellettini, J Bellinger, A Belloni, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, A Boveia, B Brau, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, S Carrillo, D Carlsmith, B Caron, R Carosi, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, M Cilijak, CI Ciobanu, MA Ciocci, A Clark, D Clark, M Coca, G Compostella, ME Convery, J Conway, B Cooper, K Copic, M Cordelli, G Cortiana, F Crescioli, C Cuenca Almenar, J Cuevas, R Culbertson, JC Cully, S Daronco, M Datta, S D'Auria, T Davies, D Dagenhart, P de Barbaro, S De Cecco, A Deisher, G De Lentdecker, G De Lorenzo, M Dell'orso, F Delli Paoli, L Demortier, J Deng, M Deninno, D De Pedis, PF Derwent, GP Di Giovanni, C Dionisi, B Di Ruzza, JR Dittmann, M D'Onofrio, C Dörr, S Donati, P Dong, J Donini, T Dorigo, S Dube, J Efron, R Erbacher, D Errede, S Errede, R Eusebi, HC Fang, S Farrington, I Fedorko, WT Fedorko, RG Feild, M Feindt, JP Fernandez, R Field, G Flanagan, R Forrest, S Forrester, M Franklin, JC Freeman, I Furic, M Gallinaro, J Galyardt, JE Garcia, F Garberson, AF Garfinkel, C Gay, H Gerberich, D Gerdes, S Giagu, P Giannetti, K Gibson, JL Gimmell, C Ginsburg, N Giokaris, M Giordani, P Giromini, M Giunta, G Giurgiu, V Glagolev, D Glenzinski, M Gold, N Goldschmidt, J Goldstein, A Golossanov, G Gomez, G Gomez-Ceballos, M Goncharov, O González, I Gorelov, AT Goshaw, K Goulianos, A Gresele, S Grinstein, C Grosso-Pilcher, U Grundler, J Guimaraes da Costa, Z Gunay-Unalan, C Haber, K Hahn, SR Hahn, E Halkiadakis, A Hamilton, B-Y Han, JY Han, R Handler, F Happacher, K Hara, D Hare, M Hare, S Harper, RF Harr, RM Harris, M Hartz, K Hatakeyama, J Hauser, C Hays, M Heck, A Heijboer, B Heinemann, J Heinrich, C Henderson, M Herndon, J Heuser, D Hidas, CS Hill, D Hirschbuehl, A Hocker, A Holloway, S Hou, M Houlden, S-C Hsu, BT Huffman, RE Hughes, U Husemann, J Huston, J Incandela, G Introzzi, M Iori, A Ivanov, B Iyutin, E James, D Jang, B Jayatilaka, D Jeans, EJ Jeon, S Jindariani, W Johnson, M Jones, KK Joo, SY Jun, JE Jung, TR Junk, T Kamon, PE Karchin, Y Kato, Y Kemp, R Kephart, U Kerzel, V Khotilovich, B Kilminster, DH Kim, HS Kim, JE Kim, MJ Kim, SB Kim, SH Kim, YK Kim, N Kimura, L Kirsch, S Klimenko, M Klute, B Knuteson, BR Ko, K Kondo, DJ Kong, J Konigsberg, A Korytov, AV Kotwal, AC Kraan, J Kraus, M Kreps, J Kroll, N Krumnack, M Kruse, V Krutelyov, T Kubo, SE Kuhlmann, T Kuhr, NP Kulkarni, Y Kusakabe, S Kwang, AT Laasanen, S Lai, S Lami, S Lammel, M Lancaster, RL Lander, K Lannon, A Lath, G Latino, I Lazzizzera, T Lecompte, J Lee, J Lee, YJ Lee, SW Lee, R Lefèvre, N Leonardo, S Leone, S Levy, JD Lewis, C Lin, CS Lin, M Lindgren, E Lipeles, A Lister, DO Litvintsev, T Liu, NS Lockyer, A Loginov, M Loreti, R-S Lu, D Lucchesi, P Lujan, P Lukens, G Lungu, L Lyons, J Lys, R Lysak, E Lytken, P Mack, D Macqueen, R Madrak, K Maeshima, K Makhoul, T Maki, P Maksimovic, S Malde, S Malik, G Manca, A Manousakis, F Margaroli, R Marginean, C Marino, CP Marino, A Martin, M Martin, V Martin, M Martínez, R Martínez-Ballarín, T Maruyama, P Mastrandrea, T Masubuchi, H Matsunaga, ME Mattson, R Mazini, P Mazzanti, KS McFarland, P McIntyre, R McNulty, A Mehta, P Mehtala, S Menzemer, A Menzione, P Merkel, C Mesropian, A Messina, T Miao, N Miladinovic, J Miles, R Miller, C Mills, M Milnik, A Mitra, G Mitselmakher, A Miyamoto, S Moed, N Moggi, B Mohr, CS Moon, R Moore, M Morello, P Movilla Fernandez, J Mülmenstädt, A Mukherjee, Th Muller, R Mumford, P Murat, M Mussini, J Nachtman, A Nagano, J Naganoma, K Nakamura, I Nakano, A Napier, V Necula, C Neu, MS Neubauer, J Nielsen, L Nodulman, O Norniella, E Nurse, SH Oh, YD Oh, I Oksuzian, T Okusawa, R Oldeman, R Orava, K Osterberg, C Pagliarone, E Palencia, V Papadimitriou, A Papaikonomou, AA Paramonov, B Parks, S Pashapour, J Patrick, G Pauletta, M Paulini, C Paus, DE Pellett, A Penzo, TJ Phillips, G Piacentino, J Piedra, L Pinera, J Pinfold, K Pitts, C Plager, L Pondrom, X Portell, O Poukhov, N Pounder, F Prakoshyn, A Pronko, J Proudfoot, F Ptohos, G Punzi, J Pursley, J Rademacker, A Rahaman, V Ramakrishnan, N Ranjan, I Redondo, B Reisert, V Rekovic, P Renton, M Rescigno, S Richter, F Rimondi, L Ristori, A Robson, T Rodrigo, E Rogers, S Rolli, R Roser, M Rossi, R Rossin, P Roy, A Ruiz, J Russ, V Rusu, H Saarikko, A Safonov, WK Sakumoto, G Salamanna, O Saltó, L Santi, S Sarkar, L Sartori, K Sato, P Savard, A Savoy-Navarro, T Scheidle, P Schlabach, EE Schmidt, MP Schmidt, M Schmitt, T Schwarz, L Scodellaro, AL Scott, A Scribano, F Scuri, A Sedov, S Seidel, Y Seiya, A Semenov, L Sexton-Kennedy, A Sfyrla, SZ Shalhout, MD Shapiro, T Shears, PF Shepard, D Sherman, M Shimojima, M Shochet, Y Shon, I Shreyber, A Sidoti, P Sinervo, A Sisakyan, AJ Slaughter, J Slaunwhite, K Sliwa, JR Smith, FD Snider, R Snihur, M Soderberg, A Soha, S Somalwar, V Sorin, J Spalding, F Spinella, T Spreitzer, P Squillacioti, M Stanitzki, A Staveris-Polykalas, R St Denis, B Stelzer, O Stelzer-Chilton, D Stentz, J Strologas, D Stuart, JS Suh, A Sukhanov, H Sun, I Suslov, T Suzuki, A Taffard, R Takashima, Y Takeuchi, R Tanaka, M Tecchio, PK Teng, K Terashi, J Thom, AS Thompson, E Thomson, P Tipton, V Tiwari, S Tkaczyk, D Toback, S Tokar, K Tollefson, T Tomura, D Tonelli, S Torre, D Torretta, S Tourneur, W Trischuk, S Tsuno, Y Tu, N Turini, F Ukegawa, S Uozumi, S Vallecorsa, N van Remortel, A Varganov, E Vataga, F Vazquez, G Velev, C Vellidis, G Veramendi, V Veszpremi, M Vidal, R Vidal, I Vila, R Vilar, T Vine, M Vogel, I Vollrath, I Volobouev, G Volpi, F Würthwein, P Wagner, RG Wagner, RL Wagner, J Wagner, W Wagner, R Wallny, SM Wang, A Warburton, D Waters, M Weinberger, WC Wester, B Whitehouse, D Whiteson, AB Wicklund, E Wicklund, G Williams, HH Williams, P Wilson, BL Winer, P Wittich, S Wolbers, C Wolfe, T Wright, X Wu, SM Wynne, A Yagil, K Yamamoto, J Yamaoka, T Yamashita, C Yang, UK Yang, YC Yang, WM Yao, GP Yeh, J Yoh, K Yorita, T Yoshida, GB Yu, I Yu, SS Yu, JC Yun, L Zanello, A Zanetti, I Zaw, X Zhang, J Zhou, S Zucchelli, CDF Collaboration

Abstract:

We have searched for exclusive gammagamma production in proton-antiproton collisions at sqrt[s]=1.96 TeV, using 532 pb(-1) of integrated luminosity taken by the run II Collider Detector at Fermilab. The event signature requires two electromagnetic showers, each with transverse energy E(T)>5 GeV and pseudorapidity |eta|<1.0, with no other particles detected in the event. Three candidate events are observed. We discuss the consistency of the three events with gammagamma, pi(0)pi(0), or eta eta production. The probability that other processes fluctuate to >or=3 events is 1.7x10(-4). An upper limit on the cross section of pp-->p + gammagamma + p production is set at 410 fb with 95% confidence level.

Search for exclusive γγ production in hadron-hadron collisions

Physical Review Letters 99:24 (2007)

Authors:

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

Abstract:

We have searched for exclusive γγ production in proton-antiproton collisions at s=1.96TeV, using 532pb-1 of integrated luminosity taken by the run II Collider Detector at Fermilab. The event signature requires two electromagnetic showers, each with transverse energy ET>5GeV and pseudorapidity |η|<1.0, with no other particles detected in the event. Three candidate events are observed. We discuss the consistency of the three events with γγ, π0π0, or ηη production. The probability that other processes fluctuate to 3 events is 1.7×10-4. An upper limit on the cross section of pp̄→p+γγ+p̄ production is set at 410 fb with 95% confidence level. © 2007 The American Physical Society.

Study of the decay Bs(0)-->Ds(*)Ds(*).

Phys Rev Lett 99:24 (2007) 241801

Authors:

VM Abazov, B Abbott, M Abolins, BS Acharya, M Adams, T Adams, E Aguilo, SH Ahn, M Ahsan, GD Alexeev, G Alkhazov, A Alton, G Alverson, GA Alves, M Anastasoaie, LS Ancu, T Andeen, S Anderson, B Andrieu, MS Anzelc, Y Arnoud, M Arov, A Askew, B Asman, 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, A-F Barfuss, P Bargassa, P Baringer, J Barreto, JF Bartlett, U Bassler, D Bauer, S Beale, 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, G Blazey, F Blekman, S Blessing, D Bloch, K Bloom, A Boehnlein, D Boline, TA Bolton, 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, H Castilla-Valdez, S Chakrabarti, D Chakraborty, K Chan, KM Chan, A Chandra, F Charles, E Cheu, F Chevallier, DK Cho, S Choi, B Choudhary, L Christofek, T Christoudias, S Cihangir, D Claes, B Clément, C Clément, Y Coadou, M Cooke, WE Cooper, M Corcoran, F Couderc, M-C Cousinou, S Crépé-Renaudin, D Cutts, M Cwiok, H da Motta, A Das, G Davies, K De, P de Jong, SJ de Jong, E De La Cruz-Burelo, C De Oliveira Martins, JD Degenhardt, F Déliot, M Demarteau, R Demina, D Denisov, SP Denisov, S Desai, HT Diehl, M Diesburg, A Dominguez, H Dong, LV Dudko, L Duflot, SR Dugad, D Duggan, A Duperrin, J Dyer, A Dyshkant, M Eads, D Edmunds, J Ellison, VD Elvira, Y Enari, S Eno, P Ermolov, H Evans, A Evdokimov, VN Evdokimov, AV Ferapontov, T Ferbel, F Fiedler, F Filthaut, W Fisher, HE Fisk, M Ford, M Fortner, H Fox, S Fu, S Fuess, T Gadfort, CF Galea, E Gallas, E Galyaev, C Garcia, A Garcia-Bellido, V Gavrilov, P Gay, W Geist, D Gelé, CE Gerber, Y Gershtein, D Gillberg, G Ginther, N Gollub, B Gómez, A Goussiou, PD Grannis, H Greenlee, ZD Greenwood, EM Gregores, G Grenier, Ph Gris, J-F Grivaz, A Grohsjean, S Grünendahl, MW Grünewald, F Guo, J Guo, G Gutierrez, P Gutierrez, A Haas, NJ Hadley, P Haefner, S Hagopian, J Haley, I Hall, RE Hall, L Han, K Hanagaki, P Hansson, K Harder, A Harel, R Harrington, JM Hauptman, R Hauser, J Hays, T Hebbeker, D Hedin, JG Hegeman, JM Heinmiller, AP Heinson, U Heintz, C Hensel, K Herner, G Hesketh, MD Hildreth, R Hirosky, JD Hobbs, B Hoeneisen, H Hoeth, M Hohlfeld, SJ Hong, R Hooper, P Houben, Y Hu, Z Hubacek, V Hynek, I Iashvili, R Illingworth, AS Ito, S Jabeen, M Jaffré, S Jain, K Jakobs, C Jarvis, R Jesik, K Johns, C Johnson, M Johnson, A Jonckheere, P Jonsson, A Juste, D Käfer, S Kahn, E Kajfasz, AM Kalinin, JM Kalk, JR Kalk, S Kappler, D Karmanov, J Kasper, P Kasper, I Katsanos, D Kau, R Kaur, V Kaushik, R Kehoe, S Kermiche, N Khalatyan, A Khanov, A Kharchilava, YM Kharzheev, D Khatidze, H Kim, TJ Kim, MH Kirby, B Klima, JM Kohli, J-P Konrath, M Kopal, VM Korablev, J Kotcher, B Kothari, A Koubarovsky, AV Kozelov, D Krop, A Kryemadhi, T Kuhl, A Kumar, S Kunori, A Kupco, T Kurca, J Kvita, D Lam, S Lammers, G Landsberg, J Lazoflores, P Lebrun, WM Lee, A Leflat, F Lehner, V Lesne, J Leveque, P Lewis, J Li, L Li, QZ Li, SM Lietti, JGR Lima, D Lincoln, J Linnemann, VV Lipaev, R Lipton, Z Liu, L Lobo, A Lobodenko, M Lokajicek, A Lounis, P Love, HJ Lubatti, M Lynker, AL Lyon, AKA Maciel, RJ Madaras, P Mättig, C Magass, A Magerkurth, N Makovec, PK Mal, HB Malbouisson, S Malik, VL Malyshev, HS Mao, Y Maravin, B Martin, R McCarthy, A Melnitchouk, A Mendes, L Mendoza, PG Mercadante, M Merkin, KW Merritt, A Meyer, J Meyer, M Michaut, H Miettinen, T Millet, J Mitrevski, J Molina, RK Mommsen, NK Mondal, J Monk, RW Moore, T Moulik, GS Muanza, M Mulders, M Mulhearn, O Mundal, L Mundim, E Nagy, M Naimuddin, M Narain, NA Naumann, HA Neal, JP Negret, P Neustroev, H Nilsen, C Noeding, A Nomerotski, SF Novaes, T Nunnemann, V O'Dell, DC O'Neil, G Obrant, C Ochando, V Oguri, N Oliveira, D Onoprienko, N Oshima, J Osta, R Otec, GJ Otero y Garzón, M Owen, P Padley, M Pangilinan, N Parashar, S-J Park, SK Park, J Parsons, R Partridge, N Parua, A Patwa, G Pawloski, PM Perea, K Peters, Y Peters, P Pétroff, M Petteni, R Piegaia, J Piper, M-A Pleier, PLM Podesta-Lerma, VM Podstavkov, Y Pogorelov, M-E Pol, A Pompos, BG Pope, AV Popov, C Potter, WL Prado da Silva, HB Prosper, S Protopopescu, J Qian, A Quadt, B Quinn, MS Rangel, KJ Rani, K Ranjan, PN Ratoff, P Renkel, S Reucroft, M Rijssenbeek, I Ripp-Baudot, F Rizatdinova, S Robinson, RF Rodrigues, C Royon, P Rubinov, R Ruchti, G Sajot, A Sánchez-Hernández, MP Sanders, A Santoro, G Savage, L Sawyer, T Scanlon, D Schaile, RD Schamberger, Y Scheglov, H Schellman, P Schieferdecker, C Schmitt, C Schwanenberger, A Schwartzman, R Schwienhorst, J Sekaric, S Sengupta, H Severini, E Shabalina, M Shamim, V Shary, AA Shchukin, RK Shivpuri, D Shpakov, V Siccardi, RA Sidwell, V Simak, V Sirotenko, P Skubic, P Slattery, D Smirnov, RP Smith, GR Snow, J Snow, S Snyder, S Söldner-Rembold, L Sonnenschein, A Sopczak, M Sosebee, K Soustruznik, M Souza, B Spurlock, J Stark, J Steele, V Stolin, DA Stoyanova, J Strandberg, S Strandberg, MA Strang, M Strauss, R Ströhmer, D Strom, M Strovink, L Stutte, S Sumowidagdo, P Svoisky, A Sznajder, M Talby, P Tamburello, A Tanasijczuk, W Taylor, P Telford, J Temple, B Tiller, F Tissandier, M Titov, VV Tokmenin, M Tomoto, T Toole, I Torchiani, T Trefzger, S Trincaz-Duvoid, D Tsybychev, B Tuchming, C Tully, PM Tuts, R Unalan, L Uvarov, S Uvarov, S Uzunyan, B Vachon, PJ van den Berg, B van Eijk, R Van Kooten, WM van Leeuwen, N Varelas, EW Varnes, A Vartapetian, IA Vasilyev, M Vaupel, P Verdier, LS Vertogradov, M Verzocchi, F Villeneuve-Seguier, P Vint, J-R Vlimant, E Von Toerne, M Voutilainen, M Vreeswijk, HD Wahl, J Walder, L Wang, MHLS Wang, J Warchol, G Watts, M Wayne, G Weber, M Weber, H Weerts, A Wenger, N Wermes, M Wetstein, A White, D Wicke, GW Wilson, SJ Wimpenny, M Wobisch, DR Wood, TR Wyatt, Y Xie, S Yacoob, R Yamada, M Yan, T Yasuda, YA Yatsunenko, K Yip, HD Yoo, SW Youn, C Yu, J Yu, A Yurkewicz, A Zatserklyaniy, C Zeitnitz, D Zhang, T Zhao, B Zhou, J Zhu, M Zielinski, D Zieminska, A Zieminski, V Zutshi, EG Zverev, D0 Collaboration

Abstract:

We report a study of the decay Bs(0)-->Ds(*)Ds(*) using a data sample corresponding to 1.3 fb(-1) of integrated luminosity collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron collider. One Ds(*) meson was partially reconstructed in the decay Ds-->phi mu nu, and the other Ds(*) meson was identified using the decay Ds-->phi pi where no attempt was made to distinguish Ds and Ds(*) states. For the branching fraction Br(Bs(0)-->Ds(*)Ds(*)) we obtain a 90% C.L. range [0.002,0.080] and central value 0.039(-0.017)(+0.019)(stat)(-0.015)(+0.016)(syst). This was subsequently used to make the most precise estimate of the width difference DeltaGamma(s)CP in the Bs(0)-Bs(0) system: DeltaGamma(s)CP/Gamma(s)=0.079(-0.035)(+0.038)(stat)(-0.030)(+0.031)(syst).

Study of the decay Bs0→Ds(*)Ds(*)

Physical Review Letters 99:24 (2007)

Authors:

VM Abazov, B Abbott, M Abolins, BS Acharya, M Adams, T Adams, E Aguilo, SH Ahn, M Ahsan, GD Alexeev, G Alkhazov, A Alton, G Alverson, GA Alves, M Anastasoaie, LS Ancu, 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, AF Barfuss, P Bargassa, P Baringer, J Barreto, JF Bartlett, U Bassler, D Bauer, S Beale, 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, G Blazey, F Blekman, S Blessing, D Bloch, K Bloom, A Boehnlein, D Boline, TA Bolton, 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, H Castilla-Valdez, S Chakrabarti, D Chakraborty

Abstract:

We report a study of the decay Bs0→Ds(*)Ds(*) using a data sample corresponding to 1.3fb-1 of integrated luminosity collected by the D0 experiment in 2002-2006 during run II of the Fermilab Tevatron collider. One Ds(*) meson was partially reconstructed in the decay Ds→ μν, and the other Ds(*) meson was identified using the decay Ds→ π where no attempt was made to distinguish Ds and Ds* states. For the branching fraction Br(Bs0→Ds(*)Ds(*)) we obtain a 90% C.L. range [0.002,0.080] and central value 0.039-0.017+0.019(stat)-0.015+0.016(syst). This was subsequently used to make the most precise estimate of the width difference ΔΓsCP in the Bs0-B̄s0 system: ΔΓsCP/ Γs=0.079-0.035+0.038(stat)-0.030+0.031(syst). © 2007 The American Physical Society.

First results of the trip-t based T2K front end electronics performance with GM-APD

Proceedings of Science (2007)

Authors:

A Vacheret, M Noy, M Raymond, A Weber

Abstract:

The TRIP-t front end board (TFB) will read out Geiger-mode multi-pixel Avalanche Photo-Diodes (GM-APD) in several T2K detector systems. We report the first tests of the TFB electronics with GM-APD. Measurements of GM-APD charge spectra, energy and time resolution have been performed. Individual channel voltage trimming circuit functionality has also been tested. These results indicate very good performance of the TFB prototype with both 400 and 100 pixels GMAPD from Hamamatsu photonics. © Copyright owned by the author(s).