Search for right-handed W bosons in top quark decay

Physical Review D - Particles, Fields, Gravitation and Cosmology 72:1 (2005) 1-8

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, Y Arnoud, A Askew, B Åsman, ACSA Jesus, O Atramentov, C Autermann, C Avila, F Badaud, A Baden, B Baldin, PW Balm, S Banerjee, E Barberis, P Bargassa, P Baringer, C Barnes, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, S Beauceron, M Begel, A Bellavance, SB Beri, G Bernardi, R Bernhard, 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, U Blumenschein, A Boehnlein, O Boeriu, TA Bolton, F Borcherding, G Borissov, K Bos, T Bose, A Brandt, R Brock, G Brooijmans, A Bross, NJ Buchanan, D Buchholz, M Buehler, V Buescher, S Burdin, TH Burnett, E Busato, CP Buszello, JM Butler, J Cammin, S Caron, W Carvalho, BCK Casey, NM Cason, H Castilla-Valdez, S Chakrabarti, D Chakraborty, KM Chan, A Chandra, D Chapin, F Charles, E Cheu, DK Cho, S Choi, B Choudhary, T Christiansen, L Christofek, D Claes

Abstract:

We present a measurement of the fraction f+ of right-handed W bosons produced in top quark decays, based on a candidate sample of tt̄ events in the lepton+jets decay mode. These data correspond to an integrated luminosity of 230pb-1, collected by the D0 detector at the Fermilab Tevatron pp̄ Collider at s=1.96TeV. We use a constrained fit to reconstruct the kinematics of the tt̄ and decay products, which allows for the measurement of the leptonic decay angle θ* for each event. By comparing the cos θ* distribution from the data with those for the expected background and signal for various values of f+, we find f+=0.00±0.13(stat) ±0.07(syst). This measurement is consistent with the standard model prediction of f+=3.6×10-4. © 2005 The American Physical Society.

Search for First-Generation Scalar Leptoquarks in $\bm{p \bar{p}}$ collisions at $\sqrt{s}$=1.96 TeV

(2005)

Authors:

The CDF Collaboration, 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, T Arisawa, J-F Arguin, A Artikov, W Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, GJ Barker, VE Barnes, BA Barnett, S Baroiant, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, J Bellinger, A Belloni, E Ben-Haim, D Benjamin, A Beretvas, T Berry, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, A Bocci, A Bodek, G Bolla, A Bolshov, D Bortoletto, J Boudreau, S Bourov, B Brau, C Bromberg, E Brubaker, J Budagov, HS Budd, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, M Casarsa, D Carlsmith, R Carosi, S Carron, M Cavalli-Sforza, A Castro, P Catastini, D Cauz, A Cerri, L Cerrito, J Chapman, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, JP Chou, S Chuang, K Chung, W-H Chung, YS Chung, M Cijliak, CI Ciobanu, MA Ciocci, AG Clark, D Clark, M Coca, A Connolly, M Convery, J Conway, B Cooper, K Copic, M Cordelli, G Cortiana, J Cranshaw, J Cuevas, A Cruz, R Culbertson, C Currat, D Cyr, D Dagenhart, S DaRonco, S D'Auria, P deBarbaro, S DeCecco, A Deisher, G DeLentdecker, M Dell'Orso, S Demers, L Demortier, M Deninno, D DePedis, PF Derwent, T Devlin, C Dionisi, JR Dittmann, P DiTuro, C Dörr, A Dominguez, S Donati, M Donega, J Donini, M D'Onofrio, T Dorigo, K Ebina, J Efron, J Ehlers, R Erbacher, M Erdmann, D Errede, S Errede, R Eusebi, H-C Fang, S Farrington, I Fedorko, WT Fedorko, RG Feild, M Feindt, JP Fernandez, RD Field, G Flanagan, LR Flores-Castillo, A Foland, S Forrester, GW Foster, M Franklin, JC Freeman, Y Fujii, I Furic, A Gajjar, M Gallinaro, J Galyardt, M Garcia-Sciveres, AF Garfinkel, C Gay, H Gerberich, DW Gerdes, E Gerchtein, S Giagu, P Giannetti, A Gibson, K Gibson, C Ginsburg, K Giolo, M Giordani, M Giunta, G Giurgiu, V Glagolev, D Glenzinski, M Gold, N Goldschmidt, D Goldstein, J Goldstein, G Gomez, G Gomez-Ceballos, M Goncharov, O González, I Gorelov, AT Goshaw, Y Gotra, K Goulianos, A Gresele, M Griffiths, C Grosso-Pilcher, U Grundler, J GuimaraesdaCosta, C Haber, K Hahn, SR Hahn, E Halkiadakis, A Hamilton, B-Y Han, R Handler, F Happacher, K Hara, M Hare, RF Harr, RM Harris, F Hartmann, K Hatakeyama, J Hauser, C Hays, H Hayward, B Heinemann, J Heinrich, M Hennecke, M Herndon, C Hill, D Hirschbuehl, A Hocker, KD Hoffman, A Holloway, S Hou, MA Houlden, BT Huffman, Y Huang, RE Hughes, J Huston, K Ikado, J Incandela, G Introzzi, M Iori, Y Ishizawa, C Issever, A Ivanov, Y Iwata, B Iyutin, E James, D Jang, B Jayatilaka, D Jeans, H Jensen, EJ Jeon, M Jones, KK Joo, SY Jun, T Junk, T Kamon, J Kang, M KaragozUnel, PE Karchin, Y Kato, Y Kemp, R Kephart, U Kerzel, V Khotilovich, B Kilminster, DH Kim, HS Kim, JE Kim, MJ Kim, MS Kim, SB Kim, SH Kim, YK Kim, M Kirby, L Kirsch, S Klimenko, M Klute, B Knuteson, BR Ko, H Kobayashi, DJ Kong, K Kondo, J Konigsberg, K Kordas, A Korn, A Korytov, AV Kotwal, A Kovalev, J Kraus, I Kravchenko, A Kreymer, J Kroll, M Kruse, V Krutelyov, SE Kuhlmann, S Kwang, AT Laasanen, S Lai, S Lami, S Lammel, M Lancaster, R Lander, K Lannon, A Lath, G Latino, I Lazzizzera, C Lecci, T LeCompte, J Lee, J Lee, SW Lee, R Lefèvre, N Leonardo, S Leone, S Levy, JD Lewis, K Li, C Lin, CS Lin, M Lindgren, E Lipeles, TM Liss, A Lister, DO Litvintsev, T Liu, Y Liu, NS Lockyer, A Loginov, M Loreti, P Loverre, R-S Lu, D Lucchesi, P Lujan, P Lukens, G Lungu, L Lyons, J Lys, R Lysak, E Lytken, D MacQueen, R Madrak, K Maeshima, P Maksimovic, G Manca, F Margaroli, R Marginean, C Marino, A Martin, M Martin, V Martin, M Martínez, T Maruyama, H Matsunaga, M Mattson, P Mazzanti, KS McFarland, D McGivern, PM McIntyre, P McNamara, R McNulty, A Mehta, S Menzemer, A Menzione, P Merkel, C Mesropian, A Messina, T Miao, N Miladinovic, J Miles, L Miller, R Miller, JS Miller, C Mills, R Miquel, S Miscetti, G Mitselmakher, A Miyamoto, N Moggi, B Mohr, R Moore, M Morello, PA MovillaFernandez, J Muelmenstaedt, A Mukherjee, M Mulhearn, T Muller, R Mumford, A Munar, P Murat, J Nachtman, S Nahn, I Nakano, A Napier, R Napora, D Naumov, V Necula, J Nielsen, T Nelson, C Neu, MS Neubauer, T Nigmanov, L Nodulman, O Norniella, T Ogawa, SH Oh, YD Oh, T Ohsugi, T Okusawa, R Oldeman, R Orava, W Orejudos, K Osterberg, C Pagliarone, E Palencia, R Paoletti, V Papadimitriou, AA Paramonov, S Pashapour, J Patrick, G Pauletta, M Paulini, C Paus, D Pellett, A Penzo, TJ Phillips, G Piacentino, J Piedra, KT Pitts, C Plager, L Pondrom, G Pope, X Portell, O Poukhov, N Pounder, F Prakoshyn, A Pronko, J Proudfoot, F Ptohos, G Punzi, J Rademacker, MA Rahaman, A Rakitine, S Rappoccio, F Ratnikov, H Ray, B Reisert, V Rekovic, P Renton, M Rescigno, F Rimondi, K Rinnert, L Ristori, WJ Robertson, A Robson, T Rodrigo, S Rolli, R Roser, R Rossin, C Rott, J Russ, V Rusu, A Ruiz, D Ryan, H Saarikko, S Sabik, A Safonov, R St Denis, WK Sakumoto, G Salamanna, D Saltzberg, C Sanchez, L Santi, S Sarkar, K Sato, P Savard, A Savoy-Navarro, 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, F Semeria, L Sexton-Kennedy, I Sfiligoi, MD Shapiro, T Shears, PF Shepard, D Sherman, M Shimojima, M Shochet, Y Shon, I Shreyber, A Sidoti, A Sill, P Sinervo, A Sisakyan, J Sjolin, A Skiba, AJ Slaughter, K Sliwa, D Smirnov, JR Smith, FD Snider, R Snihur, M Soderberg, A Soha, SV Somalwar, J Spalding, M Spezziga, F Spinella, P Squillacioti, H Stadie, M Stanitzki, B Stelzer, O Stelzer-Chilton, D Stentz, J Strologas, D Stuart, JS Suh, A Sukhanov, K Sumorok, H Sun, T Suzuki, A Taffard, R Tafirout, H Takano, R Takashima, Y Takeuchi, K Takikawa, M Tanaka, R Tanaka, N Tanimoto, M Tecchio, PK Teng, K Terashi, RJ Tesarek, S Tether, J Thom, AS Thompson, E Thomson, P Tipton, V Tiwari, S Tkaczyk, D Toback, K Tollefson, T Tomura, D Tonelli, M Tönnesmann, S Torre, D Torretta, S Tourneur, W Trischuk, R Tsuchiya, S Tsuno, D Tsybychev, N Turini, F Ukegawa, T Unverhau, S Uozumi, D Usynin, L Vacavant, A Vaiciulis, A Varganov, S VejcikIII, G Velev, V Veszpremi, G Veramendi, T Vickey, R Vidal, I Vila, R Vilar, I Vollrath, I Volobouev, M vonderMey, P Wagner, RG Wagner, RL Wagner, W Wagner, R Wallny, T Walter, Z Wan, MJ Wang, SM Wang, A Warburton, B Ward, S Waschke, D Waters, T Watts, M Weber, WC WesterIII, B Whitehouse, D Whiteson, AB Wicklund, E Wicklund, HH Williams, P Wilson, BL Winer, P Wittich, S Wolbers, C Wolfe, M Wolter, M Worcester, S Worm, T Wright, X Wu, F Würthwein, A Wyatt, A Yagil, T Yamashita, K Yamamoto, J Yamaoka, C Yang, UK Yang, W Yao, GP Yeh, J Yoh, K Yorita, T Yoshida, I Yu, S Yu, JC Yun, L Zanello, A Zanetti, I Zaw, F Zetti, J Zhou, S Zucchelli

Search for First-Generation Scalar Leptoquarks in $\bm{p \bar{p}}$ collisions at $\sqrt{s}$=1.96 TeV

ArXiv hep-ex/0506074 (2005)

Authors:

The CDF Collaboration, 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, T Arisawa, J-F Arguin, A Artikov, W Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, GJ Barker, VE Barnes, BA Barnett, S Baroiant, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, J Bellinger, A Belloni, E Ben-Haim, D Benjamin, A Beretvas, T Berry, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, A Bocci, A Bodek, G Bolla, A Bolshov, D Bortoletto, J Boudreau, S Bourov, B Brau, C Bromberg, E Brubaker, J Budagov, HS Budd, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, M Casarsa, D Carlsmith, R Carosi, S Carron, M Cavalli-Sforza, A Castro, P Catastini, D Cauz, A Cerri, L Cerrito, J Chapman, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, JP Chou, S Chuang, K Chung, W-H Chung, YS Chung, M Cijliak, CI Ciobanu, MA Ciocci, AG Clark, D Clark, M Coca, A Connolly, M Convery, J Conway, B Cooper, K Copic, M Cordelli, G Cortiana, J Cranshaw, J Cuevas, A Cruz, R Culbertson, C Currat, D Cyr, D Dagenhart, S DaRonco, S D'Auria, P deBarbaro, S DeCecco, A Deisher, G DeLentdecker, M Dell'Orso, S Demers, L Demortier, M Deninno, D DePedis, PF Derwent, T Devlin, C Dionisi, JR Dittmann, P DiTuro, C Dörr, A Dominguez, S Donati, M Donega, J Donini, M D'Onofrio, T Dorigo, K Ebina, J Efron, J Ehlers, R Erbacher, M Erdmann, D Errede, S Errede, R Eusebi, H-C Fang, S Farrington, I Fedorko, WT Fedorko, RG Feild, M Feindt, JP Fernandez, RD Field, G Flanagan, LR Flores-Castillo, A Foland, S Forrester, GW Foster, M Franklin, JC Freeman, Y Fujii, I Furic, A Gajjar, M Gallinaro, J Galyardt, M Garcia-Sciveres, AF Garfinkel, C Gay, H Gerberich, DW Gerdes, E Gerchtein, S Giagu, P Giannetti, A Gibson, K Gibson, C Ginsburg, K Giolo, M Giordani, M Giunta, G Giurgiu, V Glagolev, D Glenzinski, M Gold, N Goldschmidt, D Goldstein, J Goldstein, G Gomez, G Gomez-Ceballos, M Goncharov, O González, I Gorelov, AT Goshaw, Y Gotra, K Goulianos, A Gresele, M Griffiths, C Grosso-Pilcher, U Grundler, J GuimaraesdaCosta, C Haber, K Hahn, SR Hahn, E Halkiadakis, A Hamilton, B-Y Han, R Handler, F Happacher, K Hara, M Hare, RF Harr, RM Harris, F Hartmann, K Hatakeyama, J Hauser, C Hays, H Hayward, B Heinemann, J Heinrich, M Hennecke, M Herndon, C Hill, D Hirschbuehl, A Hocker, KD Hoffman, A Holloway, S Hou, MA Houlden, BT Huffman, Y Huang, RE Hughes, J Huston, K Ikado, J Incandela, G Introzzi, M Iori, Y Ishizawa, C Issever, A Ivanov, Y Iwata, B Iyutin, E James, D Jang, B Jayatilaka, D Jeans, H Jensen, EJ Jeon, M Jones, KK Joo, SY Jun, T Junk, T Kamon, J Kang, M KaragozUnel, PE Karchin, Y Kato, Y Kemp, R Kephart, U Kerzel, V Khotilovich, B Kilminster, DH Kim, HS Kim, JE Kim, MJ Kim, MS Kim, SB Kim, SH Kim, YK Kim, M Kirby, L Kirsch, S Klimenko, M Klute, B Knuteson, BR Ko, H Kobayashi, DJ Kong, K Kondo, J Konigsberg, K Kordas, A Korn, A Korytov, AV Kotwal, A Kovalev, J Kraus, I Kravchenko, A Kreymer, J Kroll, M Kruse, V Krutelyov, SE Kuhlmann, S Kwang, AT Laasanen, S Lai, S Lami, S Lammel, M Lancaster, R Lander, K Lannon, A Lath, G Latino, I Lazzizzera, C Lecci, T LeCompte, J Lee, J Lee, SW Lee, R Lefèvre, N Leonardo, S Leone, S Levy, JD Lewis, K Li, C Lin, CS Lin, M Lindgren, E Lipeles, TM Liss, A Lister, DO Litvintsev, T Liu, Y Liu, NS Lockyer, A Loginov, M Loreti, P Loverre, R-S Lu, D Lucchesi, P Lujan, P Lukens, G Lungu, L Lyons, J Lys, R Lysak, E Lytken, D MacQueen, R Madrak, K Maeshima, P Maksimovic, G Manca, F Margaroli, R Marginean, C Marino, A Martin, M Martin, V Martin, M Martínez, T Maruyama, H Matsunaga, M Mattson, P Mazzanti, KS McFarland, D McGivern, PM McIntyre, P McNamara, R McNulty, A Mehta, S Menzemer, A Menzione, P Merkel, C Mesropian, A Messina, T Miao, N Miladinovic, J Miles, L Miller, R Miller, JS Miller, C Mills, R Miquel, S Miscetti, G Mitselmakher, A Miyamoto, N Moggi, B Mohr, R Moore, M Morello, PA MovillaFernandez, J Muelmenstaedt, A Mukherjee, M Mulhearn, T Muller, R Mumford, A Munar, P Murat, J Nachtman, S Nahn, I Nakano, A Napier, R Napora, D Naumov, V Necula, J Nielsen, T Nelson, C Neu, MS Neubauer, T Nigmanov, L Nodulman, O Norniella, T Ogawa, SH Oh, YD Oh, T Ohsugi, T Okusawa, R Oldeman, R Orava, W Orejudos, K Osterberg, C Pagliarone, E Palencia, R Paoletti, V Papadimitriou, AA Paramonov, S Pashapour, J Patrick, G Pauletta, M Paulini, C Paus, D Pellett, A Penzo, TJ Phillips, G Piacentino, J Piedra, KT Pitts, C Plager, L Pondrom, G Pope, X Portell, O Poukhov, N Pounder, F Prakoshyn, A Pronko, J Proudfoot, F Ptohos, G Punzi, J Rademacker, MA Rahaman, A Rakitine, S Rappoccio, F Ratnikov, H Ray, B Reisert, V Rekovic, P Renton, M Rescigno, F Rimondi, K Rinnert, L Ristori, WJ Robertson, A Robson, T Rodrigo, S Rolli, R Roser, R Rossin, C Rott, J Russ, V Rusu, A Ruiz, D Ryan, H Saarikko, S Sabik, A Safonov, R St Denis, WK Sakumoto, G Salamanna, D Saltzberg, C Sanchez, L Santi, S Sarkar, K Sato, P Savard, A Savoy-Navarro, 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, F Semeria, L Sexton-Kennedy, I Sfiligoi, MD Shapiro, T Shears, PF Shepard, D Sherman, M Shimojima, M Shochet, Y Shon, I Shreyber, A Sidoti, A Sill, P Sinervo, A Sisakyan, J Sjolin, A Skiba, AJ Slaughter, K Sliwa, D Smirnov, JR Smith, FD Snider, R Snihur, M Soderberg, A Soha, SV Somalwar, J Spalding, M Spezziga, F Spinella, P Squillacioti, H Stadie, M Stanitzki, B Stelzer, O Stelzer-Chilton, D Stentz, J Strologas, D Stuart, JS Suh, A Sukhanov, K Sumorok, H Sun, T Suzuki, A Taffard, R Tafirout, H Takano, R Takashima, Y Takeuchi, K Takikawa, M Tanaka, R Tanaka, N Tanimoto, M Tecchio, PK Teng, K Terashi, RJ Tesarek, S Tether, J Thom, AS Thompson, E Thomson, P Tipton, V Tiwari, S Tkaczyk, D Toback, K Tollefson, T Tomura, D Tonelli, M Tönnesmann, S Torre, D Torretta, S Tourneur, W Trischuk, R Tsuchiya, S Tsuno, D Tsybychev, N Turini, F Ukegawa, T Unverhau, S Uozumi, D Usynin, L Vacavant, A Vaiciulis, A Varganov, S VejcikIII, G Velev, V Veszpremi, G Veramendi, T Vickey, R Vidal, I Vila, R Vilar, I Vollrath, I Volobouev, M vonderMey, P Wagner, RG Wagner, RL Wagner, W Wagner, R Wallny, T Walter, Z Wan, MJ Wang, SM Wang, A Warburton, B Ward, S Waschke, D Waters, T Watts, M Weber, WC WesterIII, B Whitehouse, D Whiteson, AB Wicklund, E Wicklund, HH Williams, P Wilson, BL Winer, P Wittich, S Wolbers, C Wolfe, M Wolter, M Worcester, S Worm, T Wright, X Wu, F Würthwein, A Wyatt, A Yagil, T Yamashita, K Yamamoto, J Yamaoka, C Yang, UK Yang, W Yao, GP Yeh, J Yoh, K Yorita, T Yoshida, I Yu, S Yu, JC Yun, L Zanello, A Zanetti, I Zaw, F Zetti, J Zhou, S Zucchelli

Abstract:

We report on a search for pair production of first-generation scalar leptoquarks ($LQ$) in $p \bar{p}$ collisions at $\sqrt{s}$=1.96 TeV using an integrated luminosity of 203 $pb^{-1}$ collected at the Fermilab Tevatron collider by the CDF experiment. We observe no evidence for $LQ$ production in the topologies arising from $LQ \bar{LQ} \to eqeq$ and $LQ \bar{LQ} \to eq \nu q$, and derive 95% C.L. upper limits on the $LQ$ production cross section. %as a function of $\beta$, where $\beta$ is the branching fraction for $LQ \to eq$. The results are combined with those obtained from a separately reported CDF search in the topology arising from $LQ\bar{LQ} \to \nu q \nu q$ and 95% C.L. lower limits on the LQ mass as a function of $\beta = BR(LQ \to eq) $ are derived. The limits are 236, 205 and 145 GeV/c$^2$ for $\beta$ = 1, $\beta$ = 0.5 and $\beta$ = 0.1, respectively.

Helicity of the W boson in lepton + jets tt̄ events

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 617:1-2 (2005) 1-10

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, 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, 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, L Duflot, SR Dugad, A Duperrin, A Dyshkant, D Edmunds, J Ellison, JT Eltzroth, VD Elvira

Abstract:

We examine properties of tt̄ candidate events in lepton + jets final states to establish the helicities of W bosons in t→W+b decays. Our analysis is based on a direct calculation of a probability density for each event to correspond to a tt̄ final state, as a function of the helicity of the W boson. Using the 125 events/pb of data collected by the DØ experiment at the Fermilab Tevatron pp̄ Collider at s=1.8 TeV, we obtain a longitudinal helicity fraction F0=0.56±0.31, consistent with the prediction of F0=0.70 from the standard model. © 2005 Elsevier B.V. All rights reserved.

Characterization of 1600 Hamamatsu 16-anode photomultipliers for the MINOS Far detector

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 545:3 (2005) 852-871

Authors:

K Lang, J Day, S Eilerts, S Fuqua, A Guillen, M Kordosky, M Lang, J Liu, W Opaska, M Proga, P Vahle, A Winbow, G Drake, J Thomas, C Andreopoulos, N Saoulidou, P Stamoulis, G Tzanakos, M Zois, A Weber, D Michael

Abstract:

We are reporting results of the characterization of over 1600 multi-anode R5900-00-M16 photomultipliers manufactured by Hamamatsu Photonics K.K., and installed in the MINOS Far detector. We have conducted extensive tests of the uniformity of gain and collection efficiency of individual anodes, the cross-talk among all 16 channels, the dark noise, and the linearity of response. In our studies we used a blue light-emitting diode to illuminate phototubes through 1.2 mm diameter optical fibers. In this paper, we present summaries of the main characteristics of the tested photomultipliers. © 2005 Elsevier B.V. All rights reserved.