Measurement of the Proton Structure Function F_2 at Very Low Q^2 at HERA

ArXiv hep-ex/0005018 (2000)

Measurement of the differential dijet mass cross section in pp¯ collisions at s=1.8 TeV

Physical Review D American Physical Society (APS) 61:9 (2000) 091101

Authors:

T Affolder, H Akimoto, A Akopian, MG Albrow, P Amaral, SR Amendolia, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, T Asakawa, W Ashmanskas, M Atac, F Azfar, P Azzi-Bacchetta, N Bacchetta, MW Bailey, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, M Barone, G Bauer, F Bedeschi, S Belforte, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, S Bertolucci, B Bevensee, A Bhatti, C Bigongiari, M Binkley, D Bisello, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, M Campbell, A Caner, W Carithers, J Carlson, D Carlsmith, J Cassada, A Castro, D Cauz, A Cerri, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, MT Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, S Cihangir, CI Ciobanu, AG Clark, A Connolly, J Conway, J Cooper, M Cordelli, D Costanzo, J Cranshaw, D Cronin-Hennessy, R Cropp, R Culbertson, D Dagenhart, F DeJongh, S Dell’Agnello, M Dell’Orso, R Demina, L Demortier, M Deninno, PF Derwent, T Devlin, JR Dittmann, S Donati, J Done, T Dorigo, N Eddy, K Einsweiler, JE Elias, E Engels, W Erdmann, D Errede, S Errede, Q Fan, RG Feild, C Ferretti, I Fiori, B Flaugher, GW Foster, M Franklin, J Freeman, J Friedman, Y Fukui, S Galeotti, M Gallinaro, T Gao, M Garcia-Sciveres, AF Garfinkel, P Gatti, C Gay, S Geer, DW Gerdes, P Giannetti, P Giromini, V Glagolev, M Gold, J Goldstein, A Gordon, AT Goshaw, Y Gotra, K Goulianos, H Grassmann, C Green, L Groer, C Grosso-Pilcher, M Guenther, G Guillian, J Guimaraes da Costa, RS Guo, C Haber, E Hafen, SR Hahn, C Hall, T Handa, R Handler, W Hao, F Happacher, K Hara, AD Hardman, RM Harris, F Hartmann, K Hatakeyama, J Hauser, J Heinrich, A Heiss, M Herndon, B Hinrichsen, KD Hoffman, C Holck, R Hollebeek, L Holloway, R Hughes, J Huston, J Huth, H Ikeda, J Incandela, G Introzzi, J Iwai, Y Iwata, E James, H Jensen, M Jones, U Joshi, H Kambara, T Kamon, T Kaneko, K Karr, H Kasha, Y Kato, TA Keaffaber, K Kelley, M Kelly, RD Kennedy, R Kephart, D Khazins, T Kikuchi, M Kirk, BJ Kim, HS Kim, MJ Kim, SH Kim, YK Kim, L Kirsch, S Klimenko, P Koehn, A Köngeter, K Kondo, J Konigsberg, K Kordas, A Korn, A Korytov, E Kovacs, J Kroll, M Kruse, SE Kuhlmann, K Kurino, T Kuwabara, AT Laasanen, N Lai, S Lami, S Lammel, JI Lamoureux, M Lancaster, G Latino, T LeCompte, AM Lee, S Leone, JD Lewis, M Lindgren, TM Liss, JB Liu, YC Liu, N Lockyer, J Loken, M Loreti, D Lucchesi, P Lukens, S Lusin, L Lyons, J Lys, R Madrak, K Maeshima, P Maksimovic, L Malferrari, M Mangano, M Mariotti, G Martignon, A Martin, JAJ Matthews, J Mayer, P Mazzanti, KS McFarland, P McIntyre, E McKigney, M Menguzzato, A Menzione, C Mesropian, T Miao, R Miller, JS Miller, H Minato, S Miscetti, M Mishina, G Mitselmakher, N Moggi, E Moore, R Moore, Y Morita, A Mukherjee, T Muller, A Munar, P Murat, S Murgia, M Musy, J Nachtman, S Nahn, H Nakada, T Nakaya, I Nakano, C Nelson, D Neuberger, C Newman-Holmes, C-YP Ngan, P Nicolaidi, H Niu, L Nodulman, A Nomerotski, SH Oh, T Ohmoto, T Ohsugi, R Oishi, T Okusawa, J Olsen, C Pagliarone, F Palmonari, R Paoletti, V Papadimitriou, SP Pappas, D Partos, J Patrick, G Pauletta, M Paulini, C Paus, L Pescara, TJ Phillips, G Piacentino, KT Pitts, R Plunkett, A Pompos, L Pondrom, G Pope, M Popovic, F Prokoshin, J Proudfoot, F Ptohos, G Punzi, K Ragan, A Rakitine, D Reher, A Reichold, W Riegler, A Ribon, F Rimondi, L Ristori, WJ Robertson, A Robinson, T Rodrigo, S Rolli, L Rosenson, R Roser, R Rossin, WK Sakumoto, D Saltzberg, A Sansoni, L Santi, H Sato, P Savard, P Schlabach, EE Schmidt, MP Schmidt, M Schmitt, L Scodellaro, A Scott, A Scribano, S Segler, S Seidel, Y Seiya, A Semenov, F Semeria, T Shah, MD Shapiro, PF Shepard, T Shibayama, M Shimojima, M Shochet, J Siegrist, G Signorelli, A Sill, P Sinervo, P Singh, AJ Slaughter, K Sliwa, C Smith, FD Snider, A Solodsky, J Spalding, T Speer, P Sphicas, F Spinella, M Spiropulu, L Spiegel, L Stanco, J Steele, A Stefanini, J Strologas, F Strumia, D Stuart, K Sumorok, T Suzuki, T Takano, R Takashima, K Takikawa, P Tamburello, M Tanaka, B Tannenbaum, W Taylor, M Tecchio, PK Teng, K Terashi, S Tether, D Theriot, R Thurman-Keup, P Tipton, S Tkaczyk, K Tollefson, A Tollestrup, H Toyoda, W Trischuk, JF de Troconiz, J Tseng, N Turini, F Ukegawa, J Valls, S Vejcik, G Velev, R Vidal, R Vilar, I Volobouev, D Vucinic, RG Wagner, RL Wagner, J Wahl, NB Wallace, AM Walsh, C Wang, CH Wang, MJ Wang, T Watanabe, D Waters, T Watts, R Webb, H Wenzel, WC Wester, AB Wicklund, E Wicklund, HH Williams, P Wilson, BL Winer, D Winn, S Wolbers, D Wolinski, J Wolinski, S Wolinski, S Worm, X Wu, J Wyss, A Yagil, W Yao, GP Yeh, P Yeh, J Yoh, C Yosef, T Yoshida, I Yu, S Yu, A Zanetti, F Zetti, S Zucchelli

Measuring CP violation and B0s-B̄0s mixing using B0s → J/ψφ with φ → K+K-, J/ψ → μ+μ-

Journal of Physics G Nuclear and Particle Physics 26:5 (2000) 741-743

Authors:

F Azfar, T Huffman, L Lyons, A Reichold, D Waters

Abstract:

We present a preliminary study of a new technique for measuring B0s mixing and CP violation using the decay B0s → J/ψφ, φ K+K-, J/ψ → μ+μ-. This technique utilizes the unequal lifetimes of the B0s CP even and odd eigenstates, and an angular variable decomposition of the CP content of the final state. This study is based on CDF Run-I observations and Run-II projections, and predicts that the B0s mixing parameter cursive Greek chis can be measured with high accuracy in untagged samples if this approach is adopted. A large CP asymmetry may also be possible to measure. The accuracy of this method is shown to increase for higher values of cursive Greek chis as the lifetime splitting of the CP eigenstates increases. The measurement of cursive Greek chis does not depend on tagging, whereas the observation of a CP-violating asymmetry does.

Introduction: heavy flavour working group

J PHYS G NUCL PARTIC 26:5 (2000) 721-722

Authors:

BT Huffman, M Kramer, M Sutton

The Q2 dependence of dijet cross sections in γp interactions at HERA

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 479:1-3 (2000) 37-52

Authors:

J Breitweg, S Chekanov, M Derrick, D Krakauer, S Magill, B Musgrave, A Pellegrino, J Repond, R Stanek, R Yoshida, MCK Mattingly, G Abbiendi, F Anselmo, P Antonioli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, G Cara Romeo, G Castellini, L Cifarelli, F Cindolo, A Contin, N Coppola, M Corradi, S De Pasquale, P Giusti, G Iacobucci, G Laurenti, G Levi, A Margotti, T Massam, R Nania, F Palmonari, A Pesci, A Polini, G Sartorelli, Y Zamora Garcia, A Zichichi, C Amelung, A Bornheim, I Brock, K Coböken, J Crittenden, R Deffner, H Hartmann, K Heinloth, E Hilger, P Irrgang, HP Jakob, A Kappes, UF Katz, R Kerger, E Paul, H Schnurbusch, A Stifutkin, J Tandler, KC Voss, A Weber, H Wieber, DS Bailey, O Barret, NH Brook, B Foster, GP Heath, HF Heath, JD McFall, D Piccioni, E Rodrigues, J Scott, RJ Tapper, M Capua, A Mastroberardino, M Schioppa, G Susinno

Abstract:

The dependence of the photon structure on the photon virtuality, Q2, is studied by measuring the reaction e+p → e+ + jet + jet + X at photon-proton centre-of-mass energies 134 < W < 223 GeV. Events have been selected in the Q2 ranges ≃ 0 GeV2, 0.1-0.55 GeV2, and 1.5-4.5 GeV2, having two jets with transverse energy E(T)/(jet) > 5.5 GeV in the final state. The dijet cross section has been measured as a function of the fractional momentum of the photon participating in the hard process, x(γ)/(OBS). The ratio of the dijet cross section with x(γ)/(OBS) < 0.75 to that with x(γ)/(OBS) > 0.75 decreases as Q2 increases. The data are compared with the predictions of NLO pQCD and leading-order Monte Carlo programs using various parton distribution functions of the photon. The measurements can be interpreted in terms of a resolved photon component that falls with Q2 but remains present at values of Q2 up to 4.5 GeV2. However, none of the models considered gives a good description of the data. (C) Copyright 2000 Elsevier Science B.V.