Observation of exclusive electron-positron production in hadron-hadron collisions

Physical Review Letters 98:11 (2007)

Authors:

A Abulencia, 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, 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, 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, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, S Budroni, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, S Carillo, D Carlsmith, B Caron, R Carosi, 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 Ciljak, CI Ciobanu, MA Ciocci

Abstract:

We present the first observation of exclusive e+e- production in hadron-hadron collisions, using pp̄ collision data at s=1.96TeV taken by the run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532pb-1. We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy ET>5GeV and pseudorapidity |η|<2. With these criteria, 16 events are observed compared to a background expectation of 1.9±0.3 events. These events are consistent in cross section and properties with the QED process pp̄→p+e+e-+p̄ through two-photon exchange. The measured cross section is 1.6-0.3+0.5(stat)±0.3(syst)pb. This agrees with the theoretical prediction of 1.71±0.01pb. © 2007 The American Physical Society.

Evidence for deceleration in the radio jets of GRS 1915+105?

Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 375:3 (2007) 1087-1098

Authors:

JCA Miller-Jones, MP Rupen, RP Fender, A Rushton, GG Pooley, RE Spencer

Ruling out a massive asymptotic giant-branch star as the progenitor of supernova 2005cs

Monthly Notices of the Royal Astronomical Society: Letters Oxford University Press (OUP) 376:1 (2007) l52-l56

Authors:

JJ Eldridge, S Mattila, SJ Smartt

Measurement of sigma(Lambda_b)/sigma(B0) x B(Lambda_b->Lambda_c pi)/B(B0->Dpi) in ppbar Collisions at sqrt(s)=1.96 TeV

Physical Review Letters 98 (2007) 122002 7pp

Authors:

JC Tseng, Y Le, M Martin, P Maksimovic

Precision determination of the D0 mass.

Physical review letters 98:9 (2007) 092002

Authors:

C Cawlfield, BI Eisenstein, I Karliner, D Kim, N Lowrey, P Naik, M Selen, EJ White, J Wiss, RE Mitchell, MR Shepherd, D Besson, TK Pedlar, D Cronin-Hennessy, KY Gao, J Hietala, Y Kubota, T Klein, BW Lang, R Poling, AW Scott, A Smith, P Zweber, S Dobbs, Z Metreveli, KK Seth, A Tomaradze, J Ernst, KM Ecklund, H Severini, W Love, V Savinov, O Aquines, Z Li, A Lopez, S Mehrabyan, H Mendez, J Ramirez, GS Huang, DH Miller, V Pavlunin, B Sanghi, IPJ Shipsey, B Xin, GS Adams, M Anderson, JP Cummings, I Danko, D Hu, B Moziak, J Napolitano, Q He, J Insler, H Muramatsu, CS Park, EH Thorndike, F Yang, TE Coan, YS Gao, M Artuso, S Blusk, J Butt, J Li, N Menaa, R Mountain, S Nisar, K Randrianarivony, R Sia, T Skwarnicki, S Stone, JC Wang, K Zhang, G Bonvicini, D Cinabro, M Dubrovin, A Lincoln, DM Asner, KW Edwards, RA Briere, T Ferguson, G Tatishvili, H Vogel, ME Watkins, JL Rosner, NE Adam, JP Alexander, DG Cassel, JE Duboscq, R Ehrlich, L Fields, RS Galik, L Gibbons, R Gray, SW Gray, DL Hartill, BK Heltsley, D Hertz, CD Jones, J Kandaswamy, DL Kreinick, VE Kuznetsov, H Mahlke-Krüger, PUE Onyisi, JR Patterson, D Peterson, J Pivarski, D Riley, A Ryd, AJ Sadoff, H Schwarthoff, X Shi, S Stroiney, WM Sun, T Wilksen, SB Athar, R Patel, V Potlia, J Yelton, P Rubin, CLEO Collaboration

Abstract:

A precision measurement of the D0 meson mass has been made using approximately 281 pb(-1) of e+e- annihilation data taken with the CLEO-c detector at the psi(3770) resonance. The exclusive decay D0-->K_{S}phi has been used to obtain M(D0)=1864.847+/-0.150(stat)+/-0.095(syst) MeV. This corresponds to M(D0D*0)=3871.81+/-0.36 MeV, and leads to a well-constrained determination of the binding energy of the proposed D0D*0 molecule X(3872), as Eb=0.6+/-0.6 MeV.