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.

ILC Reference Design Report Volume 1 - Executive Summary

ArXiv 0712.1950 (2007)

Authors:

James Brau, Yasuhiro Okada, Nicholas Walker

Search for Bs --> mu+mu- and Bd --> mu+mu- Decays with 2fb-1 of ppbar Collisions

ArXiv 0712.1708 (2007)

Authors:

CDF Collaboration, T Aaltonen

Evidence for D0-D0bar mixing using the CDF II Detector

ArXiv 0712.1567 (2007)

Authors:

CDF Collaboration, T Aaltonen

Measurement of (anti)deuteron and (anti)proton production in DIS at HERA

Nuclear Physics B 786:1-2 (2007) 181-205

Authors:

S Chekanov, M Derrick, S Magill, B Musgrave, D Nicholass, J Repond, R Yoshida, MCK Mattingly, M Jechow, N Pavel, AG Yagües Molina, S Antonelli, P Antonioli, G Bari, M Basile, L Bellagamba, M Bindi, D Boscherini, A Bruni, G Bruni, L Cifarelli, F Cindolo, A Contin, M Corradi, S De Pasquale, G Iacobucci, A Margotti, R Nania, A Polini, G Sartorelli, A Zichichi, D Bartsch, I Brock, S Goers, H Hartmann, E Hilger, HP Jakob, M Jüngst, OM Kind, AE Nuncio-Quiroz, E Paul, R Renner, U Samson, V Schönberg, R Shehzadi, M Wlasenko, NH Brook, GP Heath, JD Morris, T Namsoo, M Capua, S Fazio, A Mastroberardino, M Schioppa, G Susinno, E Tassi, JY Kim, KJ Ma, ZA Ibrahim, B Kamaluddin, WAT Wan Abdullah, Y Ning, Z Ren, F Sciulli, J Chwastowski, A Eskreys, J Figiel, A Galas, M Gil, K Olkiewicz, P Stopa, L Zawiejski, L Adamczyk, T Bołd, I Grabowska-Bołd, D Kisielewska, J Łukasik, M Przybycień, L Suszycki, A Kotański, W Słomiński, V Adler, U Behrens, I Bloch, C Blohm, A Bonato, K Borras, R Ciesielski, N Coppola, A Dossanov, V Drugakov, J Fourletova, A Geiser, D Gladkov, P Göttlicher, J Grebenyuk, I Gregor, T Haas, W Hain, C Horn

Abstract:

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300-318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3 < pT / M < 0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements. © 2007 Elsevier B.V. All rights reserved.