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Questions on uncertainties in parton distributions

Journal of Physics G: Nuclear and Particle Physics 28:10 (2002) 2717-2722

Authors:

RS Thorne, H Böttcher, AM Cooper-Sarkar, B Reisert, V Shekelyan, WJ Stirling, DR Stump, A Vogt

Abstract:

A discussion is presented of the manner in which uncertainties in parton distributions and related quantities are determined. One of the central problems is the criteria used to judge what variation of the parameters describing a set of partons is acceptable within the context of a global fit. Various ways of addressing this question are outlined.
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The structure function working group summary

Acta Physica Polonica B 33:10 (2002) 3075-3098

Authors:

V Chekelian, A Cooper-Sarkar, R Thorne

Abstract:

A summary of the experimental and theoretical presentations in the Structure Function Working Group on the proton and photon unpolarized structure functions is given.
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Search for a W' Boson Decaying to a Top and Bottom Quark Pair in 1.8 TeV p-pbar Collisions

ArXiv hep-ex/0209030 (2002)
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Branching ratio measurements of exclusive B+ decays to charmonium with the collider detector at fermilab

Physical Review D Particles Fields Gravitation and Cosmology 66:5 (2002) 520051-520057

Authors:

D Acosta, T Affolder, H Akimoto, MG Albrow, D Ambrose, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, W Badgett, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Behari, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, J Berryhill, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, C Bromberg, M Brozovic, E Brubaker, N Bruner, J Budagov, HS Budd, K Burkett, G Busetto, KL Byrum, S Cabrera, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, W Caskey, 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, JY Chung, WH Chung, YS Chung, CI Ciobanu, AG Clark, M Coca, AP Colijn, A Connolly, M Convery, J Conway, M Cordelli, J Cranshaw, R Culbertson, D Dagenhart, S D'Auria

Abstract:

We report on measurements of the branching ratios of the decays B+→Xcl0(1P)K+ and B+ →J/ψK+π+π-, where Xcl0(1P)→J/ψγ and J/ψ→μ+μ- in pp collisions at √s= 1.8 TeV. Using a data sample from an integrated luminosity of 110 pb-1 collected by the Collider Detector at Fermilab we measure the branching ratios to be BR(B+→Xcl0(1P) K+)=15.5±5.4(stat)±1.5(syst)±1.3(br)× 10-4 and BR(B+ →J/ψK+π+π-)=6.9 ±1.8(stat)±1.1(syst)±0.4(br)×10-4 where (br) is due to the finite precision on BR(B-→J/ψK+), BR(Xcl0(1P)→J/ψγ)is used to normalize the signal yield, and (syst) encompasses all other systematic uncertainties.
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Measurement of the Q2 and energy dependence of diffractive interactions at HERA: The ZEUS collaboration

European Physical Journal C 25:2 (2002) 169-187

Authors:

S Chekanov, D Krakauer, S Magill, B Musgrave, A Pellegrino, J Repond, R Yoshida, MCK Mattingly, P Antonioli, G Anzivino, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, G Cara Romeo, M Chiarini, L Cifarelli, F Cindolo, A Contin, M Corradi, S De Pasquale, P Giusti, G Iacobucci, G Levi, A Margotti, T Massam, R Nania, C Nemoz, F Palmonari, A Pesci, G Sartorelli, Y Zamora Garcia, A Zichichi, G Aghuzumtsyan, D Bartsch, I Brock, J Crittenden, S Goers, H Hartmann, E Hilger, P Irrgang, HP Jakob, A Kappes, UF Katz, R Kerger, O Kind, E Paul, J Rautenberg, R Renner, H Schnurbusch, A Stifutkin, J Tandler, KC Voss, A Weber, DS Bailey, NH Brook, JE Cole, B Foster, GP Heath, HF Heath, S Robins, E Rodrigues, J Scott, RJ Tapper, M Wing, R Ayad, M Capua, L Iannotti, A Mastroberardino, M Schioppa, G Susinno, JY Kim, YK Kim, JH Lee, IT Lim, MY Pac, A Caldwell, M Helbich, X Liu, B Mellado, S Paganis, WB Schmidke, F Sciulli, J Chwastowski, A Eskreys, J Figiel, K Olkiewicz, MB Przybycień, P Stopa, L Zawiejski, B Bednarek, I Grabowska-Bold, K Jeleń, D Kisielewska, AM Kowal, M Kowal, T Kowalski, B Mindur

Abstract:

Diffractive dissociation of virtual photons, γ*p → Xp, has been studied in ep interactions with the ZEUS detector at HERA. The data cover photon virtualities 0.17 < Q2 < 0.70 GeV2 and 3 < Q2 < 80 GeV2 with 3 < MX < 38 GeV, where MX is the mass of the hadronic final state. Diffractive events were selected by two methods: the first required the detection of the scattered proton in the ZEUS leading proton spectrometer (LPS); the second was based on the distribution of MX. The integrated luminosities of the low- and high-Q2 samples used in the LPS-based analysis are ≃ 0.9 pb-1 and ≃ 3.3 pb-1, respectively. The sample used for the MX-based analysis corresponds to an integrated luminosity of ≃ 6.2 pb-1. The dependence of the diffractive cross section on W, the virtual photon-proton centre-of-mass energy, and on Q2 is studied. In the low-Q2 range, the energy dependence is compatible with Regge theory and is used to determine the intercept of the Pomeron trajectory. The W dependence of the diffractive cross section exhibits no significant change from the low-Q2 to the high-Q2 region. In the low-Q2 range, little Q2 dependence is found, a significantly different behaviour from the rapidly falling cross section measured for Q2 > 3 GeV2. The ratio of the diffractive to the virtual photon-proton total cross section is studied as a function of W and Q2. Comparisons are made with a model based on perturbative QCD.
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