Measurements of bottom-antibottom azimuthal production correlations in proton-antiproton collisions at s=1.8TeV
Physical Review D Particles Fields Gravitation and Cosmology 71:9 (2005) 1-39
Authors:
D Acosta, T Affolder, MG Albrow, D Ambrose, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, W Badgett, 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, A Beretvas, 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, C Bromberg, E Brubaker, J Budagov, HS Budd, K Burkett, G Busetto, KL Byrum, S Cabrera, M Campbell, W Carithers, D Carlsmith, A Castro, D Cauz, A Cerri, L Cerrito, J Chapman, C Chen, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, ML Chu, JY Chung, WH Chung, YS Chung, CI Ciobanu, AG Clark, M Coca, A Connolly, M Convery, J Conway, M Cordelli, J Cranshaw, R Culbertson, D Dagenhart, S D'Auria, P De Barbaro, S De Cecco, S Dell'Agnello, M Dell'Orso, S Demers, L Demortier, M Deninno, D De Pedis, PF Derwent, C Dionisi, JR Dittmann, A Dominguez, S Donati, M D'Onofrio, T Dorigo, N Eddy, R Erbacher, D Errede, S Errede
Abstract:
We have measured the azimuthal angular correlation of bb̄ production, using 86.5pb-1 of data collected by Collider Detector at Fermilab (CDF) in pp̄ collisions at s=1.8TeV during 1994-1995. In high-energy pp̄ collisions, such as at the Tevatron, bb̄ production can be schematically categorized into three mechanisms. The leading-order (LO) process is "flavor creation," where both b and b̄ quarks substantially participate in the hard scattering and result in a distinct back-to-back signal in final state. The "flavor excitation" and the "gluon splitting" processes, which appear at next-leading-order (NLO), are known to make a comparable contribution to total bb̄ cross section, while providing very different opening angle distributions from the LO process. An azimuthal opening angle between bottom and antibottom, Δ, has been used for the correlation measurement to probe the interaction creating bb̄ pairs. The Δ distribution has been obtained from two different methods. One method measures the Δ between bottom hadrons using events with two reconstructed secondary vertex tags. The other method uses bb̄→(J/ ψX)(X′) events, where the charged lepton () is an electron (e) or a muon (μ), to measure Δ between bottom quarks. The bb̄ purity is determined as a function of Δ by fitting the decay length of the J/ψ and the impact parameter of the. Both methods quantify the contribution from higher-order production mechanisms by the fraction of the bb̄ pairs produced in the same azimuthal hemisphere, ftoward. The measured ftoward values are consistent with both parton shower Monte Carlo and NLO QCD predictions. © 2005 The American Physical Society.
