Abstract
We have measured the azimuthal angular correlation of production, using of data collected by Collider Detector at Fermilab (CDF) in collisions at during 1994–1995. In high-energy collisions, such as at the Tevatron, production can be schematically categorized into three mechanisms. The leading-order (LO) process is “flavor creation,” where both and 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 cross section, while providing very different opening angle distributions from the LO process. An azimuthal opening angle between bottom and antibottom, , has been used for the correlation measurement to probe the interaction creating pairs. The distribution has been obtained from two different methods. One method measures the between bottom hadrons using events with two reconstructed secondary vertex tags. The other method uses events, where the charged lepton () is an electron () or a muon (), to measure between bottom quarks. The purity is determined as a function of by fitting the decay length of the and the impact parameter of the . Both methods quantify the contribution from higher-order production mechanisms by the fraction of the pairs produced in the same azimuthal hemisphere, . The measured values are consistent with both parton shower Monte Carlo and NLO QCD predictions.
20 More- Received 24 November 2004
DOI:https://doi.org/10.1103/PhysRevD.71.092001
©2005 American Physical Society