"Search for rare hadronic B decays" - Bài báo của ĐHQGHN trong Web of Science
Authors: Akers, R.
A search for rare decays of B hadrons has been performed using approximately two million hadronic Z ° decays collected by the OPAL experiment between 1990 and 1993. The exclusive decay channels B~ ° --~ lr+~r -, B ° ~ K+cr - , B ° --~ 7r+K - and B ° ~ K+K - have been studied. Such decays include contributions from flavour changing neutral current processes such as hadronic penguin decays. No significant excess of events has been observed in the 7r+~r -, ~r+K - and K+K - invariant mass distributions. Consequently, upper limits on the B ° branching ratios, Br (B°---~r+~ -) < 4.7 × 10 -5 and Br (B°---~K +~r-) < 8.1 × 10 -5, and on the B ° branching ratios, Br (Bs°--*~'+K -) < 2.6 x 10-' and Br (B°---+K+K -) < 1.4 x 10 -4, have been set at the 90% confidence level. These limits assume that the ratio of the partial decay widths of the Z °, F(Z°---~ bb)/F (Z ° ~ hadrons), is 0.217 and that the fractions of B ° and B ° mesons produced during fragmentation are 39.5% and 12% respectively. The B ° branching ratio limits are the first such limits obtained.
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