Journal article

Study of J/psi -> p(p)over-bar,Lambda(Lambda)over-bar and observation of eta(c)->Lambda(Lambda)over-bar at Belle

C-H Wu, M-Z Wang, K Abe, I Adachi, H Aihara, V Aulchenko, T Aushev, S Bahinipati, AM Bakich, V Balagura, A Bay, K Belous, U Bitenc, I Bizjak, S Blyth, A Bondar, A Bozek, TE Browder, Y Chao, A Chen Show all

PHYSICAL REVIEW LETTERS | AMER PHYSICAL SOC | Published : 2006

Abstract

We study the baryonic charmonium decays of B mesons B+-->etacK+ and B+-->J/psiK+, where the etac and J/psi subsequently decay into a pp[over] or LambdaLambda[over] pair. We measure the J/psi-->pp[over] and LambdaLambda[over] anisotropy parameters alphaB=-0.60+/-0.13+/-0.14 (pp[over]), -0.44+/-0.51+/-0.31 (LambdaLambda[over ]) and compare to results from e;{+}e;{-}-->J/psi formation experiments. We also report the first observation of etac-->LambdaLambda[over]. The measured branching fraction is B(etac-->LambdaLambda[over ])=(0.87(+0.24)/(-0.21)(stat)(+0.09/-0.14) (syst)+/-0.27(PDG))x10-3. This study is based on a 357 fb-1 data sample recorded on the Upsilon(4S) resonance with the Belle detec..

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