Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of J/psi to p pbar, Lambda Lambdabar and observation of eta_c to
  Lambda Lambdabar at Belle   We study the baryonic charmonium decays of B mesons, B+ to etac K+ and B+ to
J/psi K+, where the etac and J/psi subsequently decay into a p pbar or Lambda
Lambdabar pair. We measure the J/psi to p pbar, Lambda Lambdabar anisotropy
parameters, alpha_B = -0.60 +- 0.13 +-0.14 (p pbar), -0.44 +- 0.51 +- 0.31
(Lambda Lambdabar) and compare to results from e+e- to J/psi formation
experiments. We also report the first observation of etac to Lambda Lambdabar.
The measured branching fraction is B(etac to Lambda Lambdabar) = (0.87 +0.24
-0.21(stat) +0.09 -0.14(syst) +- 0.27 (PDG)) x 10^-3. This study is based on a
357 fb^-1 data sample recorded on the Upsilon(4S) resonance with the Belle
detector at the KEKB asymmetric-energy e+e- collider.

28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
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The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
10
The categories of this paper are: q-bio