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arXiv · 0804.2180

Two-photon decay of pseudoscalar quarkonia

J. P. Lansberg·T. N. Pham
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Abstract

We report on our recent evaluation of the two-photon width of the pseudoscalar quarkonia, eta_c(nS) and eta_b(nS) in an approach based on Heavy-Quark Spin Symmetry (HQSS). To what concerns the 1S state eta_c, our parameter-free computation agrees with experiments, as well as most of other theoretical works. On the other hand, our computation for the 2S-state looks 2S like a confirmation that there may exist an anomaly related to the decay of eta_c(2S), especially in the light of the new preliminary result of the Belle collaboration. We also point out that the essentially model-independent ratio of eta_b two-photon width to the Upsilon leptonic width and the eta_b two-photon width could be used to extract the strong coupling constant alpha_s.

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J. P. Lansberg, T. N. Pham. 2008-04-14. Two-photon decay of pseudoscalar quarkonia. https://doi.org/10.1063/1.2987179

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