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arXiv · hep-ph/9403272

An Interesting Charmonium State Formation and Decay : $p \bar p \to ^1D_2 \to ^1P_1 γ$

M. Anselmino·F. Caruso·F. Murgia·M. R. Negrao
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Abstract

Massless perturbative QCD forbids, at leading order, the exclusive annihilation of proton-antiproton into some charmonium states, which, however, have been observed in the $p\bar p$ channel, indicating the significance of higher order and non perturbative effects in the few GeV energy region. The most well known cases are those of the $^1S_0$ ($η_c$) and the $^1P_1$. The case of the $^1D_2$ is considered here and a way of detecting such a state through its typical angular distribution in the radiative decay $^1D_2 \to$ $^1P_1 γ$ is suggested. Estimates of the branching ratio $BR(^1D_2 \to p\bar p)$, as given by a quark-diquark model of the nucleon, mass corrections and an instanton induced process are presented.

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M. Anselmino, F. Caruso, F. Murgia, M. R. Negrao. 1994-03-11. An Interesting Charmonium State Formation and Decay : $p \bar p \to ^1D_2 \to ^1P_1 γ$. https://doi.org/10.1103/physrevd.51.2478

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