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arXiv · 1705.01179

Light-by-light forward scattering sum rules for charmonium states

Igor Danilkin·Marc Vanderhaeghen
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Abstract

We apply three forward light-by-light scattering sum rules to charmonium states. We show that these sum rules imply a cancellation between charmonium bound state contributions, which are mostly known from the $γγ$ decay widths of these states, and continuum contributions above $D \bar D$ threshold, for which we provide a duality estimate. We also show that two of these sum rules allow to predict the yet unmeasured $γ^\ast γ$ coupling of the $χ_{c1}(1P)$ state, which can be tested at present high-luminosity $e^+ e^-$ colliders.

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Igor Danilkin, Marc Vanderhaeghen. 2017-08-25. Light-by-light forward scattering sum rules for charmonium states. https://doi.org/10.1103/physrevd.96.056003

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