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arXiv · 1703.04682

$χ_c$ decays and the gluon content of the $η'$, $η$ mesons

L. A. Harland-Lang·V. A. Khoze·M. G. Ryskin·A. G. Shuvaev
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Abstract

The large mass of the $η'$ meson indicates that a sizeable gluon component is present in the meson wave function. However, the $χ_{c0}$ and $χ_{c2}$ decays to $η'$ mesons, which proceed via a purely gluonic intermediate state and we would therefore naïvely expect to be enhanced by such a component, are in fact relatively suppressed. We argue that this apparent contradiction may be resolved by a proper treatment of interference effects in the decay. In particular, by accounting for the destructive interference between the quark and gluon components of the $η'$ distribution function, in combination with a model for strange quark mass effects, we demonstrate that the observed $χ_{c(0,2)}\toη(')η(')$ branching ratios can be reproduced for a reasonable gluon component of the $η'$, $η$ mesons.

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L. A. Harland-Lang, V. A. Khoze, M. G. Ryskin, A. G. Shuvaev. 2017-04-25. $χ_c$ decays and the gluon content of the $η'$, $η$ mesons. https://doi.org/10.1016/j.physletb.2017.04.046

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