PoS - Proceedings of Science
Volume 390 - 40th International Conference on High Energy physics (ICHEP2020) - Posters: Strong Interactions and Hadron Physics
Inclusive $\Upsilon (1S) \to \eta^{(\prime)} + X$ Decays with Account of $\alpha_s$ Running in Effective $\eta^{(\prime)} g^* g$-Vertex
A. Parkhomenko,* A. Ali, A.V. Rusov
*corresponding author
Full text: pdf
Pre-published on: February 10, 2021
Published on:
Abstract
The $\eta^\prime$-meson energy spectrum in the inclusive $\Upsilon (1S) \to \eta^{(\prime)} g g g \to \eta^{(\prime)} + X$ decay measured by the CLEO Collaboration in 2002 allowed one to constrain the lowest Gegenbauer coefficients $B^q_2$ and $B^g_2$ of the quark-antiquark and gluonic distribution amplitudes of the $\eta^\prime$-meson entering the $\eta^\prime g^* g$ effective vertex function (EVF). The fitting procedure of the CLEO data on the hard part of the $\eta^\prime$-meson energy spectrum was based on the theoretical expression calculated in the leading-order perturbative QCD in the static-quark limit for the orthoquarkonium. The resulting constraints were combined with the existing ones on these coefficients from an analysis of the $\eta^\prime - \gamma$ transition form factor. The updated measurements of the $\eta^\prime$-meson energy spectrum by the CLEO Collaboration in 2006 are not in accord with the so-calculated theoretical $\eta^\prime$-energy spectrum. As a first step, we incorporate the dependence of the strong coupling constant in the $\eta^\prime g^* g$ EVF on the quark energy and determine the Gegenbauer coefficients. With this values we compute the $\eta$- and $\eta$-meson energy spectra in the inclusive decay $\Upsilon (1S) \to \eta^{(\prime)} g g g \to \eta^{(\prime)} + X$, which can be tested against the high statistics Belle and Belle-II data from $\Upsilon (1S)$-decays.
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.