Effects of isospin violation in the $e^+e^- \rightarrow B^{(*)}\bar B^{(*)}$ cross sections

A. E. Bondar; A. I. Milstein; R. V. Mizuk; S. G. Salnikov

doi:10.1007/jhep05(2022)170

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arXiv · 2204.03961

Effects of isospin violation in the $e^+e^- \rightarrow B^{()}\bar B^{()}$ cross sections

A. E. Bondar·A. I. Milstein·R. V. Mizuk·S. G. Salnikov

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Abstract

Model estimates are obtained for the influence of Coulomb effects on the ratio of the cross sections for the production of charged and neutral $B\bar B$ and $B^*\bar B^*$ pairs in $e^+e^-$ annihilation. It is shown that the difference between the masses of charged and neutral mesons obtained under the assumption that this ratio is constant on a scale of the order of the beam energy spread can differ from the true one by $\delta M \sim 0.03\,\mbox{MeV}$ at the energy of $\Upsilon (5S)$ and by $\delta M \sim 0.4\,\mbox{MeV}$ at the energy of $\Upsilon (4S)$. Thus, the errors given in the PDG for the difference between the masses of charged and neutral $B$ mesons, based on the results obtained at the energy of $\Upsilon (4S)$, are strongly underestimated. Similar measurements at the energy of $\Upsilon (5S)$ will have an order of magnitude smaller systematic shift for the mass difference. This circumstance should be taken into account when planning future experiments at the $B$ factory in KEK.

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A. E. Bondar, A. I. Milstein, R. V. Mizuk, S. G. Salnikov. 2022-04-08. Effects of isospin violation in the $e^+e^- \rightarrow B^{(*)}\bar B^{(*)}$ cross sections. https://doi.org/10.1007/jhep05(2022)170

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