Role of multichannel pi pi scattering in decays of bottomia

TL;DR

This paper investigates how multichannel pi pi scattering influences Upsilon-meson decays, explaining spectral features through coupled-channel effects without revealing new insights into f0 mesons.

Contribution

It introduces a model-independent analysis of final state interactions in Upsilon decays, explaining spectral shapes via coupled-channel effects.

Findings

The two-humped di-pion mass distribution in Upsilon(3S) -> Upsilon(1S) pi pi is explained by coupled-channel effects.

Bottomia decay data do not provide new information on the nature of f0 mesons.

Final state interactions are crucial for understanding decay spectra.

Abstract

The effect of isoscalar S-wave multichannel pi pi -> pi pi, K antiK, eta eta scattering is considered in the analysis of decay data of the Upsilon-mesons. We show that when allowing for the final state interaction contribution to the decays Upsilon(mS) -> Upsilon(nS) pi pi (m>n, m=2,3, n=1,2) in our model-independent approach, we can explain the two-pion energetic spectra of these Upsilon transitions including the two-humped shape of the di-pion mass distribution in Upsilon(3S) -> Upsilon(1S) pi pi as the coupled-channel effect. It is shown also that the considered bottomia decay data do not offer new insights into the nature of the f0 mesons, which were not already deduced in our previous analyses of pseudoscalar meson scattering data.