Strong decays and dipion transitions of Upsilon(5S)

TL;DR

This paper investigates the dipion transitions of the Upsilon(5S) state using the Field Correlator Method, successfully reproducing experimental spectra and decay widths, and extending previous work on lower Upsilon states.

Contribution

It applies the Field Correlator Method to analyze Upsilon(5S) dipion transitions, fixing parameters from earlier studies and calculating decay widths and spectra with good experimental agreement.

Findings

Calculated decay widths match experimental data.

Reproduced $ ext{ππ}$ spectra including FSI effects.

Extended the method to the Upsilon(5S) state.

Abstract

Dipion transitions of $\Upsilon (nS)$ with $n=5, n'=1,2,3$ are studied using the Field Correlator Method, applied previously to dipion transitions with $n=2,3,4$ The only two parameters of effective Lagrangian were fixed in that earlier study, and total widths $\Gamma_{\pi\pi} (5, n')$ as well as pionless decay widths $\Gamma_{BB} (5S), \Gamma_{BB^*} (5S), \Gamma_{B^*B^*}(5S)$ and $\Gamma_{KK} (5, n')$ were calculated and are in a reasonable agreement with experiment. The experimental $\pi\pi$ spectra for $(5,1)$ and (5,2) transitions are well reproduced taking into account FSI in the $\pi\pi$.