Study of $\chi_{b1,2}(2P) \to \omega \Upsilon(1S)$ transitions in $\Upsilon(3S) \to \gamma \chi_{b1,2}(2P)$ decays at BaBar

TL;DR

This study reports precise measurements of specific bottomonium state transitions involving omega and upsilon particles, using BaBar data, with new angular distribution measurements and no evidence for certain decay modes.

Contribution

It provides the first measurements of the angular distributions of $ ext{chi}_{b1,2}(2P)$ transitions and improves the precision of their branching fractions.

Findings

Signals observed with negligible background.

First angular distribution measurements performed.

No evidence for $ ext{chi}_{b0}(2P) o extomega extUpsilon(1S)$ decay.

Abstract

Results are presented on $\chi_{b1,2}(2P) \to \omega \Upsilon(1S)$ transitions from $e^+e^- \to \Upsilon(3S) \to \gamma \chi_{b1,2}(2P)$ decays. The data were collected with the BaBar detector at the PEP-II asymmetric-energy $e^+e^-$ collider at SLAC. The integrated luminosity of the data sample is 28.0 fb$^{-1}$, corresponding to $121.3 \times 10^6$ $\Upsilon(3S)$ decays. Signals of $\chi_{b1,2}(2P)$ are observed over a negligible background. Improved precision measurements of branching fractions are obtained. First measurements of the $\chi_{b1,2}(2P)$ angular distributions are performed. No evidence is found for the presence of a $\chi_{b0}(2P) \to \omega \Upsilon(1S)$ decay mode.