Observation of $e^+e^-\to\omega\chi_{bJ}(1P)$ and search for $X_b \to \omega\Upsilon(1S)$ at $\sqrt{s}$ near 10.75 GeV

TL;DR

This study reports the first observation of $e^+e^- o ext{omega} ext{chi}_{bJ}(1P)$ at 10.745 GeV, analyzes energy dependence related to the $
0753$ state, and searches for an $X_b$ state decaying into $ ext{omega} ext{Upsilon}(1S)$, finding no significant signal.

Contribution

First observation of $e^+e^- o ext{omega} ext{chi}_{bJ}(1P)$ at a specific energy and analysis of its energy dependence related to the $
0753$ state, providing insights into bottomonium structures.

Findings

Observation of $ ext{omega} ext{chi}_{bJ}(1P)$ signals at 10.745 GeV

Energy dependence consistent with the $
0753$ state

No significant $X_b$ signal observed between 10.45 and 10.65 GeV/$c^2$

Abstract

We study the processes $e^+e^-\to\omega\chi_{bJ}(1P)$ ($J$ = 0, 1, or 2) using samples at center-of-mass energies $\sqrt{s}$ = 10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, and 4.7 fb$^{-1}$ of integrated luminosity, respectively. These data were collected with the Belle II detector during special operations of the SuperKEKB collider above the $\Upsilon(4S)$ resonance. We report the first observation of $\omega\chi_{bJ}(1P)$ signals at $\sqrt{s}$ = 10.745 GeV. By combining Belle II data with Belle results at $\sqrt{s}$ = 10.867 GeV, we find energy dependencies of the Born cross sections for $e^+e^-\to \omega\chi_{b1,b2}(1P)$ to be consistent with the shape of the $\Upsilon(10753)$ state. These data indicate that the internal structures of the $\Upsilon(10753)$ and $\Upsilon(10860)$ states may differ. Including data at $\sqrt{s}$ = 10.653 GeV, we also search for the bottomonium equivalent of the $X(3872)$ state decaying into $\omega\Upsilon(1S)$. No significant signal is observed for masses between 10.45 and 10.65 GeV/$c^2$.