Observation of two charged bottomonium-like resonances

TL;DR

This paper reports the discovery of two narrow charged bottomonium-like resonances at approximately 10610 and 10650 MeV/c^2 in Upsilon(5S) decays, providing new insights into exotic hadron states.

Contribution

First observation of two charged bottomonium-like resonances in Upsilon(5S) decays, with detailed measurements of their masses, widths, and quantum numbers.

Findings

Resonances at 10610 and 10650 MeV/c^2 observed

Measured widths are approximately 15.6 and 14.4 MeV

Quantum numbers favor I^G(J^P)=1^+(1^+) for both states

Abstract

We report the observation of two narrow structures at 10610MeV/c^2 and 10650MeV/c^2 in the pi^{\pm}Upsilon(nS) (n=1,2,3) and pi^{\pm}h_b(mP) (m=1,2) mass spectra that are produced in association with a single charged pion in Upsilon(5S) decays. The measured masses and widths of the two structures averaged over the five final states are M_1=10608.4\pm2.0MeV/c^2, Gamma_1=15.6\pm2.5MeV and M_2=10653.2\pm1.5MeV/c^2, Gamma_2=14.4\pm3.2MeV. Analysis favors quantum numbers of I^G(J^P)=1^+(1^+) for both states. The results are obtained with a 121.4fb^{-1} data sample collected with the Belle detector near the Upsilon(5S) resonance, at the KEKB asymmetric-energy e+e- collider.