Experimental study of χb(2P)→ππχb(1P)

Abstract

We have searched for the di-pion transition χb(2P) →ππχb(1P) in the CLEO III sample of Υ(3S) decays in the exclusive decay chain: Υ(3S)→γχb(2P), χb(2P) →ππχb(1P), χb(1P)→γΥ(1S), Υ(1S)→ℓ+ℓ-. Our studies include both π+π- and π0π0, each analyzed both in fully-reconstructed events and in events with one pion undetected. We show that the null hypothesis is not substantiated. Under reasonable assumptions, we find the partial decay width to be Γ(χb(2P)→ππχb(1P))=(0.83±0.22±0. 08±0.19)keV, with the uncertainties being statistical, internal CLEO systematics, and common systematics from outside sources. © 2006 The American Physical Society.