Model-Independent Determination of the Spin of the ?- and Its Polarization Alignment in ?(3686) ? ?-(?)over-bar+

Abstract

We present an analysis of the process psi(3686) -> Omega(-)(Omega) over bar (+)(Omega(-). K-Lambda, (Omega) over bar (+) K+ (Lambda) over bar,(Omega) over bar (+) Lambda -> p pi(-), (Lambda) over bar -> p (p) over bar pthorn) based on a dataset of 448 x 10(6) psi(o3686) decays collected with the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process psi(368)-> O-O thorn and the decay parameters of the subsequent decay O-. K-. oO thorn. Kthorn. THORN are measured for the first time by a fit to the angular distribution of the complete decay chain, and the spin of the O- is determined to be 3=2 for the first time since its discovery more than 50 years ago.