Abstract
The weak decay parameter of the is an important quantity for the extraction of polarization observables in various experiments. Moreover, in combination with from decay it provides a measure for matter-antimatter asymmetry. The weak decay parameter also affects the decay parameters of the and baryons and, in general, any quantity in which the polarization of the is relevant. The recently reported value by the BESIII Collaboration of 0.750(9)(4) is significantly larger than the previous PDG value of 0.642(13) that had been accepted and used for over 40 years. In this work we make an independent estimate of , using an extensive set of polarization data measured in kaon photoproduction in the baryon resonance region and constraints set by spin algebra. The obtained value is 0.721(6)(5). The result is corroborated by multiple statistical tests as well as a modern phenomenological model, showing that our new value yields the best description of the data in question. Our analysis supports the new BESIII finding that is significantly larger than the previous PDG value. Any experimental quantity relying on the value of should therefore be reconsidered.
- Received 19 April 2019
- Revised 9 September 2019
DOI:https://doi.org/10.1103/PhysRevLett.123.182301
© 2019 American Physical Society