Hyperon decays revisited

Study of the rare hyperon decay

“…Contrary to theoretical expectation [2,10], we see little evidence for the resonant decay. To derive an upper limit on the resonant contribution including both statistical and systematic uncertainties, we performed a Monte Carlo simulation of a large sample of hypothetical experiments that took into account the probability distribution from the unbinned maximum-likelihood fit as well as the uncertainty in the branching-ratio normalizing factor (treated as Gaussian-distributed).…”

“…The Ω − is the only ground-state hyperon massive enough to have such a ∆S = 1, three-body, nonleptonic weak decay. This decay has long been assumed by theorists to proceed predominantly via the Ξ * 0 1530 intermediate state [1,2]. Based on four observed Ω − → Ξ − π + π − events, Bourquin et al established the best previous measurement of the branching ratio: B(Ω − → Ξ − π + π − ) = 4.3 +3.4 −1.3 × 10 −4 [3].…”

“…However, they were unable to distinguish the nonresonant channel from the resonant Ω − → Ξ * 0 1530 π − → Ξ − π + π − decay. In interpreting this observation, the Particle Data Group (PDG) adopted the assumption by Finjord and Gaillard [2] that the Ξ − π + π − final state in Ω − decay arises entirely from the Ξ * 0 [4]. Yet, until now, that assumption has not been tested by experiment.…”

Measurement of theΩ−magnetic moment

“…The decay parameter y^ has not been directly measured, but the valueof the decay parameter ttj^-( -0.026 ±0.026) [25] The implies /j^2~ 1. The sign of /n is predicted to be positive [26][27][28]. The A polarization was determined by measuring the asymmetry in the distribution of the decay proton in the A rest frame, which is given by…”

Rare Nonleptonic Decays of the Omega Hyperon: Measurements of the Branching Ratios for Ω^∓ --> Ξ$*0\atop{(1530)}$ (anti-Ξ$*0\atop{(1530)}$) π^∓ and Ω^∓→ Ξ^∓ π^± π^∓

“…The type-1 weak interaction was thought to dominate and the rough estimate of the decay-rate ratio yielded A standard QCD-inspired description was examined in [10]. It was assumed that the decay proceeds through the resonance channel (1.2), "as suggested by the data" from [2], where a search for Ω …”