New measurements of properties of the. cap omega. /sup -/ hyperon

Journal Article · Fri Jul 01 00:00:00 EDT 1988 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.38.19· OSTI ID:7148717

Luk, K B; Beretvas, A; Deck, L; Devlin, T; Rameika, R; Whitman, R; Handler, R; Lundberg, B; Pondrom, L; Sheaff, M; others, and

We have obtained a sample of 1743 reconstructed ..cap omega../sup -/..--> lambda..K/sup -/ events produced by protons on a Be target at production angles of 5.0 and 7.5 mrad. The ..cap omega../sup -/ lifetime, based on a subset of 1096 events, was measured to be tau(..cap omega../sup -/) = (0.811 +- 0.037) x 10/sup -10/ sec, where the uncertainty is statistical and the systematic uncertainty is estimated to be small. The helicity of the daughter ..lambda.. yielded the product of asymmtery parameters ..cap alpha../sub ..lambda../..cap alpha../sub ..cap omega../ = -0.022 +- 0.051 which, in turn, yields ..cap alpha../sub ..cap omega../ = -0.034 +- 0.079. The average daughter-..lambda.. polarization in the decay region was measured to be P/sub ..lambda../ = 0.12 +- 0.08 approximately perpendicular to the charged-hyperon beam line. The ..cap omega../sup -/ polarization in the same region, i.e., after the precession magnet, depends on the sign of ..gamma../sub ..cap omega../, which is unknown at present. The two possibilities are P/sub ..cap omega../ = P/sub ..lambda../ if ..gamma../sub ..cap omega../approx. =+1 and P/sub ..cap omega../ = -(5/3P/sub ..lambda../ if ..gamma../sub ..cap omega../approx. =-1. The magnitude of the polarization vector is only 1.5 standard deviations different from zero, and this prevented a meaningful measurement of the ..cap omega../sup -/ magnetic moment. If the broken-SU(6) prediction for the moment, ..mu..(..cap omega../sup -/) = -1.83..mu../sub N/, is assumed to be true, then the precession of the ..cap omega../sup -/ in the magnetic field is small and the values of P/sub ..cap omega../ above are also true at the production target. If this polarization is different from zero and correct in sign, then it cannot be simultaneously reconciled with theoretical predictions for the sign of ..gamma../sub ..cap omega../ and for the sign of the production polarization.

• Research Organization: Department of Physics and Astronomy, Rutgers: The State University, P.O. Box 849, Piscataway, New Jersey 08854
• OSTI ID: 7148717
• Journal Information: Phys. Rev. D; (United States), Vol. 38:1
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
OMEGA PARTICLES
PARTICLE PRODUCTION
WEAK HADRONIC DECAY
ASYMMETRY
BERYLLIUM 9 TARGET
EXPERIMENTAL DATA
GEV RANGE 100-1000
HELICITY
INCLUSIVE INTERACTIONS
KAONS MINUS
LAMBDA PARTICLES
LIFETIME
MAGNETIC MOMENTS
MULTIWIRE PROPORTIONAL CHAMBERS
POLARIZATION
PROTON REACTIONS
SCINTILLATION COUNTERS
SU-6 GROUPS
BARYON REACTIONS
BARYONS
BOSONS
CHARGED-PARTICLE REACTIONS
DATA
DECAY
ELEMENTARY PARTICLES
ENERGY RANGE
FERMIONS
GEV RANGE
HADRON REACTIONS
HADRONS
HYPERONS
INFORMATION
INTERACTIONS
KAONS
LAMBDA BARYONS
LIE GROUPS
MEASURING INSTRUMENTS
MESONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUMERICAL DATA
OMEGA BARYONS
PARTICLE DECAY
PARTICLE INTERACTIONS
PARTICLE PROPERTIES
PROPORTIONAL COUNTERS
PSEUDOSCALAR MESONS
RADIATION DETECTORS
STRANGE MESONS
STRANGE PARTICLES
SU GROUPS
SYMMETRY GROUPS
TARGETS
WEAK PARTICLE DECAY
645102* - High Energy Physics- Particle Interactions & Properties-Experimental- Weak Interactions & Properties