Professor Brian Foster OBE, FRS

Abstract:

An additive diquark model is proposed to relate the forward cross sections of meson-baryon quasi-two-body reactions. The model consists of a quark-diquark structure for baryons combined with additivity of quark-(di)quark amplitudes. Good agreement is found between this model, which contains only one free parameter, and a large body of experimental data for charge-exchange and strangeness-exchange meson-baryon two-body reactions. This is in contrast to the SU(6)-symmetric additive quark model which disagrees violently with the data. © 1979 The American Physical Society.

Abstract:

An enhancement in the (ΣK) mass spectrum at threshold is observed in K-p interactions at 4.2 GeV/c. It appeats both in the neutral and negative charge states. Corresponding ΛK mass distributions show weak evidence for an effect close to this threshold (∼1680 MeV). Although the interpretation of the (ΣK) enhancement by itself is ambiguous, a (ΣK)-(ΛK) coupled channel analysis gives results compatible with its interpretation as a new Ξ*. © 1978.

Abstract:

Forty Ω- events have been observed in a large (133 events/βb) experiment at 4.2 GeV/c incident K- momentum. Thirty nine of the events come from the three-body reaction K-p→Ω-K+K0. The Ω- is mainly produced in the forward hemisphere (direction of the incident K-). The lifetime is measured to be τ = (0.75 +0.14-0.11 × 10-10 sec substantially less than the Particle Data Group value of (1.3 -0.3+0.2) × 10-10 sec. The mass is determined to be 1671.7 ± 0.6 MeV, in good agreement with other determinations. The decay asymmetry parameter α (for the decay mode Ω- → ΛK-) is found to be -0.2 ± 0.4. © 1978.