A. Simon

Measurement of the lifetime

We present the measurement of the lifetime of the Omega_c we have performed using three independent data samples from two different decay modes. Using a Sigma- beam of 340 GeV/c we have obtained clean signals for the Omega_c decaying into Xi- K- pi+ pi+ and Omega- pi+ pi- pi+, avoiding topological cuts normally used in charm analysis. The short but measurable lifetime of the Omega_c is demonstrated by a clear enhancement of the signals at short but finite decay lengths. Using a continuous maximum likelihood method we determined the lifetime to be tau(Omega_c) = 55 +13-11(stat) +18-23(syst) fs. This makes the Omega_c the shortest living weakly decaying particle observed so far. The short value of the lifetime confirms the predicted pattern of the charmed baryon lifetimes and demonstrates that the strong interaction plays a vital role in the lifetimes of charmed hadrons.

Search for the pentaquark candidate Θ(1540)+ in the hyperon beam experiment WA89

We report on a high-statistics search for the {theta}(1540){sup +} resonance in {sigma}{sup -}-nucleus collisions at 340 GeV/c. No evidence for this resonance was found in our data sample which contains 13 million K{sub s}{sup 0}{yields}{pi}{sup +}{pi}{sup -} decays above background. For the decay channel {theta}{sup +}{yields}K{sub s}{sup 0}p and the kinematic range x{sub F}> 0.05, we find the production cross section to be BR({theta}{sup +}{yields}K{sub s}{sup 0}p){sigma}{sub 0}<1.8 {mu}b per nucleon at 99% C.L.

Search for the exotic Ξ--(1860) resonance in 340 GeV/c Σ- -nucleus interactions

We report on a high statistics search for the

Xi- production by Sigma-, pi- and neutrons in the hyperon beam experiment at CERN

Xi^{--}(1860)

V-0, (Xi)over-bar(+) and Omega(-) inclusive production cross sections measured in hyperon experiment WA89 at CERN

resonance in

A measurement of Lambda polarization in inclusive production by Sigma- of 340-GeV/c in C and Cu targets

Sigma^-

A study of \(\Sigma^{\pm}\), \(\Sigma^{*\pm}\) and \(\overline{\Sigma}^-_{1385}\) production in the hyperon beam experiment WA89 at CERN

-nucleus collisions at 340GeV/c. No evidence for this resonance is found in our data sample which contains 676000

First observation of the

Xi^-

\Xi^{-} \pi^{+}

candidates above background. For the decay channel

decay mode of the

Xi^{--}(1860) to Xi^-pi^-