Search for the pentaquark candidate ${\Theta }^{+}$(1540) in the hyperon beam experiment WA89

Abstract

We report on a high-statistics search for the \t1540 resonance in ${\Sigma }^{-}$-nucleus collisions at 340 \gevc1 . No evidence for this resonance was found in our data sample which contains 13 millions $K_s^0\to {\pi }^{+}{\pi }^{-}$ decays above background. For the decay channel ${\Theta }^{+}\to K_s^{0}p$ and the kinematic range $x_F>$ 0.05 we find the production cross section to be $BR({\Theta }^{+}\to K_s^{0}p)\cdot {\sigma }_0<$ 1.8 $\mu$b per nucleon at 99% CL.

5 pages, 4 figures