Partial wave analysis of $\bar pp \to \bar \Lambda \Lambda$

Abstract

A partial wave analysis of PS185 data for $\bar pp \to \bar \Lambda \Lambda$ is presented. A 3 S 1 cusp is identified in the inverse process $\bar \Lambda \Lambda \to \bar p p$ at threshold, using detailed balance to deduce cross sections from $\bar pp \to \bar \Lambda \Lambda$ . Partial wave amplitudes for $\bar pp$ 3 P 0, 3 F 3, 3 D 3 and 3 G 3 exhibit a behaviour very similar to resonances observed in Crystal Barrel data. With this identification, the $\bar pp \to \bar \Lambda \Lambda$ data then provide evidence for a new I = 0, J PC = 1- resonance with mass $M = 2290 \pm 20$ MeV, $\Gamma = 275 \pm 35$ MeV, coupling to both 3 S 1 and 3 D 1.