Direct Observation of PI-2(1680) in the RHO-0-PI-System

In the reaction of x- dissociation into a p+p-z'- system on a Cu nucleus, a clear enhancement in the poz- effective-mass distribution has been observed in the 1;2( 1680) region. Partial-wave analysis shows that this enhancement is due to the P-wave and has a resonant nature. Coherent and incoherent cross-sections for this enhancement have been measured