Fifth force finished?

Recent experiments involving the decay of $K20$ mesons indicate that a proposed fifth fundamental force does not appear to exist. The new force had been suggested as an explanation for the discovery by J. H. Christenson and collaborators, that $K20$ mesons seemed to decay into $π+$ and $π−.$ This decay is forbidden by $CP$ invariance, which requires that in particle interactions, the eigenvalue of the product of the charge conjugation operator, C, and the parity operator, P, remain the same. If $CP$ invariance is violated, this implies that time is not reversible in the interaction, since the product of C, P, and T (the time reversal operator) is believed to be conserved.