A new KL0 decay channel

Abstract

Abstract In this Letter the rate for the decay K L 0 ⇒ K ± e ∓ ( ν ¯ / ν ) of ( 0.0979 ± 0.0037 ) s −1 has been calculated in the hypothesis of the conserved vector current and, assuming the CP violation very small, the two rates for the decay K L 0 ¯ ⇒ K − e + ν and K L 0 ⇒ K + e − ν ¯ are foreseen very similar. Such a decay was never taken into account in the past, due to the very low phase space factor yielding a branching ratio for K L decay BR = ( 0.5071 ± 0.0199 ) × 10 −8 . Now, with the very intense K beams foreseen at KEK, J-PARC, BNL, CERN and LNF the observation of this decay seems feasible. With samples of very large statistical significance a new measurement of the indirect CP violation parameter ϵ could be done.