Test ofΔS=ΔQin the Time Distribution ofKl30Decays

Abstract

\Ve have investigated the weak-interaction AS =AQ selection rule in the time distribution of leptonic decays of neutral K mesons. From a sample of approximately 20 000 visible K mesons produced in the reaction^-p-Eon in the BNL 30-in. liquid-hydrogen bubble chamber, we have identified Kr i e i v (92 events); Kr;'pfv (24 events): K -i~l v , 1 charge ambiguous K -r+l ITv, 1 mass ambiguous (10 events); K -rr+ T -y , p y > 90 iVleV/c ) (72 events) . We present a maximum-likelihood determination of the amplitude ratio x = A (AS = -08 ) / A (AS = +AQ ) . Our sample of charge-identified muon and electron events yields Rex, =0.19?8:1! , I-, =0.16+!:i! , Rexp =0.35+8::;, 1 m r~= 0 . 4 2~~:~~ .Combining all 126 of our charge-identified leptonic decays, we obtain as our best resultThe AS = M prediction Rex = Imv = O lies on the 2.4-standard-deviation contour of this result.