Violation of|ΔI|=12Rule in theKπ3

Abstract

The experimental value of the branching ratio T(K 2° -^x + +7r~+7r°)/r(i£ + ->7r + +7r~+7r 0 ) obtained by Alexander et al. differs from the prediction of the A/ = J rule by 30%. We assume that the major part of the violation of the A/ = \ rule in K v $ decay comes from the chain of processes K° -> r\ -» 7r + +7r~-j-7r°, as pointed out by Bouchiat et al. With this assumption, we get a relation between the coupling constant / 2 iey/47r and the width T(V -»7r + +7r~+7r°). We use the experimental value of the branching ratio r(?? -> neutrals)/r (rj -> 7r + -{-7r~-f-7r 0 ) ~ 3.0 to infer the unknown branching ratio r(r)°-*2y)/r(r}°->Tr + -\-7r~-\-Tr°) and the theory of unitary symmetry to deduce the value of the width T(Y)° -> 27) from the experimental decay rate of ir° -> 2y. Further, if only pion and 77-meson pole terms are responsible for the mass difference m(Ki°) -m(K 2°) , we can also derive the value of the coupling constant /W 0 /^. These two coupling constants / 2 xV/4T and j^x V/4TT are illustrated as a function of the deviation x from the Al = J rule. Under the same assumption we obtain a result that r (K 2° -• > 2y) is comparable to r (K 2° -> 7r + +7r~+7r°) or is negligibly small according as /KV and /KV are of the same sign or not. If the deviation x = 30% is really correct, the decay rate of 2~->?7-f-7r~ can be explained with g 2 2°nK 0 /4:ir<l. On the other hand, if the extended A/ = J rule is valid for the couplings of K-ir and K-rj, we obtain the following results: #=15%, m(Ki 0 )<m (K 2°) , /VV°/47r = 2.8XlCr 16 , T(K 2° -> 2 7 ) = 8X10 3 sec" 1 and the decay rate 2T -» n+ir~ can be fitted with g 2 2°»W4"7r~6. Precise experiments are desired on the decay K 2° -> 2y as well as on the decay K 2 Q -» 71-++7r--r-7r°.I F the I Al I = 1/2 rule were valid, the rate of K 2° -»7r++7r~+7r 0 decay can be related to that of K+-7r + +7r°+7r 0 decay.

Measurement of the two photon decay of the K_L⁰ meson

“…5 Bev/c steps from 1 Bev/c to 8 B~V / C and over the decay points in .5 ft steps ' from -1 f t to -7 f t for Run 4, and from -1 f t t'o -9 f t for Runs 6 and 7.…”