arXiv subjects

M. Shifman

Publications and source records attributed to M. Shifman.

200 records · Page 12Linked to original sources

arXiv1992

Nonleptonic decays of K mesons revisited

We estimate nonfactorizable 1/$N_c$ contributions in the $K\rightarrow 2π$ amplitudes using the approach proposed in our previous work. It is demonstrated that for the conventional (nonpenguin) operators these contributions are close in magnitude to factorizable $1/N_c$ parts and have the opposite sign. Thus, an approximate rule of discarding $1/N_c$ corrections in $K\rightarrow 2π$ decays is theoretically confirmed. As a result we find an extra suppression of the matrix element of $O_4$ ($ΔI=3/2$) and an extra enhancement of the matrix element of $O_1$ ($ΔI=1/2$). The parameter $B$ describing $K^0-\bar K^0$ mixing is also discussed.

hep-ph↗

arXiv1992

Nonfactorizable Amplitudes in Weak Nonleptonic Decays of Heavy Mesons

We discuss nonfactorizable $1/N_c$ contributions in the amplitudes of non-leptonic exclusive decays of the type $B\rightarrow Dπ$ ($N_c$ is the number of colors). In a certain kinematical limit rather reliable estimates are possible. It is demonstrated that the nonfactorizable parts are of the same order as the factorizable $1/N_c$ parts of the ampiltudes, and have the opposite sign. Thus, an approximate rule of discarding $1/N_c$ corrections in the nonleptonic exclusive decays emerges dynamically. It is shown that this rule is not exact and the degree of compensation is different in different channels. Our predictions make use of the fact that a key matrix element that measures deviations from factorization can be determined using the heavy quark effective theory.

hep-ph↗