Extraction of the CKM angle $\gamma$ from the new "mixed " system of $B^{+}\to {\pi }^{+}{K}^0$ and $B_d^0\to {\pi }^0{K}^0$ decays

Abstract

In this paper we try to extract the CKM angle $\gamma$ from the new "mixed" system of $B^{+}\to {\pi }^{+}{K}^0$ and $B_d^0\to {\pi }^0{K}^0$ decays. We also made an update for the constraints on the angle $\gamma$ from the observables $R$ and $A_0$. In the parametrization, the SU(2) isospin symmetry of strong interactions has been applied. We found the following results: (a) the measured value of $R$ is now very close to unit, the bound on the angle $\gamma$ from the measurement of $R$ is therefore not as promising as before, but some bounds on $\gamma$ can still be read off from $r-\gamma$ plane if $r$ could be fixed by using an additional input; (b) the measured $R_1$ implies a limit on the strong phase ${\Delta }_1$; (c) due to the contribution from the color allowed electroweak penguin, the minimal value of $R_1$ can be larger than unit. For ${ϵ}_1=0.2$ and $R_1=1.2$, the range of $65^{\circ }\le \gamma \le 115^{\circ }$ will be excluded, such bounds on $\gamma$ are interesting and complimentary to the limits from global fit; (d) the dependences of extraction of $\gamma$ on the variation of parameters ${ϵ}_1$, $\rho$, $r_1$ and strong phases are also studied.

Comments: 22 pages, Latex file, 12 EPS figures. two typos are corrected. To be published in Phys. Rev. D