Isospin Amplitude Analysis of $B o \pi\pi$ Decays within the Standard Model

摘要

Taking into account the recent measurements of the branching ratios and CPasymmetries in the $B \to \pi\pi$ decays by the BABAR and BELLE collaborations,an amplitude analysis based on the isospin symmetry is reported. These dataallow to get an independent determination of the CKM unitarity-triangle angle$\gamma$. One of the best-fit solutions gives the range $\gamma = (65 \pm5)^\circ$, in excellent agreement with the global CKM fit within the StandardModel. The other parameters from this fit confirm the earlier analyses that thedata on $B \to \pi\pi$ decays require various topological amplitudes(neglecting the electroweak ones) to be of comparable magnitude with largestrong-phase differences.