The analysis presented has been done with the BABAR detector located at the PEP-II collider, Stanford. The channels B0 to pi+pi- and K+pi- are analyzed to measure their branching ratios and to study CP violation. The aim is to measure the angle alpha of the unitarity triangle of the CKM matrix. The analysis implies a thorough understanding of B physics. A new tool of validation of generic analyses like the present one is presented. The phenomenological interpretation of the results is performed using the CKMFitter package, within two different theoretical frameworks. The recent results of the Belle experiment are discussed as well. News on the isospin analysis from B to pipi are given.
