Measurement of the CKM angle alpha/phi2 with B -> rho rho decays at Belle and BABAR

We overview recent measurements in B -> rho rho decays which are based on data samples collected at the PEP-II and KEKB asymmetric-energy e+e- colliders with the BABAR and Belle detectors. Special emphasis is given to the determination of the CP-violating coefficients A and S from an analysis of B -> rho+ rho- decays. The values of A and S, branching fractions, and longitudinal polarization fractions of B -> rho rho decays are used to constrain the Cabibbo-Kobayashi-Maskawa phase alpha/phi2 using an isospin analysis; the solution consistent with the standard model is 71 deg. < alpha < 113 deg. at 68 C.L.