Reducing the Error on alpha in B-> pi pi, rho rho, rho pi

Abstract

Theoretical errors in the extraction of alpha from B -> pi^+ pi^-, rho^+ rho^-, rho pi decays are usually given in terms of upper bounds on alpha_eff-alpha obtained from isospin or from SU(3) relations, where alpha_eff is measured through CP asymmetries. We show that mild assumptions about magnitudes and strong phases of penguin and tree amplitudes (|P/T| < 1 and |delta| < pi/2) in B -> pi pi and B -> rho rho, imply alpha_eff > alpha, thus reducing by a factor two the error in alpha. Similarly, the assumptions |p_+-/t_+-| < 1, |δ_-| < pi/2 <|δ_+| in B -> rho pi lead to a cancellation between two terms in alpha_eff-alpha. Current data support these conditions.

10 pages, 2 figures, small corrections, few references added, final version to appear in Phys. Lett. B

References in corpus (1)

• On measuring alpha in B(t)-> rho^\pm pi^\mp

Cited by in corpus (15)

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• CP asymmetry and branching ratio of B -> pi pi
• Theory of hadronic B decays
• Precision Tests of Flavor and CP violation in B Decays
• SU(3) and CP violating weak and strong final state phases for B_{d}^{0} and B_{s}^{0} decays
• B-> rho pi, rho rho, pi pi: hunting for alpha