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

Abstract

Defining a most economical parametrization of time-dependent B-> rho^\pm pi^\mp decays, including a measurable phase alpha_{eff} which equals the weak phase alpha in the limit of vanishing penguin amplitudes, we propose two ways for determining alpha in this processes. We explain the limitation of one method, assuming only that two relevant tree amplitudes factorize and that their relative strong phase, delta_t, is negligible. The other method, based on broken flavor SU(3), permits a determination of alpha in B^0-> rho^\pm pi^\mp in an overconstrained system using also rate measurements of B^{0,+}-> K^* pi and B^{0,+}->rho K. Current data are shown to restrict two ratios of penguin and tree amplitudes, r_\pm, to a narrow range around 0.2, and to imply an upper bound |alpha_{eff} - alpha| < 15 degrees. Assuming that delta_t is much smaller than 90 degrees, we find alpha =(93\pm 16) degrees and (102 \pm 20) degrees using BABAR and BELLE results for B(t)-> rho^\pm pi^mp. Avoiding this assumption for completeness, we demonstrate the reduction of discrete ambiguities in alpha with increased statistics, and show that SU(3) breaking effects are effectively second order in r_\pm.

23 pages, 2 figures, data and references updated, to be published in Phys. Rev. D

References in corpus (3)

• Observation of the Decays B0->K+pi-pi0 and B0->rho-K+
• Evidence of B0 --> rho0 pi0
• Constraints on the CKM Angle gamma from B -> K*+- pi-+

Cited by in corpus (23)

• The Physics of the B Factories
• Two body B decays with isosinglet final states in SCET
• New Physics at a Super Flavor Factory
• Isospin-breaking effects on alpha extracted in B --> pi pi, rho rho, rho pi
• Improved method for CKM constraints in charmless three-body B and B_s decays
• Measurements of CP-Violating Asymmetries in B0 to a1(1260)^{+-} pi^{-+} Decays
• Measurement of CP Asymmetries and Branching Fractions in a Time-Dependent Dalitz Analysis of B^0-->(rho pi)^0 and a Constraint on the Quark Mixing Angle phi_2
• Study of B0 -> rho+-pi-+ Time-dependent CP Violation at Belle
• A precise determination of $\alpha$ using $B^0\to {\rho }^{+}{\rho }^{-}$ and $B^{+}\to K^{\ast 0}{\rho }^{+}$
• Suppression of flavor symmetry breaking in B decay sum rules
• Measurement of branching fractions of B decays to K1(1270)pi and K1(1400)pi and determination of the CKM angle alpha from B0 --> a1(1260)+/- pi-/+
• Weak phase alpha from B^0-> a_1^{+-}(1260) pi^{-+}
• Reducing the Error on alpha in B-> pi pi, rho rho, rho pi
• Determination of gamma from Charmless B --> M1 M2 Decays Using U-Spin
• Branching Ratios and CP Asymmetries of B \to a_1(1260) πand a_1(1260) K Decays
• Determination of gamma from charmless B^+/- -> M^0 M^+/- decays using U-spin
• CP Asymmetries in B->K pi, K*pi, rho K Decays
• Penguin pollution estimates relevant for phi_2/alpha extraction
• Measurement of the CKM angle alpha with the B-factories
• Weak Phases and CP Violation
• Precision Tests of Flavor and CP violation in B Decays
• CP-Violation in B_{q} Decays and Final State Strong Phases
• CP Violation Results from B Decays at BaBar