Direct CP Violation in B∓ → π∓ω, π∓ρ0, π0ρ∓, and in B0(B) → π∓ρ± With an Enhanced Branching Ratio for πρ
2008
We present a novel dynamics for generating sizable CP-violating asymmetries in the decays of charged B → πω, πρ, πρ, and in B0(B) → πρ. The dynamics for the necessary final-state interactions involves the mixing of G-parity eigenstates of the system (D ∗ D,DD) with the G = ±1 states of πω and πρ, respectively. The dynamical effect is enhanced by the empirically large branching ratio for decays to (D ∗ D,DD). A correlated result is a markedly enhanced branching ratio for B0(B) → πρ, which has now been observed in two experiments. Direct CP violation in the decays of charged and neutralB mesons is the central theme in current experiments [1, 2, 3] at the two B-meson factories. Today, some forty years after the discovery of indirect CP violation in the two-pion decay of K L [4], direct CP violation has been established only in the matrix elements for the two-pion decays of the neutral K system.[5] It is yet to be established in decays of a charged particle. Recently, one experiment [1] has given results which indicate a sizable CP-violating asymmetry in the decays B∓ → π∓η, as predicted by theoretical estimates in 1991 [6], and also in the decays B∓ → K∓η.[7] Further, one experiment [2] has given a large direct CP violation in B0(B) → π−π+.[8] This group has now given an indication [3] of a sizable asymmetry in B∓ → π∓ω. All of these decays have similar, low branching ratios measured to be in the range of (2 − 7) × 10−6. In order to have direct CP violation observable, there must be (strong) interactions among particles in the final states.[6] It is physically clear that if there exists a decay channel with an empirically large branching ratio (i. e. a large decay amplitude) which has the same, conserved strong-interaction quantum numbers as the final hadron state, then decay into this channel followed by even a small mixing with the final state, will produce the essential strong-interaction, imaginary contribution to the amplitude, which will be sizable.[8] When the large decay amplitude involves a term in the CKM matrix with a different weak phase from the term relevant to the direct decay into the final state, then the necessary conditions for observing an asymmetry are met.[6] This dynamical mechanism explains [8] the large, direct CP violation observed in B0(B) → π+π−.[2] In a correlated way, the same dynamics predicts an enhanced branching ratio for B0(B) → ππ, as is observed [9, 10]. Mixing with the isospin-zero
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