On Puzzles and Non-Puzzles in B -> pi pi, pi K Decays

Abstract

Recently, we have seen interesting progress in the exploration of CP violation in B^0_d -> pi^+ pi^-: the measurements of mixing-induced CP violation by the BaBar and Belle collaborations are now in good agreement with each other, whereas the picture of direct CP violation is still unclear. Using the branching ratio and direct CP asymmetry of B^0_d -> pi^- K^+, this situation can be clarified. We predict A_CP^dir(B_d -> pi^+ pi^-) = -0.24+-0.04, which favours the BaBar result, and extract gamma=(70.0^{+3.8}_{-4.3})deg, which agrees with the unitarity triangle fits. Extending our analysis to other B -> pi K modes and B^0_s -> K^+ K^- with the help of the SU(3) flavour symmetry and plausible dynamical assumptions, we find that all observables with colour-suppressed electroweak penguin contributions are measured in excellent agreement with the Standard Model. As far as the ratios R_{c,n} of the charged and neutral B -> pi K branching ratios are concerned, which are sizeably affected by electroweak penguin contributions, our Standard-Model predictions have almost unchanged central values, but significantly reduced errors. Since the new data have moved quite a bit towards these results, the "B -> pi K puzzle" for the CP-conserving quantities has been significantly reduced. However, the mixing-induced CP violation of B^0_d -> pi^0 K_S does look puzzling; if confirmed by future measurements, this effect could be accommodated through a modified electroweak penguin sector with a large CP-violating new-physics phase. Finally, we point out that the established difference between the direct CP asymmetries of B^+- -> pi^0 K^+- and B_d -> pi^-+ K^+- appears to be generated by hadronic and not by new physics.

12 pages, 4 figures. References added, to appear in EPJC

References in corpus (31)

• CP Violation and the CKM Matrix: Assessing the Impact of the Asymmetric B Factories
• QCD factorization for B->PP and B->PV decays
• Decays of $B$ Mesons to Two Light Pseudoscalars
• The 2004 UTfit Collaboration Report on the Status of the Unitarity Triangle in the Standard Model
• Anatomy of Prominent B and K Decays and Signatures of CP-Violating New Physics in the Electroweak Penguin Sector
• B -> pi pi, New Physics in B -> pi K and Implications for Rare K and B Decays
• New Strategies to Extract $\beta$ and $\gamma$ from $B_d\to {\pi }^{+}{\pi }^{-}$ and $B_s\to K^{+}{K}^{-}$
• Determination of the Weak Phase gamma from Rate Measurements in B^+- -> pi K, pi pi Decays
• Constraining the CKM angle $\gamma$ and penguin contributions through combined $B\to \pi K$ branching ratios
• Solution to the B -> pi K Puzzle in a Flavor-Changing Z' Model
• Model-independent electroweak penguins in B decays to two pseudoscalars
• Kaon Distribution Amplitude from QCD Sum Rules
• Strategies for Fixing the CKM-angle $\gamma$ and Obtaining Experimental Insights into the World of Electroweak Penguins
• CP asymmetry Relations Between ${\bar{B}}^0\to \pi \pi$ and ${\bar{B}}^0\to \pi K$ Rates
• Measurement of Charge Asymmetries in Charmless Hadronic in B Meson Decays
• Trojan Penguins and Isospin Violation in Hadronic B Decays
• Constraints on the CKM Angle $\gamma$ and Strong Phases from $B\to \pi K$ Decays
• The B -> pi K Puzzle and its Relation to Rare B and K Decays
• Rates and Asymmetries in $B\to K\pi$ Decays
• Observation of Bs->K+K- and Measurements of Branching Fractions of Charmless Two-body Decays of B0 and Bs Mesons in p-pbar Collisions at sqrt(s)=1.96 TeV
• A Possibility of large electro-weak penguin contribution in B -> K pi modes
• Determining the CKM Unitarity Triangle From $B$ Decays to Charged Pions and Kaons
• New Aspects of B -> pi pi, pi K and their Implications for Rare Decays
• Charmless decays B->pipi, piK and KK in broken SU(3)symmetry
• Electromagnetic corrections to non-leptonic two-body B and D decays
• A General Analysis of $\gamma$ Determinations from $B\to \pi K$ Decays
• Rate and CP-asymmetry sum rules in $B\to K\pi$
• Constraining Penguin Contributions and the CKM Angle $\gamma$ through $B_d\to {\pi }^{+}{\pi }^{-}$
• Sum rule for rate and CP asymmetry in $B^{+}\to K^{+}{\pi }^0$
• Waiting for the Discovery of B^0_d -> K^0 \bar K^0
• Highlights of the B-Physics Landscape

Cited by in corpus (38)

• B, D and K decays
• Waiting for Precise Measurements of K^+->pi^+ nu nu and K_L->pi^0 nu nu
• Measurement of CP Asymmetries and Branching Fractions in Charmless Two-Body B-Meson Decays to Pions and Kaons
• New Physics at a Super Flavor Factory
• $Z^{\prime }$ models with less-minimal flavour violation
• $B_{s,d}\to \pi \pi ,\pi K,KK$: Status and Prospects
• In Pursuit of New Physics with B^0_s -> K^+K^-
• Possible resolution of the B -> pi pi, pi K puzzles
• Benchmarks for the New-Physics Search through CP Violation in B^0->pi^0 K_S
• Correlating ${\epsilon }^{\prime }/\epsilon$ to hadronic $B$ decays via $U(2{)}^3$ flavour symmetry
• Exploring CP Violation and Penguin Effects through $B_d^0\to D^{+}{D}^{-}$ and $B_s^0\to D_s^{+}{D}_s^{-}$
• B_s -> phi rho^0 and B_s -> phi pi^0 as a handle on isospin-violating New Physics
• Exploring $B\to \pi \pi ,\pi K$ Decays at the High-Precision Frontier
• Towards New Frontiers with $B\to \pi K$ Decays
• Glauber gluons in spectator amplitudes for $B\to \pi M$ decays
• Searching for New Physics in b to s Hadronic Penguin Decays
• Improved measurements of branching fractions for B -> K pi and B -> pi pi decays
• Resolving the $B\to K\pi$ puzzle by Glauber-gluon effects
• Analytic Resolution of Puzzle in $B\to K\pi$ decays
• Amplitude analysis of the decay ${\overline{B}}^0\to K_S^0{\pi }^{+}{\pi }^{-}$ and first observation of the CP asymmetry in ${\overline{B}}^0\to K^{\ast }(892{)}^{-}{\pi }^{+}$
• Studying New Physics Amplitudes in Charmless B_s Decays
• Branching Ratios and CP Asymmetries of B \to a_1(1260) πand a_1(1260) K Decays
• Study of the weak annihilation contributions in charmless $B_s\to VV$ decays
• Systematic Error on Weak Phase $\gamma$ from $B\to {\pi }^{+}{\pi }^{-}$ and $B\to K\pi$
• $B\to a_1(1260)a_1(1260)$ and $b_1(1235)b_1(1235)$ decays in the perturbative QCD approach
• Generalized analysis on $B\to K^{\ast }\rho$ within and beyond the Standard Model $-$ Can it help understand the $B\to K\pi$ puzzle?
• CP Asymmetries in B->K pi, K*pi, rho K Decays
• Branching ratio and $CP$ violation of $B\to K\pi$ decays in a modified perturbative QCD approach
• $B_{d,s}^0\to f_1{f}_1$ decays with $f_1(1285)-f_1(1420)$ mixing in the perturbative QCD approach
• Flavor SU(3) analysis of charmless B->PP decays
• Probing new physics in electroweak penguins through B_d and B_s decays
• Moriond QCD 2007 - Theory Summary
• Hadronic decays of $B\to a_1(1260)b_1(1235)$ in the perturbative QCD approach
• Sum rules for B-->pi eta('), K eta('), eta(') eta(') decays
• A possible solution of $B$ arrow $\pi \pi$ puzzle in Z' model
• Glauber gluons in annihilation amplitudes for heavy meson decays
• Phenomenological analysis of charmless $B\to PV$ decays in the modified perturbative QCD approach
• Estimating QCD-factorization amplitudes through $SU(3)$ symmetry in $B\to PP$ decays