2004/02/10 by Andrzej J. Buras, Robert Fleischer, Stefan Recksiegel +2 · 1 citation
Physics and Astronomy · #Asymmetry #Branching fraction #CP violation #Electroweak interaction #Hadron #Neutrino Physics Research #Observable #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Unitarity #hep-ph
paper · pdf · doi:10.1016/j.nuclphysb.2004.07.009
published as Nucl.Phys. B697 (2004) 133-206 · 78 pages, 12 figures, LaTeX
arxiv created 2004/02/10 · openalex publication_date 2004/08/05 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The recent observation of Bd -> pi0 pi0 at the B factories with a surprisingly large branching ratio represents a challenge for theory, and complements the amazingly small Bd -> pi+ pi- rate. We point out that all puzzling B -> pi pi features can be accommodated in the Standard Model (SM) through non-factorizable hadronic interference effects, extract the relevant parameters, and predict the CP asymmetries of Bd -> pi0 pi0. Using then SU(3) flavour-symmetry and plausible dynamical assumptions, we fix the hadronic B -> pi K parameters through their B -> pi pi counterparts, and determine the CKM angle gamma, with a result in remarkable accordance with the usual fits for the unitarity triangle. We may then analyse the B -> pi K system in the SM, where we find agreement with the experimental picture, with the exception of those observables that are significantly affected by electroweak (EW) penguins, thereby suggesting new physics (NP) in this sector. Indeed, a moderate enhancement of these topologies and a large CP-violating NP phase allow us to describe any currently observed feature of the B -> pi K modes, and to predict the CP-violating Bd -> pi0 KS observables. If we then restrict ourselves to a specific scenario where NP enters only through Z0 penguins, we obtain a link to rare K and B decays, where the most spectacular NP effects are an enhancement of the KL -> pi0 nu nubar rate by one order of magnitude with BR(KL -> pi0 nu nubar) ~ 4 BR(K+ -> pi+ nu nubar), BR(KL -> pi0 e+ e-) = O(10-10), (sin 2beta)pi nu nubar < 0, and a large forward-backward CP asymmetry in Bd -> K^* mu+ mu-. We address also epsilon'/epsilon and other prominent decays, including B -> phi K and B -> J/psi K modes.