CP violation and the CKM matrix: assessing the impact of the asymmetric B factories
Abstract
We present an uptodate profile of the CabibboKobayashiMaskawa matrix with emphasis on the interpretation of recent CPviolation results from the B factories. For this purpose, we review all relevant experimental and theoretical inputs from the contributing domains of electroweak interaction. We give the “standard” determination of the apex of the Unitarity Triangle, namely the Wolfenstein parameters overlineρ and overlineη, by means of a global CKM fit. The fit is dominated by the precision measurement of sin 2 β by the B factories. A detailed numerical and graphical study of the impact of the results is presented. We propose to include sin 2α from the recent measurement of the timedependent CPviolating asymmetries in B^0toρ^ + ρ^, using isospin relations to discriminate the penguin contribution. The constraint from \varepsilon^′/\varepsilon is discussed. We study the impact from the branching fraction measurement of the rare kaon decay K^ + toπ^ + νoverlineν, and give an outlook into the reach of a future measurement of K^0_Ltoπ^0νoverlineν. The B system is investigated in detail. We display the constraint on 2β + γ and γ from B^0to D^{(*)±}π^mp and B^ + to D^{(*)0}K^ + decays, respectively. A significant part of this paper is dedicated to the understanding of the dynamics of B decays into ππ, Kπ, ρπ, ρρ and modes related to these by flavor symmetry. Various phenomenological approaches and theoretical frameworks are discussed. We find a remarkable agreement of the ππ and Kπ data with the other constraints in the unitarity plane when the hadronic matrix elements are calculated within QCD Factorization, where we apply a conservative treatment of the theoretical uncertainties. A global fit of QCD Factorization to all ππ and Kπ data leads to precise predictions of the related observables. However sizable phenomenological power corrections are preferred. Using an isospinbased phenomenological parameterization, we analyze separately the Bto Kπ decays, and the impact of electroweak penguins in response to recent discussions. We find that the present data are not sufficiently precise to constrain either electroweak parameters or hadronic amplitude ratios. We do not observe any unambiguous sign of New Physics, whereas there is some evidence for potentially large nonperturbative rescattering effects. Finally we use a modelindependent description of a large class of New Physics effects in both B^0overline B^0 mixing and B decays, namely in the bto d and bto s gluonic penguin amplitudes, to perform a new numerical analysis. Significant nonstandard corrections cannot be excluded yet, however Standard Model solutions are favored in most cases. In the appendix to this paper we propose a frequentist method to extract a confidence level on ∆ m_s from the experimental information on B^0_s overline B_s^0 oscillation. In addition we describe a novel approach to combine potentially inconsistent measurements. All results reported in this paper have been obtained with the numerical analysis package CKMfitter, featuring the frequentist statistical approach Rfit.
 Publication:

European Physical Journal C
 Pub Date:
 May 2005
 DOI:
 10.1140/epjc/s2005021691
 arXiv:
 arXiv:hepph/0406184
 Bibcode:
 2005EPJC...41....1C
 Keywords:

 High Energy Physics  Phenomenology;
 High Energy Physics  Experiment;
 High Energy Physics  Lattice
 EPrint:
 Final version accepted for publication in EPJ C, updated results and plots are available at: http://ckmfitter.in2p3.fr or http://www.slac.stanford.edu/xorg/ckmfitter/ (mirror)