Direct CP violation in hadronic B decays

There are different approaches for the hadronic B decay calculations, recently. In this paper, we upgrade three of them, namely factorization, QCD factorization and the perturbative QCD approach based on k _T factorization, using new parameters and full wave functions. Although they get similar results for many of the branching ratios, the direct CP asymmetries predicted by them are different, which can be tested by recent experimental measurements of B factories.     

CP violation in two-body hadronic decays of B_c mesons

Using the next-to-leading-order low-energy effective Hamiltonian, the CP asymmetries for -meson decays into meson pairs are calculated in the spectator approximation. We do not compute the hadronic matrix elements directly; instead, we use the amplitude ratios to estimate the CP asymmetries. This is quite different from previous treatments in the literature. The values of the momentum squared carried by the virtual particles in timelike penguin diagrams are also carefully discussed. From our calculated results, the best decay modes to observe CP violation in decays would be , , , , and , each of them needs about of events in experiment. Received: 17 December 1998 / Published online: 30 June 1999     

CP violation andZ boson decays

We present a general discussion ofCP-violating effects in the following two and three body decays of theZ boson:Z→l ⁺ l ^?,Z→l ⁺ l ^?γ, wherel=e, μ, τ andZ→2 jets,Z→ 2 jets+γ, andZ→ 3 jets. Experimental observables sensitive toCP violation in these decays are discussed systematically for the case that polarizations of final state particles are not observed. It is shown that the standard model predicts only extremely smallCP-violating effects for the above decays. PossibleCP-violating interactions beyond the standard model are parametrized in terms of aCP-odd effective Lagrangian containing coupling constants proportional to Λ _P ^-1 and Λ _P ^-2 . Here Λ _CP is the mass scale associated with the assumed new interactions. We give estimates of the bounds obtainable for Λ _CP in experiments at LEP1.     

CP violation in radiative Z decays

We propose to test the CP symmetry in the reactions Z → μ⁺μ^?γ and Z → τ⁺τ^?γ. The experimental analysis of angular correlations allows to determine a set of effective couplings: the electric and weak dipole moments of the muon and the tau lepton, and in particular chirality conserving 4-particle couplings, all of which can be induced by CP-violation in renormalizable theories of electroweak interactions beyond the Standard Model. We update an indirect bound on the weak dipole moment of the muon.     

CP violation and top quark decays

We investigate how to testCP invariance in the weak decay of top quarks. A prediction ofCP violation from the Standard Model is made by an explicit calculation. The effect is very small as expected. We then use a form factor approach to parametrize possible new interactions ofCP violation. The differences between the form factor approach and an effective Lagrangian approach are discussed. The sensitivity of ourCP-odd observables to the form factors is estimated.     

The discovery of CP violation in B-meson decays

We present the KEK B-factory project, which discovered CP violation in B-meson decays and proved that the Kobayashi-Maskawa theory correctly explains CP violation in meson decays.(Communicated by Toshimitsu YAMAZAKI, M.J.A.).     

CP violation for neutral charmed meson decays into CP eigenstates

The CP asymmetries for the decays of the neutral charmed meson into CP eigenstates are carefully studied. Formulas and numerical results are presented. The impact on experiments is briefly discussed.     

New re1ults on CP violation in B-meson decays

37 years after the discovery of CP violation in π⁺π⁻ decays of neutral K mesons, the experiments BABAR and BELLE have found a second system which violates CP symmetry. J K_S^O decays of neutral B mesons show very large symmetry breaking. The effect has now, with the most recent data, a significance of about 13 standard deviations. The presentation describes the B-meson factories, the experiments, and their analyses. The results are in agreement with the Standard Model explanation of CP violation, i. e. with different couplings of the Higgs boson to quarks and antiquarks.