Cosmology and CP Violation

We describe the role of CP violation in the generation of the baryon asymmetry of the Universe, in the framework of baryogenesis through leptogenesis, with emphasis on the possible relationship between CP violation at low energies and that required by leptogenesis. It is emphasized that a direct link between these two manifestations of CP violation only exists in the framework of specific flavour structures for the fundamental leptonic mass matrices.Comment: 11 pages, Invited Talk at Flavor Physics And CP Violation (FPCP 2003) 3-6 Jun 2003, Paris, Franc

CP Violation and New Physics

We describe some of the extensions of the SM, including models with spontaneous CP violation, where New Physics relevant for CP violation may arise. It is emphasized that the SM predicts a series of exact relations among various measurable quantities, such as moduli of CKM matrix elements and rephasing invariant phases. These exact relations provide a stringent test of the SM, with the potential to reveal New Physics.Comment: Invited talk at Workshop on the CKM Unitarity Triangle, IPPP Durham, April 2003. 8 pages, 1 figur

The Higgs Sector and electron electric dipole moment in next-to-minimal supersymmetry with explicit CP violation

We study the explicit CP violation of the Higgs sector in the next--to--minimal supersymmetric model with a gauge singlet Higgs field. Our numerical predictions show that electric dipole moment of electron lies around the present experimental upper limits. The mass of the lightest Higgs boson is quite sensitive to the CP violating phases in the theory. It is observed that as the vacuum expectation value of the singlet gets higher values, CP violation increases.Comment: 20 pages, 16 figure

Group-theoretic restrictions on generation of CP-violation in multi-Higgs-doublet models

It has been known since decades that imposing a symmetry group G on the scalar sector of multi-Higgs-doublet models has consequences for CP-violation. In all examples of two- and three-Higgs-doublet models equipped with symmetries, one observes the following intriguing property: if G prevents explicit CP-violation (CPV), at least in the neutral Higgs sector, then it also prevents spontaneous CPV, and if G allows explicit CPV, then it allows for spontaneous CPV. One is led to conjecture that this is a general phenomenon. In this paper, we prove this conjecture for any rephasing symmetry group G and any number of doublets.Comment: 16 page

CP violation conditions in N-Higgs-doublet potentials

Conditions for CP violation in the scalar potential sector of general N-Higgs-doublet models (NHDMs) are analyzed from a group theoretical perspective. For the simplest two-Higgs-doublet model (2HDM) potential, a minimum set of conditions for explicit and spontaneous CP violation is presented. The conditions can be given a clear geometrical interpretation in terms of quantities in the adjoint representation of the basis transformation group for the two doublets. Such conditions depend on CP-odd pseudoscalar invariants. When the potential is CP invariant, the explicit procedure to reach the real CP-basis and the explicit CP transformation can also be obtained. The procedure to find the real basis and the conditions for CP violation are then extended to general NHDM potentials. The analysis becomes more involved and only a formal procedure to reach the real basis is found. Necessary conditions for CP invariance can still be formulated in terms of group invariants: the CP-odd generalized pseudoscalars. The problem can be completely solved for three Higgs-doublets.Comment: RevTeX4 used. Minor modifications, in particular, the parameter counting of $Z$. v3: Eqs.(28)-(31) correcte

Jarlskog-like invariants for theories with scalars and fermions

Within the framework of theories where both scalars and fermions are present, we develop a systematic prescription for the construction of CP-violating quantities that are invariant under basis transformations of those matter fields. In theories with Spontaneous Symmetry Breaking, the analysis involves the vevs' transformation properties under a scalar basis change, with a considerable simplification of the study of CP violation in the scalar sector. These techniques are then applied in detail to the two Higgs-doublet model with quarks. It is shown that there are new invariants involving scalar-fermion interactions, besides those already derived in previous analyses for the fermion-gauge and scalar-gauge sectors.Comment: 12 pages, Latex, no figure

A Highly Predictive Ansatz for Leptonic Mixing and CP Violation

We suggest a simple highly predictive ansatz for charged lepton and light neutrino mass matrices, based on the assumption of universality of Yukawa couplings. Using as input the charged lepton masses and light neutrino masses, the six parameters characterizing the leptonic mixing matrix $V_{PMNS}$, are predicted in terms of a single phase $\phi$, which takes a value around $\phi={\frac{\pi}{2}}$. Correlations among variuos physical quantities are obtained, in particular $V^{PMNS}_{13}$ is predicted as a function of ${\Delta}m^2_{21}$, ${\Delta}m^2_{31}$ and $\sin^2(\theta_{sol})$, and restricted to the range $0.167<|V^{PMNS}_{13}|<0.179$.Comment: 9 pages, 4 figure