5,450 research outputs found

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

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    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

    Flavour Physics and CP Violation in the Standard Model and Beyond

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    We present the invited lectures given at the Third IDPASC School which took place in Santiago de Compostela in January 2013. The students attending the school had very different backgrounds, some of them were doing their Ph.D. in experimental particle physics, others in theory. As a result, and in order to make the lectures useful for most of the students, we focused on basic topics of broad interest, avoiding the more technical aspects of Flavour Physics and CP Violation. We make a brief review of the Standard Model, paying special attention to the generation of fermion masses and mixing, as well as to CP violation. We describe some of the simplest extensions of the SM, emphasising novel flavour aspects which arise in their framework.Comment: Invited talk at the Third IDPASC School 2013, January 21st - February 2nd 2013, Santiago de Compostela, Galiza, Spain; 36 pages, 8 figures, 2 tables; version with few misprints correcte

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

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    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

    Unitarity triangles and geometrical description of CP violation with Majorana neutrinos

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    We generalize the geometrical description of CP violation in the Standard Model in terms of a unitarity triangle. For three left-handed Majorana neutrinos CP violation in the lepton sector is determined by three unitarity triangles. With three additional right-handed neutrinos 15 quadrangles are required to characterize CP violation. We show the relation of the unitarity polygons with physical observables.Comment: Revtex, 6 pages, 5 eps figures. Some typos fixed and a reference added. To appear in PR

    A Highly Predictive Ansatz for Leptonic Mixing and CP Violation

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    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 VPMNSV_{PMNS}, are predicted in terms of a single phase ϕ\phi, which takes a value around ϕ=π2\phi={\frac{\pi}{2}}. Correlations among variuos physical quantities are obtained, in particular V13PMNSV^{PMNS}_{13} is predicted as a function of Δm212{\Delta}m^2_{21}, Δm312{\Delta}m^2_{31} and sin2(θsol)\sin^2(\theta_{sol}), and restricted to the range 0.167<V13PMNS<0.1790.167<|V^{PMNS}_{13}|<0.179.Comment: 9 pages, 4 figure

    Jarlskog-like invariants for theories with scalars and fermions

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    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

    Texture Zeros and Weak Basis Transformations

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    We investigate the physical meaning of some of the "texture zeros" which appear in most of the Ansatze on quark masses and mixings. It is shown that starting from arbitrary quark mass matrices and making a suitable weak basis transformation one can obtain some of these sets of zeros which therefore have no physical content. We then analyse the physical implications of a four-texture zero Ansatz which is in agreement with all present experimental data.Comment: 11 pages, typeset using revte

    An alternative explanation of the origin of the signal in diffusion-weighted MRI

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    I formulated an alternative explanation for the origin of the signal in diffusion-weighted MRI (DWI) and tested it in a simple experimental model using gelatin. My findings indicate that the signal in DWI is influenced by the passage of water from the sol to the gel state, independently of the presence of cell structures or membrane-dependent diffusion
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