5,450 research outputs found
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
Flavour Physics and CP Violation in the Standard Model and Beyond
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
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
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
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 , are
predicted in terms of a single phase , which takes a value around
. Correlations among variuos physical quantities are
obtained, in particular is predicted as a function of
, and , and
restricted to the range .Comment: 9 pages, 4 figure
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
Texture Zeros and Weak Basis Transformations
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
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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