4,334 research outputs found
The Role of Invariant Functions in Understanding Masses and Mixings
One of the central questions in theoretical particle physics, since already
several decades, has been that of "masses and mixings of the quarks. With the
entry of neutrino oscillations into the field, the issue of lepton masses has
added a new dimension to the problem. In the literature one finds many models
of quark and lepton mass matrices. However, the mass and mixing problems remain
unsolved.
In this talk I will present my own contributions to this field, however as
you may expect without offering a solution. I encourage you to go ahead and
think about the problem but be aware of the pitfalls.Comment: Talk presented at the conference SNOW 200
Ambiguities pertaining to quark-lepton complementarity
Recently the possible origin of the so-called quark-lepton complementarity
relations has received a considerable amount of attention. We point out some of
the inherent ambiguities in such analyses
The quark mixing matrix with manifest Cabibbo substructure and an angle of the unitarity triangle as one of its parameters
The quark mixing matrix is parameterised such that its "Cabibbo substructure"
is emphasised. One can choose one of the parameters to be an arbitrarily chosen
angle of the unitarity triangle, for example the angle (also called
)
Recursive parameterisation and invariant phases of unitary matrices
We present further properties of a previously proposed recursive scheme for
parameterisation of n-by-n unitary matrices. We show that the factors in the
recursive formula may be introduced in any desired order. The method is used to
study the invariant phases of unitary matrices. The case of four-by-four
unitary matrices is investigated in detail. We also address the question of how
to construct symmetric unitary matrices using the recursive approach
A recursive parameterisation of unitary matrices
A simple recursive scheme for parameterisation of n-by-n unitary matrices is
presented.Comment: Notations simplified and more details give
Invariants of Lepton Mass Matrices and CP and T Violation in Neutrino Oscillations
CP and T asymmetries in neutrino oscillations, in vacuum as well as in
matter, are expressed in terms of invariant functions of lepton mass matrices.Comment: 9 page
Neutrino Sector with Majorana Mass Terms and Friedberg-Lee Symmetry
We examine a recently proposed symmetry/condition by Friedberg and Lee in the
framework where three right-handed neutrinos are added to the spectrum of the
three-family Minimal Standard Model. It is found that the right-handed
neutrinos are very special, with respect to this symmetry. In the symmetry
limit the neutrinos are massless and that may be a hint about why they are
light. Imposed as a condition and not as a full symmetry, we find that one of
the three right-handed neutrinos simply decouples (has only gravitational
interactions) and that there is a massless interacting neutrino. The possible
relation of the model to the see-saw mechanism is briefly discussed
Weak interactions in atoms and nuclei
The paper is mainly concerned with possible weak interaction effects in atoms, including neutral currents and the effect of parity conserving and violating Hamiltonians. A very brief summary of parity violation in nuclei is also given. (11 refs)
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