61,659 research outputs found
The present development of time service in Brazil, with the application of the TV line-10 method for coordination and synchronization of atomic clocks
Various methods presently used for the dissemination of time at several levels of precision are described along with future projects in the field. Different aspects of time coordination are reviewed and a list of future laboratories participating in a National Time Scale will be presented. A Brazilian Atomic Time Scale will be obtained from as many of these laboratories as possible. The problem of intercomparison between the Brazilian National Time Scale and the International one will be presented and probable solutions will be discussed. Needs related to the TV Line-10 method will be explained and comments will be made on the legal aspects of time dissemination throughout the country
Leptonic Invariants, Neutrino Mass-Ordering and the Octant of
We point out that leptonic weak-basis invariants are an important tool for
the study of the properties of lepton flavour models. In particular, we show
that appropriately chosen invariants can give a clear indication of whether a
particular lepton flavour model favours normal or inverted hierarchy for
neutrino masses and what is the octant of . These invariants can
be evaluated in any conveniently chosen weak-basis and can also be expressed in
terms of neutrino masses, charged lepton masses, mixing angles and CP violation
phases.Comment: 10 pages, no figure
Non-Factorizable Phases, Yukawa Textures and the Size of sin (2 beta)
We emphasize the crucial r\^ ole played by non-factorizable phases in the
analysis of the Yukawa flavour structure performed in weak bases with Hermitian
mass matrices and with vanishing entries. We show that non-factorizable
phases are important in order to generate a sufficiently large .
A method is suggested to reconstruct the flavour structure of Yukawa couplings
from input experimental data both in this Hermitian basis and in a
non-Hermitian basis with a maximal number of texture zeros. The corresponding
Froggatt--Nielsen patterns are presented in both cases.Comment: 15 pages, 3 figure
Noncommutative Field Theory: Nonrelativistic Fermionic Field Coupled to the Chern-Simons Field in 2+1 Dimensions
We study a noncommutative nonrelativistic fermionic field theory in 2+1
dimensions coupled to the Chern-Simons field. We perform a perturbative
analysis of model and show that up to one loop the ultraviolet divergences are
canceled and the infrared divergences are eliminated by the noncommutative
Pauli term.Comment: Some references adde
Yukawa Textures, New Physics and Nondecoupling
We point out that New Physics can play an important r\^ ole in rescuing some
of the Yukawa texture zero ans\" atze which would otherwise be eliminated by
the recent, more precise measurements of . As an example, a detailed
analysis of a four texture zero ansatz is presented, showing how the presence
of an isosinglet vector-like quark which mixes with standard quarks, can render
viable this Yukawa texture. The crucial point is the nondecoupling of the
effects of the isosinglet quark, even for arbitrary large values of its mass.Comment: 13 pages, no figure
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