1,902 research outputs found
Status and implications of neutrino masses: a brief panorama
With the historic discovery of the Higgs boson our picutre of particle physics would have been complete were it nor for the neutrino sector and cosmology. I briefly discuss the role of neutrino masses and mixing upon gauge coupling unification, electroweak breaking and the flavor sector. Time is ripe for new discoveries such as leptonic CP violation, charged lepton flavor violation and neutrinoless double beta decay. Neutrinos could also play a role is elucidating the nature of dark matter and cosmic inflation
Can one ever prove that neutrinos are Dirac particles?
According to the "Black Box" theorem the experimental confirmation of
neutrinoless double beta decay () would imply that at least one
of the neutrinos is a Majorana particle. However, a null signal
cannot decide the nature of neutrinos, as it can be suppressed even for
Majorana neutrinos. In this letter we argue that if the null
decay signal is accompanied by a quadruple beta decay signal,
then at least one neutrino should be a Dirac particle. This argument holds
irrespective of the underlying processes leading to such decays.Comment: 5 pages, 3 figure
Consistency of the dynamical high-scale type-I seesaw mechanism
We analyze the consistency of electroweak breaking within the simplest
high-scale Standard Model type-I seesaw mechanism. We derive the full two-loop
RGEs of the relevant parameters, including the quartic Higgs self-coupling of
the Standard Model. For the simplest case of bare "right-handed" neutrino mass
terms we find that, with large Yukawa couplings, the Higgs quartic
self-coupling becomes negative much below the seesaw scale, so that the model
may be inconsistent even as an effective theory. We show, however, that the
"dynamical" type-I high-scale seesaw with spontaneous lepton number violation
has better stability properties.Comment: 29 pages, 10 figures, 1 table, Published versio
SO(3) family symmetry and axions
Motivated by the idea of comprehensive unification, we study a gauged SO(3)
flavor extension of the extended Standard Model, including right-handed
neutrinos and a Peccei-Quinn symmetry with simple charge assignments. The model
accommodates the observed fermion masses and mixings and yields a
characteristic, successful relation among them. The Peccei-Quinn symmetry is an
essential ingredient.Comment: 9 pages, matches published versio
Dynamical seesaw mechanism for Dirac neutrinos
So far we have not been able to establish that, as theoretically expected,
neutrinos are their own anti-particles. Here we propose a dynamical way to
account for the Dirac nature of neutrinos and the smallness of their mass in
terms of a new variant of the seesaw paradigm in which the energy scale of
neutrino mass generation could be accessible to the current LHC experiments.Comment: 7 pages, 1 figur
Light majoron cold dark matter from topological defects and the formation of boson stars
We show that for a relatively light majoron ( eV) non-thermal
production from topological defects is an efficient production mechanism.
Taking the type I seesaw as benchmark scheme, we estimate the primordial
majoron abundance and determine the required parameter choices where it can
account for the observed cosmological dark matter. The latter is consistent
with the scale of unification. Possible direct detection of light majorons with
future experiments such as PTOLEMY and the formation of boson stars from the
majoron dark matter are also discussed.Comment: 27 pages, 3 figures; v2: references added, matches published versio
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