Search results for "Majoron"
showing 10 items of 50 documents
Solar neutrino oscillation parameters and the broken R parity majoron
1989
Matter-enhanced neutrino-oscillation parameters can be probed in a variety of conventional experiments in supergravity models where the small neutrino mass arises from spontaneous R-parity violation. A combined analysis of astrophysical and laboratory limits tends to exclude regions of oscillation parameters where the high-energy neutrinos are adiabatically converted. This suggests the possibility of a large reduction in the pp and /sup 7/Be neutrino flux even for a mildly reduced /sup 8/B neutrino flux, thus stressing the importance of gallium experiments.
A CMB search for the neutrino mass mechanism and its relation to the Hubble tension
2020
AbstractThe majoron, a pseudo-Goldstone boson arising from the spontaneous breaking of global lepton number, is a generic feature of many models intended to explain the origin of the small neutrino masses. In this work, we investigate potential imprints in the cosmic microwave background (CMB) arising from massive majorons, should they thermalize with neutrinos after Big Bang Nucleosynthesis via inverse neutrino decays. We show that measurements of the CMB are currently sensitive to neutrino-majoron couplings as small as $$\lambda \sim 10^{-13}$$λ∼10-13, which if interpreted in the context of the type-I seesaw mechanism correspond to a lepton number symmetry breaking scale $$v_L \sim {\math…
Weak Interactions and Solar Neutrinos: Testing the Oscillation Hypothesis
1988
Various proposals for understanding the reduced solar neutrino flux in terms of non-standard neutrino propagation properties are briefly reviewed in the context of weak interaction theory. Emphasis is given to neutrino oscillation models which may be tested experimentally, despite the small mass parameter involved. Spontaneous lepton number (and R parity) breaking in supergravity — the supersymmetric doublet Majoron model — solves the solar neutrino problem through matter-enhanced neutrino oscillations. The spectrum of supersymmetric particles is restricted in a way that will be probed by high energy collider experiments. In addition, low energy processes associated with the existence of th…
Matter Effects in Neutrino Propagation
1989
After briefly reviewing the Mikheyev-Smirnov-Wolfenstein effect, I present a particle physics model where the required small neutrino mass arises from spontaneous R parity violation in supergravity theories. It is related to measurable processes associated with the existence of the Majoron and of supersymmetric (SUSY) particles. Astrophysical and laboratory limits tend to exclude regions of oscillation parameters where the high energy neutrinos are adiabatically converted. This suggests the possibility of a large reduction in the pp and 7 Be neutrino flux even for a mildly reduced 8 B neutrino flux, thus stressing the importance of the gallium experiments. Finally I consider other types of …
Connecting neutrino physics with dark matter
2014
The origin of neutrino masses and the nature of dark matter are two of the most pressing open questions of the modern astro-particle physics. We consider here the possibility that these two problems are related, and review some theoretical scenarios which offer common solutions. A simple possibility is that the dark matter particle emerges in minimal realizations of the see-saw mechanism, like in the majoron and sterile neutrino scenarios. We present the theoretical motivation for both models and discuss their phenomenology, confronting the predictions of these scenarios with cosmological and astrophysical observations. Finally, we discuss the possibility that the stability of dark matter o…
Light majoron cold dark matter from topological defects and the formation of boson stars
2019
We show that for a relatively light majoron ($\ll 100 $ 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.
Stability of the VEV hierarchy and Higgs boson invisibility in majoron models
1988
Abstract We study the stability of the lepton-number breaking VEV under radiative corrections in the doublet and triplet majoron models, including the effects of a heavy top quark. We find that it is possible to maintain the hierarchy between the VEV's, at the one-loop level, by fine tuning the ratio of two coupling constants in the Higgs potential. For a top quark heavier than 50–60 GeV the required relation depends strongly on the top mass. We use this relation to show that the decay mode of the neutral Higgs boson to majorons may be the dominant one for a wide range of the Higgs mass, thus making its detection, in this class of models, more problematic.
Sterile neutrino portal to Dark Matter I: the U(1) B−L case
2017
In this paper we explore the possibility that the sterile neutrino and Dark Matter sectors in the Universe have a common origin. We study the consequences of this assumption in the simple case of coupling the dark sector to the Standard Model via a global $U(1)_{B-L}$, broken down spontaneously by a dark scalar. This dark scalar provides masses to the dark fermions and communicates with the Higgs via a Higgs portal coupling. We find an interesting interplay between Dark Matter annihilation to dark scalars - the CP-even that mixes with the Higgs and the CP-odd which becomes a Goldstone boson, the Majoron - and heavy neutrinos, as well as collider probes via the coupling to the Higgs. Moreove…
The KeV Majoron as a dark matter particle
1993
We consider a very weakly interacting KeV majoron as dark matter particle (DMP), which provides both the critical density $\rho_{cr} = 1.88 \times 10^{-29} h^{2}$ $g/cm^{3}$ and the galactic scale $M_{gal}$ $\sim m^{3}_{Pl}/m^{2}_{J} \sim 10^{12} M_{\odot} (m_{J}/1 KeV)^{-2}$ for galaxy formation. The majoron couples to leptons only through some new "directly interacting particles", called DIPS, and this provides the required smallness of the coupling constants. If the masses of these DIPS are greater than the scale $V_s$ characterizing the spontaneous violation of the global lepton symmetry they are absent at the corresponding phase transition ($T \sim V_s$) and the majorons are produced d…
Phase-space factors and half-life predictions for Majoron-emitting β−β− decay
2015
A complete calculation of phase space factors (PSFs) for Majoron-emitting 0νβ − β − decay modes is presented. The calculation makes use of exact Dirac wave functions with finite nuclear size and electron screening and includes lifetimes, single-electron spectra, summed electron spectra, and angular electron correlations. Combining these results with recent microscopic interacting boson model nuclear matrix elements (NMEs) we make half-life predictions for the ordinary Majoron decay (spectral index n=1 ). Furthermore, comparing theoretical predictions with the obtained experimental lower bounds for this decay mode we are able to set limits on the effective Majoron-neutrino coupling constant …