Search results for "Majoron"
showing 10 items of 50 documents
Astrophysical bound on the majoron-Higgs-boson coupling
1989
Abstract We show that the coupling of the “standard” Higgs boson to majorons, that could lead to a very fast decay of the neutral Higgs scalar to invisible modes, can be bounded using astrophysical arguments. We discuss the relevance of this bound for low-energy phenomenology related to majoron production. The bound so obtained may also jeopardize the stability of the VEV hierarchy in the doublet and triplet majoron models if the mass of the top quark is less than the W mass. A similar analysis may be applied to other models which exhibit Goldstone-or pseudo-Goldstone-bosons in the spectrum.
Searching for New Physics in two-neutrino double beta decay with CUPID
2021
Abstract In the past few years, attention has been drawn to the fact that a precision analysis of two-neutrino double beta decay (2υββ) allows the study of interesting physics cases like the emission of Majoron bosons and possible Lorentz symmetry violation. These processes modify the summed-energy distribution of the two electrons emitted in 2υββ. CUPID is a next-generation experiment aiming to exploit 100Mo-enriched scintillating Li2MoO4 crystals, operating as cryogenic calorimeters. Given the relatively fast half-life of 100Mo 2υββ and the large exposure that can be reached by CUPID, we expect to measure with very high precision the 100Mo 2υββ spectrum shape, reaching great sensitivities…
Nuclear matrix elements for Majoron emitting double-$\beta$ decay
2021
A complete calculation of the nuclear matrix elements (NMEs) for Majoron emitting neutrinoless double beta decay within the framework of IBM-2 for spectral indices $n=1,3,7$ is presented. By combining the results of this calculation with previously calculated phase-space factors (PSFs) we give predictions for expected half-lives. By comparing with experimental limits on the half-lives we set limits on the coupling constants $\ensuremath{\langle}{g}_{ee}^{M}\ensuremath{\rangle}$ of all proposed Majoron-emitting models.
Modified majoron model for cosmological anomalies
2020
The vacuum expectation value $v_s$ of a Higgs triplet field $\Delta$ carrying two units of lepton number $L$ induces neutrino masses $\propto v_s$. The neutral component of $\Delta$ gives rise to two Higgs particles, a pseudoscalar $A$ and a scalar $S$. The most general renormalizable Higgs potential $V$ for $\Delta $ and the Standard-Model Higgs doublet $\Phi$ does not permit the possibility that the mass of either $A$ or $S$ is small, of order $v_s$, while the other mass is heavy enough to forbid the decay $Z\to A S$ to comply with LEP 1 data. We present a model with additional dimension-6 terms in $V$, in which this feature is absent and either $A$ or $S$ can be chosen light. Subsequentl…
Neutrino masses, Majorons, and muon decay
1987
5 páginas, 3 figuras.
Hyperchargeless triplet Majoron model.
1989
We study the general conditions to maintain the scale of the lepton-number-breaking vacuum expectation value at the electroweak scale. It is shown that the only possibilities are if the main component of the resulting Majoron is a hyperchargeless complex triplet or a neutral singlet. Models with a hyperchargeless triplet, even though phenomenologically more interesting, seem to be very difficult to build because they like to break charge conservation. However, we have found a particular extension, by adding an additional neutral singlet, that solves this problem. The model can give a Majorana mass to the neutrinos in the eV range, ..mu -->..e..gamma.. can proceed with branching ratios at th…
Seesaw Majoron Model of Neutrino Mass and Novel Signals in Higgs Boson Production at LEP
1998
We perform a careful study of the neutral scalar sector of a model which includes a singlet, a doublet, and a triplet scalar field under $SU(2)$. This model is motivated by neutrino physics, since it is simply the most general version of the seesaw model of neutrino mass generation through spontaneous violation of lepton number. The neutral Higgs sector contains three CP-even and one massive CP-odd Higgs boson $A$, in addition to the massless CP-odd majoron $J$. The weakly interacting majoron remains massless if the breaking of lepton number symmetry is purely spontaneous. We show that the massive CP-odd Higgs boson may invisibly decay to three majorons, as well as to a CP-even Higgs $H$ bo…
A search for invisible Higgs bosons produced in e+e- interactions at LEP 2 energies
1999
Searches for HZ production with the Higgs boson decaying into an invisible final state have been performed with the data collected by the DELPHI experiment up to the centre-of-mass energy of 183 GeV. The hadronic and muon pair final states of the Z boson were analysed. From the absence of signal, upper limits on the cross-section and the corresponding Higgs boson mass limits were set at 95% confidence level. The results are interpreted as excluded parameter regions in the framework of the minimal supersymmetric standard model and in the simplest Majoron model with one Higgs doublet and one Higgs singlet field. (C) 1999 Elsevier Science B.V. All rights reserved.
Constraining the invisible neutrino decay with KM3NeT-ORCA
2019
Several theories of particle physics beyond the Standard Model consider that neutrinos can decay. In this work we assume that the standard mechanism of neutrino oscillations is altered by the decay of the heaviest neutrino mass state into a sterile neutrino and, depending on the model, a scalar or a Majoron. We study the sensitivity of the forthcoming KM3NeT-ORCA experiment to this scenario and find that it could improve the current bounds coming from oscillation experiments, where three-neutrino oscillations have been considered, by roughly two orders of magnitude. We also study how the presence of this neutrino decay can affect the determination of the atmospheric oscillation parameters $…
Updated CMB and x- and gamma-ray constraints on Majoron dark matter
2013
The Majoron provides an attractive dark matter candidate, directly associated with the mechanism responsible for spontaneous neutrino mass generation within the standard model SU(3)(c) circle times SU(2)(L) circle times U(1)(Y) framework. Here we update the cosmological and astrophysical constraints on Majoron dark matter coming from the cosmic microwave background and a variety of x- and gamma-ray observations.