Search results for "Majoron"
showing 10 items of 50 documents
17 keV neutrino in a singlet-triplet majoron model
1991
Abstract We investigate the possibility of a cosmologically safe 17 keV neutrino which may have been observed in the decays of tritium, S 35 , and C 14 within a singlet-triplet majoron model. Consideration of the leptonic decay of K + and X rays associated with the radiative decay of massive relic neutrinos severely constrains the scale of the spontaneous lepton number violation. It is argued that the mass density of relic 17 keV neutrinos is constrained as Ω v ⩽ 0.05 h −1 (0.01/ sin 2 θ ) in view of the observed diffuse X ray background.
Majoron effects in rare kaon decays
1989
Abstract We analyze, in the framework of the recently introduced doublet majoron model, the contribution from the emission of a pair of light scalars to the decay K + → π + + nothing . We find that, for reasonable choices of the parameters, the new scalar contribution may be as large as one additional neutrino-antineutrino mode and provide a substantial modification of the pion spectrum. The effect may be a few times larger in the triplet majoron model.
Production and decays of supersymmetric Higgs bosons in spontaneously brokenRparity
2005
We study the mass spectra, production and decay properties of the lightest supersymmetric CP-even and CP-odd Higgs bosons in models with spontaneously broken R-parity (SBRP). We compare the resulting mass spectra with expectations of the Minimal Supersymmetric Standard Model (MSSM), stressing that the model obeys the upper bound on the lightest CP-even Higgs boson mass. We discuss how the presence of the additional scalar singlet states affects the Higgs production cross sections, both for the Bjorken process and the "associated production". The main phenomenological novelty with respect to the MSSM comes from the fact that the spontaneous breaking of lepton number leads to the existence of…
Inflation and majoron dark matter in the neutrino seesaw mechanism
2014
We propose that inflation and dark matter have a common origin, connected to the neutrino mass generation scheme. As a model we consider spontaneous breaking of global lepton number within the seesaw mechanism. We show that it provides an acceptable inflationary scenario consistent with the recent cosmic microwave background B-mode observation by the BICEP2 experiment. The scheme may also account for the baryon asymmetry of the Universe through leptogenesis for reasonable parameter choices.
Supersymmetric Unification with Radiative Breaking of R-parity
1996
We show how R-parity can break spontaneously as a result of radiative corrections in unified N=1 supergravity models. We illustrate this with a concrete rank-four unified model, where the spontaneous breaking of R-parity is accompanied by the existence of a physical majoron. We determine the resulting supersymmetric particle mass spectrum and show that R-parity-breaking signals may be detectable at LEP200.
Supernova Bounds on Majoron-emitting decays of light neutrinos
2000
Neutrino masses arising from the spontaneous violation of ungauged lepton-number are accompanied by a physical Goldstone boson, generically called Majoron. In the high-density supernova medium the effects of Majoron-emitting neutrino decays are important even if they are suppressed in vacuo by small neutrino masses and/or small off-diagonal couplings. We reconsider the influence of these decays on the neutrino signal of supernovae in the light of recent Super-Kamiokande data on solar and atmospheric neutrinos. We find that majoron-neutrino coupling constants in the range $3\times 10^{-7}\lsim g\lsim 2\times 10^{-5}$ or $g \gsim 3 \times 10^{-4}$ are excluded by the observation of SN1987A. T…
Majorons: a simultaneous solution to the large and small scale dark matter problems
1984
Abstract It is shown that the existence of majorons, which enable a heavy neutrino, 500 eV ≲ mνH ≲ 25 keV to decay into a light neutrino mνL ≲ 8 eV and a majoron, with lifetime 104 yr ≲ τνH ≲ 108 yr can solve both the large and small scale dark matter problems. For a primordial “Zeldovich” spectrum of fluctuations the limits are m v H ≲ 550 eV and τ v H > 107 to 108 yr (the ranges mνH ≲ eV and τνH ≳ 108 yr are allowed by the model but galaxy formation becomes problematic). The large scale dark matter problem is how to achieve the critical density as implied by inflation, the small scale problems deal with the halos of galaxies and galaxy formation and perturbation growth. The heavy neutrino…
X-ray photons from late-decaying majoron dark matter
2008
An attractive way to generate neutrino masses as required to account for current neutrino oscillation data involves the spontaneous breaking of lepton number. The resulting majoron may pick up a mass due to gravity. If its mass lies in the kilovolt scale, the majoron can play the role of late-decaying Dark Matter (LDDM), decaying mainly to neutrinos. In general the majoron has also a sub-dominant decay to two photons leading to a mono-energetic emission line which can be used as a test of the LDDM scenario. We compare expected photon emission rates with observations in order to obtain model independent restrictions on the relevant parameters. We also illustrate the resulting sensitivities w…
Radiative Seesaw Dark Matter
2021
The singlet majoron model of seesaw neutrino mass is appended by one dark Majorana fermion singlet $\chi$ with $L=2$ and one dark complex scalar singlet $\zeta$ with $L=1$. This simple setup allows $\chi$ to obtain a small radiative mass anchored by the same heavy right-handed neutrinos, whereas the one-loop decay of the standard-model Higgs boson to $\chi \chi + \bar{\chi} \bar{\chi}$ provides the freeze-in mechanism for $\chi$ to be the light dark matter of the Universe.
Supersymmetric majoron signatures and solar neutrino oscillations
1988
Spontaneous R-parity breaking in supergravity solves the solar neutrino problem through matter-enhanced neutrino oscillations. The model may be tested in collider experiments and through ``dynamical'' effects associated with the existence of a weakly interacting majoron. Apart from astrophysical effects, majoron emission can produce observable changes in \ensuremath{\mu} and \ensuremath{\tau} decay spectra for parameter values that substantially reduce the solar neutrino flux. A signature of the model is the possible observation of the decay \ensuremath{\mu}\ensuremath{\rightarrow}e+majoron.