Search results for "Oscillation"
showing 10 items of 1257 documents
ν¯inducedK¯production off the nucleon
2012
The charged-current antikaon production off nucleons induced by antineutrinos is studied at low and intermediate energies. We extend here our previous calculation on kaon production induced by neutrinos. We have developed a microscopic model that starts from the SU(3) chiral Lagrangians and includes background terms and the resonant mechanisms associated to the lowest lying resonance in the channel, namely, the ${\ensuremath{\Sigma}}^{*}(1385)$. Our results could be of interest for the background estimation of various neutrino oscillation experiments like MiniBooNE and SuperK. They can also be helpful for the planned $\overline{\ensuremath{\nu}}$ experiments like $\mathrm{MINER}\ensuremath{…
Probing a Supersymmetric Model for Neutrino Masses at Ultrahigh Energy Neutrino Telescopes
2008
A bilinear R-Parity breaking SUSY model for neutrino mass and mixing predicts the lightest superparticle to decay mainly into a pair of tau leptons or b quarks along with a neutrino for relatively light SUSY spectra. This leads to a distinctive triple bang signature of SUSY events at ultrahigh energy neutrino telescopes like IceCube or Antares. While the expected signal size is only marginal at IceCube, it will be promising for a future multi-km^3 size neutrino telescope.
Four-neutrino oscillations and the solar neutrino problem
2000
We perform a fit of solar neutrino data in the framework of the two four-neutrino schemes that are compatible with the results of all neutrino oscillation experiments. These schemes allow simultaneous transitions of solar nu_e's into active nu_mu's, nu_tau's and sterile nu_s. The data imply that the SMA solution is valid for any combination of nu_e->active and nu_e->sterile transitions, whereas the LMA, LOW and VO solutions disappear when nu_e->nu_s transitions are dominant.
Neutrino masses and mixings from supersymmetry with bilinear R-parity violation: A theory for solar and atmospheric neutrino oscillations
2000
The simplest unified extension of the MSSM with bi-linear R--Parity violation naturally predicts a hierarchical neutrino mass spectrum, in which one neutrino acquires mass by mixing with neutralinos, while the other two get mass radiatively. We have performed a full one-loop calculation of the neutralino-neutrino mass matrix in the bi-linear \rp MSSM, taking special care to achieve a manifestly gauge invariant calculation. Moreover we have performed the renormalization of the heaviest neutrino, needed in order to get meaningful results. The atmospheric mass scale and maximal mixing angle arise from tree-level physics, while solar neutrino scale and oscillations follow from calculable one-lo…
Leptonic Generation Mixing, Noncommutative Geometry and Solar Neutrino Fluxes
1997
Triangular mass matrices for neutrinos and their charged partners contain full information on neutrino mixing in a most concise form. Although the scheme is general and model independent, triangular matrices are typical for reducible but indecomposable representations of graded Lie algebras which, in turn, are characteristic for the standard model in noncommutative geometry. The mixing matrix responsible for neutrino oscillations is worked out analytically for two and three lepton families. The example of two families fixes the mixing angle to just about what is required by the Mikheyev-Smirnov-Wolfenstein resonance oscillation of solar neutrinos. In the case of three families we classify a…
Bimaximal mixing from the leptonic new texture for triangular mass matrices
1999
An analysis of the leptonic texture for the new triangular mass matrices has been carried out. In particular, it is shown that both bimaximal and nearly bimaximal solutions for solar and atmospheric neutrino anomalies can be generated within this pattern. We have also derived exact and compact parametrization of the leptonic mixing matrix in terms of the lepton masses and the parameters $\alpha, \beta'$ and $\delta$. A consistency with the CHOOZ reactor result for $V_m{_{13}}$ and a smallness of the Jarlskog's invariant parameter are obtained.
Neutrino masses from operator mixing
2002
We show that in theories that reduce, at the Fermi scale, to an extension of the standard model with two doublets, there can be additional dimension five operators giving rise to neutrino masses. In particular there exists a singlet operator which can not generate neutrino masses at tree level but generates them through operator mixing. Under the assumption that only this operator appears at tree level we calculate the neutrino mass matrix. It has the Zee mass matrix structure and leads naturally to bimaximal mixing. However, the maximal mixing prediction for solar neutrinos is very sharp even when higher order corrections are considered. To allow for deviations from maximal mixing a fine t…
SN 1987A and the status of oscillations solutions to the solar neutrino problem
2002
We study neutrino oscillations and the level-crossing probability ${P}_{\mathrm{LSZ}}$ in power-law potential profiles $A(r)\ensuremath{\propto}{r}^{n}.$ We give local and global adiabaticity conditions valid for all mixing angles $\ensuremath{\vartheta}$ and discuss different representations for ${P}_{\mathrm{LSZ}}.$ For the ${1/r}^{3}$ profile typical of supernova envelopes we compare our analytical to numerical results and to earlier approximations used in the literature. We then perform a combined likelihood analysis of the observed SN 1987A neutrino signal and of the latest solar neutrino data, including the recent SNO CC measurement. We find that, unless all relevant supernova paramet…
Neutrino masses and mixing: 2008 status
2009
We review the current status (as of the end of 2008) of neutrino mass and mixing determinations, focusing on the hints of θ 13 > 0 , recently emerged in our global analysis.
Leptogenesis with Single Right-Handed Neutrino Dominance
2001
We make an analytic and numerical study of leptogenesis in the framework of the (Supersymmetric) Standard Model plus the see-saw mechanism with a U(1) family symmetry and single right-handed neutrino dominance. In presenting our analytic and numerical results we make a clear distinction between the theoretically clean asymmetry parameter $\epsilon_1$ and the baryon asymmetry $Y_B$. In calculating $Y_B$ we propose and use a fit to the solutions to the Boltzmann equations which gives substantially more reliable results than parametrisations previously used in the literature. Our results show that there is a decoupling between the low energy neutrino observables and the leptogenesis prediction…