Search results for "sterile"
showing 10 items of 164 documents
Testing the Standard Model and beyond with the LENA proposal
2014
We discuss the possibility of a precision measurement of the electroweak mixing angle and a probe for new physics in the leptonic process of neutrino electron scattering. In the new physics schemes we explore the case of non standard neutrino interactions (NSI). The LENA proposal, currently under discussion, considers a large detector and the use of an articial, 51 Cr, radioactive neutrino source with of 5 MCi intensity. We also discuss the possible use of the solar neutrino
Omnibus experiment: CPT and CP violation with sterile neutrinos
2016
We propose to probe both the CPT and CP violation together with the search for sterile neutrinos in one do-it-all experiment. This omnibus experiment would utilize neutrino oscillometry with large scintillator detectors like LENA, JUNO or RENO-50 and manmade radioactive sources similar to the ones used by the GALLEX experiment. Our calculations indicate that such an experiment is realistic and could be performed in parallel to the main research plan for JUNO, LENA, or RENO-50. Assuming as the starting point the values of the oscillation parameters indicated by the current global fit (in 3 active + 1 sterile scenario) and requiring at least 5 sigma confidence level, we estimate that with the…
Calibration campaign of the Borexino detector for the search of sterile neutrinos with SOX
2020
Abstract The SOX (Short distance Oscillations with boreXino) experiment aims to investigate possible anomalous oscillatory behaviours in neutrinos, including the existence of sterile neutrinos, by exploiting the very low radioactive background of the Borexino detector. A calibration campaign is crucial to achieve a deeper understanding of the energy response and the spatial reconstruction accuracies of the detector. It will be performed with a suite of low-activity radioactive sources which will map the whole active volume, especially nearby the inner vessel. The calibration points at the border of the active zones will be extremely important to study the neutron detection efficiency. The c…
Search for sterile neutrinos with SOX: Monte Carlo studies of the experiment sensitivity and systematic effects
2020
Abstract Some neutrino experiments reveal anomalous results which can make room for new physics beyond the three-flavor neutrino oscillation model. These hints suggest the existence of sterile neutrinos with mass m <eV. SOX will be a short-baseline disappearance experiment aiming to test this hypotesis, performed with the liquid scintillator detector Borexino at Gran Sasso National Laboratory in Italy [1]. Due to the good energy and position resolution, a light sterile neutrino can create an oscillatory pattern in the signal. The SOX sensitivity, the related analysis and systematics will be briefly discussed.
Active-active and active-sterile neutrino oscillation solutions to the atmospheric neutrino anomaly
1998
We perform a fit to the full data set corresponding to 33.3 kt-yr of data of the Super-Kamiokande experiment as well as to all other experiments in order to compare the two most likely solutions to the atmospheric neutrino anomaly in terms of oscillations in the $\nu_\mu \to \nu_\tau$ and $\nu_\mu \to \nu_s$ channels. Using state-of-the-art atmospheric neutrino fluxes we have determined the allowed regions of oscillation parameters for both channels. We find that the $\Delta m^2$ values for the active-sterile oscillations (both for positive and negative $\Delta m^2$) are higher than for the $\nu_\mu \to \nu_\tau$ case, and that the increased Super-Kamiokande sample slightly favours $\nu_\mu…
Neutrino mass and new light gauge boson in superstring models
1987
Abstract The proposal that the neutrino owes the smallness of its mass to the spontaneous breaking of R parity in superstring models with an additional gauge boson coupled to the right-handed neutrino is analysed. The right-handed neutrino can not in general decouple from the low-energy theory in models with supersymmetry at the TeV scale and which possess the light Higgs doublets necessary for generating fermion masses. Experimental limits on neutrino mass then imply an upper limit on the new gauge boson mass m Zr ⪅ 220 GeV.
Bounds on sterile neutrino mixing for cosmologically interesting mass range
1997
This talk summarizes our recent work which studied the impact of resonant $\nu_e \to\nu_s$ and $\bar{\nu}_e\to\bar{\nu}_s$ ($\nu_s$ is a sterile neutrino) conversions on supernova physics, under the assumption that the mass of the sterile state is in the few eV -cosmologically significant range.
Symmetrical Parametrizations of the Lepton Mixing Matrix
2011
Advantages of the original symmetrical form of the parametrization of the lepton mixing matrix are discussed. It provides a conceptually more transparent description of neutrino oscillations and lepton number violating processes like neutrinoless double beta decay, clarifying the significance of Dirac and Majorana phases. It is also ideal for parametrizing scenarios with light sterile neutrinos.
Flavour-symmetric type-II Dirac neutrino seesaw mechanism
2018
We propose a Standard Model extension with underlying A4 flavour symmetry where small Dirac neutrino masses arise from a Type-II seesaw mechanism. The model predicts the "golden" flavour-dependent bottom-tau mass relation, requires an inverted neutrino mass ordering and non-maximal atmospheric mixing angle. Using the latest neutrino oscillation global fit we derive restrictions on the oscillation parameters, such as a correlation between Dirac CP phase and the lightest neutrino mass.
Sterile neutrinos with altered dispersion relations revisited
2020
In this paper we investigate neutrino oscillations with altered dispersion relations in the presence of sterile neutrinos. Modified dispersion relations represent an agnostic way to parameterize new physics. Models of this type have been suggested to explain global neutrino oscillation data, including deviations from the standard three-neutrino paradigm as observed by a few experiments. We show that, unfortunately, in this type of models new tensions arise turning them incompatible with global data.