The indications in favor of the existence of light sterile neutrinos at the eV scale found in short-baseline neutrino oscillation experiments is reviewed. The future perspectives of short-baseline ...neutrino oscillation experiments and the connections with β-decay measurements of the neutrino masses and with neutrinoless double-β decay experiments are discussed.
With the observation of neutrino masses and mixings, the study of their electromagnetic interactions has assumed greater relevance both as verification of the nu standard model, and as a guide to new ...physics. After a standard description of massive neutrinos, this review assembles the present state of the art in the study of their electromagnetic interactions. Possible measurements of their static properties as test of new physics are described, a well as their behavior in strong magnetic fields. As such it should be helpful to both particle physicists and astrophysicists. A review is given of the theory and phenomenology of neutrino electromagnetic interactions, which provide powerful tools to probe the physics beyond the standard model. After a derivation of the general structure of the electromagnetic interactions of Dirac and Majorana neutrinos in the one-photon approximation, the effects of neutrino electromagnetic interactions in terrestrial experiments and in astrophysical environments are discussed. The experimental bounds on neutrino electromagnetic properties are presented and the predictions of theories beyond the standard model are confronted.
We address the phenomenology of light sterile neutrinos, with an emphasis on short-baseline neutrino oscillations. After reviewing the observed short-baseline neutrino oscillation anomalies, we ...discuss the global fit of the data and the current appearance-disappearance tension. We also review briefly the effects of light sterile neutrinos in β decay, neutrinoless double-β decay, and cosmology. Finally, we discuss future perspectives of the search for the effects of eV-scale sterile neutrinos.
Recently, several models have been suggested to reduce the tension between Gallium and reactor antineutrino spectral ratio data which is found in the framework of 3+1 active-sterile neutrino mixing. ...Among these models, we consider the extensions of 3+1 mixing with a finite wavepacket size, or the decay of the heaviest neutrino ν4, or the possibility to have a broad ν4 mass distribution. We consider the reactor antineutrino rate data and we show that these models cannot eliminate the tension between Gallium and reactor rate data that is found in the 3+1 neutrino mixing framework. Indeed, we show that the parameter goodness of fit remains small. We consider also a model which explains the Gallium Anomaly with non-standard decoherence in the framework of three-neutrino mixing. We find that it is compatible with the reactor rate data.
We calculate the statistical significance of the anomalous deficit of electron neutrinos measured in the radioactive source experiments of the GALLEX and SAGE solar neutrino detectors, taking into ...account the uncertainty of the detection cross section. We found that the statistical significance of the anomaly is {approx}3.0{sigma}. A fit of the data in terms of neutrino oscillations favors at {approx}2.7{sigma} short-baseline electron neutrino disappearance with respect to the null hypothesis of no oscillations.
A
bstract
We consider quantum-decoherence effects in neutrino oscillation data. Working in the open quantum system framework we adopt a phenomenological approach that allows to parameterize the ...energy dependence of the decoherence effects. We consider several phenomenological models. We analyze data from the reactor experiments RENO, Daya Bay and KamLAND and from the accelerator experiments NOvA, MINOS/MINOS+ and T2K. We obtain updated constraints on the decoherence parameters quantifying the strength of damping effects, which can be as low as Γ
ij
≲ 8 × 10
−
27
GeV at 90% confidence level in some cases. We also present sensitivities for the future facilities DUNE and JUNO.
In various extensions of the Standard Model of particle physics, and intriguingly even in the three-generation Standard Model without neutrino masses, neutrinos are allowed to have very tiny electric ...charges. After a review of the theoretical scenarios that allow the emergence of such charges, we discuss the existing observational limits and we derive new stringent direct upper bounds for the charges of the muon and tau neutrinos. We also point out a flavor-universal lower bound on neutrino charges which is obtained from the weak gravity conjecture, that is based on the hypothesis that gravity is the weakest force. We finally present a new flavor-universal upper bound on neutrino charges based on astrophysical observations of Magnetars.
Light sterile neutrinos can be excited by oscillations with active neutrinos in the early universe. Their properties can be constrained by their contribution as extra-radiation, parameterized in ...terms of the effective number of neutrino species Neff, and to the universe energy density today Ωνh2. Both these parameters have been measured to quite a good precision by the Planck satellite experiment. We use this result to update the bounds on the parameter space of (3+1) sterile neutrino scenarios, with an active-sterile neutrino mass squared splitting in the range (10−5–102) eV2. We consider both normal and inverted mass orderings for the active and sterile states. For the first time we take into account the possibility of two non-vanishing active-sterile mixing angles. We find that the bounds are more stringent than those obtained in laboratory experiments. This leads to a strong tension with the short-baseline hints of light sterile neutrinos. In order to relieve this disagreement, modifications of the standard cosmological scenario, e.g. large primordial neutrino asymmetries, are required.
An overview of neutrino electromagnetic properties, which open a door to the new physics beyond the Standard Model, is given. The effects of neutrino electromagnetic interactions both in terrestrial ...experiments and in astrophysical environments are discussed. The experimental bounds on neutrino electromagnetic characteristics are summarized. Future astrophysical probes of electromagnetic neutrinos are outlined.
The discovery of the Higgs boson at LHC was another milestone achievement for the Standard Model. However, neutrinos do not fit into this extremely successful theory of particle physics. Various theoretical scenarios beyond the Standard Model predict electromagnetic interactions of neutrinos. We focus on electromagnetic neutrinos as potential messengers of new physics in laboratory experiments and astrophysical processes.
We present an upgrade of the 3+1 global fit of short-baseline neutrino oscillation data obtained with the addition of KARMEN and LSND νe+C12→Ng.s.12+e− scattering data. We discuss the implications ...for the measurements of the effective neutrino mass in β-decay and neutrinoless double-β-decay experiments. We find respective predicted ranges of about 0.1–0.7 eV and 0.01–0.1 eV.
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