Related papers: A chiral model for sterile neutrino
We construct a family of simple gauge models in which three sterile neutrinos become naturally light by virtue of a generalized seesaw mechanism involving a chiral gauge symmetry. Examples where the chiral gauge group is SU(5)', SU(7)',…
Light sterile neutrinos with a mass of $\sim 1$ eV continue to be interesting due to multiple hints from terrestrial experiments. This simple hypothesis suffers from strong astrophysical constraints, in particular from the early universe as…
We formulate a set of naturalness criteria for sterile neutrinos (\nu') to be light, needed for reconciling the LSND neutrino anomaly with the other neutrino data. A light sterile neutrino becomes as natural as the light active neutrinos if…
We use an effective-field-theory approach to construct models with naturally light sterile neutrinos, due to either exact or accidental global symmetries. The most attractive models we find are based on gauge symmetries, either discrete or…
Taken at face value, current experimental data indicate the existence of a new particle, the sterile neutrino, which must be a singlet under the Standard Model gauge group. Although they are not detectable through traditional means, such…
A sterile neutrino in addition to the three known neutrinos seems unavoidable if one wants a simultaneous understanding of the results of the LSND experiment indicating $\nu_{\mu}-\nu_e$ oscillation together with other evidences for…
In usual particle models, sterile neutrinos can account for the dark matter of the Universe only if they have masses in the keV range and are warm dark matter. Stringent cosmological and astrophysical bounds, in particular imposed by X-ray…
A sterile neutrino with a mass around the keV scale could be an interesting candidate for warm dark matter. Although there are several scenarios and production mechanisms known in which such a particle could yield the correct abundance,…
We explore the possibilities of dark matter production in a U(1) extension of the standard model, also called the super-weak model. The freeze-in and freeze-out mechanisms are described in detail, assuming the lightest sterile neutrino in…
Sterile neutrino dark matter, a popular alternative to the WIMP paradigm, has generally been studied in non-supersymmetric setups. If the underlying theory is supersymmetric, we find that several interesting and novel dark matter features…
Sterile neutrinos with masses in the keV range are viable candidates for the warm dark matter. We analyze existing data for the extragalactic diffuse X-ray background for signatures of sterile neutrino decay. The absence of detectable…
Neutrino masses are usually described by adding to the Standard Model some SU(2)-singlet fermions that have the Yukawa couplings, as well as some Majorana mass terms. The number of such fields and the scales of their Majorana masses are not…
A simultaneous understanding of the results of the LSND experiment indicating $\nu_{\mu}-\nu_e$ oscillation together with other evidences for neutrino oscillations from solar and atmospheric neutrino data seems to require the existence of…
We propose a class of dark matter models based on a chiral $U(1)$ gauge symmetry acting on a dark sector. The chiral $U(1)$ protects the masses of the dark sector fermions, and also guarantees the stability of the dark matter particle by…
A simple model to accomodate light sterile neutrinos naturally with large mixing with the usual neutrinos has been proposed. The standard model gauge group is extended to include an $SU(2)_S$ gauge symmetry. Heavy triplet higgs scalars give…
We investigate a model with an extra $Z_{2}$ gauge symmetry in the Standard Model. We assume that only the scalars and the leptons carry non-zero charge. The symmetry gives a structure to the mass matrix for the neutrinos. With two extra…
We review sterile neutrinos as possible Dark Matter candidates. After a short summary on the role of neutrinos in cosmology and particle physics, we give a comprehensive overview of the current status of the research on sterile neutrino…
Sterile right-handed neutrinos can be naturally embedded in a low scale gauged $U(1)_{B-L}$ extension of the standard model. We show that, within a low reheating scenario, such a neutrino is an interesting candidate for dark matter. We…
If light sterile neutrinos are needed to understand the neutrino puzzles, as is currently indicated, a major theoretical challenge is to understand why its mass is so small. It is a more serious problem than understanding the small mass of…
Sterile neutrinos may be one of the best Warm Dark Matter candidates we have today. Both lower and upper bounds on the mass of the sterile neutrino come from astronomical observations. We show that the proper inclusion of the neutrino…