Light Sterile Neutrino in the Minimal Extended Seesaw

Physics Letters B (Impact Factor: 6.02). 10/2011; 714(2-5). DOI: 10.1016/j.physletb.2012.06.074
Source: arXiv

ABSTRACT Motivated by the recent observations on sterile neutrinos, we present a
minimal extension of the canonical type-I seesaw by adding one extra singlet
fermion. After the decoupling of right-handed neutrinos, an eV-scale mass
eigenstate is obtained without the need of artificially inserting tiny mass
scales or Yukawa couplings for sterile neutrinos. In particular, the
active-sterile mixing is predicted to be of the order of 0.1. Moreover, we show
a concrete flavor A_4 model, in which the required structures of the minimal
extended seesaw are realized. We also comment on the feasibility of
accommodating a keV sterile neutrino as an attractive candidate for warm dark

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    Journal of High Energy Physics 08/2014; 08:057. DOI:10.1007/JHEP08(2014)057 · 6.22 Impact Factor
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    ABSTRACT: We study a large extra dimension model with active and sterile Dirac neutrinos. The sterile neutrino masses stem from compactification of an extra dimension with radius R and are chosen to have masses around eV or keV, in order to explain short-baseline anomalies or act as warm dark matter candidates. We study the effect of the sterile neutrino Kaluza-Klein tower in short-baseline oscillation experiments and in the beta spectrum as measurable by KATRIN-like experiments. (C) 2014 The Authors. Published by Elsevier B.V.
    Physics Letters B 07/2014; 737. DOI:10.1016/j.physletb.2014.08.035 · 6.02 Impact Factor
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    ABSTRACT: If the hints for light sterile neutrinos from short-baseline anomalies are to be taken seriously, global fits indicate active-sterile mixings of a magnitude comparable to the known reactor mixing. We therefore study the conditions under which the active-sterile and reactor mixings could have the same origin in an underlying flavour model. As a starting point, we use $\mu-\tau$ symmetry in the active neutrino sector, which (for three neutrinos) yields a zero reactor neutrino angle and a maximal atmospheric one. We demonstrate that adding one sterile neutrino can change this setting, so that the active-sterile mixing and non-zero $\theta_{13}$ can be generated simultaneously. From the phenomenological perspective, electron (anti)neutrino disappearance can be easily accommodated, while muon neutrino disappearance can vanish. It is, however, difficult to reconcile the LSND results with this scenario. From the theory perspective, the setting requires the misalignment of some of the flavon vacuum expectation values, which may be achieved in an $A_4$ or $D_4$ flavour symmetry model using extra dimensions.
    Journal of High Energy Physics 02/2014; 2014(7). DOI:10.1007/JHEP07(2014)039 · 6.22 Impact Factor


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