Neutrinos are the only particles in the Standard Model (SM) of particle physics that have only been observed with left handed chirality to date. If right handed (RH) neutrinos exist, they could be responsible for several phenomena that have no explanation within the SM, including neutrino oscillations, the baryon asymmetry of the universe, dark matter (DM) and dark radiation (DR). After a pedagogical introduction, we review recent progress in the phenomenology of RH neutrinos. We in particular discuss the mass ranges suggested by hints for neutrino oscillation anomalies and DR (eV), sterile neutrino DM scenarios (keV) and experimentally testable theories of baryogenesis (GeV to TeV). We summarize constraints from theoretical considerations, laboratory experiments, astrophysics and cosmology for each of these.

http://inspirehep.net/record/1225646/files/arXiv:1303.6912.pdf

The Phenomenology of Right Handed Neutrinos

Precision Tau Physics

The non-unitarity of the effective leptonic mixing matrix at low energies is a generic signal of extensions of the Standard Model (SM) with extra fermionic singlet particles, i.e. “sterile” or “right-handed” neutrinos, to account for the observed neutrino masses. The low energy effects of such extensions can be described in a model-independent way by the Minimal Unitarity Violation (MUV) scheme, an effective field theory extension of the SM. We perform a global fit of the MUV scheme parameters to the present experimental data, which yields the up-to-date constraints on leptonic non-unitarity. Furthermore, we investigate the sensitivities and discovery prospects of future experiments. In particular, FCC-ee/TLEP would be a powerful probe of flavour-conserving non-unitarity for singlet masses up to ∼60 TeV. Regarding flavour-violating non-unitarity, future experiments on muon-to-electron conversion in nuclei could even probe extensions with singlet masses up to ∼0.3 PeV.

/pdf/non-unitarity-of-the-leptonic-mixing-matrix-present-bounds-2g1wxpif54.pdf

Non-unitarity of the leptonic mixing matrix: present bounds and future sensitivities

Author(s): Bartoszek, L; et al. | Abstract: The Mu2e experiment at Fermilab will search for charged lepton flavor violation via the coherent conversion process mu- N --g e- N with a sensitivity approximately four orders of magnitude better than the current world's best limits for this process. The experiment's sensitivity offers discovery potential over a wide array of new physics models and probes mass scales well beyond the reach of the LHC. We describe herein the preliminary design of the proposed Mu2e experiment. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2 approval.

Mu2e Technical Design Report

Flavour covariant transport equations: An application to resonant leptogenesis

Author(s): Project, The Mu2e; Collaboration; Abrams, RJ; Alezander, D; Ambrosio, G; Andreev, N; Ankenbrandt, CM; Asner, DM; Arnold, D; Artikov, A; Barnes, E; Bartoszek, L; Bernstein, RH; Biery, K; Biliyar, V; Bonicalzi, R; Bossert, R; Bowden, M; Brandt, J; Brown, DN; Budagov, J; Buehler, M; Burov, A; Carcagno, R; Carey, RM; Carosi, R; Cascella, M; Cauz, D; Cervelli, F; Chandra, A; Chang, JK; Cheng, C; Ciambrone, P; Coleman, RN; Cooper, M; Corcoran, MC; Cordelli, M; Davydov, Y; Gouvea, AL de; Lorenzis, L De; Debevec, PT; DeJongh, F; Densham, C; Deuerling, G; Dey, J; Falco, S Di; Dixon, S; Djilkibaev, R; Drendel, B; Dukes, EC; Dychkant, A; Echenard, B; Ehrlich, R; Evans, N; Evbota, D; Fang, I; Fast, JE; Feher, S; Fischler, M; Frank, M; Frlez, E; Fung, SS; Gallo, G; Galucci, G; Gaponenko, A; Genser, K; Giovannella, S; Glagolev, V; Glenzinski, D; Gnani, D; Goadhouse, S; Gollin, GD; Grace, C; Grancagnolo, F; Group, C; Hanson, J; Hanson, S; Happacher, F; Heckmaier, E; Hedin, D; Hertzog, DW; Hirosky, R; Hitlin, DG; Ho, E; Huang, X | Abstract: Mu2e at Fermilab will search for charged lepton flavor violation via the coherent conversion process mu- N --g e- N with a sensitivity approximately four orders of magnitude better than the current world's best limits for this process. The experiment's sensitivity offers discovery potential over a wide array of new physics models and probes mass scales well beyond the reach of the LHC. We describe herein the conceptual design of the proposed Mu2e experiment. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-1 approval, which was granted July 11, 2012.

D. Alezander

Papers

Mu2e Conceptual Design Report