2002/01/31 by Thomas Appelquist, Bogdan A. Dobrescu, Eduardo Ponton +2 · 4 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Neutrino Physics Research #Particle physics theoretical and experimental studies #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.65.105019
published as Phys.Rev. D65 (2002) 105019 · 34 pages, Latex, 2 eps figures. Change in the normalization convention for the warp factor; other minor changes
arxiv created 2002/03/25 · openalex publication_date 2002/05/14 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We examine the origin of neutrino masses and oscillations in the context of the six-dimensional standard model. The space-time symmetries of this model explain proton stability and forbid Majorana neutrino masses. The consistency of the six-dimensional theory requires three right-handed neutrinos, and therefore Dirac neutrino masses are allowed. We employ the idea that the smallness of these masses is due to the propagation of the right-handed neutrinos in a seventh, warped dimension. We argue that this class of theories is free of gravitational anomalies. Although an exponential hierarchy arises between the neutrino masses and the electroweak scale, we find that the mass hierarchy among the three neutrino masses is limited by higher-dimension operators. All current neutrino oscillation data, except for the LSND result, are naturally accommodated by our model. In the case of the solar neutrinos, the model leads to the large mixing angle, MSW solution. The mechanism employed, involving three right-handed neutrinos coupled to a scalar in an extra dimension, may explain the features of the neutrino spectrum in a more general class of theories that forbid Majorana masses.