出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We study the model-building conditions under which an observable 0 -
decay signal is predicted due to Kaluza{Klein singlet neutrinos in theories with large extra
dimensions. Our analysis is based on 5-dimensional singlet-neutrino models compacti ed
on an S1=Z2 orbifold, where the Standard{Model elds are localized on a 3-brane. We
show that sizeable 0 rates within the above minimal 5-dimensional framework would
require a non-vanishing shift of the 3-brane from the orbifold xed points by an amount
smaller than the typical scale (100 MeV)−1 characterizing the Fermi nuclear momentum.
The resulting 5-dimensional models predict a sizeable e
ective Majorana-neutrino mass
that could be several orders of magnitude larger than the light neutrino masses.
