Abstract
We study bulk fermion fields in various multi-brane models with localized gravity. The chiral zero mode that these models support can be identified as a right-handed sterile neutrino. In this case small neutrino Dirac masses can naturally appear due to a localization of the bulk fermion zero mode wavefunction, in an analogous way to graviton, without invoking the see-saw mechanism. The conditions and the options for localization are discussed in detail. It is shown that, considering a well motivated five dimensional mass term, the localization behaviour of this mode can resemble the graviton's at least in a region of the parameter space. As a result, the ''+-+'', ''++'' models can support, in addition to the ultralight graviton KK state, an ultralight localized and strongly coupled bulk fermion KK mode. We find that there are severe constraints on the parameter space of ''+-+'' and ''++'' models if the neutrino properties resulting from this light fermion state are to be reasonable. Furthermore, in the case that also the Bigravity scenario is realized the above special KK mode can induce too large mixing between the neutrino and the KK tower sterile modes restricting even more the allowed parameter space.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
