Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bulk Fermions in Multi-Brane Worlds   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.

19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph