Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Naturally Light Neutrinos and Unification in Theories with Low Scale
  Quantum Gravity   Within low scale theories traditional see-saw and scalar triplet mechanisms,
for neutrino mass suppression, do not work out anymore and for realistic model
building some new ideas are needed. In this paper we suggest mechanism,
different from existing ones, which provides natural suppression of the
neutrino masses. The mechanism is realized through extended scalars of 4, 5 or
6 dimensional $SU(2)_L$ multiplets. Scenario, with fundamental mass scale $M_f$
in a $\sim 10^{3}$ TeV range, requires 4-plets guaranteeing neutrino masses
$\stackrel{<}{\sim}1$ eV. For theories with $M_f= few \cdot 10$ TeV 5-plets
should be involved, while in scenarios with $M_f=$ few TeV, 6-plets could be
efficient.
  The considered mechanism could be successfully applied also for
supersymmetric theories, building scenarios with various values of low $M_f$.
  Within considered models we also address the question of gauge coupling
unification. For low scale unification, existence of compact extra dimensions
turns out to be crucial. Due to additional scalar multiplets, some new examples
of unification are found for both - non SUSY and SUSY cases. Within non SUSY
scenarios introduced $SU(2)_L$ scalars take advantage and are important for
successful unification.

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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: math
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: stat