Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: D-Instanton Generated Dirac Neutrino Masses   We present a stringy mechanism to generate Dirac neutrino masses by
D-instantons in an experimentally relevant mass scale without fine-tuning.
Within Type IIA string theory with intersecting D6-branes, we spell out
specific conditions for the emergence of such couplings and provide a class of
supersymmetric local SU(5) Grand Unified models, based on the Z_2 x Z'_2
orientifold compactification, where perturbatively absent Dirac neutrino masses
can be generated by D2-brane instantons in the experimentally observed mass
regime, while Majorana masses remain absent, thus providing an intriguing
mechanism for the origin of small neutrino masses due to non-perturbative
stringy effects.

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The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: econ