D-Instanton Generated Dirac Neutrino Masses
Abstract
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.
Cite
@article{arxiv.0803.2876,
title = {D-Instanton Generated Dirac Neutrino Masses},
author = {Mirjam Cvetic and Paul Langacker},
journal= {arXiv preprint arXiv:0803.2876},
year = {2009}
}
Comments
4 pages, 1 figure minor corrections, the version to be published in Phys. Rev. D