2008/12/30 by Kokorelis, Christos
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.0812.4804
We examine the issue of generating the perturbatively absent \bf 10 ⋅ \bf 10 ⋅ \bf 5H SU(5)/flipped SU(5)Yukawa couplings in type II D-brane orientifold compactifications of string theory both at the perturbative (PER) and the non-perturbative (NP) level. We find at the PER level, higher order terms like \bf 10 ⋅ \bf 10 ⋅ \bf 5H ⋅\bf 5H ⋅ \bf 5H ⋅ \bf 5H ⋅ \bf 1H ⋅ \bf 1H in SU(5) may be responsible for the relevant quark mass generation in models with general intersecting D6-branes. Euclidean D2-brane instantons on the other hand can also generate at the NP via the term \bf 10 ⋅ \bf 10 ⋅ \bf 5H ⋅\bf 5H ⋅ \bf 5H ⋅ \bf 5H the relevant quark masses by the use of just the U(1)b brane, for SU(5) and flipped SU(5) GUTS classes of models. We provide local examples of rigid O(1) instantons within the T6/\mathbb Z2 × \mathbb Z2' toroidal orientifold with torsion, whose NP contribution to the masses gets minimal as it is induced by just a duplicated disk diagram.