Quark Masses from Gaugino Condensation in String Theories

TL;DR

This paper proposes a string theory-based mechanism involving Sp(N) gauge groups to generate quark Yukawa couplings that are absent at perturbative level in certain GUT models, leading to fermion mass generation via condensates.

Contribution

It introduces a novel non-perturbative mechanism for quark mass generation in string compactifications with D-branes and Sp(N) gauge groups, addressing missing Yukawa couplings.

Findings

Quark masses can be generated through fermionic condensates involving Sp(N) gauge groups.

The mechanism relies on non-perturbative condensates of charged fermions in string compactifications.

Constraints on non-chiral states charged under Sp gauge groups are identified for strong coupling conditions.

Abstract

We present a mechanism able to generate the perturbatively absent up/down $<{\bf 10} \cdot {\bf 10} \cdot {\bf 5}^H>$ quark Yukawa couplings of SU(5)/flipped SU(5) GUTS in Type II orientifold compactifications with D-branes. The mechanism works when there are Sp(N) gauge groups involved. The ${\bf {\bar 5}}$'s get charged under the Sp(N) gauge groups and the generation of quark masses proceeds via the generation of the fermionic Sp(N) singlet condensate $<{\bf {\bar 5} \cdot {\bar 5} \cdot {\bar 5} \cdot {\bar 5}}>$ in the term $(1/{M_s^5}) {\bf 10} \cdot {\bf 10} \cdot < {\bf {\bar 5} \cdot {\bar 5} \cdot {\bar 5} \cdot {\bar 5}}>$. Also non-chiral states charged under Sp gauge groups may become constrained by the requirement of Sp's becoming strongly coupled.