Up-type quark masses in SU(5) F-theory models
Anamaría Font, Fernando Marchesano, Diego Regalado, Gianluca Zoccarato
TL;DR
This work analyzes up-type quark masses in local SU(5) F-theory GUTs by computing $10 imes10 imes5$ Yukawas at an $E_6$ point. A T-brane Higgs background combined with non-perturbative instanton effects generates a rank-3 holomorphic Yukawa matrix with a hierarchical structure that yields a realistic top mass and quark mass ratios after normalizing the wavefunctions. The authors derive holomorphic Yukawas via a residue formula and confirm them with physical Yukawas from overlapping wavefunctions, showing an ${ m O}(1)$ top Yukawa and $(1, ilde{oldsymbol{ ilde{oldsymbol{oldsymbol{oldsymbol{oldsymbol{}}}}}}, ilde{oldsymbol{ ilde{oldsymbol{oldsymbol{}}}}^2))$ hierarchies in the up-type sector. They demonstrate how primitive hypercharge fluxes and non-perturbative effects jointly produce the observed up-quark mass pattern, within a bottom-up local framework that connects local data to MSSM phenomenology. The results suggest that SU(5) F-theory GUTs with T-branes are capable of accommodating SM flavor structure, including the large top mass, and point to future work on CKM realizations and global completions.
Abstract
F-theory SU(5) unification has been proposed as a scenario where the mass of the top quark is naturally large, as opposed to type II SU(5) models. We analyze this claim from the viewpoint of local SU(5) F-theory models, by explicitly computing the 10 x 10 x 5 Yukawa couplings that are developed in the vicinity of an E6 singularity. Realizing this singularity via T-branes allows for a non-trivial mass for the top quark, while lighter generations of up-type quarks still have vanishing Yukawa couplings. Nevertheless, we show that by taking instanton effects into account non-vanishing Yukawas are induced for all U-quark families, together with a hierarchical structure at the level of the superpotential. Finally, by solving for internal wavefunction profiles we compute physical U-quark Yukawa couplings and show that this F-theory scenario allows to describe the measured top quark mass, as well as the observed quotients of U-quark masses.
