F-theory uplifts and GUTs

TL;DR

This work demonstrates how F-theory uplifts of Type IIB orientifolds with shrinkable del Pezzo divisors lead to singular Calabi–Yau fourfolds whose Weierstrass fibrations encode non-perturbative gauge enhancements. By analyzing two explicit quintic del Pezzo transitions, the authors connect D7-brane data to base geometries, apply the Tate algorithm, and identify possible GUT structures including $SO(10)$ spinors and exceptional groups off the orientifold locus. They find that while perturbative groups like $SO(8)\times SO(8)$ or $SP(8)\times SO(16)$ arise, non-perturbative enhancements can realize richer symmetries, though the studied models do not yield perturbative $SU(5)$ top Yukawas. The results illuminate constraints and opportunities for GUT model building in globally consistent F-theory settings, motivating exploration of broader complete intersections to realize complete Yukawa structures.

Abstract

We study the F-theory uplift of Type IIB orientifold models on compact Calabi-Yau threefolds containing divisors which are del Pezzo surfaces. We consider two examples defined via del Pezzo transitions of the quintic. The first model has an orientifold projection leading to two disjoint O7-planes and the second involution acts via an exchange of two del Pezzo surfaces. The two uplifted fourfolds are generically singular with minimal gauge enhancements over a divisor and, respectively, a curve in the non-Fano base. We study possible further degenerations of the elliptic fiber leading to F-theory GUT models based on subgroups of E8.