A landscape of orientifold vacua

Abstract

We present a vast landscape of O3/O7 orientifolds that descends from the famous set of complete intersection Calabi-Yau threefolds (CICY). We give distributions of topological data relevant for phenomenology such as the orientifold-odd Hodge numbers, the D3-tadpole, and multiplicities of O3 and O7-planes. Somewhat surprisingly, almost all of these orientifolds have conifold singularities whose deformation branches are projected out by the orientifolding. However, they can be resolved, so most of the orientifolds actually descend from a much larger and possibly new set of CY threefolds that can be reached from the CICYs via conifold transitions. We observe an interesting class of N = 1 geometric transitions involving colliding O-planes. Finally, as an application, we use our dataset to produce examples of orientifolds that satisfy the topological requirements for the existence of ultra-light throat axions (thraxions) as proposed in [1]. The database can be accessed here: www.desy.de/∼westphal/orientifold webpage/cicy orientifolds.html.

Conifold Vacua with Small Flux Superpotential

“…These components — a small classical flux superpotential, [ 2–5 ] a warped throat region, [ 6–11 ] a potential for the Kähler moduli from Euclidean D3‐branes or strong gauge dynamics, [ 12–23 ] and a supersymmetry‐breaking sector from anti‐D3‐branes [ 24–31 ] — are by now rather well understood separately . A remaining challenge in the pursuit of explicit examples of KKLT de Sitter vacua is to exhibit Calabi‐Yau orientifolds that contain all these components at once, through calculations in which corrections to the leading approximations are demonstrably well‐controlled.…”

Moduli Stabilization with Non‐Geometric Fluxes — Comments on Tadpole Contributions and de‐Sitter Vacua

“…In Equation () we have defined tadpole charges , which play an important role for moduli stabilization. They connect the open‐ and closed‐string sectors to each other and give rise to strong restrictions (see for instance [39–47] for recent discussions of this question). In this section we present arguments that the should contribute to the tadpole cancellation conditions () in the same way as D‐branes and not as anti‐D‐branes.…”

Harmonic hybrid inflation

“…1 Axions are an ubiquitous presence in most models of string compactifications, see e.g. [7][8][9][10]. String theory axions appear with an exponentially wide spectrum of masses suggesting some of them as suitable inflaton candidates.…”

“…Furthermore, a recently found database listing all ambient-space descending O3/O7orientifolds of the set of Complete Intersection Calabi-Yaus (CICYs) contains thousands of explicit examples of compact CYs whose topology supports the existence of such thraxions [10]. For other O3/O7-orientifold constructions in the Kreuzer-Skarke database see [72,73].…”