A new CY elliptic fibration and tadpole cancellation

TL;DR

This paper extends the study of tadpole cancellation in F-theory by generalizing elliptic fibrations, discovering a new case of universal tadpole cancellation, and analyzing the existence of Sen limits with correct brane content.

Contribution

It introduces a new CY elliptic fibration, generalizes previous fibrations, and explores the existence of Sen limits with proper brane configurations.

Findings

Identified a new elliptic fibration with non-Kodaira fibers.

Discovered a new case of universal tadpole cancellation.

Argued the possible non-existence of a Sen limit with correct brane content.

Abstract

Tadpole cancellation in Sen limits in F-theory was recently studied by Aluffi and Esole. We extend their results, generalizing the elliptic fibrations they used and obtaining a new case of universal tadpole cancellation, at least numerically. We could not find an actual Sen limit having the correct brane content, and we argue that such a limit may not exist. We also give a uniform description of the fibration used by Aluffi and Esole as well as a new, simple, fibration which has non-Kodaira type fibers.