Dyon Death Eaters

TL;DR

This paper investigates the decay processes of 1/4-BPS dyons in type IIB string theory, deriving a general stability equation and exploring its mathematical structure and implications for moduli space.

Contribution

It introduces a master equation for marginal stability of 1/4-BPS dyons, extending previous work on half-BPS decays and connecting to Farey sequences and Ford circles.

Findings

Derived a generalized marginal stability equation for 1/4-BPS dyons

Linked walls of marginal stability to Farey sequences and Ford circles

Identified intersecting stability curves within moduli space

Abstract

We study general two-body decays of primitive and non-primitive 1/4-BPS dyons in four-dimensional type IIB string compactifications. We find a ``master equation'' for marginal stability that generalises the curve found by Sen for half-BPS decay, and analyse this equation in a variety of cases including decays to 1/4-BPS products. For half-BPS decays, an interesting and useful relation is exhibited between walls of marginal stability and the mathematics of Farey sequences and Ford circles. We exhibit an example in which two curves of marginal stability intersect in the interior of moduli space.