BPS States with Extra Supersymmetry

TL;DR

This paper explores the conditions under which BPS states in string theory, M-theory, and supersymmetric field theories can preserve more than half of the original supersymmetry, including the possibility of 3/4 supersymmetry.

Contribution

It demonstrates that certain charge configurations can lead to BPS states preserving more than half of the supersymmetry, and investigates their existence in various theories.

Findings

Configurations with more than half supersymmetry are possible.

States preserving 3/4 supersymmetry are analyzed.

Discussion on the actual occurrence of such states in theories.

Abstract

A state saturating a BPS bound derived from a supersymmetry algebra preserves some fraction of the supersymmetry. This fraction of supersymmetry depends on the charges carried by the system, and we show that in general there are configurations of charges for which a BPS state would preserve more than half the original supersymmetry. We investigate configurations that could preserve 3/4 supersymmetry in string theory, M-theory and supersymmetric field theories and discuss whether states saturating these bounds actually occur in these theories.