Half-Branes, Singular Brane Intersections, and Kaluza-Klein reduction

TL;DR

This paper investigates subtle aspects of brane intersections, revealing that many seemingly singular configurations are smooth in higher dimensions and proposing mechanisms that negate the need for half-branes in string theory.

Contribution

It demonstrates that certain singular brane intersections lift to smooth higher-dimensional configurations and introduces a mechanism for Z2 confinement effects eliminating half-branes.

Findings

Many singular D2/D6 intersections are smooth in 11D

A mechanism for Z2 confinement effects is proposed

Half-branes are shown to be unnecessary in some cases

Abstract

Two subtle aspects of brane intersections are investigated. The first concerns the `half-branes' that arise in discussions of the Hanany-Witten effect, often in the D0/D8 setting. The second involves the validity of seemingly singular classical BPS brane intersections. A study of holomorphic curves in the background of a Kaluza-Klein monopole and the associated reduction to type IIA supergravity sheds light on both issues. Many seemingly singular D2/D6 intersections are shown to lift to smooth configurations of M2-branes in 11-dimensions, and a mechanism is found for certain $Z_2$ confinement effects in type II string theories that eliminates any need for half-branes.