Contents

# Contents

## Idea

The brane intersection of M5-branes with MO9-planes – the “half M5-brane”.

Equivalently:

graphics grabbed from HSS18, Example 2.2.7

graphics grabbed from SS 19, Section 4

## In string theory

### As Yang-Mills instantons in heterotic string theory

In (dual) heterotic string theory wrapped NS5-branes are equivalently Yang-Mills instantons in the transversal Yang-Mills theory (Strominger 90, Witten 96, p. 10) – as is generally the case for Dp-D(p+4)-brane bound states (see there).

### As half NS5-branes in type I’

(For more see at half NS5-brane.)

If a black NS5-brane sits at an O8-plane, hence at the orientifold fixed point-locus, then in the ordinary $\mathbb{Z}/2$-quotient it appears as a “half-brane” with only one copy of D6-branes ending on it:

from GKSTY 02

(In Hanany-Zaffaroni 99 this is interpreted in terms of the 't Hooft-Polyakov monopole.)

The lift to M-theory of this situation is an M5-brane intersecting an M9-brane (see at MO5-plane and at heterotic M-theory on ADE-orbifolds):

from GKSTY 02

Alternatively the O8-plane may intersect the black D6-branes away from the black NS5-brane:

from HKLY 15

In general, some of the NS5 sit away from the O8-plane, while some sit on top of it:

graphics grabbed from Apruzzi-Fazzi 17, p. 18

brane intersections/bound states/wrapped branes

S-duality$\,$bound states:

intersecting$\,$M-branes:

## References

### As heterotic Yang-Mills instantons

Discussion as Yang-Mills instantons (“small instantons”):

### As half M5-branes

Last revised on November 26, 2019 at 13:48:14. See the history of this page for a list of all contributions to it.