World Volume Approach to Absorption by Non-dilatonic Branes

TL;DR

This paper compares classical absorption cross sections of massless scalars by extremal branes in string and M-theory, finding agreement and suggesting a unitary, string-theoretic description for 3-branes.

Contribution

It provides the first detailed comparison between classical gravity calculations and world volume theories for multiple types of extremal branes, confirming the validity of string theory descriptions.

Findings

Classical cross sections match world volume theory predictions.

Agreement in energy and brane number scaling across all three cases.

Exact match for low energy dilaton absorption by 3-branes with string theory.

Abstract

We calculate classical cross sections for absorption of massless scalars by the extremal 3-branes of type IIB theory, and by the extremal 2- and 5-branes of M-theory. The results are compared with corresponding calculations in the world volume effective theories. For all three cases we find agreement in the scaling with the energy and the number of coincident branes. For 3-branes, whose stringy description is known in detail in terms of multiple D-branes, the string theoretic absorption cross section for low energy dilatons is in exact agreement with the classical gravity. This suggests that scattering from extremal 3-branes is a unitary process well described by perturbative string theory.