paper

Type II and heterotic one loop string effective actions in four dimensions

arXiv:hep-th/0703026 · doi:10.1088/1126-6708/2007/06/052

Abstract

We analyze the reduction to four dimensions of the R^4 terms which are part of the ten-dimensional string effective actions, both at tree level and one loop. We show that there are two independent combinations of R^4 present, at one loop, in the type IIA four dimensional effective action, which means they both have their origin in M-theory. The d=4 heterotic effective action also has such terms. This contradicts the common belief thathere is only one R^4 term in four-dimensional supergravity theories, given by the square of the Bel-Robinson tensor. In pure N=1 supergravity this new R^4 combination cannot be directly supersymmetrized, but we show that, when coupled to a scalar chiral multiplet (violating the U(1) -symmetry), it emerges in the action after elimination of the auxiliary fields.

v2: 22 pages. Discussion on the new R^4 term and extended supergravity has been abridged and improved. Published version

References in corpus (5)

Cited by in corpus (8)