On R^{4} threshold corrections in type IIB string theory and (p,q)string instantons
Abstract
We obtain the exact nonperturbative thresholds of R^{4} terms in type 1113 string theory compactified to eight and seven dimensions. These thresholds are given by the perturbative treelevel and oneloop results together with the contribution of the Dinstantons and of the ( p, q)string instantons. The invariance under Uduality is made manifest by rewriting the sum as a nonholomorphicinvariant modular function of the corresponding discrete Uduality group. In the eightdimensional case, the threshold is the sum of an order1 Eisenstein series for SL(2, Z) and an order3/2 Eisenstein series for SL(3, Z) . The sevendimensional result is given by the order3/2 Eisenstein series for SL(5, Z) . We also conjecture formulae for the nonperturbative thresholds in lowerdimensional compactifications and discuss the relation with Mtheory.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1997
 DOI:
 10.1016/S05503213(97)006457
 arXiv:
 arXiv:hepth/9707018
 Bibcode:
 1997NuPhB.508..509K
 Keywords:

 High Energy Physics  Theory
 EPrint:
 24 pages