arXiv subjects
Publications and source records attributed to Marco Serone.
By scaling arguments we show that the presence of a $R^4$-term in the eleven dimensional supergravity effective lagrangian, if it is visible in (M)atrix theory, should produce a correction to the five-loops effective lagrangian of two moving D0-branes.
We study the moduli dependence of a class of couplings in $K3\times T^2$ compactifications of type I string theory, for which one-loop amplitudes can be written in terms of an N=2 supersymmetric index. This index is determined for generic models as a function of the BPS spectrum. As an application we compute the one-loop moduli dependence of the $F_g W^{2g}$ couplings, where W is the N=2 gravitational superfield, for type I compactifications based on the Gimon-Johnson K3 orientifolds, showing explicitly their dependence on the aforementioned index.
We test the conjectured Type I-Heterotic Duality in four dimensions by analyzing a given class of higher derivative F-terms of the form $F_gW^{2g}$, with W the N=2 gravitational superfield. We study a particular dual pair of theories, the O(2,2) heterotic model and a type I model based on the K3 $Z_2$ orbifold theory constructed by Gimon and Polchinski, further compactified on a torus. The $F_g$ couplings appear at 1-loop on both theories; because of the weak-weak nature of this duality in four dimensions, it is meaningful to compare the heterotic $F_g$'s with the corresponding type I couplings perturbatively. We compute the $F_g$'s in type I, showing that they receive contributions only from N=2 BPS states and that in the appropriate limit they coincide with the heterotic couplings, in agreement with the given duality.
We study a special class of higher derivative F-terms of the form $F_{g,n}W^{2g}(Πf)^{n}$ where W is the N=2 gravitational superfield and $Π$ is the chiral projector applied to a non-holomorphic function $f$ of the heterotic dilaton vector superfield. We analyze these couplings in the heterotic theory on $K3\times T^2$ , where it is found they satisfy an anomaly equation as the well studied $F_{g,0}$ terms. We recognize that, near a point of SU(2) enhancement, a given generating function of the leading singularity of the $F_{g,n}$ reproduces the free energy of a c=1 string at an arbitrary radius R. According to the N=2 heterotic-type II duality in 4d, we then study these couplings near a conifold singularity, using its local description in terms of intersecting D-5-branes. In this context, it turns out that there exists, among the other states involved, a vector gauge field reproducing the heterotic leading singularity structure.