Related papers: U-duality Invariant Dyon Spectrum in type II on T^…
We study the properties of half-supersymmetric branes in string theory with 32 supercharges from a purely group-theoretical point of view using the U-duality symmetry of maximal supergravity and the R-symmetry of the corresponding…
As a novel application of string junctions, we provide evidence for the existence of stable non-BPS dyons with magnetic charge greater than 1 in (the semiclassical regime of) N=2 SU(2) Super-Yang-Mills theory. In addition, we find a new…
We consider the possibility that neutrinoless double beta decay may occur in models with unbroken lepton number via the emission of a massive gauge boson with electron lepton number $-2$. We determine the shape of the $\beta\,\beta$ sum…
The weak coupling spectrum of BPS saturated states of pure $N=2$ supersymmetric SU$(n)$ gauge theory is investigated. The method uses known results on the dyon spectrum of the analogous theory with $N=4$ supersymmetry, along with the action…
We study geometric engineering of Argyres-Douglas superconformal theories realized by type IIB strings propagating in singular Calabi-Yau threefolds. We use this construction to count the degeneracy of light BPS states under small…
We study the $SU(N)$ self-dual Chern-Simons-Higgs systems with adjoint matter coupling, and show that the sixth order self-dual potential has $p(N)$ gauge inequivalent degenerate minima, where $p(N)$ is the number of partitions of $N$. We…
It has recently been conjectured that the type IIA string theory compactified on K3 and the heterotic string theory compactified on a four dimensional torus describe identical string theories. The fundamental heterotic string can be…
String theory compactified on a three-torus possesses an SL(5,Z) U-duality group. We investigate the realisation of this symmetry on the Born-Infeld theory on a three-brane, and discuss a U-duality covariant formulation of the BPS sector of…
Using the techniques of two dimensional conformal field theory we construct time dependent classical solutions in open string theory describing the decay of an unstable D-brane in the presence of background electric field, and explicitly…
The observed deviations from the Standard Model in several b -> s mu mu processes can be explained in terms of a new vector boson produced on-shell in B meson decays. A mass of 2.5-3 GeV and a total width of 10-20% allow to hide the…
psi and Upsilon decays may be used to search for light neutral spin-1 or spin-0 bosons associated with a broken extra-U(1) symmetry, local or global, acting axially on quarks and leptons, as may be present in supersymmetric theories with a…
Physical quark-number charges of dyons are determined, via a formula which generalizes that of Witten for the electric charge, in N=2 supersymmetric theories with $SU(2) \times U(1)^{N_f} $ gauge group. The quark numbers of the massless…
Topological insulators and D-brane charges in string theory can both be classified by the same family of groups. In this paper, we extend this connection via a geometric transform, giving a novel duality of topological insulators which can…
Four-graviton, eight-derivative couplings in the low energy effective action of toroidal type II string compactifications are tightly constrained by U-duality invariance and by supersymmetry. In this note, we revisit earlier proposals for…
We study (0,2) two-dimensional theories in type IIB configurations with D5 branes wrapping blow-up ${\bf{P}}^1$ cycles of deformed resolutions for $A_n$ singularities or in T-dual IIA configurations with suspended D4 branes. We consider…
We consider the perturbative contributions to the R^4, D^4 R^4 and D^6 R^4 interactions in toroidally compactified type II string theory. These BPS interactions do not receive perturbative contributions beyond genus three. We derive Poisson…
We present two new backgrounds of type IIA string theory preserving 16 supercharges. One is a Wilson line for (-1) to the left-moving spacetime fermion number, and the other is an orbifold by a reflection of four coordinates, along with the…
This is an introductory review on the eleven-dimensional description of the BPS bound states of type II superstring theories, and on the role of supermembranes in M-theory. The first part describes classical solutions of 11d supergravity…
We write down couplings of the fields on a single BPS Dp-brane with noncommutative world-volume coordinates to the RR-forms in type II theories, in a manifestly background independent way. This generalises the usual Chern-Simons action for…
In two very detailed, technical, and fundamental works, Jun Li constructed a theory of Gromov-Witten invariants for a singular scheme of the gluing form $Y_1\cup_D Y_2$ that arises from a degeneration $W/{\Bbb A}^1$ and a theory of relative…