Three Body Interactions, Angular Momentum and Black Hole Moduli Spaces

We investigate the dynamics of a pair of (4+1)-dimensional black holes in the moduli approximation and with fixed angular momentum. We find that spinning black holes at small separations are described by the de Alfaro, Fubini and Furlan model. For more than two black holes, we find an explicit expression for the three-body interactions in the moduli metric by associating them with the one-loop three-point amplitude of a four-dimensional $\phi^3$ theory. We also investigate the dynamics of a three black hole system in various approximations.Comment: 20 pages, phyzz

Wilsonian Proof for Renormalizability of N=1/2 Supersymmetric Field Theories

We provide Wilsonian proof for renormalizability of four-dimensional quantum field theories with ${\cal N}=1/2$ supersymmetry. We argue that the non-hermiticity inherent to these theories permits assigning noncanonical scaling dimension both for the Grassman coordinates and superfields. This reassignment can be done in such a way that the non(anti)commutativity parameter is dimensionless, and then the rest of the proof ammounts to power counting. The renormalizability is also stable against adding standard four-dimensional soft-breaking terms to the theory. However, with the new scaling dimension assignments, some of these terms are not just relevant deformations of the theory but become marginal.Comment: 10 pages, no figure, v2: minor correctio

Direct Proof Of Tree-Level Recursion Relation In Yang-Mills Theory

Recently, by using the known structure of one-loop scattering amplitudes for gluons in Yang-Mills theory, a recursion relation for tree-level scattering amplitudes has been deduced. Here, we give a short and direct proof of this recursion relation based on properties of tree-level amplitudes only.Comment: 10 pp. Added section 4: Proof of MHV Recursion Relation

Superconformal Black Hole Quantum Mechanics

In recent work, the superconformal quantum mechanics describing D0 branes in the AdS_2xS^2xCY_3 attractor geometry of a Calabi-Yau black hole with D4 brane charges p^A has been constructed and found to contain a large degeneracy of chiral primary bound states. In this paper it is shown that the asymptotic growth of chiral primaries for N D0 branes exactly matches the Bekenstein-Hawking area law for a black hole with D4 brane charge p^A and D0 brane charge N. This large degeneracy arises from D0 branes in lowest Landau levels which tile the CY_3xS^2 horizon. It is conjectured that such a multi-D0 brane CFT1 is holographically dual to IIA string theory on AdS_2xS^2xCY_3.Comment: 8 page

Renormalizability of N=1/2 Wess-Zumino model in superspace

In this letter we use the spurion field approach adopted in hep-th/0307099 in order to show that by adding F and F^2 terms to the original lagrangian, the N=1/2 Wess-Zumino model is renormalizable to all orders in perturbation theory. We reformulate in superspace language the proof given in the recent work hep-th/0307165 in terms of component fields.Comment: 8 pages, minor change

Consistency Conditions on S-Matrix of Spin 1 Massless Particles

Motivated by new techniques in the computation of scattering amplitudes of massless particles in four dimensions, like BCFW recursion relations, the question of how much structure of the S-matrix can be determined from purely S-matrix arguments has received new attention. The BCFW recursion relations for massless particles of spin 1 and 2 imply that the whole tree-level S-matrix can be determined in terms of three-particle amplitudes (evaluated at complex momenta). However, the known proofs of the validity of the relations rely on the Lagrangian of the theory, either by using Feynman diagrams explicitly or by studying the effective theory at large complex momenta. This means that a purely S-matrix theoretic proof of the relations is still missing. The aim of this paper is to provide such a proof for spin 1 particles by extending the four-particle test introduced by P. Benincasa and F. Cachazo in arXiv:0705.4305[hep-th] to all particles. We show how n-particle tests imply that the rational function built from the BCFW recursion relations possesses all the correct factorization channels including holomorphic and anti-holomorphic collinear limits. This in turn implies that they give the correct S-matrix of the theory.Comment: 24 pages, 4 figure

On the Numerical Evaluation of One-Loop Amplitudes: the Gluonic Case

We develop an algorithm of polynomial complexity for evaluating one-loop amplitudes with an arbitrary number of external particles. The algorithm is implemented in the Rocket program. Starting from particle vertices given by Feynman rules, tree amplitudes are constructed using recursive relations. The tree amplitudes are then used to build one-loop amplitudes using an integer dimension on-shell cut method. As a first application we considered only three and four gluon vertices calculating the pure gluonic one-loop amplitudes for arbitrary external helicity or polarization states. We compare our numerical results to analytical results in the literature, analyze the time behavior of the algorithm and the accuracy of the results, and give explicit results for fixed phase space points for up to twenty external gluons.Comment: 22 pages, 9 figures; v2: references added, version accepted for publicatio

Closed-Form Decomposition of One-Loop Massive Amplitudes

We present formulas for the coefficients of 2-, 3-, 4- and 5-point master integrals for one-loop massive amplitudes. The coefficients are derived from unitarity cuts in D dimensions. The input parameters can be read off from any unitarity-cut integrand, as assembled from tree-level expressions, after simple algebraic manipulations. The formulas presented here are suitable for analytical as well as numerical evaluation. Their validity is confirmed in two known cases of helicity amplitudes contributing to gg -> gg and gg -> gH, where the masses of the Higgs and the fermion circulating in the loop are kept as free parameters.Comment: 37 page

On Instantons and Zero Modes of N=1/2 SYM Theory

We study zero modes of N=1/2 supersymmetric Yang-Mills action in the background of instantons. In this background, because of a quartic antichiral fermionic term in the action, the fermionic solutions of the equations of motion are not in general zero modes of the action. Hence, when there are fermionic solutions, the action is no longer minimized by instantons. By deforming the instanton equation in the presence of fermions, we write down the zero mode equations. The solutions satisfy the equations of motion, and saturate the BPS bound. The deformed instanton equations imply that the finite action solutions have U(1) connections which are not flat anymore.Comment: 9 pages, latex file, added references, minor change