15245043
Seiberg-Witten maps and noncommutative Yang-Mills theories for arbitrary gauge groups
Seiberg-Witten maps and a recently proposed construction of noncommutative Yang-Mills theories (with matter fields) for arbitrary gauge groups are reformulated so that their existence to all orders is manifest. The ambiguities of the construction which originate from the freedom in the Seiberg-Witten map are discussed with regard to the question whether they can lead to inequivalent models, i.e., models not related by field redefinitions.
118395460
Nonpolynomial gauge invariant interactions of 1-form and 2-form gauge potentials
A four dimensional gauge theory with nonpolynomial but local interactions of 1-form and 2-form gauge potentials is constructed. The model is a nontrivial deformation of a free gauge theory with nonpolynomial dependence on the deformation parameter (= gauge coupling constant).
116908765
Gauge Covariant Algebras and Local BRST Cohomology
The formulation of the local BRST cohomology on infinite jet bundles and its relation and reduction to gauge covariant algebras are reviewed. As an illustration, we compute the local BRST cohomology for geodesic motion in (pseudo-) Riemannian manifolds and discuss briefly the result (symmetries, constants of the motion, consistent deformations).
120563531
The gravitational anomalies
Abstract We determine all solutions to the consistency equations which have to be satisfied by anomalies in gravitational theories with a Poincare-invariant ground state.
119057407
Extended antifield formalism
Abstract The antifield formalism is extended so as to incorporate the rigid symmetries of a given theory. To that end, it is necessary to introduce global ghosts not only for the given rigid symmetries, but also for all the higher order conservation laws, associated with conserved antisymmetric tensors j μ 1 3 μ k fulfilling ϖ μ 1 j μ 1 3 μ k 2~ 0. Otherwise, one may encounter obstructions of the type discussed in by the authors. These higher order conservation laws are shown to define additional rigid symmetries of the master equation and to form — together with the standard symmetries — an interesting algebraic structure. They lead furthermore to independent Ward identities which are derived in the standard manner, because the resulting master (“Zinn-Justin”) equation capturing both the gauge symmetries and the rigid symmetries of all orders takes a known form. Issues such as anomalies or consistent deformations of the action preserving some set of rigid symmetries can be also systematically analysed in this framework.
13550118
New supersymmetric gauge theories: the double tensor multiplet and its interactions
Abstract The double tensor multiplet of D=4 , N=2 supersymmetry, relevant to type IIB superstring vacua, is derived and its gauge invariant and N=2 supersymmetric interactions are analysed, both self-interactions and interactions with vector multiplets and hypermultiplets. Using deformation theory, it is shown that the lowest dimensional nontrivial interaction vertices of this type have dimension 5 and all dimension 5 vertices are determined. They give rise to new N=2 supersymmetric gauge theories of the `exotic' type which are local but nonpolynomial in some of the fields and coupling constants. Explicit examples of such models are constructed.
119875841
Cancellation of soft interactions with spectators in the Drell-Yan process
Abstract We verify by explicit calculation, to 2-loop order, the cancellation of soft interactions with spectators in the Drell-Yan process. We employ a model in which a “meson” consists of a parton and a spectator parton, each moving along parallel eikonal lines. The process occurs in the collision of two such “mesons” at velocities near the speed of light. The calculation is sensitive to gluons with wavelengths of the order of or greater than the meson size.
16723250
Generalized forward scattering amplitudes in QCD at high temperature
We extend to a general class of covariant gauges an approach which relates the thermal Green functions to forward scattering amplitudes of thermal particles. A brief discussion of the nontransversality of the thermal gluon polarization tensor is given in this context. This method is then applied to the calculation of the ln(T) contributions associated with general configurations of two- and three-point gluon functions. The results are Lorentz covariant and have the same structure as the ultraviolet divergent contributions which occur at zero temperature. {copyright} {ital 1997} {ital The American Physical Society}
118914118
General structure of the photon self-energy in noncommutative QED
We study the behavior of the photon two point function, in noncommutative QED, in a general covariant gauge and in arbitrary space-time dimensions. We show, to all orders, that the photon self-energy is transverse. Using an appropriate extension of the dimensional regularization method, we evaluate the one-loop corrections, which show that the theory is renormalizable. We also prove, to all orders, that the poles of the photon propagator are gauge independent and briefly discuss some other related aspects.
119728198
Open and Closed Superstring Five-Point Amplitudes at Tree-Level
In this contribution the tree-level effective actions for gluons and gravitons, as derived from Open and Closed Superstring theories, are reviewed respectively. As known for a long time, at zero order in α′ (the string fundamental constant) the first action is pure Yang-Mills while the second one is pure Einstein-Hilbert. The first Superstring Theory corrections turn up to appear at order in the first case while they appear at in the second one, as known from the three and four-point scattering amplitudes for gluons and gravitons, respectively. Recent work involving the order contributions to the Yang-Mills action is reviewed with some detail, including the authors' present line of research. Also, the uncharted territory of five graviton scattering is commented, looking forward to derive the Superstring Theory corrections to the Einstein-Hilbert action.
117343979
Classical transport equation in noncommutative QED at high temperature
We show that the high temperature behavior of non-commutative QED may be simply obtained from Boltzmann transport equations for classical particles. The transport equation for the charge neutral particle is shown to be characteristically different from that for the charged particle. These equations correctly generate, for arbitrary values of the non-commutative parameter �, the leading, gauge independent hard thermal loops, arising from the fermion and the gauge sectors. We briefly discuss the generating functional of hard thermal amplitudes.