No abstract

For quantum field theories that flow between ultraviolet and infrared fixed points, central functions, defined from two-point correlators of the stress tensor and conserved currents, interpolate between central charges of the UV and IR critical theories. We develop techniques that allow one to calculate the flows of the central charges and that of the Euler trace anomaly coefficient in a general N=1 supersymmetric gauge theory. Exact, explicit formulas for SU (N c ) gauge theories in the conformal window are given and analysed. The Euler anomaly coefficient always satisfies the inequality a U V − a IR > 0. This is new evidence in strongly coupled theories that this quantity satisfies a four-dimensional analogue of the c-theorem, supporting the idea of irreversibility of the RG flow. Various other implications are discussed.

No abstract

We investigate the 'giant gravitons' of McGreevy, Susskind and Toumbas [1]. We demonstrate that these are BPS configurations which preserve precisely the same supersymmetries as a 'point-like' graviton. We also show that there exist 'dual' giant gravitons consisting of spherical branes expanding into the AdS component of the spacetime. Finally, we discuss the realization of the stringy exclusion principle within this expanded framework.

We discuss rupergravity from an S-matrix point of view. Kinematical constraints on helicity amplitudes determine the spin-2 and spin-3/2 Born amplitudes almos! uniquely, and force Born ar.lplitudes in~olving spin-5 / 2 fermions to vanish. Global supersymmetry is then used to determine the Born amplitudes con~pletely. We suggest that Lorentz invariance, presence of only one (dimensional) coupling io!~stdiit K, and global supersymmetry lead to a unique locally supergauge-invnrii~!~~ theory of spin-2 and spin-3/2 particles. We draw similar conclusions for a model uniting supergmvity and the Wess-Zurnino scalar multiplrt.

Using N = 1 superspace techniques in four dimensions we show how to perturbatively compute the superpotential generated for the glueball superfield upon integrating out massive charged fields. The technique applies to arbitrary gauge groups and representations. Moreover we show that for U (N ) gauge theories admitting a large N expansion the computation dramatically simplifies and we prove the validity of the recently proposed recipe for computation of this quantity in terms of planar diagrams of matrix integrals. November, 2002

No abstract

In addition to the familiar contribution from a holomorphic function F, the Kähler potential of the scalars in the nonabelian N = 2 vector multiplet receives contributions from a real function H. We determine the latter at the one-loop level, taking into account both supersymmetric matter and gauge loops. The function H characterizes the four-point coupling of the N = 2 vector-multiplet vectors for constant values of their scalar superpartners. We discuss the consequences of our results.