All-orders singular emission in gauge theories.

Multiple Singular Emission in Gauge Theories

I derive a class of functions unifying all singular limits for the emission of a given number of soft or collinear gluons in tree-level gauge-theory amplitudes. Each function is a generalization of the single-emission antenna function of ref. [1]. The helicity-summed squares of these functions are thus also generalizations to multiple singular emission of the Catani–Seymour dipole factorization...

Comment on Two Dimensional O(N) and Sp(N) Yang Mills Theories as String Theories

We write down all orders large N expansions for the dimensions of irreducible representations of O(N) and Sp(N). We interpret all the terms in these expansions as symmetry factors for singular worldsheet configurations, involving collapsed crosscaps and tubes. We use it to complete the interpretation of two dimensional Yang Mills Theories with these gauge groups, on arbitrary two dimensional ma...

Soft Photon Theorem for High Energy Amplitudes in Yukawa and Scalar Theories

We study the emission of soft photons coupling to high energy fixed angle scattering processes at first order in the electromagnetic coupling but to all loop orders in a class of theories without soft divergences, including massive and massless Yukawa and scalar theories. We adapt a method introduced by del Duca for quantum electrodynamics to show that subleading corrections to the soft photon ...

Adler-Bardeen theorem and cancellation of gauge anomalies to all orders in nonrenormalizable theories

Matching conditions and duality in N=1 SUSY gauge theories in the conformal window.

We discuss duality in N = 1 SUSY gauge theories in Seiberg’s conformal window, (3Nc/2) < Nf < 3Nc. The ’t Hooft consistency conditions – the basic tool for establishing the infrared duality – are considered taking into account higher order α corrections. The conserved (anomaly free) R current is built to all orders in α. Although this current contains all orders in α the ’t Hooft consistency co...