Non-supersymmetric loop amplitudes and MHV vertices

Abstract We show how the MHV diagram description of Yang–Mills theories can be used to study non-supersymmetric loop amplitudes. In particular, we derive a compact expression for the cut-constructible part of the general one-loop MHV multi-gluon scattering amplitude in pure Yang–Mills theory. We show that in special cases this expression reduces to known amplitudes—the amplitude with adjacent negative-helicity gluons, and the five gluon non-adjacent amplitude. Finally, we briefly discuss the twistor space interpretation of our result.