Past exam of the mathematics course of the University of Cambridge 2013 iii Paper 44 3 ii Solution Created 2026-10-03 Updated 2026-10-07
For the asymptotically free beta function, separation of variables givesThe anomalous-dimension integral is elementary:For a reference two-point factor regular and nonzero at the free coupling, , so the large-momentum correction is a power of . These are asymptotic freedom and logarithmic two-point scaling from a cubic beta function. If the supplied beta and gamma expressions are leading small-coupling terms rather than exact functions, they fix the leading logarithmic exponent, while subleading corrections and the prefactor depend on higher orders.