Non-Perturbative Renormalisation on the Lattice

Research Team: Dirk Broemmel, Thomas Rae
Investigators: Jonathan Flynn

This is an example graph we are computing in the project.

Renormalisation provides means to explain the scale dependence of fundamental parameters and observables of a quantum field theory. The most prominent example was rewarded with a Nobel prize and describes the scale dependence (running) of the coupling constant in QCD, leading to phenomena known as confinement and asymptotic freedom on either end of the energy scale.

From a theorist's point of view the renormalisation factors not only describe the scale dependence but are also a vital ingredient to make a connection to experiments and are required for meaningful results from a theoretical calculation. In this project we compute renormalisation factors non-perturbatively to match our lattice simulations and also to obtain more accurate results. The parameters we are interested in include the

fermion wave function
quark mass
operators connected to parton distribution amplitudes, c.f. Parton Distribution Amplitudes for Mesons
weak operators, e.g. for the Kaon bag parameter, c.f. K → π π decays in lattice QCD

The calculations are performed within the UKQCD and RBC collaborations.

Computational Modelling Group

Non-Perturbative Renormalisation on the Lattice

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