Matthew Spraggs

Lattice calculation of the leading strange quark-connected contribution to the muon g - 2

A bstractWe present results for the leading hadronic contribution to the muon anomalous magnetic moment due to strange quark-connected vacuum polarisation effects. Simulations were performed using RBC-UKQCD’s Nf = 2 + 1 domain wall fermion ensembles with physical light sea quark masses at two lattice spacings. We consider a large number of analysis scenarios in order to obtain solid estimates for residual systematic effects. Our final result in the continuum limit is aμ(2)had,s = 53.1(9)(− 3+ 1) × 10− 10.

An exploratory study of heavy domain wall fermions on the lattice

A bstractWe report on an exploratory study of domain wall fermions (DWF) as a lattice regularisation for heavy quarks. Within the framework of quenched QCD with the tree-level improved Symanzik gauge action we identify the DWF parameters which minimise discretisation effects. We find the corresponding effective 4d overlap operator to be exponentially local, independent of the quark mass. We determine a maximum bare heavy quark mass of amh ≈ 0.4, below which the approximate chiral symmetry and O(a)-improvement of DWF are sustained. This threshold appears to be largely independent of the lattice spacing. Based on these findings, we carried out a detailed scaling study for the heavy-strange meson dispersion relation and decay constant on four ensembles with lattice spacings in the range 2.0-5.7 GeV. We observe very mild a2 scaling towards the continuum limit. Our findings establish a sound basis for heavy DWF in dynamical simulations of lattice QCD with relevance to Standard Model phenomenology.

Computing the muon anomalous magnetic moment using the hybrid method with physical quark masses

I present our work on the leading strange quark-connected contribution to the muon anomalous magnetic moment using RBC/UKQCD physical point domain wall fermion ensembles. I also present preliminary results of a computation of the light quark-connected contribution using a similar approach.