Computing the Adler function from the vacuum polarization function

Understand

We use a lattice determination of the hadronic vacuum polarization tensor to study the associated Ward identities and compute the Adler function.

• The vacuum polarization tensor is computed from a combination of point-split and local vector currents, using two flavours of O($a$)-improved Wilson fermions.
• Partially twisted boundary conditions are employed to obtain a fine momentum resolution.
• The modifications of the Ward identities by lattice artifacts and by the use of twisted boundary conditions are monitored.