Speaker
Description
Finite-volume effects constitute one of the main sources of systematic uncertainty in lattice determinations of the hadronic vacuum polarization (HVP) contribution to the muon's $g-2$. In this talk, we investigate these effects in a lattice QCD setup with C$^\star$ boundary conditions. We compute the HVP intermediate-window observable on four gauge ensembles generated by the RC$^\star$ collaboration, with identical bare parameters and pion mass $m_\pi \simeq 400$ MeV, but different physical volumes in the range 1.7-3.5 fm. This setup allows for a controlled numerical study of the volume dependence while keeping all other parameters fixed. In addition, we present ongoing work on an extension of the Hansen-Patella method to C$^\star$ boundary conditions, towards a theoretical understanding of the observed finite-volume effects.