ChPT loops for the lattice: pion mass and decay constant, HVP at finite volume and $n\bar n$-oscillations

TL;DR

This paper provides advanced loop calculations in Chiral Perturbation Theory, including finite volume effects on hadronic vacuum polarization, three-loop pion properties, and chiral corrections to neutron-antineutron oscillations, enhancing lattice QCD analyses.

Contribution

It introduces higher loop order results in ChPT for finite volume effects, pion mass and decay constant at three loops, and neutron-antineutron oscillation corrections, advancing theoretical precision.

Findings

Finite volume two-loop results for hadronic vacuum polarization.

Three-loop calculations of pion mass and decay constant.

Chiral corrections to neutron-antineutron oscillations.

Abstract

I present higher loop order results for several calculations in Chiral perturbation Theory. 1) Two-loop results at finite volume for hadronic vacuum polarization. 2) A three-loop calculation of the pion mass and decay constant in two-flavour ChPT. For the pion mass all needed auxiliary parameters can be determined from lattice calculations of $\pi\pi$-scattering. 3) Chiral corrections to neutron-anti-neutron oscillations.