  Precision experimental tests of the Standard Model of particle physics (SM)
are one of our best hopes for discovering what new physics lies beyond the SM
(BSM). Key in the search for new physics is the connection between theory and
experiment. Forging this connection for searches involving low-energy hadronic
or nuclear environments requires the use of a non-perturbative theoretical
tool, lattice QCD. We present two recent lattice QCD calculations by the CalLat
collaboration relevant for new physics searches: the nucleon axial coupling,
$g_A$, whose precise value as predicted by the SM could help point to new
physics contributions to the so-called "neutron lifetime puzzle", and hadronic
matrix elements of short-ranged operators relevant for neutrinoless double beta
decay searches.
