The Standard Model on a finite bosonic lattice with continuum Weyl fermions

Abstract

We investigate a formulation of the Standard Model with gauge and Higgs fields regulated on a finite bosonic lattice, while quarks and leptons remain continuum Weyl fermions. This retains the familiar continuum treatment of anomalies, spectral flow, and fermion zero modes. Standard Model anomaly cancellation permits a consistent, gauge-invariant phase for the massless chiral determinant. Yukawa interactions are incorporated with a gauge-covariant spectral cutoff acting on the interaction vertices, not on the fermion propagator. Under the stated analytic conditions, the cutoff can be removed by the local subtractions expected from one-loop power counting, yielding a finite, exactly gauge-invariant functional integral at fixed bosonic lattice spacing and spacetime volume, including topologically nontrivial backgrounds. At zero Yukawa coupling and on smooth weak-field backgrounds, we establish agreement between the appropriately chirality-matched overlap and continuum Weyl fermion determinants up to local counterterms. We also establish reflection positivity at zero Yukawa coupling and zero theta for a modified gauge-field reconstruction; its continuum equivalence with Craig's original reconstruction is not proved. The bosonic continuum limit remains open.

arXiv comment113 pages. v2 adds a weak-field equivalence result showing that Craig's overlap fermion weight agrees with the continuum Weyl determinant up to local counterterms. It also discusses Witten's recent eta-invariant formulation of chiral gauge theories and establishes its equivalence to the determinant-line phase prescription used here