The S, U and \Delta\rho parameters in the Zaragoza proposal for lattice chiral gauge fermions

TL;DR

This paper demonstrates that the Zaragoza proposal for lattice chiral gauge fermions accurately reproduces continuum parameters at one loop without fine tuning or fermion doubling, supported by a specific symmetry.

Contribution

It shows that the Zaragoza scheme uniquely achieves correct parameter values without fine tuning or fermion doubling, supported by a newly identified symmetry.

Findings

Reproduces continuum S, U, and Δρ parameters at one loop

No need for explicit fine tuning of counterterms

Fermion doubling is not necessary in this scheme

Abstract

Using the Zaragoza proposal for lattice chiral gauge fermions, the S, U and \Delta\rho parameters have been calculated at one loop. It is shown that the continuum values for these quantities can be reproduced without requiring explicit fine tuning of counterterms. Furthermore, fermion fields doubling is not necessary. To the best of our knowledge, the Zaragoza proposal is the only scheme which has these properties. A necessary (although not sufficient) symmetry is found to support the calculations. Previous results for some of these parameters in other lattice chiral regularizations are revisited in the light of this symmetry.