Quenched chiral perturbation theory for baryon form factors

TL;DR

This paper introduces a new method for quickly calculating the leading nonanalytic behavior of hadronic observables in quenched chiral perturbation theory, with applications to baryon masses and magnetic moments.

Contribution

It presents an intuitive technique for analyzing quenched chiral perturbation theory, allowing separation of various contributions to baryon magnetic moments and accounting for SU(3) symmetry violations.

Findings

The method effectively separates full, sea, valence, and quenched valence contributions.

The u-quark contribution to the proton magnetic moment highlights nonanalytic behavior.

The approach accounts for SU(3)-flavor symmetry violations in baryon and meson masses.

Abstract

A new intuitive method for the rapid calculation of the leading nonanalytic behavior of hadronic observables in quenched chiral perturbation theory is presented. After proving the technique in a consideration of baryon masses, the quenched magnetic moments of octet baryons are addressed. The technique provides a separation of magnetic moment contributions into full, sea, valence and quenched valence contributions, the latter being the conventional view of the quenched approximation. Both baryon mass and meson mass violations of SU(3)-flavor symmetry are accounted for. A comprehensive examination of the individual quark-sector contributions to octet baryon magnetic moments reveals that the u-quark contribution to the proton magnetic moment provides an optimal opportunity to directly view nonanalytic behavior associated with the quenched meson cloud of baryons in the quenched approximation.