The QCD rotator in the chiral limit

TL;DR

This paper calculates the low-lying spectrum of QCD in the delta-regime using chiral perturbation theory up to NNL order, providing a simple formula involving key constants to aid parameter determination.

Contribution

It presents a detailed calculation of the QCD spectrum in the delta-regime at NNL order, linking it to low energy constants for improved parameter extraction.

Findings

Spectrum expressed in terms of F, Lambda1, and Lambda2

Results facilitate precise determination of low energy constants

Provides a theoretical framework for numerical QCD studies

Abstract

The low lying spectrum of QCD in the delta-regime is calculated here in chiral perturbation theory up to NNL order. The spectrum has a simple form in terms of the pion decay constant F and a combination of the low energy constants Lambda1 and Lambda2. Since measuring low lying stable masses is among the easiest numerical tasks, the results should help fixing these parameters to good precision.