The "Folk Theorem" on Effective Field Theory: How Does It Fare in Nuclear Physics?

TL;DR

This paper reviews the application of effective field theory, based on Weinberg's Folk Theorem, to nuclear physics, highlighting recent advances in high-precision calculations and novel predictions for compact star properties.

Contribution

It demonstrates the use of a scale-invariant hidden local symmetric Lagrangian in nuclear EFT, extending its application to astrophysical phenomena and predicting new stellar properties.

Findings

High-precision calculations for solar fusion and beta decay processes.

Predicted early onset of conformal sound velocity in massive stars.

Suggested emergence of hidden symmetries like scale and local symmetry in stellar matter.

Abstract

This is a brief history of what I consider as very important, some of which truly seminal, contributions made by young Korean nuclear theorists, mostly graduate students working on PhD thesis in 1990's and early 2000's, to nuclear effective field theory, nowadays heralded as the first-principle approach to nuclear physics. The theoretical framework employed is an effective field theory anchored on a scale-invariant hidden local symmetric Lagrangian constructed along the line of Weinberg's "Folk Theorem" on effective field theory. The problems addressed are the high-precision calculations on the thermal $np$ capture, the solar $pp$ fusion process, the solar $hep$ process -- John Bahcall's challenge to nuclear theorists -- and the quenching of $g_A$ in giant Gamow-Teller resonances and the whopping enhancement of first-forbidden beta transitions in astrophysical processes. Extending adventurously the strategy to a wild uncharted domain in which a systematic implementation of the "theorem" is far from obvious, the same effective Lagrangian is applied to the structure of compact stars. A surprising result on the properties of massive stars, totally different from what has been obtained up to day in the literature, is predicted, such as the precocious onset of conformal sound velocity together with the possible emergence of hidden symmetries such as scale symmetry and hidden local symmetry.