Radial excitations of mesons and nucleons from QCD sum rules

TL;DR

This paper uses QCD sum rules and least squares fitting to estimate the masses of the first radial excitations of nucleons and light mesons, finding results consistent with experiments and highlighting the suppressed decay constant of π(1300).

Contribution

It introduces a novel application of least squares fitting within QCD sum rules to determine radial excitation properties of mesons and nucleons.

Findings

Extracted masses align with experimental data.

Decay constant of π(1300) is tiny and suppressed.

First radial excitations of mesons and nucleons are characterized.

Abstract

Within the framework QCD sum rules, we use the least square fitting method to investigate the first radial excitations of the nucleon and light mesons such as $\rho$, $K^{*}$, $\pi$ , $\varphi$. The extracted masses of these radial excitations are consistent with the experimental data. Especially we find that the decay constant of $\pi(1300)$, which is the the first radial excitation of $\pi$, is tiny and strongly suppressed as a consequence of chiral symmetry.