A multiquark approach to excited hadrons and Regge trajectories

TL;DR

This paper introduces a multiquark model for excited hadrons, especially light mesons, which better matches experimental data and naturally produces linear Regge trajectories, challenging traditional string-based models.

Contribution

It presents a novel multiquark framework for hadron spectroscopy that explains meson spectra and Regge trajectories without relying on string models.

Findings

Better agreement with experimental meson classifications.

Derivation of linear Regge trajectories from multiquark assumptions.

Relation between quark mass and condensates.

Abstract

We propose a novel approach to construction of hadron spectroscopy. The case of light nonstrange mesons is considered. By assumption, all such mesons above 1 GeV appear due to creation of constituent quark-antiquark pairs inside the pi or rho (omega) mesons. These spin-singlet or triplet pairs dictate the quantum numbers of formed resonance. The resulting classification of light mesons turns out to be in a better agreement with the experimental observations than the standard quark model classification. It is argued that the total energy of quark components should be proportional to the hadron mass squared rather than the linear mass. As a byproduct a certain relation expressing the constituent quark mass via the gluon and quark condensate is put forward. We show that our approach leads to an effective mass counting scheme for meson spectrum and results in the linear Regge and radial Regge trajectories by construction. An experimental observation of these trajectories might thus serve as an evidence not for string but for multiquark structure of highly excited hadrons.