How to understand $ρ$ Resonance from the Quark Model and $ππ$ $P$-wave phase shift

Fuente: arXiv
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Main Authors: Zhao, Wen-Ze, Ni, Ru-Hui, Wu, Jia-Jun
Format: Preprint
Published: 2026
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author Zhao, Wen-Ze
Ni, Ru-Hui
Wu, Jia-Jun
author_facet Zhao, Wen-Ze
Ni, Ru-Hui
Wu, Jia-Jun
contents As the lightest isovector vector meson, the $ρ$ meson is an important object for investigating the structure of resonant states in strong interactions. Owing to its strong coupling to the $ππ$ channel and its large decay width, the conventional constituent quark model treatment, in which it is simply regarded as a pure $q\bar q$ bound state while the hadronic-channel coupling effects are neglected, is insufficient to fully characterize its physical properties. To this end, in the present work we establish a unified framework for studying the structure and resonant properties of the $ρ$ meson by combining the quark-gluon and hadronic degrees of freedom. At the quark-gluon level, we first determine the parameters of the chiral quark model by refitting a set of narrow mesons for which open OZI-allowed strong-decay channels are absent or strongly suppressed. With these parameters fixed, the bare mass of the $ρ$ meson is obtained and used as the input for the subsequent hadronic-level analysis. At the hadronic level, based on inverse scattering theory, we construct a model including the coupling between the bare state and the $ππ$ continuum, extract the $ρ_0-ππ$ interaction using the $P$-wave $ππ$ scattering phase-shift data, and further calculate the width of the $ρ$ meson as well as the bare-state component in the physical state. The present work also provides a generalizable analytical framework for further studies of other hadronic resonances with significant channel-coupling effects.
format Preprint
id arxiv_https___arxiv_org_abs_2604_24270
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle How to understand $ρ$ Resonance from the Quark Model and $ππ$ $P$-wave phase shift
Zhao, Wen-Ze
Ni, Ru-Hui
Wu, Jia-Jun
High Energy Physics - Phenomenology
High Energy Physics - Experiment
As the lightest isovector vector meson, the $ρ$ meson is an important object for investigating the structure of resonant states in strong interactions. Owing to its strong coupling to the $ππ$ channel and its large decay width, the conventional constituent quark model treatment, in which it is simply regarded as a pure $q\bar q$ bound state while the hadronic-channel coupling effects are neglected, is insufficient to fully characterize its physical properties. To this end, in the present work we establish a unified framework for studying the structure and resonant properties of the $ρ$ meson by combining the quark-gluon and hadronic degrees of freedom. At the quark-gluon level, we first determine the parameters of the chiral quark model by refitting a set of narrow mesons for which open OZI-allowed strong-decay channels are absent or strongly suppressed. With these parameters fixed, the bare mass of the $ρ$ meson is obtained and used as the input for the subsequent hadronic-level analysis. At the hadronic level, based on inverse scattering theory, we construct a model including the coupling between the bare state and the $ππ$ continuum, extract the $ρ_0-ππ$ interaction using the $P$-wave $ππ$ scattering phase-shift data, and further calculate the width of the $ρ$ meson as well as the bare-state component in the physical state. The present work also provides a generalizable analytical framework for further studies of other hadronic resonances with significant channel-coupling effects.
title How to understand $ρ$ Resonance from the Quark Model and $ππ$ $P$-wave phase shift
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2604.24270