Role of hidden-color components in the tetraquark mixing model

Hungchong Kim; K. S. Kim

doi:10.1140/epjc/s10052-024-13072-2

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2024) 84: 726
https://doi.org/10.1140/epjc/s10052-024-13072-2

Regular Article - Theoretical Physics

Role of hidden-color components in the tetraquark mixing model

Hungchong Kim¹^a and K. S. Kim²

¹ Center for Extreme Nuclear Matters, Korea University, 02841, Seoul, Korea
² School of Liberal Arts and Science, Korea Aerospace University, 412-791, Goyang, Korea

^a bkhc5264@korea.ac.kr

Received: 20 May 2024
Accepted: 29 June 2024
Published online: 23 July 2024

Abstract

Multiquarks can have two-hadron components and hidden-color components in their wave functions. The presence of two-hadron components in multiquarks introduces a potential source of confusion, particularly with respect to their resemblance to hadronic molecules. On the other hand, hidden-color components are essential for distinguishing between multiquarks and hadronic molecules. In this work, we study the hidden-color components in the wave functions of the tetraquark mixing model, a model that has been proposed as a suitable framework for describing the properties of two nonets in the $J^{P} = 0^{+}$ $J^{P}=0^{+}$ channel: the light nonet [ $a_{0} (980)$ $a_{0} (980)$ , $K_{0}^{*} (700)$ $K_{0}^{*} (700)$ , $f_{0} (500)$ $f_{0} (500)$ , $f_{0} (980)$ $f_{0} (980)$ ] and the heavy nonet [ $a_{0} (1450)$ $a_{0} (1450)$ , $K_{0}^{*} (1430)$ $K_{0}^* (1430)$ , $f_{0} (1370)$ $f_{0} (1370)$ , $f_{0} (1500)$ $f_{0} (1500)$ ]. Our analysis reveals a substantial presence of hidden-color components within the tetraquark wave functions. To elucidate the impact of hidden-color components on physical quantities, we conduct computations of the hyperfine masses, $⟨ V_{CS} ⟩$ $\langle V_{CS}\rangle$ , for the two nonets, considering scenarios involving only the two-meson components and those incorporating the hidden-color components. We demonstrate that the hidden-color components constitute an important part of the hyperfine masses, such that the mass difference formula, $Δ M \approx Δ ⟨ V_{CS} ⟩$ $\Delta M\approx \Delta \langle V_{CS}\rangle$ , which has been successful for the two nonets, cannot be achieved without the hidden-color contributions. This can provide another evidence supporting the tetraquark nature of the two nonets.

© The Author(s) 2024

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