Understanding the Structure of Doubly-Heavy Tetraquarks based on the Diquark Model

Fuente: arXiv
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Main Authors: Weber, Maximilian, Suenaga, Daiki, Harada, Masayasu
Format: Preprint
Published: 2026
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author Weber, Maximilian
Suenaga, Daiki
Harada, Masayasu
author_facet Weber, Maximilian
Suenaga, Daiki
Harada, Masayasu
contents We investigate the $T_{cc}$ tetraquark, treating it as a bound state of a heavy diquark and a light antidiquark. Using the Silvestre-Brac potential and solving the Schrödinger equation via the Gaussian Expansion Method, we find that the excitation energy between the heavy diquark and light antidiquark is unexpectedly larger than that between the two light anti-quarks within the anti-diquark -- contrary to the naive expectation where the former is smaller than the latter. We trace this inversion of the mass hierarchy to the centrifugal force acting on the light degree of freedom. Applying the same framework to other systems ($T_{bb}, Λ_b, Λ_c$) yields qualitatively identical behavior, demonstrating the robustness of the mechanism. These results provide new insights into diquark dynamics and the mass structure of exotic hadrons.
format Preprint
id arxiv_https___arxiv_org_abs_2603_03764
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Understanding the Structure of Doubly-Heavy Tetraquarks based on the Diquark Model
Weber, Maximilian
Suenaga, Daiki
Harada, Masayasu
High Energy Physics - Phenomenology
Nuclear Theory
We investigate the $T_{cc}$ tetraquark, treating it as a bound state of a heavy diquark and a light antidiquark. Using the Silvestre-Brac potential and solving the Schrödinger equation via the Gaussian Expansion Method, we find that the excitation energy between the heavy diquark and light antidiquark is unexpectedly larger than that between the two light anti-quarks within the anti-diquark -- contrary to the naive expectation where the former is smaller than the latter. We trace this inversion of the mass hierarchy to the centrifugal force acting on the light degree of freedom. Applying the same framework to other systems ($T_{bb}, Λ_b, Λ_c$) yields qualitatively identical behavior, demonstrating the robustness of the mechanism. These results provide new insights into diquark dynamics and the mass structure of exotic hadrons.
title Understanding the Structure of Doubly-Heavy Tetraquarks based on the Diquark Model
topic High Energy Physics - Phenomenology
Nuclear Theory
url https://arxiv.org/abs/2603.03764