Two-pion exchange for coupled-channel scattering of two heavy mesons

Fuente: arXiv
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Autori principali: Chacko, J. T., Baru, V., Hanhart, C., Krug, S. L.
Natura: Preprint
Pubblicazione: 2024
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author Chacko, J. T.
Baru, V.
Hanhart, C.
Krug, S. L.
author_facet Chacko, J. T.
Baru, V.
Hanhart, C.
Krug, S. L.
contents To improve the theoretical understanding of multiquark states like $Z_b(10610)$ and $Z_b(10650)$, we calculate the heavy-meson heavy-(anti)meson scattering potential up to next-to-leading order, $O(Q^2)$, within chiral effective field theory ($χ$EFT) employing a power counting scheme that explicitly keeps track with the large momentum scale $Q \sim \sqrt{2μδ}$ (where $δ= m_V - m_P$ is the vector-pseudoscalar mass difference and $μ$ their reduced mass) introduced by the coupled channel dynamics. We provide expressions for the two-pion exchange (TPE) terms up to $O(Q^2)$ and their partial-wave decomposition. We show that these potentials are well-approximated by contact terms at $O(Q^2)$, with minor residual non-analytic TPE contributions, supporting $χ$EFT convergence in the theoretical predictions for $Z_b(10610)$ and $Z_b(10650)$, as well as their spin partners. These findings are also relevant for $D^{(*)}D^{(*)}$ scattering, especially for the $T_{cc}$ state, for both physical and lattice QCD data with moderately larger pion masses. We further demonstrate that the differences between isovector and isoscalar potentials for heavy mesons are naturally explained by the TPE contributions.
format Preprint
id arxiv_https___arxiv_org_abs_2411_13303
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Two-pion exchange for coupled-channel scattering of two heavy mesons
Chacko, J. T.
Baru, V.
Hanhart, C.
Krug, S. L.
High Energy Physics - Phenomenology
Nuclear Theory
To improve the theoretical understanding of multiquark states like $Z_b(10610)$ and $Z_b(10650)$, we calculate the heavy-meson heavy-(anti)meson scattering potential up to next-to-leading order, $O(Q^2)$, within chiral effective field theory ($χ$EFT) employing a power counting scheme that explicitly keeps track with the large momentum scale $Q \sim \sqrt{2μδ}$ (where $δ= m_V - m_P$ is the vector-pseudoscalar mass difference and $μ$ their reduced mass) introduced by the coupled channel dynamics. We provide expressions for the two-pion exchange (TPE) terms up to $O(Q^2)$ and their partial-wave decomposition. We show that these potentials are well-approximated by contact terms at $O(Q^2)$, with minor residual non-analytic TPE contributions, supporting $χ$EFT convergence in the theoretical predictions for $Z_b(10610)$ and $Z_b(10650)$, as well as their spin partners. These findings are also relevant for $D^{(*)}D^{(*)}$ scattering, especially for the $T_{cc}$ state, for both physical and lattice QCD data with moderately larger pion masses. We further demonstrate that the differences between isovector and isoscalar potentials for heavy mesons are naturally explained by the TPE contributions.
title Two-pion exchange for coupled-channel scattering of two heavy mesons
topic High Energy Physics - Phenomenology
Nuclear Theory
url https://arxiv.org/abs/2411.13303