Eur. Phys. J. C (2026) 86: 629
https://doi.org/10.1140/epjc/s10052-026-15861-3

Regular Article - Theoretical Physics

Probing the nature of $D_{1}K$ and $D_{2}K$ molecules through $D_s^{(\ast )}\pi \pi$ and $D_{s0(s1)}\pi$ decays

Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, 300350, Tianjin, China

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Received: 16 April 2026
Accepted: 17 May 2026
Published online: 9 June 2026

Abstract

We study the two- and three-body decays of the $I=0$$D_{1}K$ and $D_{2}K$ molecular states $T_{c\overline{s}1}^{\ast }$ and $T_{c\overline{s}2}^{\ast }$ into $D_s^{(\ast )}$ mesons and pions. Triangle singularities produce narrow peaks in the $D_s^{\ast }\pi$ and $D_s\pi$ invariant mass spectra near the $D^{\ast }K$ and DK thresholds. The isospin-violating two-body decays $T_{c\overline{s}1}^{\ast }\to D_{s1}(2460){\pi }^0$, $T_{c\overline{s}2}^{\ast }\to D_{s1}(2460){\pi }^0$, and $T_{c\overline{s}2}^{\ast }\to D_{s0}^{\ast }(2317){\pi }^0$ exhibit large partial widths, reflecting the strong couplings inherent to molecular states. These predictions, obtained within heavy hadron chiral perturbation theory and the chiral unitary approach, provide complementary signatures for identifying $D_{1}K$ and $D_{2}K$ molecules at experiments.