In this work we present an attempt to describe the X1(2900) found by the LHCb collaboration, in the experimental data on the invariant mass spectrum of D-K+, as a three-meson molecular state of the KρD¯ system. We discuss that the interactions in all the subsystems are attractive in nature, with the ρD¯ interaction generating D¯1(2420) and the Kρ resonating as K1(1270). We find that the system can form a three-body state but with a mass higher than that of X1(2900). We investigate the KρD system too, finding that the three-body dynamics generates an isoscalar state, which can be related to Ds1∗(2860), and an exotic isovector state. This latter state has a mass similar to that of the X0(2900) and X1(2900) states found by LHCb, but a very small width (∼7.4±0.9 MeV) and necessarily requires more than two quarks to describe its properties. We hope that our findings will encourage experimental investigations of the isovector KρD state. Finally, in the pursuit of finding a description for X1(2900), we study the πK̄∗D∗ system where K̄∗D∗ forms 0+, 1+, and 2+ states. We do not find a state that can be associated with X1(2900).

B. B. M., K. P. K., and A. M. T. gratefully acknowledge the support from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Grants No. 2020/00676-8, No. 2019/17149-3, and No. 2019/16924-3. K. P. K. and A. M. T. are also thankful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for Grants No. 305526/2019-7 and No. 303945/2019-2. This work is partly supported by the Spanish Ministerio de Economía y Competitividad and European FEDER funds under Contract No. PID2020–112777 GBI00, and by Generalitat Valenciana under Contract No. PROMETEO/2020/023. This project has received funding from the European Unions 10 Horizon 2020 research and innovation programme under Grant Agreement No. 824093 for the “STRONG-2020” project.

Peer reviewed