The T_cs (2900) as a threshold effect from the interaction of the D^*K^*, D^*_sρ channels

Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de Paterna, Aptdo. 22085, 46071 Valencia, Spain

^* e-mail: Raquel.Molina@ific.uv.es
^* e-mail: Eulogio.Oset@ific.uv.es

Published online: 16 February 2024

Abstract

Abstract. We investigate the D*K* and D_sρ^* interaction in coupled channels within the hidden gauge formalism. A structure is developed around their thresholds, short of producing a bound state, which leads to a peak in the D_s⁺π¯ mass distribution in the B⁰ → D¯⁰ D_s⁺π¯ decay compatible with the experimental data. We conclude that the interaction between the D^* K^* and D_sρ^* is essential to produce the cusp structure that we associate to the recently seen T_cs¯(2900), and that its experimental width is mainly due to the decay width of the ρ meson. The peak obtained together with a smooth background reproduces fairly well the experimental mass distribution observed in the B⁰ → D¯⁰ D_s⁺π¯ decay.