<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi><mml:mover accent="true"><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover></mml:mrow></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:mn>2900</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> as a threshold effect from the interaction of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>D</mml:mi><mml:mo>*</mml:mo></mml:msup><mml:msup><mml:mi>K</mml:mi><mml:mo>*</mml:mo></mml:msup></mml:math>, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>D</mml:mi><mml:mi>s</mml:mi><mml:mo>*</mml:mo></mml:msubsup><mml:mi>ρ</mml:mi></mml:math> channels
R. Molina, E. Oset
Abstract
We look at the mass distribution of the ${D}_{s}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ in the ${B}^{0}\ensuremath{\rightarrow}{\overline{D}}^{0}{D}_{s}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay, where a peak has been observed in the region of the ${D}_{s}^{*}\ensuremath{\rho}$, ${D}^{*}{K}^{*}$ thresholds. By creating these two channels together with a ${\overline{D}}^{0}$ in ${B}^{0}$ decay and letting them interact as coupled channels, we obtain a structure around their thresholds, short of producing a bound state, which leads to a peak in the ${D}_{s}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ mass distribution in the ${B}^{0}\ensuremath{\rightarrow}{\overline{D}}^{0}{D}_{s}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay. We conclude that the interaction between the ${D}^{*}{K}^{*}$ and ${D}_{s}^{*}\ensuremath{\rho}$ is essential to produce the cusp structure that we associate to the recently seen ${T}_{c\overline{s}}(2900)$, and that its experimental width is mainly due to the decay width of the $\ensuremath{\rho}$ meson. The peak obtained together with a smooth background reproduces fairly well the experimental mass distribution observed in the ${B}_{0}\ensuremath{\rightarrow}{\overline{D}}^{0}{D}_{s}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay.