Predictions for the $\Lambda_b \to J/\psi ~ \Lambda(1405)$ decay

Understand

We calculate the shape of the $\pi\Sigma$ and $\bar K N$ invariant mass distributions in the $\Lambda_b \to J/\psi\, \pi\Sigma$ and $\Lambda_b \to J/\psi \,\bar K N$ decays that are dominated by the $\Lambda(1405)$ resonance.

• The weak interaction part is the same for both processes and the hadronization into the different meson-baryon channels in the final state is related by SU(3) symmetry.
• The most important feature is the implementation of the meson-baryon final-state interaction using two chiral unitary models from different theoretical groups.
• Both approaches give a good description of antikaon-nucleon scattering data, the complex energy shift in kaonic hydrogen and the line shapes of $\pi \Sigma K$ in photoproduction, based on the two-pole scenario for the $\Lambda (1405)$.