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

TL;DR

This paper predicts the invariant mass distributions in certain Lambda_b decays, emphasizing the role of the Lambda(1405) resonance and using two chiral models to describe meson-baryon interactions.

Contribution

It introduces a detailed analysis of Lambda_b decays involving the Lambda(1405), utilizing two different chiral unitary models to predict line shapes and resonance features.

Findings

Reaction reflects the higher mass pole of Lambda(1405)

Both models successfully describe scattering data and kaonic hydrogen

Predicted meson-baryon distribution line shapes and strengths

Abstract

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 $\Lambda (1405)$. We find that this reaction reflects more the higher mass pole and we make predictions of the line shapes and relative strength of the meson-baryon distributions in the final state.