Predictions for the [Formula: see text] decay.

L Roca,M Mai,E Oset,Ulf-G Meißner

doi:10.1140/epjc/s10052-015-3438-1

Abstract

We calculate the shape of the pi Sigma and bar{K} N invariant mass distributions in the Lambda _b rightarrow J/psi , pi Sigma and Lambda _b rightarrow 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 given by symmetry arguments. 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.

Highlights

A different line of investigation has been opened in [8] following the findings of chiral unitary theory, where these scalar mesons are dynamically generated from the interaction of pseudoscalar mesons
It should be mentioned that the use of unitarized chiral perturbation theory (ChPT) to explore the physics of heavy meson decays was pioneered in Refs. [15,16], and this has recently been employed to quantify the S-wave pollution in semileptonic B decays [17]
Later in Ref. [47] it was applied to meson–baryon scattering in the strangeness S = −1 sector, adjusting the free parameters of the model to the available scattering data

Summary

Introduction

Some studies made use of heavy quark effective theory to evaluate related amplitudes as for the process b → clνl [69] In contrast to these later works, the one presented here, as well as the one of [66], does not perform a microscopic study of the reaction, since we do not aim at obtaining absolute rates; instead we exploit the dynamics of the coupled channels to relate the distributions of invariant masses in different final states, hopefully contributing to a better understanding of the meson–baryon interaction and the nature of some resonances, in particular the (1405)

Formalism

Summary of the Bonn model

Summary of the MV model

Results

Summary