The $\Lambda_b \to J/\psi ~ K ~ \Xi$ decay and the higher order chiral terms of the meson baryon interaction

TL;DR

This paper investigates the decay of Lambda_b into J/psi, K, and Xi particles, emphasizing the role of higher order chiral interactions in meson-baryon dynamics and proposing these decays as probes for such interactions.

Contribution

It demonstrates the sensitivity of Lambda_b decays to higher order chiral terms and highlights their potential to improve understanding of meson-baryon interactions at higher energies.

Findings

Decay rates are sizable and measurable.

Invariant mass distributions are dominated by next-to-leading order terms.

Decay processes are sensitive to higher order chiral interaction details.

Abstract

We study the weak decay of the $\Lambda_b$ into $ J/\psi ~ K ~ \Xi$ and $J/\psi ~ \eta ~ \Lambda$ states, and relate these processes to the $\Lambda_b \to J/\psi ~ \bar K ~N$ decay mode. The elementary weak transition at the quark level proceeds via the creation of a $J/\psi$ meson and an excited $sud$ system with $I=0$, which upon hadronization leads to $\bar K N$ or $\eta \Lambda$ pairs. These states undergo final state interaction in coupled channels and produce a final meson-baryon pair. The $K \Xi$ state only occurs via rescattering, hence making the $\Lambda_b \to J/\psi ~ K ~ \Xi$ process very sensitive to the details of the meson-baryon interaction in strangeness $S=-1$ and isospin $I=0$. We show that the corresponding invariant mass distribution is dominated by the next-to-leading order terms of the chiral interaction. The $I=0$ selectivity of this decay, and its large sensitivity to the higher order terms, makes its measurement very useful and complementary to the $K^- p \to K \Xi$ cross section data. The rates of the $\Lambda_b \to J/\psi ~ K ~ \Xi$ and $\Lambda_b \to J/\psi ~ \eta ~ \Lambda$ invariant mass distributions are sizable compared to those of the $\Lambda_b \to J/\psi ~ \bar K ~N$ decay, which is measured experimentally, thus, we provide arguments for an experimental determination of these decay modes that will help us understand better the chiral dynamics at higher energies.