Theoretical study of the Lambda(1405) resonance in Xi_b^0 -> D^0 pi Sigma decay

TL;DR

This paper provides a theoretical analysis of the Lambda(1405) resonance formation in Xi_b^0 decays, predicting how final state interactions influence observable mass distributions, and emphasizing the importance of reaction mechanism details.

Contribution

It introduces a detailed theoretical model for the decay process, highlighting the role of final state interactions and interference effects in shaping the Lambda(1405) signal.

Findings

The pi Sigma mass distribution is strongly affected by interference effects.

The Kbar N channel is absent in the dominant decay component.

Final state interactions are crucial for understanding the Lambda(1405) formation.

Abstract

We study the mechanism of the weak decay process of Xi_b^0 into D^0 with a meson-baryon pair. It is shown that the dominant component of the prompt weak decay produces the meson-baryon pair with the spectator strange quark being transferred to the baryon, so that the Kbar N channel is absent. Subsequent final state interaction then reflects the pi Sigma originated Lambda(1405) formation amplitude, which has been difficult to access in previous experimental studies. We predict the line shapes of the pi Sigma invariant mass distribution using a realistic chiral meson-baryon amplitude for the final state interaction. It is shown that the interference between the direct and the rescattering contributions can strongly distort the peak structure of the Lambda(1405) in the mass distribution. This indicates the necessity of a detailed investigation of the reaction mechanism in order to extract the Lambda(1405) property in the pi Sigma mass distribution.