$\Lambda^+_\mathrm{c}$ polarimetry using the dominant hadronic mode

TL;DR

This paper introduces a generalized polarimeter vector field for spin-half baryon decays and applies it to $\Lambda^+_c$ decays, providing a model-agnostic framework to measure polarization and improve amplitude analyses.

Contribution

It develops a new formalism for baryon polarimetry and applies it to $\Lambda^+_c$ decays using recent amplitude analysis data.

Findings

Derived a kinematic-dependent polarimeter vector distribution.

Expressed the polarized decay rate in a model-agnostic form.

Facilitates polarization measurements and amplitude analysis inclusion.

Abstract

The polarimeter vector field for multibody decays of a spin-half baryon is introduced as a generalisation of the baryon asymmetry parameters. Using a recent amplitude analysis of the $\Lambda^+_\mathrm{c} \to p K^- \pi^+$ decay performed at the LHCb experiment, we compute the distribution of the kinematic-dependent polarimeter vector for this process in the space of Mandelstam variables to express the polarised decay rate in a model-agnostic form. The obtained representation can facilitate polarisation measurements of the $\Lambda^+_\mathrm{c}$ baryon and eases inclusion of the $\Lambda^+_\mathrm{c} \to p K^- \pi^+$ decay mode in hadronic amplitude analyses.