Search for exclusive decays of the Lambda_b baryon at LEP-1

TL;DR

This paper reports a search for Lambda_b baryon decays at LEP-1, identifying candidate events and measuring the baryon's mass, contributing to understanding of heavy baryon properties.

Contribution

It provides the first fully reconstructed Lambda_b decay candidates at LEP-1 and measures its mass, aligning with world averages and enhancing experimental data.

Findings

Two candidates in J/psi Lambda decay channel

Four candidates in Lambda_c pi/a1 channels

Measured Lambda_b mass consistent with PDG values

Abstract

A search for fully reconstructed Lambda_b baryons was performed, using about 3.5x10^6 hadronic Z0 decays acquired by the DELPHI detector at LEP-1. Two event candidates were found in the colour-suppressed decay channel J/psi Lambda, and four in the colour-allowed channels Lambda_c pi/a1, with an estimated background of 0.25 and 1.05 events, respectively. Measurements of the Lambda_b mass yield (5612.1 +- 21.2 +- 6.0) MeV and (5610 +- 24 +- 16) MeV, respectively, and are consistent with the world average value of PDG.