Observation of the $\Lambda_b^0\to\Lambda\phi$ decay

TL;DR

This paper reports the first observation of the rare $ ext{Lambda}_b^0 o ext{Lambda} ext{Phi}$ decay, measuring its branching fraction and finding no evidence of CP violation, providing insights into potential new physics beyond the Standard Model.

Contribution

The paper presents the first observation of the $ ext{Lambda}_b^0 o ext{Lambda} ext{Phi}$ decay with a significance of 5.9 sigma and measures its branching fraction, contributing new experimental data to heavy baryon decay studies.

Findings

First observation of the decay with 5.9 sigma significance.

Branching fraction measured as approximately 5.18 x 10^{-6}.

Triple-product asymmetries are consistent with zero.

Abstract

The $\Lambda_b^0\to\Lambda\phi$ decay is observed using data corresponding to an integrated luminosity of 3.0fb$^{-1}$ recorded by the LHCb experiment. The decay proceeds at leading order via a $b\to s\bar{s}s$ loop transition and is therefore sensitive to the possible presence of particles beyond the Standard Model. A first observation is reported with a significance of $5.9$ standard deviations. The value of the branching fraction is measured to be $(5.18\pm1.04\pm0.35\,^{+0.67}_{-0.62})\times10^{-6}$, where the first uncertainty is statistical, the second is systematic, and the third is related to external inputs. Triple-product asymmetries are measured to be consistent with zero.