First Measurement of the Decay Asymmetry in the pure W-boson-exchange Decay $\Lambda_{c}^{+}\to\Xi^{0}K^{+}$

TL;DR

This paper reports the first measurement of the decay asymmetry in the pure W-boson-exchange decay of the Lambda_c+ baryon to Xi0 and K+, using angular analysis of data collected at BESIII, revealing a near-zero asymmetry and phase shift solutions.

Contribution

The study provides the first experimental measurement of the decay asymmetry in Lambda_c+ to Xi0 K+ decay, offering new insights into W-boson-exchange processes in charmed baryon decays.

Findings

Decay asymmetry measured as 0.01±0.16(stat)±0.03(syst).

Phase shift between S- and P-wave amplitudes identified with two solutions.

Results suggest non-interference between S- and P-wave amplitudes.

Abstract

Based on $4.4~\text{fb}^{-1}$ of $e^{+}e^{-}$ annihilation data collected at the center-of-mass energies between $4.60$ and $4.70~\text{GeV}$ with the BESIII detector at the BEPCII collider, the pure \textit{W}-boson-exchange decay $\Lambda_{c}^{+}\to\Xi^{0}K^{+}$ is studied with a full angular analysis. The corresponding decay asymmetry is measured for the first time to be $\alpha_{\Xi^{0}K^{+}}=0.01\pm0.16({\rm stat.})\pm0.03({\rm syst.})$. This result reflects the non-interference effect between the $S$- and $P$-wave amplitudes. The phase shift between $S$- and $P$-wave amplitudes has two solutions, which are $\delta_{p}-\delta_{s}=-1.55\pm0.25({\rm stat.})\pm0.05({\rm syst.})~\text{rad}$ or $1.59\pm0.25({\rm stat.})\pm0.05({\rm syst.})~\text{rad}$.