Amplitude Analysis of Singly Cabibbo-Suppressed Decay $\Lambda^{+}_{c}\to p K^{+} K^{-}$

TL;DR

This paper performs an amplitude analysis of the decay $^{+}_{c} o pK^{+}K^{-}$, measuring branching fractions of various sub-decays, including first-time observations, and updates the overall decay branching ratio with improved precision.

Contribution

It provides the first observation of certain decay modes and significantly improves the precision of the branching fraction measurement for $^{+}_{c} o pK^{+}K^{-}$.

Findings

First observation of $^{+}_{c} o par{f}_{0}(980)$ and $^{+}_{c} o (1405)K^{+}$ decays.

Branching fraction of $^{+}_{c} o pK^{+}K^{-}$ updated to $(9.94 extpm0.65_{ ext{stat}} extpm0.50_{ ext{syst}}) imes10^{-4}$.

Analysis improves measurement precision by a factor of 1.5.

Abstract

Using a sample of $e^{+}e^{-}$ annihilation data corresponding to an integrated luminosity of 4.4 $\rm{fb}^{-1}$ collected with the BESIII detector at the BEPCII collider and produced at center-of-mass energies from $4600$ to $4698~\rm{MeV}$, an amplitude analysis is performed of the singly Cabibbo-suppressed decay $\Lambda^{+}_{c}\to pK^{+}K^{-}$. The branching fractions of $\Lambda^{+}_{c}\to p\phi(1020)$, $pf_{0}(980)$, $\Lambda(1405)K^{+}$, and $\Lambda(1670)K^{+}$ are measured, where the latter two modes are decays that are observed for the first time. At the same time, with the detection efficiency based on the results of the amplitude analysis, the branching fraction of $\Lambda^{+}_{c}\to pK^{+}K^{-}$ is updated to be $(9.94\pm0.65_{\text{stat.}}\pm0.50_{\text{syst.}})\times10^{-4}$, which is consistent with the current world average value within one standard deviation. The result supersedes the previous BESIII measurement with precision improved by approximately a factor of 1.5.