First measurement of $e^+ e^- to pK^{0}_{S}bar{n}K^{-} + c.c.$ above open charm threshold

The process $e^+e^-rightarrow pK^{0}_{S}bar{n}K^{-} + c.c.$ and its intermediate processes are studied for the first time, using data samples collected with the BESIII detector at BEPCII at center-of-mass energies of 3.773, 4.008, 4.226, 4.258, 4.358, 4.416, and 4.600 GeV, with a total integrated luminosity of 7.4 fb$^{-1}$. The Born cross section of $e^+e^- to p K^{0}_Sbar{n}K^- + c.c.$ is measured at each center-of-mass energy, but no significant resonant structure in the measured cross-section line shape between 3.773 and 4.600 GeV is observed. No evident structure is detected in the $pK^-$, $nK^{0}_S$, $pK^0_{S}$, $nK^+$, $pbar{n}$, or $K^{0}_S K^-$ invariant mass distributions except for $Lambda(1520)$. The Born cross sections of $e^+e^-rightarrowLambda(1520)bar{n}K^{0}_{S} + c.c.$ and $e^+e^-rightarrow Lambda(1520)bar{p}K^{+} + c.c.$ are measured, and the 90% confidence level upper limits on the Born cross sections of $e^+e^-rightarrowLambda(1520)bar{Lambda}(1520)$ are determined at the seven center-of-mass energies.