KAONIC HELIUM-4 L-SERIES YIELD MEASUREMENT AT 2.25 g/l DENSITY BY SIDDHARTA-2 at DAΦNE

This article presents the results of the kaonic helium-4 measurement conducted by the SIDDHARTA-2 experiment, aiming to provide crucial insights into the low-energy strong interaction in the strangeness sector. High-precision X-ray spectroscopy is used to examine the interaction between negatively charged kaons and nuclei in atomic systems. The SIDDHARTA-2 setup was optimized through the kaonic helium-4 measurement in preparation for the challenging kaonic deuterium measurement. The kaonic helium-4 measurement at a new density of 2.25 g/l is reported, providing the absolute and relative yields for the L-series transitions, which are essential data for understanding kaonic atom cascade processes.