INFN-LNF Laboratori Nazionali di Frascati
The new Chief Editor of Nuclear Physics A has selected, among the journal’s most significant articles of recent years, the study conducted by the SIDDHARTA‑2 collaboration on the X‑ray transitions of kaonic helium‑4, confirming the role of the INFN Frascati National Laboratory and of DAΦNE as a top‑level infrastructure for exotic‑atom physics.
As part of the relaunch of the international journal Nuclear Physics A, the SIDDHARTA‑2 scientific collaboration at the INFN Frascati National Laboratory has achieved an important recognition, with one of its works selected among the five most significant (Top 5) articles published in the journal in recent years.
The article “New measurements of kaonic helium‑4 L‑series X‑rays yields in gas with the SIDDHARTINO setup”, published in Nuclear Physics A 1029 (2023) 122567 and led by first author Diana Laura Sirghi, presented new high‑precision measurements of the X‑ray transitions of kaonic helium‑4 obtained at the DAΦNE accelerator of the LNF. The results provided fundamental information on the strong interaction between kaons and nuclei at low energies, contributing to the understanding of quantum chromodynamics in the non‑perturbative regime.
The measurements, carried out with the SIDDHARTINO experimental setup, determined the absolute yields (emission probabilities) of X‑ray transitions in gaseous helium targets at different densities, supplying new experimental data to atomic‑cascade models that describe the de‑excitation processes of kaonic atoms. These data represent a significant contribution in a parameter region that had been scarcely explored so far and constitute reference information for the theoretical development of exotic‑atom physics.
DAΦNE: a world‑class accelerator
DAΦNE, a unique machine worldwide for producing low‑energy charged‑kaon pairs through the decay of the φ meson, is the core of the experimental program dedicated to kaonic‑atom measurements at the LNF. Thanks to its ability to deliver high‑intensity, low‑energy beams, DAΦNE has enabled extremely high‑precision spectroscopic measurements that would not have been possible elsewhere. This capability has made the facility an international reference point for studies of the strong interaction in the presence of strangeness, with implications for astrophysics and for understanding matter under extreme conditions.
From the SIDDHARTINO pilot to SIDDHARTA‑2
SIDDHARTINO played a pilot role in performing precision spectroscopic measurements on exotic atomic systems, allowing detectors and analysis techniques to be tested and optimized in preparation for the more advanced measurement campaigns carried out in 2023–2024 by the SIDDHARTA‑2 program. The main goal of this program is to perform the world’s first measurement of kaonic deuterium, for which further publications are currently in preparation.
The results selected by the editor of Nuclear Physics A represent a key step toward the scientific objectives of SIDDHARTA‑2, helping to clarify fundamental dynamics of the strong interaction in the presence of strangeness and providing experimental constraints for theoretical models.
“This international recognition confirms the value of the scientific program developed in Frascati and the competitiveness of our research infrastructures,” comments Catalina Curceanu, scientific coordinator (Spokesperson) of the collaboration. “Kaonic atoms represent a unique laboratory for studying the strong interaction under extreme conditions, and the results obtained open new experimental and theoretical perspectives. The new measurements provide crucial data for atomic‑cascade models and represent a fundamental step toward the goals of SIDDHARTA‑2. The recognition by the international scientific community highlights the impact of the work carried out at the LNF.”