Kaonic atoms with SIDDHARTA-2 at the DAΦNE collider

¹ INFN-LNF, Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati, Frascati, 00044 Roma, Italy
² Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
³ Horia Hulubei National Institute of Physics and Nuclear Engineering IFIN-HH Măgurele, Romania
⁴ Stefan-Meyer-Institut für Subatomare Physik, Vienna, 1030, Austria
⁵ Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, 20133, Italy
⁶ INFN Sezione di Milano, 20133, Italy
⁷ Physik Department E62, Technische Universität München, Garching, 85748, Germany
⁸ RIKEN, Tokyo 351-0198, Japan
⁹ Faculty of Physics, Astronomy, and Applied Computer Science, Jagiellonian University, Krakow, 30-348, Poland
¹⁰ Center for Theranostics, Jagiellonian University, Krakow, Poland
¹¹ Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai, 982-0826, Japan
¹² Centro Ricerche Enrico Fermi – Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Roma, 00184, Italy
¹³ University of Vienna, Vienna Doctoral School in Physics, Vienna, 1090, Austria
¹⁴ Dipartimento di Fisica e Chimica - Emilio Segre, Universita di Palermo, Viale Delle Scienze, Edificio 18, Palermo, 90128, Italy.

^* e-mail: fsirghi@lnf.infn.it
^** current address: ASI, Agenzia Spaziale Italiana, Roma, Italy

Published online: 16 February 2024

Abstract

The most important information still missing in the field of the low-energy antikaon-nucleon inter actions studies is the experimental determination of the hadronic energy shift and width of kaonic deuterium. This measurement will be performed by the SIDDHARTA-2 experiment, installed at the DAΦNE collider and presently in data taking campaign. The precise measurement of the shift and width of the 1s level with respect to the purely electromagnetic calculated values, generated by the presence of the strong interaction, through the measurement of the X-ray transitions to this level, in kaonic hydrogen, was performed by the SIDDHARTA collaboration, the kaonic deuterium is underway by SIDDHARTA-2. These measurement will allow the first precise experimental extraction of the isospin dependent antikaon-nucleon scattering lengths, funda mental quantities for understanding low-energy QCD in the strangeness sector. The experimental challenge of the kaonic deuterium measurement is the very small X-rays yield, the even larger width (compared to kaonic hy drogen), and the difficulty to perform X-rays spectroscopy with weak signals in the high radiation environment of DAΦNE. It was, therefore, crucial to develop a new apparatus involving large-area X-rays detector system, to optimize the signal and to control and by improve the signal-to-background ratio by gaining in solid angle, increasing the timing capability, and as well implementing additional charge particle tracking veto systems.