Precision X-ray spectroscopy of kaonic atoms as a probe of low-energy kaon-nucleus interaction

¹ INFN, Laboratori Nazionali di Frascati, Via E. Fermi 40, I-00044 Frascati(Roma), Italy
² Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CNC, Victoria BC V8W 2Y2, Canada
³ Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
⁴ INFN Sezione di Milano, Via Celoria 16 - 20133 Milano, Italy
⁵ Stefan-Meyer-Institut für Subatomare Physik, Boltzmanngasse 3, 1090 Wien, Austria
⁶ IFIN-HH, Institutul National pentru Fizica si Inginerie Nucleara Horia Hulubbei, Reactorului 30, Magurele, Romania
⁷ Department of Physics, Facaulty of Science, University of Zagreb, Bijenicka 32, HR-10000 Zagreb, Croatia
⁸ INFN Sezione di Roma I and Instituto Superiore di Sanita, I-00161 Roma, Italy
⁹ Department of Physics, School of Science, The University of Tokyo, Bunkyo-ku Hongo 7-3-1, Tokyo, Japan
¹⁰ RIKEN, Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 251-0198, Japan
¹¹ Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 1-00184 Roma, Italy
¹² Universidade de Santiago de Compostela, Casas Reais 8, 15782 Santiago de Compostela, Spain
¹³ National Institute of Standards and Technology (NIST), Boulder, CO, 80303, USA
¹⁴ High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan
¹⁵ Excellence Cluster Universe, Technische Universität München, Boltzmannstraße 2, D-85748 Garching, Germany

^a e-mail: hexishi@lnf.infn.it

Published online: 4 November 2016

Abstract

In the exotic atoms where one atomic 1s electron is replaced by a K⁻, the strong interaction between the K⁻ and the nucleus introduces an energy shift and broadening of the low-lying kaonic atomic levels which are determined by only the electromagnetic interaction. By performing X-ray spectroscopy for Z = 1,2 kaonic atoms, the SIDDHARTA experiment determined with high precision the shift and width for the 1s state of K⁻ p and the 2p state of kaonic helium-3 and kaonic helium-4. These results provided unique information of the kaon-nucleus interaction in the low energy limit.