https://doi.org/10.1051/epjconf/202226201005
Pionic hydrogen and deuterium
1 Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich, Germany
2 LIBPhys, Physics Department, Coimbra University, 3004-526 Coimbra, Portugal
3 Dept. of Materials Sci. and Eng., University of Ioannina, Ioannina, 45110, Greece
4 Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, 1030 Vienna, Austria
5 Laboratory for Particle Physics, Paul Scherrer Institute, 5232 Villigen, Switzerland
6 Zentralinstitut für Elektronik, Forschungszentrum Jülich, 52425 Jülich, Germany
7 LKB, Sorbonne Université, CNRS, ENS-PSL, Collège de France, 4 place Jussieu, 75005 Paris, France
8 Institut für Theoretische Physik Universität Zürich, 8057 Zürich, Switzerland
9 Skobeltsyn Inst. of Nuclear Physics, Lomonossov Moscow State University, 119234 Moscow, Russia
10 Faculté des Sciences et Techniques, Université Abdelmalek Essaâdi, Tanger, Morocco
11 Institut des NanoSciences de Paris, CNRS, Sorbonne Université, 4 place Jussieu, 75005 Paris, France
12 I3N, Dept. of Physics, Aveiro University, 3810 Aveiro, Portugal
* e-mail: d.gotta@fz-juelich.de
Published online: 27 April 2022
The strong-interaction effects both in pionic hydrogen and deuterium atoms have been re-determined with improved precision. The hadronic shift and width in pionic hydrogen together with the hadronic shift in pionic deuterium constitute a one-fold constraint for the two independent pion-nucleon scattering lengths. Furthermore, the hadronic width in pionic deuterium measures the transition strength of s-wave pions on an isoscalar nucleon-nucleon pair which is an independent quantity not related to the pion-nucleon scattering lengths. The experiment was performed at the Paul Scherrer Institute by stopping a high-intensity low-energy pion beam in gaseous targets using the cyclotron trap. The X-rays emitted by the πH and πD atoms were analysed with a high resolution Bragg spectrometer equipped with spherically bent crystals. The pion-nucleon scattering lengths and other physical quantities extracted from the atom data are in good agreement with the results obtained from pionnucleon and nucleon-nucleon scattering experiments and confirm that a consistent picture is achieved for the low-energy pion-nucleon sector with respect to the expectations of chiral perturbation theory.
© The Authors, published by EDP Sciences, 2022
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