Redetermination of the strong-interaction width in pionic hydrogen

A. Hirtl; D. F. Anagnostopoulos; D. S. Covita; H. Fuhrmann; H. Gorke; D. Gotta; A. Gruber; M. Hennebach; P. Indelicato; Th. S. Jensen; E.-O. Le Bigot; Y.-W. Liu; V. E. Markushin; J. Marton; M. Nekipelov; J. M. F. dos Santos; L. M. Simons; Th. Strauch; M. Trassinelli; J. F. C. A. Veloso; J. Zmeskal

doi:10.1140/epja/s10050-021-00387-x

2024 Impact factor 2.8

Hadrons and Nuclei

Open Access

Eur. Phys. J. A (2021) 57: 70
https://doi.org/10.1140/epja/s10050-021-00387-x

Regular Article – Experimental Physics

Redetermination of the strong-interaction width in pionic hydrogen

A. Hirtl¹^,11, D. F. Anagnostopoulos², D. S. Covita³^,4^,12, H. Fuhrmann¹, H. Gorke⁵, D. Gotta⁶^f, A. Gruber¹^,13, M. Hennebach⁶^,14, P. Indelicato⁷, Th. S. Jensen³^,8^,15, E.-O. Le Bigot⁷, Y.-W. Liu³^,16, V. E. Markushin³, J. Marton¹, M. Nekipelov⁶^,17, J. M. F. dos Santos⁴, L. M. Simons³, Th. Strauch⁶, M. Trassinelli⁹, J. F. C. A. Veloso¹⁰ and J. Zmeskal¹

¹ Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, Kegelgasse 27, 1030, Vienna, Austria
² Department of Materials Science and Engineering, University of Ioannina, 45110, Ioannina, Greece
³ Laboratory for Particle Physics, Paul Scherrer Institute, 5232, Villigen, Switzerland
⁴ LIBPhys, Physics Department, University of Coimbra, 3004-526, Coimbra, Portugal
⁵ Zentralinstitut für Elektronik, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
⁶ Institut für Kernphysik, Forschungszentrum Jülich, 52425, Jülich, Germany
⁷ Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu, 75005, Paris, France
⁸ Institut für Theoretische Physik Universität Zürich, 8057, Zürich, Switzerland
⁹ Institut des NanoSciences de Paris, CNRS, Sorbonne Université, 4 place Jussieu, 75005, Paris, France
¹⁰ I3N, Department of Physics, Aveiro University, 3810, Aveiro, Portugal
¹¹ Atominstitut, TU Wien, 1020, Vienna, Austria
¹² Bosch Termotecnologia, S.A., EN 16-Km 3,7, 3800-533, Cacia Aveiro, Portugal
¹³ Department of Radiology and Nuclear Medicine, General Hospital of the City of Vienna, 1090, Vienna, Austria
¹⁴ DAHER Nuclear Technologies GmbH, 63457, Hanau, Germany
¹⁵ Ringkjøbing Gymnasium, Vasevej 24, 6950, Ringkjøbing, Denmark
¹⁶ Physics Department, National Tsing Hua University, 300, Hsinchu, Taiwan
¹⁷ WTI GmbH, 52428, Jülich, Germany

^f d.gotta@fz-juelich.de

Received: 2 October 2020
Accepted: 4 February 2021
Published online: 23 February 2021

Abstract

The hadronic width of the ground state of pionic hydrogen has been redetermined by X-ray spectroscopy to be $Γ_{1 s}^{π H} = (856 \pm 16_{stat} \pm 22_{sys})$ $\varGamma ^{\pi \mathrm {H}}_{1s}=(856\,\pm \,16_\mathrm{stat}\,\pm \,22_\mathrm{sys})$ meV. The experiment was performed at the high-intensity low-energy pion beam of the Paul Scherrer Institute by using the cyclotron trap and a high-resolution Bragg spectrometer with spherically bent crystals. Coulomb de-excitation was studied in detail by comparing its influence on the line shape by measuring the three different transitions K $α$ $\alpha$ , K $β$ $\beta$ , and K $γ$ $\gamma$ at various hydrogen densities. The pion-nucleon scattering lengths and other physical quantities extracted from pionic-atom data are in good agreement with the results obtained from pion-nucleon 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 Author(s) 2021

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.