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Pionic deuterium |
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| Authors: | Th Strauch F D Amaro D F Anagnostopoulos P Bühler D S Covita H Gorke D Gotta A Gruber A Hirtl P Indelicato E -O Le Bigot M Nekipelov J M F dos Santos Ph Schmid S Schlesser L M Simons M Trassinelli J F C A Veloso J Zmeskal |
| Institution: | 1. Institut für Kernphysik, Forschungszentrum Jülich, D-52425, Jülich, Germany 2. Department of Physics, Coimbra University, P-3000, Coimbra, Portugal 3. Department of Materials Science and Engineering, University of Ioannina, GR-45110, Ioannina, Greece 4. Stefan Meyer Institut for Subatomic Physics, Austrian Academy of Sciences, A-1090, Vienna, Austria 7. Laboratory for Particle Physics, Paul Scherrer Institut, CH-5232, Villigen, Switzerland 5. Zentralinstitut für Elektronik, Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany 6. Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, Case 74, 4 place Jussieu, F-75005, Paris, France 8. I3N, Department of Physics, Aveiro University, P-3810, Aveiro, Portugal |
| Abstract: | The strong-interaction shift ε 1s πD and broadening Γ 1s πD in pionic deuterium have been determined in a high statistics study of the πD(3p-1s) X-ray transition using a high-resolution crystal spectrometer. The pionic deuterium shift will provide constraints for the pion-nucleon isospin scattering lengths extracted from measurements of shift and broadening in pionic hydrogen. The hadronic broadening is related to pion absorption and production at threshold. The results are ε 1s πD = (?2356 ± 31) meV (repulsive) and Γ 1s πD meV yielding for the complex πD scattering length a πD = ?(24.99±0.33)+i(6.22 ?0.26 +0.12 )] × 10?3 m π ?1 . From the imaginary part, the threshold parameter for pion production is obtained to be α = (251 ?11 +5 ) μb. This allows, in addition, and by using results from pion absorption in 3He at threshold, the determination of the effective couplings g 0 and g 1 for s-wave pion absorption on isoscalar and isovector NN pairs. |
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