https://doi.org/10.1140/epja/i2011-11088-1
Regular Article - Experimental Physics
Pionic deuterium
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
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
7
Laboratory for Particle Physics, Paul Scherrer Institut, CH-5232, Villigen, Switzerland
8
I3N, Department of Physics, Aveiro University, P-3810, Aveiro, Portugal
* e-mail: d.gotta@fz-juelich.de
Received:
10
November
2010
Revised:
2
May
2011
Accepted:
3
July
2011
Published online:
27
July
2011
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.
© SIF, Springer-Verlag Berlin Heidelberg, 2011
