Measurement of the strong interaction shift and width of the 1S state in pionic hydrogen

Abstract The energy and line shape of the 3P-1S transition in pionic hydrogen have been measured with a reflecting crystal spectrometer combined with a cyclotron trap and Charge Coulped Devices (CCDs). The instrumental resolution was 0.7 eV (FWHM) at 2.9 keV. Results for the strong interaction energy shift and broadening of the ground state and the corresponding πN s-wave scattering lengths will be presented soon.