Precision Spectroscopy of Pionic Atoms: From Pion Mass Evaluation to Tests of Chiral Perturbation Theory
Abstract
Description
Preliminary results of the strong interaction shift and width in pionic hydrogen ($πH$) using an X-ray spectrometer with spherically bent crystals and CCDs as X-ray detector are presented. In the experiment at the Paul Scherrer Institute three different $(np\to 1s)$ transitions in $πH$ were measured. Moreover the pion mass measurement using the $(5 \to 4)$ transitions in pionic nitrogen and muonic oxygen is presented