Darmstadt 2008 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 23: Precision spectroscopy II

A 23.7: Vortrag

Donnerstag, 13. März 2008, 15:30–15:45, 3C

QED effects in high precision lifetime measurements — •José R. Crespo López-Urrutia, Günter Brenner, Volkhard Mäckel, Sascha W. Epp, and Joachim Ullrich — Max-Planck-Institut für Kernphysik, 69117 Heidelberg

The precision achieved recently in the determination of lifetimes of metastable states by using electron beam ion traps, with total uncertainties of the order of 0.15%, has allowed for the first time to become sensitive to QED contributions to the transition probability, such as the effect of the electron anomalous magnetic moment (0.45% contribution). Electric-dipole forbidden transitions are of particular interest, because of the relatively weak dependence of their line strengths on the radial part of the wave function. By systematically improving the related measurement techniques at the Heidelberg electron beam ion trap, highly accurate results for FeXIV, FeX and ArXIV have been obtained. These values, when compared with the most sophisticated predictions, allow to distinguish between the different models used for the calculation of the transition matrix elements. The lines studied are also the strongest visible coronal lines observed in the Sun, and the exact knowledge of their lifetimes has crucial importance for the determining the parameters of those and other astrophysical plasmas.