Sprecher
Beschreibung
S. Schippers$^{1,2}$, C. Brandau$^{1,3}$, S. Fuchs$^{1,2}$, M. Lestinsky$^{3}$, S-X. Wang$^{1,2}$, C. Y. Zhang$^{4}$, N. R. Badnell$^{4}$, A. Borovik Jr$^{1,5}$, M. Fogle$^6$, V. Hannen$^7$, Z. Harman$^{8}$, P-M. Hillenbrand$^{1,3}$, E. B. Menz$^{3,5}$, Y. Zhang$^{8,9}$, Z. Andelkovic$^3$, F. Herfurth$^{3}$, R. Heß$^3$, A. Kalinin$^3$, C. Kozhuharov$^3$, C. Krantz$^3$, S. Litvinov$^3$, B. Lorentz$^3$, U. Spillmann$^3$, M. Steck$^3$, G. Vorobyev$^{3}$, D. Banaś$^{10}$, S. Fritzsche$^{3,5,11}$, E. Lindroth$^{12}$, X. Ma$^{13}$, A. Müller$^1$, R. Schuch$^{12}$, A. Surzhykov$^{14,15}$, M. Trassinelli$^{16}$, K. Ueberholz$^7$, C. Weinheimer$^7$, and Th. Stöhlker$^{3,5,11}$
$^1$JLU Gießen, $^2$HFHF, $^3$GSI Darmstadt, $^4$University of Strathclyde, $^5$HI Jena, $^6$Auburn University, $^7$University of M\"unster, $^8$MPIK Heidelberg, $^9$Xian Jiantong University, $^{10}$JKU Kielce, $^{11}$FSU Jena, $^{12}$Stockholm University, $^{13}$IMPCAS Lanzhou, $^{14}$PTB Braunschweig, $^{15}$TU Braunschweig, $^{16}$UMPC Paris
Using the experimental technique of electron-ion collision spectroscopy at the electron cooler of the heavy-ion storage ring CRYRING@ESR [1] we have measured merged-beams rate coefficients for electron-ion recombination of berylliumlike Pb$^{78+}$ ions. In the electron-ion collision energy range 12-16.5 eV, we have observed $2s2p\;(^3P_1)\,19l_j$ dielectronic recombination (DR) resonances associated with a $2s^2\;^1S_0 \to 2p2p\;^3P_1$ core excitation and a simultaneous capture of the initially free electron into the $n=19$ shell of the boronlike Pb$^{77+}$ product ion. A careful analysis of the systematic experimental errors reveals that the uncertainty of the measured resonance positions amounts to $pm30$ meV. This uncertainty is lower than the theoretical uncertainty of the calculation of the $2s^2\;^1S_0 \to 2p2p\;^3P_1$ excitation energy by Malyshev et al. [2]. By considering second order QED effects and electron-electron correlation effects, which are particularly strong in berylliumlike ions, these authors obtained $E_\mathrm{exci}=244.942(52)$ eV. Within the uncertainties this agrees with our experimental finding [3], which thus constrains second order strong-field QED.
[1] C. Brandau et al., Chin. Phys. C 49, 064001 (2025),
https://doi.org/10.1088/1674-1137/adbf81
[2] A. Malyshev et al., Phys. Rev. A 110, 062824 (2024),
https://doi.org/10.1103/PhysRevA.110.062824
[3] All authors of this abstract, Phys. Rev. Lett. (submitted),
https://arxiv.org/abs/2502.15433
