# The 27th International Conference on Atomic Physics

17-22 July 2022
Royal Conservatory of Music, Toronto
America/Toronto timezone

## Surprising Results Found in Testing for the Continuous Spectrum of X-rays Predicted to Accompany the Photoejection of an Atomic Inner-shell Electron

Not scheduled
1h 30m
Abstract of recent or ongoing work (by remote / virtual participant) Precision measurement and tests of fundamental physics

### Description

R. Pratt et al. have called attention to the unsettled observational status for the radiation (intraatomic bremsstrahlung, IAB) expected upon the photoejection of inner shell electrons. We tested for such radiation in the 3 to 7 keV band produced by photoelectrons from the K shell of a copper target upon absorption of an incident 46 keV photon. Exploiting a prediction for the major background process: ordinary bremsstrahlung due to the encounter of the photoelectron with atoms other than that of its point of origin, we conclude that for our thinnest (40 nm) targets within statistical limits we observe no IAB radiation. In this manner, contemporary theory is ruled out by over 5 sigmas. Assuming no particular secondary process the intensity of observed IAB radiation is 4 sigmas below expectations. We conclude that in contrast to the sister nuclear process of internal bremsstrahlung observed upon beta decay, our understanding of intraatomic bremsstrahlung remains lacking. This work is based upon research conducted at CHESS (Cornell University High Energy Synchrotron Source) which was supported by the National Science Foundation under Award No. DMR-1332208. This work made use of the Cornell Center for Materials Research Shared Facilities which are supported through the NSF MRSEC program under Award No. DMR-1719875. Published version of this poster: Testing for the Continuous Spectrum of X-Rays Predicted to Accompany the Photoejection of an Atomic Inner Shell Electron, Philip Jacobson, Andrija Rasovic, Arthur Campello, Chase Goddard, Matthew Dykes, Yuchao Chen, J.Y. Peter Ko, Stanislav Stoupin, Gwen Gardner, Justin Oh, and Carl Franck, Phys. Rev. A 104, 042809 (2021)

Presenter name Carl Franck

### Primary authors

Carl Franck (Cornell University) Philip Jacobson (Cornell University) Arthur Campello (Cornell University)

### Presentation Materials

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