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DOE OSTI · 3389877

Shakeup and shakeoff spectra in the electron capture decay of atomic 7 Be

Guerra, Mauro [Universidade NOVA de Lisboa (Portugal)] (ORCID:0000000162864048)·Kim, Inwook [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]·Friedrich, Stephan [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]·Amaro, Pedro [Universidade NOVA de Lisboa (Portugal)]·Andoche, Adrien [Univ. Paris-Saclay, Palaiseau (France)]·Baptista, Gonçalo [Sorbonne Univ., Paris (France)]·Bray, Connor [Colorado School of Mines, Golden, CO (United States)]·Cantor, Robin [STAR Cryoelectronics LLC, Santa Fe, NM (United States)]·Diercks, David [Colorado School of Mines, Golden, CO (United States)]·Fretwell, Spencer L. [Colorado School of Mines, Golden, CO (United States)]·Gillespie, Abigail [Colorado School of Mines, Golden, CO (United States)]·Hall, John. A. [STAR Cryoelectronics LLC, Santa Fe, NM (United States)]·Harris, Cameron N. [Patrick Space Force Base, FL (United States)]·Harris, Jackson T. [XIA LLC, Oakland, CA (United States)]·Hayen, Leendert M. [University of Caen (France)]·Hervieux, Paul Antoine [University of Strasbourg (France)]·Indelicato, Paul [Sorbonne Univ., Paris (France)]·Kim, Geon Bo [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]·Leach, Kyle G. [Colorado School of Mines, Golden, CO (United States); Queen's Univ., Kingston, ON (Canada)]·Lennarz, Annika [TRIUMF, Vancouver, BC (Canada)]·Lordi, Vincenzo [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]·Machule, Peter [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)]·Marino, Andrew [Colorado School of Mines, Golden, CO (United States)]·McKeen, David [TRIUMF, Vancouver, BC (Canada)]·Mougeot, Xavier [Univ. Paris-Saclay, Palaiseau (France)]·Pinheiro, Daniel [Universidade NOVA de Lisboa (Portugal)]·Ponce, Francisco [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)]·Ruiz, Chris [TRIUMF, Vancouver, BC (Canada)]·Samanta, Amit [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)]·Santos, José Paulo [Universidade NOVA de Lisboa (Portugal)]·Smolsky, Joseph [Colorado School of Mines, Golden, CO (United States)]·Stone-Whitehead, Caitlyn [Colorado School of Mines, Golden, CO (United States)]·Templet, Joseph [Colorado School of Mines, Golden, CO (United States)]·Van De Pontseele, Wouter [Colorado School of Mines, Golden, CO (United States)]·Warburton, William K. [XIA LLC, Oakland, CA (United States)]·Waters, Benjamin [Maybell Quantum, Denver, CO (United States)]·Machado, Jorge [Universidade NOVA de Lisboa (Portugal)]
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Abstract

The most stringent laboratory-based experimental limits on the existence of submegaelectronvolt sterile neutrinos are currently set by decay spectroscopy of radioactive 7 Be embedded into superconducting sensors. The systematic uncertainties are dominated by the modeling of the electron shakeup and shakeoff spectra that are not based on state-of-the-art atomic theory and do not include electron correlations or relativistic effects. We have used the multiconfiguration Dirac-Fock formalism to obtain correlated wave functions ab initio and compute all single and double shake processes in the electron capture decay of atomic 7 Be . The simulations can explain some but not all of the observed spectral features, likely because the wave functions are modified by the Ta sensor material that the 7 Be is embedded into. The new models also show that the 𝐿/𝐾 electron capture ratio of 7 Be in Ta has previously been slightly underestimated revising the previous value of 0.070(7) to a new value of 0.0756(20).

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Guerra, Mauro [Universidade NOVA de Lisboa (Portugal)] (ORCID:0000000162864048), Kim, Inwook [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Friedrich, Stephan [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Amaro, Pedro [Universidade NOVA de Lisboa (Portugal)], Andoche, Adrien [Univ. Paris-Saclay, Palaiseau (France)], Baptista, Gonçalo [Sorbonne Univ., Paris (France)], Bray, Connor [Colorado School of Mines, Golden, CO (United States)], Cantor, Robin [STAR Cryoelectronics LLC, Santa Fe, NM (United States)], Diercks, David [Colorado School of Mines, Golden, CO (United States)], Fretwell, Spencer L. [Colorado School of Mines, Golden, CO (United States)], Gillespie, Abigail [Colorado School of Mines, Golden, CO (United States)], Hall, John. A. [STAR Cryoelectronics LLC, Santa Fe, NM (United States)], Harris, Cameron N. [Patrick Space Force Base, FL (United States)], Harris, Jackson T. [XIA LLC, Oakland, CA (United States)], Hayen, Leendert M. [University of Caen (France)], Hervieux, Paul Antoine [University of Strasbourg (France)], Indelicato, Paul [Sorbonne Univ., Paris (France)], Kim, Geon Bo [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Leach, Kyle G. [Colorado School of Mines, Golden, CO (United States); Queen's Univ., Kingston, ON (Canada)], Lennarz, Annika [TRIUMF, Vancouver, BC (Canada)], Lordi, Vincenzo [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Machule, Peter [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)], Marino, Andrew [Colorado School of Mines, Golden, CO (United States)], McKeen, David [TRIUMF, Vancouver, BC (Canada)], Mougeot, Xavier [Univ. Paris-Saclay, Palaiseau (France)], Pinheiro, Daniel [Universidade NOVA de Lisboa (Portugal)], Ponce, Francisco [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)], Ruiz, Chris [TRIUMF, Vancouver, BC (Canada)], Samanta, Amit [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)], Santos, José Paulo [Universidade NOVA de Lisboa (Portugal)], Smolsky, Joseph [Colorado School of Mines, Golden, CO (United States)], Stone-Whitehead, Caitlyn [Colorado School of Mines, Golden, CO (United States)], Templet, Joseph [Colorado School of Mines, Golden, CO (United States)], Van De Pontseele, Wouter [Colorado School of Mines, Golden, CO (United States)], Warburton, William K. [XIA LLC, Oakland, CA (United States)], Waters, Benjamin [Maybell Quantum, Denver, CO (United States)], Machado, Jorge [Universidade NOVA de Lisboa (Portugal)]. 2026-07-17. Shakeup and shakeoff spectra in the electron capture decay of atomic 7 Be. https://doi.org/10.1103/knwn-47kl

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