The Korean Physical Society 06130 22, Teheran-ro 7-gil, Gangnam-gu, Seoul, Republic of Korea 610 Representation : Tae Won NOH TEL: 02-556-4737 FAX: 02-554-1643 E-mail : webmaster@kps.or.kr Copyright(C) KPS, All rights reserved.
30 May 2022 to 4 June 2022
Virtual Seoul
Asia/Seoul timezone

Atomic structure calculations of the $^7$Be electron capture decay for BSM neutrino studies

Not scheduled
5m
Virtual Seoul

Virtual Seoul

Poster Sterile neutrinos Poster

Speaker

Jorge Machado (LIBPhys-UNL)

Description

The BeEST (Beryllium Electron capture in Superconducting Tunnel junctions) experiment searches for physics beyond the standard model (BSM) in the neutrino sector through momentum conservation in electron capture decay (EC) of $^7$Be [1]. For this purpose, $^7$Be$^+$ ions are directly implanted into high-resolution superconducting tunnel junction (STJ) quantum sensors [2], which allows the direct measurement of $^7$Li recoils after the $^7$Be decay. Despite the simple atomic structure of Li and Be, a precise model of the atomic relaxation following EC decay is essential to understand details of the spectrum and to distinguish BSM physics from known effects. In the first two phases of the experiment, some details on the spectra were found to disagree with simple models of the atomic structure. We have therefore started an effort to precisely model the atomic relaxation process, specifically the energy and the intensities of all possible transitions and of the shake-up and shake-off process after EC. To accomplish this, two complementary approaches have been applied, one using the Multiconfiguration Dirac-Fock and General Matrix Element (MCDFGME) [3] Code and another using the Flexible Atomic Code (FAC) [4]. Here we present the steps towards the calculation of a full theoretical recoil spectrum that includes all details of the atomic relaxation process.

[1] S. Friedrich, G. B. Kim, C. Bray, R. Cantor, J. Dilling, S. Fretwell, J. A. Hall, A. Lennarz, V. Lordi, P. Machule, D. McKeen, X. Mougeot, F. Ponce, C. Ruiz, A. Samanta, W. K. Warburton, and K. G. Leach, Phys. Rev. Lett. 126, 021803 (2021)
[2] S. Fretwell, K. G. Leach, C. Bray, G. B. Kim, J. Dilling, A. Lennarz, X. Mougeot, F. Ponce, C. Ruiz, J. Stackhouse, and S. Friedrich, Phys. Rev. Lett. 125, 032701 (2020).
[3] P. Indelicato and J. P. Desclaux, Phys. Rev. A 42, 5139 (1990).
[4] M. F. Gu, Canadian Journal of Physics 86, 675 (2008).

Collaboration BeEST

Primary authors

Jorge Machado (LIBPhys-UNL) Dr Pedro Amaro (LIBPhys-unl) Mauro Guerra (LIBPhys-UNL) Prof. Kyle Leach (Colorado School of Mines) Dr Stephan Friedrich (Lawrence Livermore National Laboratory) Dr Xavier Mougeot (CEA Saclay) José Paulo Santos (LIBPhys-UNL)

Presentation Materials