Secular equilibrium assessment in a CaWO4 target crystal from the dark matter experiment CRESST using Bayesian likelihood normalisation

G Angloher; S Banik; G Benato; A Bento; A Bertolini; R Breier; C Bucci; J Burkhart; L Canonica; A D'Addabbo; S Di Lorenzo; L Einfalt; A Erb; F V Feilitzsch; N Ferreiro Iachellini; S Fichtinger; D Fuchs; A Fuss; A Garai; V M Ghete; P Gorla; S Gupta; D Hauff; M Ješkovský; J Jochum; M Kaznacheeva; A Kinast; H Kluck; H Kraus; A Langenkämper; M Mancuso; L Marini; V Mokina; A Nilima; M Olmi; T Ortmann; C Pagliarone; L Pattavina; F Petricca; W Potzel; P Povinec; F Pröbst; F Pucci; F Reindl; J Rothe; K Schäffner; J Schieck; D Schmiedmayer; S Schönert; C Schwertner; M Stahlberg; L Stodolsky; C Strandhagen; R Strauss; I Usherov; F Wagner; M Willers; V Zema; CRESST Collaboration; F Ferella; M Laubenstein; S Nisi

doi:10.1016/j.apradiso.2023.110670

Secular equilibrium assessment in a CaWO₄ target crystal from the dark matter experiment CRESST using Bayesian likelihood normalisation

Appl Radiat Isot. 2023 Apr:194:110670. doi: 10.1016/j.apradiso.2023.110670. Epub 2023 Jan 21.

Authors

G Angloher¹, S Banik², G Benato³, A Bento⁴, A Bertolini¹, R Breier⁵, C Bucci³, J Burkhart⁶, L Canonica¹, A D'Addabbo³, S Di Lorenzo³, L Einfalt², A Erb⁷, F V Feilitzsch⁸, N Ferreiro Iachellini⁹, S Fichtinger¹⁰, D Fuchs¹, A Fuss², A Garai¹, V M Ghete¹⁰, P Gorla³, S Gupta¹⁰, D Hauff¹, M Ješkovský⁵, J Jochum¹¹, M Kaznacheeva⁸, A Kinast⁸, H Kluck¹⁰, H Kraus¹², A Langenkämper⁸, M Mancuso¹, L Marini¹³, V Mokina¹⁰, A Nilima¹, M Olmi³, T Ortmann⁸, C Pagliarone¹⁴, L Pattavina¹⁵, F Petricca¹, W Potzel⁸, P Povinec⁵, F Pröbst¹, F Pucci¹, F Reindl², J Rothe⁸, K Schäffner¹, J Schieck², D Schmiedmayer², S Schönert⁸, C Schwertner², M Stahlberg¹, L Stodolsky¹, C Strandhagen¹¹, R Strauss⁸, I Usherov¹¹, F Wagner¹⁰, M Willers⁸, V Zema¹; CRESST Collaboration; F Ferella¹⁶, M Laubenstein³, S Nisi³

Affiliations

¹ Max-Planck-Institut für Physik, D-80805, München, Germany.
² Institut für Hochenergiephysik der Österreichischen Akademie der Wissenschaften, A-1050, Wien, Austria; Atominstitut, Technische Universität Wien, A-1020, Wien, Austria.
³ INFN, Laboratori Nazionali del Gran Sasso, I-67100, Assergi, Italy.
⁴ Max-Planck-Institut für Physik, D-80805, München, Germany; LIBPhys-UC, Departamento de Fisica, Universidade de Coimbra, P3004 516, Coimbra, Portugal.
⁵ Comenius University, Faculty of Mathematics, Physics and Informatics, 84248, Bratislava, Slovakia.
⁶ Institut für Hochenergiephysik der Österreichischen Akademie der Wissenschaften, A-1050, Wien, Austria; Atominstitut, Technische Universität Wien, A-1020, Wien, Austria. Electronic address: [email protected].
⁷ Physik-Department and ORIGINS Excellence Cluster, Technische Universität München, D-85747, Garching, Germany; Walther-Meißner-Institut für Tieftemperaturforschung, D-85748, Garching, Germany.
⁸ Physik-Department and ORIGINS Excellence Cluster, Technische Universität München, D-85747, Garching, Germany.
⁹ Max-Planck-Institut für Physik, D-80805, München, Germany; Excellence Cluster Origins, D-85748, Garching, Germany.
¹⁰ Institut für Hochenergiephysik der Österreichischen Akademie der Wissenschaften, A-1050, Wien, Austria.
¹¹ Eberhard-Karls-Universität Tübingen, D-72076, Tübingen, Germany.
¹² Department of Physics, University of Oxford, OX1 3RH, Oxford, United Kingdom.
¹³ INFN, Laboratori Nazionali del Gran Sasso, I-67100, Assergi, Italy; GSSI-Gran Sasso Science Institute, I-67100, L'Aquila, Italy.
¹⁴ INFN, Laboratori Nazionali del Gran Sasso, I-67100, Assergi, Italy; Dipartimento di Ingegneria Civile e Meccanica, Universitä degli Studi di Cassino e del Lazio Meridionale, I-03043, Cassino, Italy.
¹⁵ INFN, Laboratori Nazionali del Gran Sasso, I-67100, Assergi, Italy; Physik-Department and ORIGINS Excellence Cluster, Technische Universität München, D-85747, Garching, Germany.
¹⁶ INFN, Laboratori Nazionali del Gran Sasso, I-67100, Assergi, Italy; Department of Physical and Chemical Sciences, University of l'Aquila, via Vetoio (COPPITO 1-2), I-67100, L'Aquila, Italy.

PMID: 36696751
DOI: 10.1016/j.apradiso.2023.110670

Abstract

CRESST is a leading direct detection sub-GeVc^-2 dark matter experiment. During its second phase, cryogenic bolometers were used to detect nuclear recoils off the CaWO₄ target crystal nuclei. The previously established electromagnetic background model relies on Secular Equilibrium (SE) assumptions. In this work, a validation of SE is attempted by comparing two likelihood-based normalisation results using a recently developed spectral template normalisation method based on Bayesian likelihood. Albeit we find deviations from SE in some cases we conclude that these deviations are artefacts of the fit and that the assumptions of SE is physically meaningful.

Keywords: Background model; Dark matter; Secular equilibrium.