Cyclotron Radiation Emission Spectroscopy of Electrons from Tritium Beta Decay and $^{83\rm m}$Kr Internal Conversion

• DOI: 10.48550/arxiv.2303.12055
• Publication Date: 2023-01-01
• Authors: Project 8 Collabo...; Esfahani, A. Ashtari; Böser, S.; Buzinsky, N.; Carmona-Benitez, ...; Claessens, C.; de Viveiros, L.; Doe, P. J.; Fertl, M.; Formaggio, J. A.; Gaison, J. K.; Gladstone, L.; Guigue, M.; Hartse, J.; Heeger, K. M.; Huyan, X.; Jones, A. M.; Kazkaz, K.; LaRoque, B. H.; Li, M.; Lindman, A.; Machado, E.; Marsteller, A.; Matthé, C.; Mohiuddin, R.; Monreal, B.; Mueller, R.; Nikkel, J. A.; Novitski, E.; Oblath, N. S.; Peña, J. I.; Pettus, W.; Reimann, R.; Robertson, R. G. H.; De Jesús, D. Rosa; Rybka, G.; Saldaña, L.; Schram, M.; Slocum, P. L.; Stachurska, J.; Sun, Y. -H.; Surukuchi, P. T.; Tedeschi, J. R.; Telles, A. B.; Thomas, F.; Thomas, M.; Thorne, L. A.; Thümmler, T.; Tvrznikova, L.; Van De Pontseele, W.; VanDevender, B. A.; Weintroub, J.; Weiss, T. E.; Wendler, T.; Young, A.; Zayas, E.; Ziegler, A.
• Keywords: High Energy Physics - Experiment (hep-ex); FOS: Physical sciences; Nuclear Experiment (nucl-ex); Nuclear Experiment; 7. Clean energy; High Energy Physics - Experiment

Project 8 has developed a novel technique, Cyclotron Radiation Emission Spectroscopy (CRES), for direct neutrino mass measurements. A CRES-based experiment on the beta spectrum of tritium has been carried out in a small-volume apparatus. We provide a detailed account of the experiment, focusing on systematic effects and analysis techniques. In a Bayesian (frequentist) analysis, we measure the tritium endpoint as $18553^{+18}_{-19}$ ($18548^{+19}_{-19}$) eV and set upper limits of 155 (152) eV (90% C.L.) on the neutrino mass. No background events are observed beyond the endpoint in 82 days of running. We also demonstrate an energy resolution of $1.66\pm0.19$ eV in a resolution-optimized magnetic trap configuration by measuring $^{83\rm m}$Kr 17.8-keV internal-conversion electrons. These measurements establish CRES as a low-background, high-resolution technique with the potential to advance neutrino mass sensitivity.<br/>41 pages, 33 figures, submitted to PRC<br/>