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

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.

[1]  S. Mohanty,et al.  Graph , 2021, The Art of Algorithm Design.

[2]  Lucy Rosenbloom arXiv , 2019, The Charleston Advisor.

[3]  D. Furse Techniques for direct neutrino mass measurement utilizing tritium $\beta$-decay , 2016 .

[4]  B. Pferdehirt Mainz , 2013 .

[5]  John K Kruschke,et al.  Bayesian data analysis. , 2010, Wiley interdisciplinary reviews. Cognitive science.

[6]  M. G. L. Nolinger,et al.  Erratum , 1997 .

[7]  David C. Joy,et al.  Monte Carlo Modeling for Electron Microscopy and Microanalysis , 1995 .

[8]  S. T. Perkins,et al.  Tables and graphs of electron-interaction cross sections from 10 eV to 100 GeV derived from the LLNL Evaluated Electron Data Library (EEDL), Z = 1--100 , 1991 .

[9]  W. Hager,et al.  and s , 2019, Shallow Water Hydraulics.

[10]  I. Miyazaki,et al.  AND T , 2022 .