Tritium Beta Spectrum Measurement and Neutrino Mass Limit from Cyclotron Radiation Emission Spectroscopy.
/ Authors
A. Ashtari Esfahani, S. Böser, N. Buzinsky, M. Carmona-Benitez, C. Claessens, L. de Viveiros, P. Doe, M. Fertl, J. Formaggio, J. K. Gaison
and 48 more authors
L. Gladstone, M. Grando, M. Guigue, J. Hartse, K. Heeger, X. Huyan, J. Johnston, A. Jones, K. Kazkaz, B. LaRoque, M. Li, A. Lindman, E. Machado, A. Marsteller, C. Matthé, R. Mohiuddin, B. Monreal, R. Mueller, J. Nikkel, E. Novitski, N. Oblath, J. Peña, W. Pettus, R. Reimann, R. Robertson, D. Rosa De Jesús, G. Rybka, L. Saldaña, M. Schram, P. Slocum, J. Stachurska, Y.-H. Sun, P. T. Surukuchi, J. Tedeschi, A. Telles, F. Thomas, M. Thomas, L. Thorne, T. Thümmler, L. Tvrznikova, W. Van De Pontseele, B. Vandevender, J. Weintroub, T. Weiss, T. Wendler, A. Young, E. Zayas, A. Ziegler
/ Abstract
The absolute scale of the neutrino mass plays a critical role in physics at every scale, from the subatomic to the cosmological. Measurements of the tritium end-point spectrum have provided the most precise direct limit on the neutrino mass scale. In this Letter, we present advances by Project 8 to the cyclotron radiation emission spectroscopy (CRES) technique culminating in the first frequency-based neutrino mass limit. With only a cm^{3}-scale physical detection volume, a limit of m_{β}<155 eV/c^{2} (152 eV/c^{2}) is extracted from the background-free measurement of the continuous tritium beta spectrum in a Bayesian (frequentist) analysis. Using ^{83m}Kr calibration data, a resolution of 1.66±0.19 eV (FWHM) is measured, the detector response model is validated, and the efficiency is characterized over the multi-keV tritium analysis window. These measurements establish the potential of CRES for a high-sensitivity next-generation direct neutrino mass experiment featuring low background and high resolution.
Journal: Physical review letters