2023/10/19 by S. Schneidewind, J. Schürmann, Schneidewind, S. +7 · 1 citation
Chemistry · Physics and Astronomy · #Data Analysis #FOS: Physical sciences #Molecular Spectroscopy and Structure #Neutrino Physics Research #Radioactive Decay and Measurement Techniques #Statistics and Probability (physics.data-an)
paper · pdf · doi:10.48550/arxiv.2310.12634
openalex publication_date 2023/10/19 · openalex created_date 2023/10/21 · openalex updated_date 2026/07/28
The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective mass of the electron antineutrino via a high-precision measurement of the tritium beta-decay spectrum in its end-point region. The target neutrino-mass sensitivity of 0.2 eV / c2 at 90% C.L. can only be achieved in the case of high statistics and a good control of the systematic uncertainties. One key systematic effect originates from the calculation of the molecular final states of T2 beta decay. In the first neutrino-mass analyses of KATRIN the contribution of the uncertainty of the molecular final-states distribution (FSD) was estimated via a conservative phenomenological approach to be 0.02 eV2 / c4. In this paper a new procedure is presented for estimating the FSD-related uncertainties by considering the details of the final-states calculation, i.e. the uncertainties of constants, parameters, and functions used in the calculation as well as its convergence itself as a function of the basis-set size used in expanding the molecular wave functions. The calculated uncertainties are directly propagated into the experimental observable, the squared neutrino mass mnu2. With the new procedure the FSD-related uncertainty is constrained to 0.0013 eV2 / c4, for the experimental conditions of the first KATRIN measurement campaign.