Beta decay of molecular tritium

Abstract

The beta decay of tritium in the form of molecular TT is the basis of sensitive experiments to measure neutrino mass. The final-state electronic, vibrational, and rotational excitations modify the beta spectrum significantly, and are obtained from theory. We report measurements of the branching ratios to specific ionization states for the isotopolog HT. Two earlier, concordant measurements gave branching ratios of HT to the bound HHe${}^{+}$ ion of 89.5% and 93.2%, in sharp disagreement with the theoretical prediction of 55-57%, raising concerns about the theory's reliability in neutrino mass experiments. Our result, 56.5(6)%, is compatible with the theoretical expectation and disagrees strongly with the previous measurements.

arXiv comment6 pages, 4 figures (Updated with minor typographical fixes)

References in corpus (8)

• Evidence for oscillation of atmospheric neutrinos
• Measurement of the rate of nu_e + d --> p + p + e^- interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory
• An improved upper limit on the neutrino mass from a direct kinematic method by KATRIN
• Current Direct Neutrino Mass Experiments
• Single electron detection and spectroscopy via relativistic cyclotron radiation
• Updated Bounds on Sum of Neutrino Masses in Various Cosmological Scenarios
• Focal-plane detector system for the KATRIN experiment
• Assessment of molecular effects on neutrino mass measurements from tritium beta decay

Cited by in corpus (6)

• Direct Measurements of Neutrino Mass
• Analysis methods for the first KATRIN neutrino-mass measurement
• KATRIN: Status and Prospects for the Neutrino Mass and Beyond
• Cyclotron Radiation Emission Spectroscopy of Electrons from Tritium Beta Decay and ${}^{83\mathrm{m}}$Kr Internal Conversion
• Demonstration of tritium adsorption on graphene
• The $\beta$-decay spectrum of Tritiated graphene: combining nuclear quantum mechanics with Density Functional Theory