Anharmonicity of internal atomic oscillation and effective antineutrino mass evaluation from gaseous molecular tritium beta-decay

摘要

Data analysis of the next-generation effective antineutrino mass measurement experiment KATRIN requires reliable knowledge of systematic corrections. In particular, the width of the daughter molecular ion excitation spectrum rovi-brational band should be known with better than 1% precision. Very precise ab initio quantum calculations exist, and we compare them with the wellknown tritium molecule parameters within the framework of a phenomenological model. The rovibrational band width with accuracy of a few percent is interpreted as a result of the zero-point atomic oscillation in the harmonic potential. The Morse interatomic potential is used to investigate the impact of anharmonic atomic oscillations. The calculated corrections cannot account for the difference between the ab initio quantum calculations and the phenomenological model.