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arXiv · 1605.01620

Tritium $β$-decay in chiral effective field theory

A. Baroni·L. Girlanda·A. Kievsky·L. E. Marcucci·R. Schiavilla·M. Viviani
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Abstract

We evaluate the Fermi and Gamow-Teller (GT) matrix elements in tritium $β$-decay by including in the charge-changing weak current the corrections up to one loop recently derived in nuclear chiral effective field theory ($χ$ EFT). The trinucleon wave functions are obtained from hyperspherical-harmonics solutions of the Schrodinger equation with two- and three-nucleon potentials corresponding to either $χ$ EFT (the N3LO/N2LO combination) or meson-exchange phenomenology (the AV18/UIX combination). We find that contributions due to loop corrections in the axial current are, in relative terms, as large as (and in some cases, dominate) those from one-pion exchange, which nominally occur at lower order in the power counting. We also provide values for the low-energy constants multiplying the contact axial current and three-nucleon potential, required to reproduce the experimental GT matrix element and trinucleon binding energies in the N3LO/N2LO and AV18/UIX calculations.

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A. Baroni, L. Girlanda, A. Kievsky, L. E. Marcucci, R. Schiavilla, M. Viviani. 2017-01-04. Tritium $β$-decay in chiral effective field theory. https://doi.org/10.1103/physrevc.94.024003

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