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  • Open Access

Perturbative χEFT calculations of the deuteron and triton up to N2LO

Oliver Thim*, Andreas Ekström, and Christian Forssén

  • *Contact author: oliver.thim@chalmers.se
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Phys. Rev. C 112, 064008 – Published 22 December, 2025

DOI: https://doi.org/10.1103/tjld-x141

Abstract

We extend previous studies of the deuteron and triton ground-state energies to next-to-next-to-leading order (N2LO) in chiral effective field theory, employing a power counting in which subleading interactions are treated perturbatively. Triton calculations are performed using the no-core shell model, and we demonstrate converged perturbative results for regulator cutoffs up to Λ≈1200 MeV. We analyze exceptional cutoffs in the 3P0 and 3S1–3D1 nucleon-nucleon channels and find a resulting cutoff dependence in the triton ground-state energy at N2LO. The effect associated with the exceptional cutoff in the 3P0 channel can be mitigated by redefining the leading-order wave function within the freedom allowed by the effective field theory. The same approach applied in the 3S1–3D1 channel remedies the effect of this exceptional cutoff on the ground state energy of the deuteron, but not for the triton.

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Information

Phys. Rev. C 112, 064008– Published 22 December, 2025
  • Received 15 October 2025
  • Accepted 1 December 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by Bibsam.

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