Nucleon-sigma terms at m_π=222 MeV with a variational analysis from lattice QCD

Abstract

Nucleon sigma terms are important for the decomposition of the nucleon mass and for searches for new physics beyond the Standard Model involving scalar interactions. A persistent tension between lattice QCD and phenomenological determinations may be due to uncontrolled excited-state contamination in lattice QCD analyses. In previous work at m_π=429 MeV, we showed that this contamination is dominated by Nσ states and can be strongly suppressed with a variational analysis using N and Nσ operators. In this talk, we present preliminary results at m_π=222 MeV, where the σ becomes unstable and decays into ππ. We investigate whether the same small variational basis can remove the expected Nππ contamination through the overlap of the Nσ operator with these states.

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BibTeX RIS

BibTeX

@misc{barca2026nucleonsigma,
  title = {{Nucleon-sigma terms at $m_π=222 ~\rm MeV$ with a variational analysis from lattice QCD}},
  author = {Lorenzo Barca and Gunnar Bali and Sara Collins and Marcel Rodekamp},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.05989},
  eprint = {2609.05989},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.05989},
  note = {CC BY-NC-ND 4.0},
}

RIS

TY  - UNPB
TI  - Nucleon-sigma terms at m_π=222 MeV with a variational analysis from lattice QCD
AU  - Lorenzo Barca
AU  - Gunnar Bali
AU  - Sara Collins
AU  - Marcel Rodekamp
PY  - 2026
DA  - 2026/09/05
PB  - arXiv
DO  - 10.48550/arxiv.2609.05989
UR  - https://arxiv.org/abs/2609.05989
AB  - Nucleon sigma terms are important for the decomposition of the nucleon mass and for searches for new physics beyond the Standard Model involving scalar interactions. A persistent tension between lattice QCD and phenomenological determinations may be due to uncontrolled excited-state contamination in lattice QCD analyses. In previous work at m_π=429 MeV, we showed that this contamination is dominated by Nσ states and can be strongly suppressed with a variational analysis using N and Nσ operators. In this talk, we present preliminary results at m_π=222 MeV, where the σ becomes unstable and decays into ππ. We investigate whether the same small variational basis can remove the expected Nππ contamination through the overlap of the Nσ operator with these states.
ER  -

Abstract

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