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arXiv · 2203.13862

The pion-nucleon sigma term from Lattice QCD

Rajan Gupta·Tanmoy Bhattacharya·Martin Hoferichter·Emanuele Mereghetti·Sungwoo Park·Boram Yoon
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Abstract

We summarize recent evidence, both from lattice QCD and chiral perturbation theory, that suggests that larger-than-expected excited-state contamination could be the reason for the tension between phenomenological determinations and previous direct lattice-QCD calculations of the pion--nucleon sigma term $\sigma_{\pi N}$. In addition, we extend the $\chi$PT analysis by calculating the corrections due to including the $\Delta(1232)$ resonance as an explicit degree of freedom. This correction is found to be small, thereby corroborating the excited-state effects found in the $\Delta$-less calculation and the result for $\sigma_{\pi N}$.

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Rajan Gupta, Tanmoy Bhattacharya, Martin Hoferichter, Emanuele Mereghetti, Sungwoo Park, Boram Yoon. 2022-03-25. The pion-nucleon sigma term from Lattice QCD. https://arxiv.org/abs/2203.13862

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