The pion-nucleon sigma term from Lattice QCD

2022/03/25 by Rajan Gupta, Tanmoy Bhattacharya, Gupta, Rajan +9
Physics and Astronomy · #Quantum Chromodynamics and Particle Interactions #Particle physics theoretical and experimental studies #Physics of Superconductivity and Magnetism

paper · pdf · doi:10.48550/arxiv.2203.13862

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 σ_πN. In addition, we extend the χPT analysis by calculating the corrections due to including the Δ(1232) resonance as an explicit degree of freedom. This correction is found to be small, thereby corroborating the excited-state effects found in the Δ-less calculation and the result for σ_πN.

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