Year: 2026
Type: preprint
Abstract: We investigate excited-state effects in nucleon sigma-terms in lattice QCD using twisted-mass clover-improved fermion ensembles. We study correlation functions with nucleon and multihadron nucleon-$σ$-meson interpolating operators. The analysis is performed using three gauge ensembles, including one ensemble simulated with two degenerate light, a strange, and a charm quark with quark masses tuned to approximately their physical value. We solve the generalized eigenvalue problem that arises from the matrix of correlators and show that the three-point function for the light sigma-term obtained using the optimal linear combination of interpolating operators has substantially reduced time dependence without loss of statistical precision. We apply Laplace filtering and investigate residual excited-state contributions in the extraction of $σ_{πN}$. Using the same optimal linear combination of correlators as for $σ_{πN}$ for the strange sigma-term we also observe suppressed excited state contributions over an extended range of source--sink time separations. For the charm sigma-term, we observe negligible time dependence within the large statistical uncertainties, and these improvements show no significant effect.
Source: arXiv (Cornell University)
Institutions: Cyprus Institute, University of Cyprus
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2162506210, G4385058657, G4479405937, Three-dimensional imaging of the nucleon using lattice QCD, Muon HVP and smeared R-ratio from Lattice QCD, G7225816264, G7477642899, Unraveling the 3D parton structure of the nucleon with lattice QCD, Precision nucleon structure from large-scale analyses and simulations in lattice QCD
OpenAlex ID: W7221984157