Lattice QCD calculations with chiral fermions of the πN sigma term σπN and strangeness sigma term σπN including chiral interpolation with continuum and volume corrections are provided in this work, with the excited-state contaminations subtracted properly. We calculate the scalar matrix element for the light/strange quark directly and find σπN = 45.9(7.4)(2.8) MeV, with the disconnected insertion part contributing 20(12)(4)%, and σπN = 40.2(11.7)(3.5) MeV, which is somewhat smaller than σπN. The ratio of the strange/light scalar matrix elements is y = 0.09(3)(1).
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This work is supported in part by U.S. DOE Grant No. DE-SC0013065. A. A. is supported in part by National Science Foundation CAREER Grant No. PHY-1151648 and by U.S. DOE Grant No. DE-FG02-95ER40907. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.
Yang, Yi-Bo; Alexandru, Andrei; Draper, Terrence; Liang, Jian; and Liu, Keh-Fei, "πN and Strangeness Sigma Terms at the Physical Point with Chiral Fermions" (2016). Physics and Astronomy Faculty Publications. 444.