title: Direct Evaluation of the Quark Content of Nucleons from Lattice QCD at the Physical Point.
abstract: We evaluate the light, strange, and charm scalar content of the nucleon using one lattice QCD ensemble generated with two degenerate light quarks with mass fixed to their physical value. We use improved techniques to evaluate the disconnected quark loops to sufficient accuracy to determine the strange and charm nucleon σ terms in addition to the light quark content σ_{πN}. We find σ_{πN}=37.2(2.6)(4.7/2.9)  MeV, σ_{s}=41.1(8.2)(7.8/5.8)  MeV, and σ_{c}=79(21)(12/8)  MeV, where the first error is statistical and the second is the systematic error due to the determination of the lattice spacing, the assessment of finite volume, and residual excited state effects.
authors.affiliation: Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Kavafi Street, Nicosia 2121, Cyprus.
authors.forename: A
authors.initials: A
authors.lastname: Abdel-Rehim
authors.affiliation: Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Kavafi Street, Nicosia 2121, Cyprus.|Department of Physics, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus.
authors.forename: C
authors.initials: C
authors.lastname: Alexandrou
authors.affiliation: Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Kavafi Street, Nicosia 2121, Cyprus.
authors.forename: M
authors.initials: M
authors.lastname: Constantinou
authors.affiliation: Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Kavafi Street, Nicosia 2121, Cyprus.|Department of Physics, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus.
authors.forename: K
authors.initials: K
authors.lastname: Hadjiyiannakou
authors.affiliation: NIC, DESY, Platanenallee 6, D-15738 Zeuthen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Jansen
authors.affiliation: Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Kavafi Street, Nicosia 2121, Cyprus.
authors.forename: Ch
authors.initials: Ch
authors.lastname: Kallidonis
authors.affiliation: Computation-based Science and Technology Research Center, The Cyprus Institute, 20 Kavafi Street, Nicosia 2121, Cyprus.
authors.forename: G
authors.initials: G
authors.lastname: Koutsou
authors.affiliation: INFN Sezione di Milano-Bicocca, Edificio U2, Piazza della Scienza 3, 20126 Milano, Italy.
authors.forename: A Vaquero
authors.initials: AV
authors.lastname: Avilés-Casco