Agadjanov A, Djukanovic D, von Hippel G, Meyer H B, Ottnad K, Wittig H
PRISMA+ Cluster of Excellence and Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany.
Helmholtz Institute Mainz, Staudingerweg 18, D-55128 Mainz, Germany.
Phys Rev Lett. 2023 Dec 29;131(26):261902. doi: 10.1103/PhysRevLett.131.261902.
We present a lattice-QCD based analysis of the nucleon sigma terms using gauge ensembles with N_{f}=2+1 flavors of O(a)-improved Wilson fermions, with a complete error budget concerning excited-state contaminations, the chiral interpolation as well as finite-size and lattice spacing effects. We compute the sigma terms determined directly from the matrix elements of the scalar currents. The chiral interpolation is based on SU(3) baryon chiral perturbation theory using the extended on-mass shell renormalization scheme. For the pion nucleon sigma term, we obtain σ_{πN}=(43.7±3.6) MeV, where the error includes our estimate of the aforementioned systematics. The tension with extractions based on dispersion theory persists at the 2.4-σ level. For the strange sigma term, we obtain a nonzero value, σ_{s}=(28.6±9.3) MeV.
我们使用具有(N_f = 2 + 1)种味的(O(a))改进威尔逊费米子的规范系综，对核子西格玛项进行了基于格点量子色动力学（lattice-QCD）的分析，并给出了关于激发态污染、手征插值以及有限尺寸和格点间距效应的完整误差预算。我们计算了直接从标量流矩阵元确定的西格玛项。手征插值基于使用扩展的壳上重整化方案的(SU(3))重子手征微扰理论。对于π介子 - 核子西格玛项，我们得到(\sigma_{\pi N}=(43.7\pm3.6))MeV，其中误差包括我们对上述系统误差的估计。与基于色散理论的提取结果之间的差异在(2.4\sigma)水平上仍然存在。对于奇异西格玛项，我们得到一个非零值(\sigma_s=(28.6\pm9.3))MeV。
