We present results for the QCD spectrum and the matrix elements of scalar and axial-vector densities at $\beta =\frac{6}{g^2}=5.4, 5.5, 5.6$. The lattice update was done using the hybrid Monte Carlo algorithm to include two flavors of dynamical Wilson fermions. We have explored quark masses in the range $m_s\le m_q\le 3m_s$. The results for the spectrum are similar to quenched simulations and mass ratios are consistent with phenomenological heavy-quark models. The results for matrix elements of the scalar density show that the contribution of sea quarks is comparable to that of the valence quarks. This has important implications for the pion-nucleon $\sigma$ term.

• Received 20 June 1991

DOI:https://doi.org/10.1103/PhysRevD.44.3272