Trinucleon longitudinal response functions $R_L(q,\omega )$ are calculated for $q$ values up to $500\text{MeV}∕c$. These are the first calculations beyond the threshold region in which both three-nucleon $\left(3N\right)$ and Coulomb forces are fully included. We employ two realistic $NN$ potentials (configuration space BonnA, $\text{AV}18$) and two $3N$ potentials (UrbanaIX, Tucson-Melborne). Complete final state interactions are taken into account via the Lorentz integral transform technique. We study relativistic corrections arising from first-order corrections to the nuclear charge operator. In addition the reference frame dependence due to our nonrelativistic framework is investigated. For $q⩽350\text{MeV}∕c$ we find that $3N$ forces give effects of between $5\%$ and $10\%$ in the peak region and of $15\%$ in the threshold region at the lowest considered momentum transfer $\left(q=174\text{MeV}∕c\right)$, while the dependence on other theoretical ingredients is small. At $q⩾400\text{MeV}∕c$ relativistic corrections to the charge operator and effects of frame dependence, especially for large $\omega$, become more important. In comparison with experimental data there is generally a rather good agreement. Exceptions are the responses at excitation energies close to threshold, where there exists a large discrepancy with experiment at higher $q$. In the ${}^3\mathrm{He}$ case one finds a much improved agreement with experiment both in the peak region and in the low-$q$–low-$\omega$ region if $3N$ forces are included. However in comparison with the existing data for ${}^3\mathrm{H}$ the inclusion of $3N$ forces appears to have the opposite effect in the peak region.

• Received 27 November 2003

DOI:https://doi.org/10.1103/PhysRevC.69.044001