Multipole strength distributions and form factors for E1, E2/E0, and E3 from ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$(e,e’f) coincidence experiments

A model-independent multipole analysis of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$(e,e’f) coincidence data, taken at four momentum transfers (0.2≤$q_{\mathrm{eff}\mathrm{\le }0.7}$ ${\mathrm{fm}}^{\mathrm{-}1}$; ω=4–22 MeV) yields both E1, E2/E0, and E3 form factors and strength distributions. The E2/E0 strength distribution in the fission channel shows two distinct bumps centered at ω≃10 and 14 MeV, exhausting up to 12 MeV (19±2)% of the isoscalar E2 sum rule. The extracted form factors can be described within a hydrodynamical model by use of parameters $c_{\mathrm{tr}/c_0=1.2\mathrm{}}$ and 1.0 for E1 and E2, respectively.