Intermediate-energy Coulomb excitation of 104Sn: Moderate E2 strength decrease approaching 100Sn

The reduced transition probability B(E2)up arrow of the first excited 2(+) state in the nucleus Sn-104 was measured via Coulomb excitation in inverse kinematics at intermediate energies. A value of 0.173(28) e(2)b(2) was extracted from the absolute cross section on a Pb target. Feeding contributions in Sn-104 from higher lying states were estimated by a reference measurement of the stable Sn-112. Corresponding only to a moderate decrease of excitation strength relative to the almost constant values observed in the proton-rich, even-A Sn106-114 isotopes, present state-of-the-art shell-model predictions, which include proton and neutron excitations across the N = Z = 50 shell closures as well as standard polarization charges, underestimate the experimental findings.