  The reduced transition probability B(E2) of the first excited 2+ state in the
nucleus 104Sn was measured via Coulomb excitation in inverse kinematics at
intermediate energies. A value of 0.163(26) e^2b^2 was extracted from the
absolute cross-section on a Pb target, while the method itself was verified
with the stable 112Sn isotope. Our result deviates significantly from the
earlier reported value of 0.10(4) e^2b^2 and corresponds to a moderate decrease
of excitation strength relative to the almost constant values observed in the
proton-rich, even-A 106-114Sn 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
