  The 4He monopole form factor is studied by computing the transition matrix
element of the electromagnetic charge operator between the 4He ground-state and
the p+3H and n+3He scattering states. The nuclear wave functions are calculated
using the hyperspherical harmonic method, by starting from Hamiltonians
including two- and three-body forces derived in chiral effective field theory.
The electromagnetic charge operator retains, beyond the leading order (impulse
approximation) term, also higher order contributions, as relativistic
corrections and meson-exchange currents. The results for the monopole form
factor are in fairly agreement with recent MAMI data. Comparison with other
theoretical calculations are also provided.
