With the discovery of the Higgs boson at CERN, the Standard Model
has been turned into a complete theory, fully consistent with all available
data. However, the Brout-Englert-Higgs
mechanism opens a new window, well beyond particle physics, which has to
be precisely explored at present and future accelerators.
There are two ways to carry out this exploration: directly, by producing new
particles, which requires very large energies, and indirectly, by measuring
their effects at quantum level, which requires high precision.
Unfortunately, no accelerator is able
to cover both aspects. This talk is aimed at this comparison, rather
than at discussing strategies, politics and techniques, but nevertheless
these issues will not be ignored.