  To clarify the electroweak symmetry breaking mechanism, we need to probe the
Higgs self-couplings, which can be measured in Higgs pair productions. The
associated production with a vector boson is special due to a clear tag in the
final state. We perform a fully differential next-to-next-to-leading-order
calculation of the Higgs pair production in association with a $W$ boson at
hadron colliders, and present numerical results at the 14 TeV LHC and a future
100 TeV hadron collider.
