A measurement of the production cross section of a Higgs boson with transverse momentum greater than 250 GeV
is presented where the Higgs boson decays to a pair of τ leptons. It is based on proton-proton collision data
collected by the CMS experiment at the CERN LHC at a center-of-mass energy of 13 TeV. The data sample
corresponds to an integrated luminosity of 138 fb−1. Because of the large transverse momentum of the Higgs
boson the τ leptons from its decays are boosted and produced spatially close, with their decay products
overlapping. Therefore, a dedicated algorithm was developed to reconstruct and identify them. The observed
(expected) significance of the measured signal with respect to the standard model background-only hypothesis
is 3.5 (2.2) standard deviations. The product of the production cross section and branching fraction is measured
to be 1.64+0.68
−0.54 times the standard model expectation. The fiducial differential production cross section is also
measured as functions of the Higgs boson and leading jet transverse momenta. This measurement extends the
probed large-transverse-momentum region in the ττ final state beyond 600 GeV.