Measurements of the Higgs production cross section in the $H \to \tau\tau$ decay channel with the ATLAS experiment

Measurements of the Higgs production cross section in the $H \to \tau\tau$ decay channel are presented. The analysis has been performed using 36.1 fb −1 of data collected by the ATLAS experiment at $\sqrt{s}$ = 13TeV proton-proton collisions at the Large Hadron Collider. The observed (expected) significance of the $H \to \tau\tau$ signal excess over the expected background amounts to 4.4 (4.1) standard deviations. This result, combined with the data taken at $\sqrt{s}$ = 7 and 8TeV, leads to an observed (expected) significance of 6.4 (5.4) standard deviations and constitutes the first ATLAS observation of $H \to \tau\tau$. All the reported measurements are in agreement with the Standard Model predictions.