Ricerc@Sapienza

In this paper, a new technique for reconstructing and identifying hadronically decaying tau (+)tau (-) pairs with a large Lorentz boost, referred to as the di-tau tagger, is developed and used for the first time in the ATLAS experiment at the Large Hadron Collider. A benchmark di-tau tagging selection is employed in the search for resonant Higgs boson pair production, where one Higgs boson decays into a boosted bb pair and the other into a boosted tau (+)tau (-) pair, with two hadronically decaying tau -leptons in the final state.

A measurement of Z → τ+τ− production cross-section is presented using data, corresponding to an integrated luminosity of 2 fb−1, from pp collisions at s=8 TeV collected by the LHCb experiment. The τ+τ− candidates are reconstructed in final states with the first tau lepton decaying leptonically, and the second decaying either leptonically or to one or three charged hadrons. The production cross-section is measured for Z bosons with invariant mass between 60 and 120 GeV/c2, which decay to tau leptons with transverse momenta greater than 20 GeV/c and pseudorapidities between 2.0 and 4.5.