Search for heavy Higgs bosons decaying into two tau leptons with the ATLAS detector using $pp$ collisions at $\sqrt{s}=13$ TeV
Phys.Rev.Lett. 125 (2020) 051801, 2020.
The collaboration

Abstract (data abstract)
CERN-LHC. A search for additional heavy neutral Higgs bosons is performed using a data sample corresponding to an integrated luminosity of 139 fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded by the ATLAS detector at the LHC. The 1l1tau_h channel fiducial region is defined as: - 1e+>=1tau_h or 1mu+>=1tau_h - ptLepton > 30 GeV - |etaMuon| < 2.4, |etaEle| < 2.47 (excluding 1.37 < |etaEle| < 1.52) - ptTauVis > 25 GeV - |etaTauVis| < 2.3 (excluding 1.37 < |etaTauVis| < 1.52) - No events with more than 1 electron (ptEle > 15 GeV) or muon (ptMuon > 7 GeV, |etaMuon|<2.5) - If multiple tau_h exist, the leading visible pt one is chosen - l and tau_h opposite electric charge - |DeltaPhi(l,tau_h)| > 2.4 rad - mT(l,MET) < 40 GeV - veto 80 < m(l,tau_h) < 110 in 1e1tau_h channel The 2tau_h channel fiducial region is defined as: - >=2tau_h - ptTauVis > 65 GeV (at least one with ptTauVis > 130 GeV, note that technically, this upper threshold was 85 GeV for ~10% of the data) - No events with an electron or muon, ptLepton > 7 (15) GeV for muons (electrons), |etaMuon| < 2.5, |etaEle| < 2.47 (excluding 1.37 < |etaEle| < 1.52) - If more than two tau_h exist, the two leading visible pt ones are chosen - The two tau_h have opposite electric charge - |DeltaPhi(tau1_h,tau2_h)| > 2.7 rad For Higgs interpretations events entering the fiducial region of each channel are categorised as: - "b-tag: if they contain a b-quark initiated jet (ptJet > 20 GeV, |etaJet|<2.5)" - "b-veto: otherwise"

Version 4 modifications: New interpretation plots have been added, in which theoretical uncertainties are considered (Tables 51 to 80).