Searches for additional Higgs bosons and for vector leptoquarks in ττ final states in proton-proton collisions at $\sqrt{s}$ = 13 TeV

Three searches are presented for signatures of physics beyond the standard model (SM) in ττ final states in proton-proton collisions at the LHC, using a data sample collected with the CMS detector at $\sqrt{s}=13TeV$, corresponding to an integrated luminosity of 138 fb${}^{-1}$. Upper limits at 95% confidence level (CL) are set on the products of the branching fraction for the decay into $\tau$ leptons and the cross sections for the production of a new boson $\varphi$, in addition to the H(125) boson, via gluon fusion $(gg\varphi )$ or in association with b quarks, ranging from $O(10pb)$ for a mass of $60GeV$ to 0.3 fb for a mass of $3.5TeV$ each. The data reveal two excesses for $gg\varphi$ production with local $p$-values equivalent to about three standard deviations at $m\varphi =0.1$ and $1.2TeV$. In a search for $t$-channel exchange of a vector leptoquark $U_1$, 95% CL upper limits are set on the dimensionless $U_1$ leptoquark coupling to quarks and $\tau$ leptons ranging from 1 for a mass of $1TeV$ to 6 for a mass of $5TeV$, depending on the scenario. In the interpretations of the $M_h^{125}$ and $M_{h,EFT}^{125}$ minimal supersymmetric SM benchmark scenarios, additional Higgs bosons with masses below $350GeV$ are excluded at 95% CL.