Search for supersymmetric neutral Higgs bosons decaying to $\tau$ pairs in the $e+\tau$-jet final state with calibration using $Z\rightarrow\tau\tau$ events at CMS

A search for the neutral Higgs bosons, $\Phi$, of the Minimal Supersymmetric Standard Model (MSSM) decaying to $\tau$ pairs in proton-proton collisions at $\sqrt{s} =$ 7 TeV is performed. The $e+\tau$-jet final state is considered in data corresponding to 2.1 fb$^{-1}$ of integrated luminosity collected by the Compact Muon Solenoid detector. The search is performed separately in the inclusive channel, sensitive to both $gg\rightarrow\Phi$ and $gg\rightarrow{b}\bar{b}\Phi$ production, and the $b$-tagged channel which maximises sensitivity to $gg\rightarrow{b}\bar{b}\Phi$. No significant excess of events over the predicted Standard Model backgrounds is observed. Upper limits are set on the $\Phi\rightarrow\tau^{+}\tau^{-}$ production cross section, $\sigma(pp\rightarrow\Phi+X)\times\mathcal{B}(\Phi\rightarrow\tau^{+}\tau^{-})$. Cross sections greater than 18 and 1.3 pb are excluded at 95\% confidence level for $m_{A}$ = 100 and $m_{A}$ = 400 GeV respectively. The limits are interpreted as constraints on tan $\beta$ in the $m_{h}^{max}$ scenario of the MSSM: Values of tan $\beta$ greater than 12 and 40 are excluded at 95\% confidence level for $m_{A}$ = 100 and $m_{A}$ = 400 GeV respectively. The inclusive channel is found to have the greatest tan $\beta$ sensitivity at large $m_{A}$ and the $b$-tagged channel to have greatest sensitivity at small $m_{A}$. The $\tau$-jet reconstruction is calibrated using $Z\rightarrow\tau^{+}\tau^{-}$ events. A measurement of the $Z\rightarrow\tau^{+}\tau^{-}$ cross section in the $e+\tau$-jet final state using the same dataset as the Higgs search yields $\sigma(pp\rightarrow Z+X)\cdot\mathcal{B}(Z\rightarrow\tau^{+}\tau^{-})=1.06_{-0.04}^{+0.05}(\text{stat.})\pm0.07(\text{syst.})\pm0.05(\text{lumi.})\text{ nb}$. The result is in good agreement with the Standard Model prediction of 0.972 $\pm$ 0.042 nb at next-to-next-to-leading order. This measurement provides a cross check of the methods used in the $\Phi\rightarrow\tau^{+}\tau^{-}$ search.