Implications of the ATLAS and CMS searches in the channel $pp \to Higgs \to \tau^+\tau^$ for the MSSM and SM Higgs bosons

Abstract

We discuss the implications of the recent constraints on the Higgs sector of the Minimal Supersymmetric extension of the Standard Model obtained by the ATLAS and CMS collaborations at the lHC with $\sqrt s=7$ TeV and 36 pb$^{-1}$ of data. The main production and detection channel that is relevant in these analyses is the gluon--gluon and bottom quark fusion mechanisms leading to neutral Higgs bosons which subsequently decay into tau lepton pairs, $gg, b\bar b \to Higgs \to \tau^+\tau^-$. In this note, we show that: i) the exclusion limits are in fact more general than indicated by the ATLAS and CMS analyses and are essentially independent of the scenario for the supersymmetric particle spectrum; ii) when the exclusion limits are applied to the lowest theory prediction for the Higgs production cross section times branching ratio, when all theoretical uncertainties are taken into account, the bounds are somewhat less stringent; iii) the exclusion limits from the $pp \to Higgs \to \tau^+ \tau^-$ process are so strong that only a modest improvement would be possible when other MSSM Higgs detection channels are considered, even with femtobarn level accumulated data. Finally and most important, we point out that the prospects for the search for the Standard Model Higgs boson in the inclusive $gg \to H \to \tau^+\tau^-$ channel, that is not currently considered by the ATLAS and CMS collaborations, turn out to be very promising and with a few inverse femtobarn data it might provide a convincing discovery signal in the difficult 115--135 GeV mass range for the standard Higgs boson.