Search for Neutral Higgs Bosons at High $\tan \beta$ in the $b(h/H/A)\to b{\tau }^{+}{\tau }^{-}$ Channel

The first search in $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ for the production of neutral Higgs bosons in association with bottom quarks and decaying in two tau leptons is presented. The cross section for this process is enhanced in many extensions of the standard model, such as its minimal supersymmetric extension (MSSM) at large $\tan \beta$. The data, corresponding to an integrated luminosity of $328{\mathrm{pb}}^{-1}$, were collected with the D0 detector at the Fermilab Tevatron Collider. An upper limit is set on the production cross section of neutral Higgs bosons in the mass range of 90 to 150 GeV, and this limit is used to exclude part of the MSSM parameter space.

Figure 1

Visible mass distributions for each tau type. Histograms show the signal and various backgrounds; points show the data. The error bands indicate the total uncertainty on the background estimation.

Figure 2

(a) The 95% C.L. expected and observed limits on the cross section times branching ratio for $p\overline{p}\to b\varphi \to b{\tau }^{+}{\tau }^{-}$ production as a function of the Higgs mass. Also shown is the $\pm 1$ standard deviation band on the expected limit. These cross section limits are used to derive exclusion regions in the ($m_A$, $\tan \beta$) plane for (b) the $m_h^{\max }$ and (c) the no-mixing scenarios of the MSSM, for both $\mu =+200\mathrm{GeV}$ and $\mu =-200\mathrm{GeV}$. Also shown is the region excluded by the LEP experiments.