Search for Neutral Supersymmetric Higgs Bosons in Multijet Events at $\sqrt{s}=1.96\mathrm{TeV}$

We have performed a search for neutral Higgs bosons produced in association with bottom quarks in $p\overline{p}$ collisions, using $260{\mathrm{pb}}^{-1}$ of data collected with the D0 detector in Run II of the Fermilab Tevatron Collider. The cross sections for these processes are enhanced in many extensions of the standard model (SM), such as in its minimal supersymmetric extension at large $\tan \beta$. The results of our analysis agree with expectations from the SM, and we use our measurements to set upper limits on the production of neutral Higgs bosons in the mass range of 90 to 150 GeV.

Figure 1

Leading-order Feynman diagrams for neutral Higgs boson production in the five-flavor scheme (top) and four-flavor scheme (bottom).

Figure 2

Fit of the invariant mass spectrum of the two leading $p_T$ jets in the doubly $b$-tagged data to a sum of backgrounds: mistags derived from data (dotted line), $b\overline{b}j(j)$ (dashed line), and other backgrounds ($Z(\to b\overline{b})+\mathrm{\text{jets}}$, $Zb$, $t\overline{t}$, and $b\overline{b}b\overline{b}$) (dash-dotted line).

Figure 3

Invariant mass spectrum of two leading jets in events with at least three $b$-tagged jets, estimated background, and the signal for a 120 GeV Higgs boson that can be excluded at the 95% C.L.

Figure 4

The expected and measured 95% C.L. upper limits on the signal cross section as a function of $m_A$. The band indicates the $\pm 1$ s.d. range on the expected limit. Also shown is the cross section for the signal at $\tan \beta =80$ in the “no mixing” scenario of the MSSM, with the theoretical uncertainty indicated by the overlaid band.

Figure 5

The 95% C.L. upper limit on $\tan \beta$ as a function of $m_A$ for two scenarios of the MSSM, “no mixing” and “maximal mixing.” Also shown are the limits obtained by the LEP experiments for the same two scenarios of the MSSM [3].