Search for Higgs-like particles produced in association with bottom quarks in proton-antiproton collisions

We report on a search for a spin-zero non–standard model particle in proton-antiproton collisions collected by the Collider Detector at Fermilab at a center-of-mass-energy of 1.96 TeV. This particle, the $\varphi$ boson, is expected to decay into a bottom-antibottom quark pair and to be produced in association with at least one bottom quark. The data sample consists of events with three jets identified as initiated by bottom quarks and corresponds to $5.4{\mathrm{fb}}^{-1}$ of integrated luminosity. In each event, the invariant mass of the two most energetic jets is studied by looking for deviations from the multijet background, which is modeled using data. No evidence is found for such a particle. Exclusion upper limits ranging from 20 to 2 pb are set for the product of production cross sections times branching fraction for the hypothetical $\varphi$ boson with mass between 100 and $300\mathrm{GeV}/c^2$. These are the most stringent constraints to date.

Figure 1

Triple-tagged events fit results projected into $m_{12}$ (top) and $x_{\mathrm{tags}}$ (bottom), under the background-only hypothesis. The $Cbb$ component is found to be negligible.

Figure 2

Result of the fit to the triple-tagged data projected into $m_{12}$ (top) and $x_{\mathrm{tags}}$ (bottom). A signal component with a mass of the $\varphi$ scalar of $160\mathrm{GeV}/c^2$ is added to the background templates.

Figure 3

Observed and expected 95% C.L. limits on $\sigma (p\overline{p}\to \varphi b)\mathcal{B}(\varphi \to b\overline{b})$ as functions of $m_{\varphi }$.