We present a search for the technicolor particles ${\rho }_T$ and ${\pi }_T$ in the process $p\overline{p}\to {\rho }_T\to W{\pi }_T$ at a center of mass energy of $\sqrt{s}=1.96\mathrm{TeV}$. The search uses a data sample corresponding to approximately $1.9{\mathrm{fb}}^{-1}$ of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is $W\to \ell \nu$ and ${\pi }_T\to b\overline{b}$, $b\overline{c}$ or $b\overline{u}$ depending on the ${\pi }_T$ charge. We select events with a single high-$p_T$ electron or muon, large missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with multiple $b$-tagging algorithms. The observed number of events and the invariant mass distributions are consistent with the standard model background expectations, and we exclude a region at 95% confidence level in the ${\rho }_T\mathrm{\text{−}}{\pi }_T$ mass plane. As a result, a large fraction of the region $m({\rho }_T)=180–250\mathrm{GeV}/c^2$ and $m({\pi }_T)=95–145\mathrm{GeV}/c^2$ is excluded.

• Received 11 December 2009

DOI:https://doi.org/10.1103/PhysRevLett.104.111802