Search for Technicolor Particles Produced in Association with a W Boson at CDF

We present a search for the technicolor particles ${\rho }_T$ and ${\pi }_T$ in the process $p\bar{p}\to {\rho }_T\to W{\pi }_T$ at a center of mass energy of $\sqrt{s}=1.96\mathrm{T}\mathrm{e}\mathrm{V}$. The search uses a data sample corresponding to approximately $1.9{\mathrm{f}\mathrm{b}}^{-1}$ of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is $W\to \mathrm{\ell }\nu$ and ${\pi }_T\to b\bar{b},b\bar{c}$ or $b\bar{u}$ 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 ${\rho }_T$-${\pi }_T$ mass plane. As a result, a large fraction of the region $m({\rho }_T)=180$ - $250\mathrm{G}\mathrm{e}\mathrm{V}\mathrm{/}{c}^2$ and $m(\pi_T) = 95$-$145 $\mathrm{G}\mathrm{e}\mathrm{V}$/c^2$ is excluded.