Improved search for $ZH\rightarrow \ell^{+}\ell^{-}b\bar{b}$ using 9.7 fb$^{-1}$ of data collected by the D0 detector

We present an improved search for the standard model Higgs boson produced in association with a $Z$ boson, using 9.7 fb$^{-1}$ of $p\bar{p}$ collision data collected by D0 detector at $\sqrt{s} =1.96$ TeV. Events are selected with two electrons or two muons that are consistent with the decay of a $Z$ boson, and at least two reconstructed jets (including at least one $b$-tagged jet). Four dedicated random forests of decision trees (RFs) are trained in order to distinguish the signal with $t\bar{t}$, $Z$+Heavy Flavor jets, $Z$+Light Flavor jets and diboson background events respectively. The final discriminant is trained separately in five regions according to the output of the RFs. Upper limits on the $ZH$ production cross-section times branching ratio to two $b$-jets are set at 95$\%$ C.L. We also use the minimum walking technicolor model ($\rho_{TC} \rightarrow Z\pi_{TC} \rightarrow \ell^+\ell^-b\bar{b}$) to interpret the results we obtained.