We search for the Standard Model Higgs boson associated with vector boson using all lepton decay mode. Signal processes are WH → lν+ττ and ZH → ll+ττ. We select 3 or 4 leptons including hadronic τ to pick candidate events out. To improve search sensitivity, we adopt Support Vector Machine (SVM) to discriminate signals from backgrounds.
Using 6.2 fb-1 data, there was not a clear discrepancy between data and our background estimation. Therefore, we extract cross section limits on the Standard Model Higgss production at 95% confidence level. The observed upper limit on assumption of MH = 115GeV/c2 is 18.5 × σSM at 95% confidence level while the expectation is 17.3, which is within one standard deviation.
We can search the Standard Model (SM) Higgs boson in several capable production channels and decay modes. Our target MH region is [100,150] GeV/c2 which we call low-mass search region because MH = 89+35-26 GeV/c2 (68% confidence level) as of July 2010, as which top quark mass and W boson mass constrain, indirectly. In the low-mass search region the standard model Higgs boson dominantly decays into b quark pair, but it can also decay into a Tau pair (~7% for MH = 120 GeV/c2).
Here, we show the results of a search for the standard model Higgs boson associated with vector boson using all leptonic decay modes. The final states considered are lν+ττ and ll+ττ.