Improvements on the Higgs searches in the high mass region at CDF

Transcription

1 Improvements on the Higgs searches in the high mass region at CDF M. Bauce on behalf of the CDF collaboration INFN Padova Higgs Hunting workshop, Orsay, 9-3 July 0 M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 /

2 Higgs production and decay Four main production mechanism at Tevatron: σ m H =65 GeV SM 0.6 pb gg H (78 %) qq WH (9 %) qq ZH (6 %) qq qq H (7 %) All of them become important with increasing sensitivity. High mass region defined for M H 35 GeV/c H WW is the dominant decay channel H ZZ is also relevant for M H ranges where WW is not the most sensitive ([40-50] & [>80] GeV/c ) This analysis considers H WW decay channel W decays: W lν, l=e,µ,τ W hadrons have large background, not yet included in the analysis M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 /

3 H WW* Analysis Multi-channel analysis leptons (e,µ) in the final state Separated by event topology Different dominant background O.S. 0 jets WW O.S. jet DY O.S. or more jets tt S.S. or more jets W+jets O.S. M ll <6 GeV/c Wγ (fake) Neural Network trained for each M H Different set of variables for different channel M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 3 /

4 H WW* with Hadronic Tau decay channel + 4% signal Include W τ + ν hadrons+ν One trigger e or µ, one hadronically decaying tau in the final state Main background: W+jets (jet faking τ) Validated with background dominated control regions Signal efficiency dominated by τ reconstruction efficiency Boosted Decision Tree (BDT): τ ID variables + kinematic variables Entries CDF Run II Preliminary eτ channel L dt = 5.9 fb m H = 65 GeV/c data (5.9 fb ) H WW Drell Yan W+jet W+γ WW/WZ/ZZ tt total Bkg error BDT output M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 4 /

5 Tri-lepton - orthogonal to the main HWW analysis + 3.8% signal I Split analysis in three channel: inz : `` S. Flav., mz ±5 GeV/c, jet inz : `` S. Flav., mz ±5 GeV/c, + jets No-Z : orthogonal to inz, any jets I NN with different set of variables L = 5.9 fb - CDF Run II 4 WH Signal (Z Removed): MH = 65 GeV/c Total tt ZZ Zgamma Wj WZ WH ZH Data NN Output M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 5 /

6 Latest results on 5.9 fb Binned likelihood for each H mass and for each channel combined Standard Model exclusion sensitivity reached around M H =65 GeV/c Exclusion limits for the different channels, M H =65 GeV/c M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 6 /

7 Future Perspective Improvements More data: fb by the end of 0 H ZZ H ZZ llνν:.45 signal events in 6 fb for M H =90 GeV/c 5 σ SM (naively) expected limit for M H =90 GeV/c H WW lνjj: in progress Significant BR but large background Improvements on lepton ID Lower leptons p T requirements Loosening lepton isolation cut CDF is on the race to the Higgs! M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 7 /

8 Additional material For further informations on the analysis see the public web page: M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 8 /

9 OS combined 95% C.L./σ SM 3 CDF Run II Preliminary - L = 5.9 fb OS Expected OS ± σ OS ± σ OS Observed Low M ll 95% C.L./σ SM CDF Run II Preliminary - L = 5.9 fb low M(ll) Expected low M(ll) ± low M(ll) ± σ σ low M(ll) Observed SS Standard Model Higgs Mass (GeV) CDF Run II Preliminary - L = 5.9 fb SS + Jets Expected SS + Jets ± SS + Jets ± σ σ Standard Model Higgs Mass (GeV) Trilepton CDF Run II Preliminary - L = 5.9 fb High Mass Expected High Mass ± High Mass ± σ σ 95% C.L./σ SM SS + Jets Observed 95% C.L./σ SM High Mass Observed Standard Model Higgs Mass (GeV) Standard Model Higgs Mass (GeV) M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 9 /

10 Tau 3 CDF Run II Preliminary - L = 5.9 fb Hsdronic Tau Expected Hsdronic Tau ± σ All channels CDF Run II Preliminary - L = 5.9 fb High Mass Expected High Mass ± σ Hsdronic Tau ± σ High Mass ± σ 95% C.L./σ SM Hsdronic Tau Observed 95% C.L./σ SM High Mass Observed Standard Model Higgs Mass (GeV) Standard Model Higgs Mass (GeV) Combined Limits High Mass σ/σsm σ/σsm Median/σSM σ/σsm σ/σsm Observed/σSM M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 /

11 Data statistical fluctuation Upward fluctuation of the data is homogeneus in NN Output range M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 /

12 Exclusion sensitivity expectation This plot considers CDF sensitivity ( CDF+D0) M. Bauce (INFN Padova) Higgs searches at CDF Orsay, 9-3 July 0 /