Measurement of H → WW* fully hadronic in HZ at 350 GeV

1. Measurement of H→WW* fullyhadronic in HZ at 350 GeV Mila Pandurović

2. Introduction HZ @350GeV σ(e+e- →HZ)=134 fb 68000 ZH evts H→WW→qqqq , Z →ff, f=e,μ,q Motivation: precision of the measurement of Signal evts: BF(H→WWqqqq)~10% 1. BF(Z→ll , l=e,µ)~7%  1%~ 500 evts 1/sqrt(N)~5% BF(Z→qq) ~70%  7% ~4800 evts 1/sqrt(N)~1.5 %

3. Signal and background processes

4. Analysis strategy Semileptonic FS: 4 jets + 2l Lepton isolation Nlept =2 FastJetFinder: Kt ex, Njets=4, R=1.2 Hadronic FS: 6 jets Lepton isolation Nlept=0 FastJetFinder: Kt ex, Njets=6, R=1.2 Preselection Multivariate analysis Extract NS, NB to get

5. Lepton definition 4jets+2electrons Lepton definition: track energy of a lepton candidate > 12 GeV Z→ee Econe[GeV] signal Etrack[GeV] Selection: - Track energy of a lepton candidate > 12 GeV  85 % reconstructed with 2 muons Cone angle : Cos θ=0.995 counts signal electrons PFO 5 Etrack[GeV]

6. Lepton definition 4jets+2 muons Econe[GeV] Z→µµ signal Etrack[GeV] counts Selection: - Track energy of a lepton candidate > 12 GeV  84 % reconstructed with 2 muons Cone angle : Cos θ=0.995 Muons electrons PFO 6 Etrack[GeV]

7. Preselection & BDT application 4jets+2l Preselection : reducing ‘hadronic’ background: qqqq, qqνν Testing additonalpreselection cuts: Event shapes - signal 4 jets, the most persistant background qqll, qql 2 jets

8. Variables4jets+2 electrons BDT trained on : HZ, Z-ll, non WW-qqqq decays qqll 3. qql Total signal Eff=30 %

9. BDT application 4jets+2muons BDT trained on : HZ, Z-ll, non WW-qqqq decays qqll 3. qql Total signal Eff=33 %

10. Lepton definition 6 jets Econe[GeV] signal Etrack[GeV] Simultaneous reconstruction of the real W, Z, Higgs. Reduced chi2 used. Producin the new one with resolutions.

11. Preselection 6 jets Preselection optimized to reduce ‘semileptonic’ bck.

12. Variables6jets BDT is trained on: 1. qqqq 2. HZ, (other H decays, Z→qq) Total signal Eff=50 %

13. Summary Analysis is coming to an+ end! Redoing 6jets with the adaquite chi2 definition – hoping for the improvement in the masses reconstruction. Will include new backgrounds but expecting easy reduction with preselection cuts only. Systematics: is Jet resolution the most critical?

14. END

15. Variables ANGLES 6 jets FS