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

Mila Pandurović, CLICdp WG meeting, 06. May 2014.

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

2Mila Pandurović, CLICdp WG meeting, 06. May 2014

Analysis recapitulationHadronic FS: 6 jet FS H→WW→qqqq , Z →qq Isolated lepton finder N=0, 6jets, Kt exclusive NEW preselection MVA Semileptonic FS: 4 jet FS H→WW→qqqq , Z →ll , l=e, μ Isolated lepton finder N=2, 4jets, Kt exclusive NEW Isolation redone


Signal and background processes Signal HZ, H→WW→qqqq σ [fb]

Z→ee 0.48

Z→ 0.48

Z→qq 9.7

Background

HZ, other H decays, Z vis. d. 92.02

e+e- →qqqq 5847

e+e- →qqll 1704

e+e- →qql 5914

e+e- →qq 324.6

NEW background added e+e- →h 53.4


6 jet signature H→WW→qqqq , Z →qq Based on the track energy of a lepton candidate and calorimeter depositions within a cone cos θ=0.995 around lepton track.

H

Hijmn

Z

Zkl

W

Wij MMMMMM22

2

2

22

Simultaneous reconstruction of the real W, Z, Higgs. W virtual is the free parameter.


BDT H→WW→qqqq , Z →ll • Preselection optimized to reduce ‘semileptonic’ bck . Main background,

qqqq, poorly responds to any kind of preselection variables.

y12 <2.0 y23<2.6 y34<3.0 y45<3.2


The preselection as loose as possible to preserve signal and maximally reduceleptonic bck.

InvMassW1>10. InvMZ>70. Evis>250.

BDT H→WW→qqqq , Z →ll


BDT H→WW→qqqq , Z →ll BDT trained on hadronic bck:

1. HZ, Z-ll, nonWW-qqqq decays2. qqqq


BDT application H→WW→qqqq , Z →ll

After MVA”close up:without qqqq

After MVAAfterPreselection

- 4 jet background hard to reduce - Trying to find more sensitive variables- angles between jets that comprise W real and Z


4 jets signature H→WW→qqqq , Z →ll

These ‘falsely reconstructed leptons’ are pared to construct a fake Z boson


Improved lepton isolation H→WW→qqqq , Z →ll Reduced the ‘definition’ of lepton reduced number of reconstructed leptons reduced lepton pairs that comprise Z boson


Summary and outlook 6 Jets Signature• Preslection cuts are focused to remove semileptonic

background• MVA trained on the 4jet and nonWW Higgs decay bck :• Remaining : qqqq other backgrounds at the signal leveloutlook• New variables- jets W1 angle and jets Z angle• Fit, TOY MC 4 Jet signature: waiting for redone files see if enything is improved outlook Fit, TOY MC, result


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

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