Associated Higgs Production with Associated Higgs Production with WH WH WWW* WWW* l l l l l l

Nishu, Suman B. Beri,

Vipin Bhatnagar

Panjab University, Chandigarh

IntroductionIntroduction

This channel involves the production of a Higgs boson in association with a W boson where the Higgs boson subsequently decays into a pair of W bosons. The final state consists of three leptons and missing transverse energy from the W lν decays.

Feynman diagram

The Higgs-Strahlung process (WH), being one of the 4 mechanisms for the production of Higgs at LHC is an important channel to understand for completeness of study of Higgs searches. Also H WW* is a dominant decay mode with a Higgs mass > 140 GeV/c2 .

MC Samples Requested

Requested Samples:

Signal : WH WWW l l l with a Higgs mass = 130 , 140 ,150 GeV/c2        

Background  : WWW (3 l )                          : WZ (3 l)                           : ZZ (4 l )                              : ttbar ( l+ l- b bbar)               : Wt (l+ l- b)                           

Earlier work done - Self generated MC data samples. MC samples requested with the production team . Samples now available on the DBS page.

Cross Sections for the Signal and Cross Sections for the Signal and Background processes Background processes

Signal:

WH (Higgs mass = 130 GeV/c2) 45.67 fb

WH (Higgs mass = 140 GeV/c2) 63.23 fb

WH (Higgs mass = 150 GeV/c2) 73.05 fb

Background Processes :

WZ 3 l± 1.025 pb

ZZ 4 l± 0.105 pb

Some details about the WorkSome details about the Work

This work is done using CMS Software version CMSSW_2_1_8 and PAT .

Higgs mass has taken to be 130 GeV/c2 for the present work.

MC samples Used:

/WH_130_3W_2lX/Summer08_IDEAL_V9_v2/GEN-SIM-RECO

/WZ_3l/Summer08_IDEAL_V9_v2/GEN-SIM-RECO

/ZZ_4l/Summer08_IDEAL_V9_v2/GEN-SIM-RECO

For the present study, we are taking the particular case of

1e and 2 muons in the final state.

PPTT distribution for leptons distribution for leptons

PT distribution for electrons PT distribution for muons

To avoid some fake leptons , a cut of PT > 15 GeV/c and || < 2.5 has been applied on leptons.

Dimuonmass PlotDimuonmass Plot

In ZZ and WZ backgrounds, a lepton pair originates from Z. So the events within a mass range of 80 – 100 GeV/c2 are rejected to reduce this background .

Missing Transverse Energy (MET)Missing Transverse Energy (MET)

As the signal events are having a significant amount of missing transverse energy. So a cut of MET > 40 GeV/c2 can be used to suppress the ZZ background.

PPTT distribution for leptons after distribution for leptons after

applying the cutsapplying the cuts

PT distribution for electrons PT distribution for muons

Efficiencies of the Selection CutsEfficiencies of the Selection Cuts

Mz < 80 GeV/c2 & MZ >100 GeV/c2

WH WZ ZZ

88.48% 35.45% 36.98%

MET > 40 GeV/c

WH WZ ZZ

68.07% 55.45% 26.8%

Acoplanarity (∆Acoplanarity (∆) between the 2 ) between the 2 muonsmuons

Future PlansFuture Plans

To continue with this work using latest versions of CMSSW and PAT.

To introduce some other cuts so as to reduce the background.

To study the signal process with Higgs mass of 140 and 150 GeV/c2 as well.

To study other background processes involved in this channel – WWW , Wt and ttbar.