LCWS08 at Chicago 2008/11/18. Simulation study of e + e - W H + W H -. Introduction Observable to be measured Analysis framework Event selection Results. Rei Sasaki (Tohoku University) with. <Experimentalist> K.Fuji (KEK) Y.Takubo (Tohoku Univ.) T.Kusano (Tohoku Univ.).
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Rei Sasaki (Tohoku University)
Y.Takubo (Tohoku Univ.)
T.Kusano (Tohoku Univ.)
S.Matsumoto (Toyama Univ.)
A , W± , Z , h
AH, WH±, ZH, F
Littlest Higgs model with T-parity
f : Breaking scale
mh : Higgs mass
AHand WH± can be searched by ILC (1TeV).
(WH±AHW±with 100% ratio)
- Large cross section
- Dark matter (AH) appears
e+e- WH+WH- is the best one to investigate
the property of the dark matter predicted in the model.
1) Energy edges of W±
lead to masses of WH± and AH bosons
2) Production angle of WH±
lead to spin of WH± boson
3) Angular distribution of reconstructed jets
from associated W± boson decays
lead to helicity of W± boson
MadGraph : for LHT process
Physsim : for Standard Model process
- helicity amplitude calculation
- gauge boson polarization effect
- phase space integration and generation
of parton 4-momenta
- parton showering and hadronization
- create vertex-detector hits
- smear charged-track parameters in central tracker
- simulate calorimeter signals as from individual segments
Ref) GLD Detector Outline Document Ver.1.2.1
- ZH decays to AHh
- followed by hqq-bar
<Standard Model background>
(Large cross section)
(Small cross section)
- followed by W±qq-bar
All events are forced to 4 jets in final state
cW2 : c2 for W± reconstruction from jets
PTmiss : Missing transverse momentum
<Cut statistics and breakdown of efficiency>
W+W- and e+e-W+W- are effectively reduced by PTmiss cut.
ZHZH is negligible after cW2 cut.
nnW+W- andW+W-Z remain after 2 cuts.
1) Cheat Emin,Emax
Ffit1 = Ferror(par[1,2])
2) CheatEmin,Emax & Fixpar[1,2]
Ffit2 = Ferror x Fpoly(par[3~9])
Ffit3 = Ferror(Emin,max) x Fpoly(Emin,max)
Signal (with all error)
<Result of fit>
mAH = 82.49±1.10 : 0.58
mWH = 367.7±1.0 : 0.50
Masses of AH and WH± are determined with high accuracy!!
<Reconstruction of WH± from W±>
WH± candidates are reconstructed as corn
If WH+ and WH- are assumed as back-to-back,
there are 2 solutions for WH± candidates.
In this mode, however , 2 solutions should be
close to true WH±.
<WH+ of generator information>
<WH+ and WH- of detector simulation>
This shape shows WH± spin as spin-1.
<Angular distribution of jets>
<Rest frame of W+>
This shape shows W± helicity as longitudinal mode.