Transcript Higgs Precision Measurement at ILC What we have done

ACFA 7th Nov.9-12 2004 Taipei Taiwan
Towards Higgs Precision Measurement at
ILC
What we have done ? & What we have to do?
JAPAN LC Physics study group Higgs subgroup
and
KEK Minamitateya Collaboration
Yoshiaki Yasui
(Tokyo Management Collage)
Why Precision Measurement?
What we can do after Higgs discovery @ LHC?

Higgs Precision Measurement
EW SSB, mass generation
Direct measurement of self coupling
e+e- →hh X
 luminosity upgraded LHC (SLHC)
 (e+e- → hh X ) >> (e+e- → hhh X)
Diouadi et.al
  SM New Physics!!
Higgs coupling may be a probe of BSM
MSSM at ILC?
But .....
Decoupling limit MH0 ≈ MH ≈ MA0 >> MZ
hhh = (3gMZ/Cw)cos2 sin()
 3gMh02/2MW = hhhSM (MhSM=Mh0)
hhhh = (3g2/Cw2)cos22
 3g2Mh02/4MW2 =SMhhhh(MhSM=Mh0)
Top Yukawa corrections are small
Hollik et.al.
Higgs self coupling = gauge coupling?
We need more idea!!
Non SUSY THD at ILC?
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Higgs self coupling as a probe of THD
Kanemura et.al LCWS’04 Paris
Baryogenesis  talk by Senaha-san
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Extra-dim at ILC?
Radion(graviscalar)-Higgs mixing
Ex:Warped Extra Dim model
Randall Sundrum
m > 2mh ⇒ hh bbbb
m <mh, >> 1 ⇒ gg 0
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
Dominici et.al. Nucl.Phys. B671 (2003)
zzh
=5GeV
hhh
=5GeV
radion mass m Planck-warped scale
Towards Higgs Precision Measurement
Machine design parameters
(CM energy, Luminosity,etc.)
Detailed study of SM Higgs
(Simulation, RC, etc.)
this talk
New Physics at ILC
(SUSY,THD,LH,Extra-Dim,etc.)
feedback
What we have done?
Priority ⇒ Higgs Physics at TeV LC
1.Higgs self coupling⇒ We started (from 2002)
2.Top Yukawa
3.Heavy Higgs, etc.
etc..
etc..
@LCWS '02 Jeju Korea
Assumption
No bkg effects
100% signal efficiency
dominant for
ECM > 1TeV
by Yasui et.al.
LCWS’04 Paris France
Quick Simulation (includes bkg.) study!!
Our Strategy for simulation studies
1.
Parton level Generator (tree level ⇔ GRACE-loop)
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2.
LCGrace
talk by Yasui, ACFA 6th India 2003
package for LC Higgs physics study:
Mh ≤ 140 GeV e+e-  6f
based on the GRACE System
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Bases ⇒ Monte Carlo integration ⇒ Cross section
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Spring ⇒ Events generator
Hadronizer
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Pythia (interface from Spring to Pythia6)
3.
Simulator (Quick Simulation → Full Simulation)
4.
Analysis
Simulation Study
Ecm = 1 TeV
main mode  W-fusion
Higgs mass = 120 GeV
SM decay Br
ISR/BSR included
ννhh quick analyses
only for hh decaying to 4b
Br(hh4b) ~ 47 %
for 120 GeV SM Higgs
Signal & bkg event generator
LCGrace (BASES+SPRING)
Signal MC: X + hh
/SM from 0.0 to 2.0 with 0.2 step
Smearing simulation at parton level
Jet energy resolution ~ 30%/√E (GeV)
(detector R&D target value)
Signal characteristics
Large missing energy, missing Pt
Only 4 b jets
M1 jj ~ Mh M2 jj ~ Mh
No isolated lepton
Signal and Background processes
By LCGrace
Main bkg processes
4b + missing
ννbbbb
(~ ννZZ, ννZγ*)
ννbbh
(~ ννZh)
Signal
(for SM)
  hh Analysis Flow
1. Likelihood
selection
bkg further reduction
Reconstructed ‘Higgs’ mass
ννbbbb
ννbbh
=
=SM
L = 1 ab-1
2. Separate Zhh & fusion
different dependence
(positive/negative interferences)
dep. of cross-section
3. Combine with Zhh analyses
for s-channel process
4. Check hh invariant mass
5. hhh measurements
Zhh
eehh
/SM
ννhh selection
Separate Zhh & fusion
ννhh channel
L = 1 ab-1
=
ννhh
ννbbh
=SM
Likelihood
(~ OPAL Higgs scheme)
counts
counts
ννbbbb
‘fusion’
‘Zhh’
Missing mass [GeV]
HH invariant mass distributions
=2  SM
=SM
Zhh
‘fusion-channel’
counts
counts
‘Zhh-channel’
=
ννhh
=SM
hh invariant mass [GeV]
hh invariant mass [GeV]
(= visible mass)
hhh Measurement sensitivity
By Yamashita et.al. LCWS 2004
Measured /SM
@1TeV
Ilumi=1 ab-1
Pol beam= -80%
95%CL upper bound
Mh=120 GeV
(SM Higgs Br)
Mh=120 GeV
67%CL range
95%CL lower bound
Use only
hh4b
(Br(hh4b)~47%)
Eff.(4b) 80%
True /SM
Precise study  Radiative corrections are also important!!
 Systematic study of the RC for Higgs physics at LC with GRACE
Radiative correction for e+e-ZHH
GRACE Phys.Lett.B576(2003)152
Zhang et al. Phys.Lett.B578(2004)349
Radiative correction for e+e-ee HH
=(O())/(tree)-1
Yasui et.al. ECFA2004 Durham UK
W
WG=W- 4r
r=2.267%
QED for Mh=120 GeV
W for Mh=120GeV
Recent progress on the loop calculations

Single Higgs production
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e+e-ZH (full number of graphs = 341)
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e+e-H (1350) Phys.Lett. B559 (2003) 252-262
A.Denner et.al. PLB 560(2003)196, NPB 660(2003)289
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Phys.Lett.B600(2004)65-76
top Yukawa
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e+e-e+e- H (4470)
e+e-t t H (2327)
Phys.Lett. B571 (2003) 163-172
Y.You et.al.PLB 571(2003)85
A.Denner et.al. PLB 575(2003)290, NPB 68(2004)85
Multi Higgs production
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e+e-ZHH (5417)
Phys.Lett. B576 (2003) 152-164
R.Zhang et.al.PLB(2004)349
e+e-ee HH (19638)  New results!! of 2 to 4
Weak corrections are sizable O(5-10)%
Summary
What we have done?
A quick simulation study has been performed for Ecm=1 TeV
For Mh=120 GeV:
measurement sensitivity (only hhbbbb only)
for =SM
/SM=1.0 +0.13 -0.11 (1)
0.78 - 1.32 (95%CL)
/SM=0.6
0.6 +0.10 -0.07 (1)
0.45 - 0.77 (95%CL)
/SM=1.4
1.4 +0.14 -0.18 (1)
1.08 - 1.70 (95%CL)
What we have to do?
Non-b decay of the Higgs  increase sensitivity
Mh>140GeV 
W-par decay of the Higgs
ννhh 8f, 10f
New version of Grace system
Radiative corrections (systematic study have been done)
sizable  include in the event generator
New Physics study