Towards Higgs Precision Towards Higgs Precision Measurement at ILCMeasurement at ILC

What we have done ? & What we have to do?What we have done ? & What we have to do?

JAPAN LC Physics study group Higgs subgroupand

KEK Minamitateya Collaboration

Yoshiaki Yasui(Tokyo Management Collage)

ACFA 7th Nov.9-12 2004 Taipei Taiwan

Why Precision MeasurementWhy Precision Measurement??Why Precision MeasurementWhy Precision Measurement??

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

What we can do after Higgs discovery @ LHC?

Higgs Precision Measurement EW SSB, mass generation

MSSM at ILC? MSSM at ILC? MSSM at ILC? MSSM at ILC?

But .....

Decoupling limit MH0 ≈ MH

≈ MA0 >> MZ

hhh = (3gMZ/Cw)cos2sin()

3gMh02/2MW = hhh

SM (MhSM=Mh0)

hhhh = (3g2/Cw

2)cos22 3g2Mh0

2/4MW2

=SMhhhh(Mh

SM=Mh0)

Top Yukawa corrections are small Hollik et.al.

Higgs self coupling = gauge coupling?

We need more idea!!

Non SUSY THD at ILC?Non SUSY THD at ILC?Non SUSY THD at ILC?Non SUSY THD at ILC?● Higgs self coupling as a probe of THD

Kanemura et.al LCWS’04 Paris

Baryogenesis talk by Senaha-san

Extra-dim at ILC?Extra-dim at ILC?Extra-dim at ILC?Extra-dim at ILC?● Radion(graviscalar)-Higgs mixing

Ex:Warped Extra Dim model Randall Sundrum

radion mass mPlanck-warped scale

Dominici et.al. Nucl.Phys. B671 (2003)

=5GeV

zzh

hhh=5GeV

m > 2mh ⇒ hh bbbbmmh, >> 1⇒ gg 0

Towards Towards Higgs Precision MeasurementHiggs Precision Measurement Towards Towards Higgs Precision MeasurementHiggs Precision Measurement

Machine design parameters(CM energy, Luminosity,etc.)

Detailed study of SM Higgs(Simulation, RC, etc.) 　　

New Physics at ILC(SUSY,THD,LH,Extra-Dim,etc.)

feedback

this talk

What we have done?What we have done?What we have done?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..

Assumption No bkg effects 100% signal efficiency

by Yasui et.al.

@@LCWS '02 Jeju KoreaLCWS '02 Jeju Korea

LCWS’04 Paris France Quick Simulation (includes bkg.) study!!

dominant for E

CM > 1TeV

1. Parton level Generator (tree level ⇔ GRACE-loop)● 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 ● Bases ⇒ Monte Carlo integration ⇒ Cross section● Spring ⇒ Events generator

2. Hadronizer● Pythia (interface from Spring to Pythia6)

3. Simulator (Quick Simulation → Full Simulation)

4. Analysis

Our Strategy for simulation studiesOur Strategy for simulation studies

Ecm = 1 TeV

main mode W-fusion

Higgs mass = 120 GeV

SM decay Br

ISR/BSR included

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)

Simulation StudySimulation Study

ννhh quick analyses

only for hh decaying to 4b

Br(hh4b) ~ 47 %

for 120 GeV SM Higgs

Signal characteristics

Large missing energy, missing PtOnly 4 b jetsM1 jj ~ Mh M2 jj ~ Mh

No isolated lepton

Signal and Background processesSignal and Background processes

Signal(for SM)

Main bkg processes 4b + missing

ννbbbb (~ ννZZ, ννZγ*)

ννbbh

(~ ννZh)

By LCGrace

1. Likelihood selection bkg further reduction

2. Separate Zhh & fusion different dependence (positive/negative interferences)

3. Combine with Zhh analyses for s-channel process

4. Check hh invariant mass

5. hhh

measurements

ννhh Analysis Flowννhh Analysis Flow

dep. of cross-section

νeνehh

Zhh

/SM

L = 1 ab-1

ννbbbb

ννbbh =SM

=

Reconstructed ‘Higgs’ mass

ννbbbb

Likelihood

ννbbh

ννhh

=

=SM

coun

ts

L = 1 ab-1

ννhh selection

(~ OPAL Higgs scheme)(~ OPAL Higgs scheme)

Missing mass [GeV]

‘Zhh’

‘fusion’

ννhh channel

coun

ts

Separate Zhh & fusion

(= visible mass)

‘fusion-channel’

hh invariant mass [GeV]co

unts

ννhh

=

=SM

hh invariant mass [GeV]

coun

ts

‘Zhh-channel’

Zhh=SM

=2 SM

HH invariant mass distributionsHH invariant mass distributionsHH invariant mass distributionsHH invariant mass distributions

Mh=120 GeV

Mea

sure

d /

SM

True /SM

95%CL upper bound

95%CL lower bound

67%CL range

Ilumi=1 ab-1

Pol beam= -80%

@1TeV

Mh=120 GeV(SM Higgs Br)

Use only hh4b(Br(hh4b)~47%)

Eff.(4b) 80%

By Yamashita et.al. LCWS 2004

hhh Measurement sensitivityhhh Measurement sensitivity

Precise study Radiative corrections are also important!! Systematic study of the RC for Higgs physics at LC with GRACE

Radiative correction for Radiative correction for ee++ee--ZHH

GRACE Phys.Lett.B576(2003)152Zhang et al. Phys.Lett.B578(2004)349

W for Mh=120GeV

QED for Mh=120 GeV

=(O())/(tree)-1

W

G=W

- 4r

r=2.267%

W

Radiative correction for Radiative correction for ee++ee--ννeeνν

ee HHHH

Yasui et.al. ECFA2004 Durham UK

Single Higgs production

● e+e-ZH (full number of graphs = 341)

● e+e-ννH (1350) Phys.Lett. B559 (2003) 252-262 A.Denner et.al. PLB 560(2003)196, NPB 660(2003)289

● e+e-e+e- H (4470) Phys.Lett.B600(2004)65-76

top Yukawa

● 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

● e+e-ZHH (5417) Phys.Lett. B576 (2003) 152-164 R.Zhang et.al.PLB(2004)349

● e+e-νeνe 　 HH (19638) New results!! of 2 to 4

Weak corrections are sizable O(5-10)%

Recent progress on the loop calculationsRecent progress on the loop calculations

A quick simulation study has been performed for Ecm=1 TeV

For Mh=120 GeV: measurement sensitivity (only hhbbbb 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)

SummarySummarySummarySummaryWhat we have done?

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