Status of LC Physics StudyStatus of LC Physics Studyin Japan (II)in Japan (II)

Higgs/GRACE /Simulation studyHiggs/GRACE /Simulation study

towards Higgs precision Measurementtowards Higgs precision Measurement

JAPAN LC Physics study groupand

KEK Minamitateya

Yoshiaki Yasui(Tokyo Management Collage)

LC Physics Study Meeting 3/6/2005 KEK

Higgs study @ILCHiggs study @ILC

SM New Physics!! Higgs coupling may be a probe of BSM

origin of EW SSB, mass generation ⇒essential role in particle physics phenomena

What we can do after Higgs discovery @ LHC? ⇒Higgs 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

MSSM at ILC

hhh = (3gMZ/Cw)cos2sin()

hhhh = (3g2/Cw

2)cos22

THDM model at ILC

Kanemura et.al LCWS’04 Paris

Loop induced huge correction

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 Korea@LCWS '02 Jeju Korea

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

dominant for E

CM > 1TeV

1)Parton level Generator (tree level )➢ LCGrace talk by Yasui, ACFA 6th India 2003

package for LC Higgs physics study: Mh ≤ 140 GeV e+e- 6 fermionbased 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

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

Select typical diagrams ( full calculation )

Reconstruction of intermediate resonances

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

Analysis Flow

ννbbbb

Likelihood

ννbbh

=

=SM

coun

ts

L = 1 ab-1

selection

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

L = 1 ab-1

ννbbbb

ννbbh =SM

=

Reconstructed ‘Higgs’ mass

Missing mass [GeV]

‘Zhh’

‘fusion’

ννhh channel

coun

ts

Separate & fusiondep. of cross-section

eehh

Zhh

/SM

(= 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 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 sensitivity

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)

SummarySummaryWhat we have done?

What we have to do?

Non-b decay of the Higgs increase sensitivity

Full 6f calculation

Mh>140GeV W-par decay of the Higgs

8f, 10f New version of Grace system

Radiative corrections are sizable!!

systematic study have been done by Grace

GRACEGRACE● GRACE is the Computer code

– automatic calculation of tree level Feynman amplitudes

● e+e- → 6 fermions #Feynman DiagramsO(10000)

– e+e- → Zh → ZW+W- → ffffff (Mh ≧ 140GeV)– e+e- → tt-bar → bbW+W- → bbffff– e+e- → Zhh → ffbbbb (Mh ≦ 140 GeV)

● Many packages in the world– AMEGIC++, EFTT6F, LUSIFER, PHEGAS, SIXFAP, WHIZARD,..– No useful tool in Asia!!

LCGrace ≠ Full calculation, HELAS is unsupported now

● Tool development is essential for ILC physics – GRACE ver.2 → GRACE ver.3 (upgrade for multi-legs)

GRACE-loopGRACE-loop

Code for the full one-loop EW corrections

Two packages in the world FeynArt/FeynCalc e+e-4 fermion GRACE-loop e+e-HH

full () for 2 to 4 processesGRACE for collider is now ready with CAIN (photon structure function)

GRACE/SUSY is under construction Non linear gauge fixing

upgrade reduce form (by Vermaseren)

Single Higgs production

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

● e+e-H (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-ee 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

e+e-e+e-eeee HH HH

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--ee

ee HHHH

Yasui et.al. ECFA2004 Durham UK

ACPPACPPInternational Research GroupInternational Research Group

ACPPACPPInternational Research GroupInternational Research Group

Russia (MSU,RAS,RFBR)

France (LAPTH,LAPP,LPC,LPMT,LPT)

Japan (KEK) GRACE ⇋ CompHEP

Tree level multi-parton Loop calculation (GRACE-loop)

MSSM (GRACE/SUSY, micrOMEHAs)

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.)

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