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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). ACFA 7 th Nov.9-12 2004 Taipei Taiwan. Towards Higgs Precision Measurement at ILC What we have done ? & What we have to do?. Why Precision Measurement ?.

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Towards Higgs Precision Measurement at ILC What we have done ? & What we have to do?

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  1. JAPAN LC Physics study group Higgs subgroup and KEK Minamitateya Collaboration Yoshiaki Yasui (Tokyo Management Collage) ACFA 7th Nov.9-12 2004 Taipei Taiwan Towards Higgs Precision Measurement at ILCWhat we have done ? & What we have to do?

  2. 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

  3. 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!!

  4. Non SUSY THD at ILC? • Higgs self coupling as a probe of THD Kanemura et.al LCWS’04 Paris Baryogenesistalk by Senaha-san

  5. Extra-dim at ILC? • Radion(graviscalar)-Higgs mixing Ex:Warped Extra Dim model Randall Sundrum • m > 2mh⇒ hh bbbb • m < mh,>>1⇒ gg 0 Dominici et.al. Nucl.Phys. B671 (2003) zzh hhh =5GeV =5GeV radion mass mPlanck-warped scale

  6. 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.) Towards Higgs Precision Measurement feedback this talk

  7. etc.. etc.. What we have done? • Priority ⇒HiggsPhysics at TeV LC • Higgs self coupling⇒We started (from 2002) • Top Yukawa • Heavy Higgs, etc.

  8. @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 (includesbkg.) study!!

  9. Our Strategy for simulation studies • Parton level Generator (tree level ⇔ GRACE-loop) • LCGrace talk by Yasui, ACFA 6th India 2003package for LC Higgs physicsstudy: Mh ≤ 140 GeV e+e- 6f • based on the GRACE System • Bases⇒ Monte Carlo integration ⇒ Cross section • Spring⇒ Events generator • Hadronizer • Pythia(interface from Spring to Pythia6) • Simulator (Quick Simulation → Full Simulation) • Analysis

  10. Simulation Study Ecm = 1 TeVmain mode  W-fusion Higgs mass = 120 GeV SM decay Br ISR/BSR included Signal & bkg event generatorLCGrace (BASES+SPRING) Signal MC: X + hh/SM from 0.0 to 2.0 with 0.2 step Smearing simulation at parton levelJet energy resolution ~ 30%/√E (GeV) (detector R&D target value) ννhh quick analyses only for hh decaying to 4b Br(hh4b) ~ 47 % for 120 GeV SM Higgs Signal characteristics Large missing energy, missing Pt Only 4 b jets M1 jj ~ Mh M2 jj ~ Mh No isolated lepton

  11. ννbbbb(~ ννZZ, ννZγ*) ννbbh (~ ννZh) Signal and Background processes By LCGrace Main bkg processes 4b + missing Signal (for SM)

  12. 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. hhhmeasurements dep. of cross-section Zhh eehh /SM Reconstructed ‘Higgs’ mass ννhhAnalysis Flow ννbbbb = ννbbh =SM L = 1 ab-1

  13. ννhh selection ννhh channel L = 1 ab-1 ννbbbb = ‘fusion’ ννhh counts counts =SM ννbbh ‘Zhh’ Likelihood Missing mass [GeV] Separate Zhh & fusion (~ OPAL Higgs scheme)

  14. ‘Zhh-channel’ ‘fusion-channel’ = =2 SM Zhh counts counts ννhh =SM =SM hh invariant mass [GeV] hh invariant mass [GeV] (= visible mass) HH invariant mass distributions

  15. @1TeV Ilumi=1 ab-1 Pol beam= -80% 95%CL upper bound Measured /SM Mh=120 GeV (SM Higgs Br) Mh=120 GeV Use only hh4b 67%CL range (Br(hh4b)~47%) Eff.(4b) 80% 95%CL lower bound True/SM hhhMeasurement sensitivity By Yamashita et.al. LCWS 2004 Precise studyRadiative corrections are also important!! Systematic study of the RC for Higgs physics at LC with GRACE

  16. Radiative correction for e+e-ZHH GRACE Phys.Lett.B576(2003)152 Zhang et al. Phys.Lett.B578(2004)349

  17. Yasuiet.al. ECFA2004 Durham UK Radiative correction for e+e-eeHH =(O())/(tree)-1 W WG=W- 4r r=2.267% QED for Mh=120 GeV W for Mh=120GeV

  18. Recent progress on the loop calculations • 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) 163-172Y.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-eeHH (19638)New results!! of 2 to 4 • Weak corrections are sizable O(5-10)%

  19. 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 Higgsννhh 8f, 10f New version of Grace system Radiative corrections (systematic study have been done) sizable  include in theevent generator New Physics study

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