Update of studies of Spin- and CP- sensitive parameters in H->VV->(ff)(ff)

1. Update of studies of Spin- and CP- sensitive parameters in H->VV->(ff)(ff) M.Kaneda, J.Kanzaki, S.Asai and J.Tanaka (University of Tokyo and KEK) Higgs WG Meeting @CERN 14 December 2005 Spin and CP of the Higgs M Kaneda

2. Introduction • After finding a Higgs-like resonance, we have to establish the nature of the resonance. • At the September meeting, we presented studies of Spin- and CP- eigenvalues of the Higgs decay in the H->WW->lvjj mode. • We present some update point in this presentation. Spin and CP of the Higgs M Kaneda

3. Outline • Parameters sensitive to Spin- and CP- eingenvalues of the Higgs Decay. • MC Samples • Event Selection • W(->jj) Mass Constraint • Expected cross section and Significance • Efficiency correction • Results • Summary and Plan Spin and CP of the Higgs M Kaneda

4. Parameters Sensitive to Spin- and CP-eigenvalues of the Higgs Decay Direction of motion of the child in the V rest frame f f f q1 V(W) V(W) q2 f f The Higgs decay point The Higgs rest frame f:: The angle between two planes defined by the fermions from two V in the rest frame of the Higgs. q:: The angle between the direction of motion of the fermion in the rest frame of W and the direction of motion of W in the rest frame of the Higgs. These variables are sensitive to the spin and CP-eigenvalues of the Higgs. Spin and CP of the Higgs M Kaneda

5. The Decay Plane Correlation Function Ref. Charles A. Nelson, Phys. Rev. D 37,1220(1998) The decay plane correlation is parameterized as: F(f) = C(1 + acosf + bcos2f) W+W- W+W- Standard Model b Standard Model a Because the jet charge is not identified, we can only measure: F*(f) = (F (f) + F (p-f))/2 = C(1 + bcos2f) and only b can be obtained for this decay mode. Spin and CP of the Higgs M Kaneda

6. The Polar Angle Distribution • The distribution of the polar angles is parameterized as: G(q) = T.(1 + cos2(q)) + L.sin2(q) L reflects the longitudinal polarization of W T reflects the transverse polarization of W • Define a variable R: R := (L – T ) / (L + T) which represents the ratio of transverse and longitudinal polarization. Spin and CP of the Higgs M Kaneda

7. MC Samples (fb) • s*Br(H->WW->lnjj(l=e,m)) • Signal: VBF H -> WW -> lvjj( l = e,m) (130GeV-500GeV) (Pythia 6.2) 400000 events for each MH (478fb-1 at MH=170GeV) • Background: • W+4jets s*Br(W->leptonic decay)= 134pb (77.6fb-1) (Alpgen + Pythia) • ttbars = 488pb(102.4fb-1) (Pythia) MH(GeV) Spin and CP of the Higgs M Kaneda

8. q(forward jet) Lepton, Missing Et PTl > 35GeV,, |h|<2.5, Number of leptons = 1 Missing Et > 25GeV Four-jets selection PT >15GeV, |h|<5.0 Number of b-jets = 0, Choose 4 highest PT jets Forward jets Select two outer jets in pseudorapidity. Pt > 40GeV , Mj1j2 > 1200GeV , | h1 - h2 | > 4.6 Central jets (two remain jets) PT1 >35GeV, PT1>15GeV,65GeV < Mjj < 90GeV Mini jet veto:pt>15GeV Event Selection e, m q n W H For MH=170GeV (The selection depends on MH ) W/Z q(central jet) q W q(central jet) q(forward jet) Spin and CP of the Higgs M Kaneda

9. W(->JJ) Mass Constraint Mh=170GeV After scaling 80GeV Before scaling GeV GeV Mjj reconstructed from two central jets EW->jj (Generator) – EW->jj(reconstructed) Because jet energy measurement is not good for W->jj, mass and energy of W are not reconstructed well. We scale jet energy to make Mw->jj = 80GeV. Spin and CP of the Higgs M Kaneda

10. Selection(W->lv Reconstruction) • By fixing MH, we can solve Evzfrom missing ET, and momentum of the lepton, and W which reconstructed from central jets. • There are two solutions Evz1,Evz2(|Evvz1|>|Ezvz2|) and we chose Evz2 (as suggested by the Monte Carlo). • Event is rejected if it has no solution for Evz. • Reconstructed mass of W->lv should be 60GeV < Mlv < 100GeV(Mh>=160GeV) q(central jet) n Missing ET q(central jet) Unknown Evz W(ln) W(jj) e,m H Higgs Mass Constraint Spin and CP of the Higgs M Kaneda

11. Distribution of cosq and f with B.G.at MH=170GeV with 30fb-1 MH=170GeV 30fb-1 MH=170GeV 30fb-1 f cosq Signal:91.5events B.G.:29.7events S/sqrt(B)=17.6 Spin and CP of the Higgs M Kaneda

12. Expected cross sections after selections Spin and CP of the Higgs M Kaneda

13. Significance with 30fb-1 S/sqrt(B)=5 MH Spin and CP of the Higgs M Kaneda

14. Efficiency correction (f, MH=170GeV) No cut and smearing Require kinematical condition f f Correction function • Lepton and jet from W can come near at f = 0. ->suppressed by the isolate condition • DRl-j>0.4 f=0 e,m q(central jet) H W W n q(central jet) Spin and CP of the Higgs M Kaneda

15. Efficiency correction (cosq, MH=170GeV) No cut and smearing Require kinematical condition cosq cosq Correction function Lepton or neutrino runs back from it’s mother W boson at cosq = 0. In this case, it has low momentum at the laboratory frame. ->suppressed by the condition of PTl or Missing ET n e,m W Spin and CP of the Higgs M Kaneda

16. Effect of Efficiency Correction MH=170GeV MH=170GeV 30fb-1 30fb-1 G(q) = T(1 + cos2(q)) + Lsin2(q) cosq cosq MH=170GeV MH=170GeV 30fb-1 30fb-1 F*(f)= C(1 + bcos2f) f f Before correction After correction Spin and CP of the Higgs M Kaneda

17. Result Error bar includes effect of background subtraction. G(q) = T(1 + cos2(q)) + Lsin2(q) R := (L – T ) / (L + T) F*(f)= C(1 + bcos2f) b R 30fb-1 30fb-1 Spin 1,CP+/-1 Spin 1,CP+/-1 Spin 0, CP-1 Spin 0, CP-1 MH MH Spin and CP of the Higgs M Kaneda

18. Summary • New efficiency corrections are applied to this analysis. • Especially for MH=160GeV~180GeV, we can observe clear signal with 30fb-1. • With this analysis, we can determine the Spin and CP of the Higgs boson. • This analysis also has a potential for the discovery of the Higgs Spin and CP of the Higgs M Kaneda

19. Plan • We will generate events of exotic models with MadGraph/HELAS. Then we examine the discrimination power of this analysis. • We will also study the angular correlation of forward jets, which is also sensitive to Spin- and CP- eigenvalues of the Higgs. (Ref. Tilman Plehn et al.,hep-ph/0105325) Spin and CP of the Higgs M Kaneda