Higgs branching ratios study Oct Hiroaki Ono (NDU) Oct ILC Physics WG general meeting

Current status of Higgs BR study Higgs branching ratios analysis publication – E cm =250 and 350 GeV H  bb, cc, gg channel – Submitted to EPJ, now under review… Detailed Baseline Document (DBD) study – Detector benchmarking study for ILD e+e-  1 TeV branching ratio study – Physics chapter Update results with Higgs mass of 125 GeV Oct ILC Physics WG general meeting

vvh detector benchmarking study Oct ILC Physics WG general meeting e + e -  vvh is one of the DBD detector benchmarking process Observable: cross section times branching ratios (σ×BRs) Decay channels: h  bb, cc, gg, WW*, μμ Jet energy resolution (Reconstructed Higgs mass) Jet clustering and reconstruction (with γγ BG overlay) Flavor tagging performance (b/c tagging) Tracking performance, momentum resolution (H  μμ) Evaluate ILD detector performance at E cm =1 TeV We perform the full detector simulation with latest reconstruction packages in ILD

Higgs physics at ILC 1 TeV Oct ILC Physics WG general meeting Higgs mainly produced via e + e -  ν e ν e h (WW-fusion) Final state only comes from Higgs decay H  bb, cc, gg (two jets) H  WW * (four jets via fully hadronic decay) H  μμ (dilepton) γγ  hadron BG is also overlaid as same as CLIC study

Simulation condition Oct ILC Physics WG general meeting Higgs mass: M h =125 GeV CM energy: E cm =1 TeV Beam polarization: P(+-0.8, -+0.2) L=500 fb -1 for both pol. Channe lBRs bb57.8% cc2.7% gg8.6% WW21.6% μμ0.02% Detector model: ILD_o1_v05 Simulation: Mokka v p00 Reconstruction: Marlin v Detector mass simulation was finished Mass reconstruction is still on-going Higgs signal sample Softwares Higgs GeV

H  bb, cc, gg channel Oct ILC Physics WG general meeting H  bb, cc, gg hadronic Simply final state forms two jets γγ  hadron background is also overlaid on signal Apply forced two jet clustering at first  Try different jet clustering algorithm Durham (LOI) k t algorithm (used in CLIC CDR for hadron collider) R parameter(jet-radius) should be tuned Only check signal samples at this moment…

Invariant mass distribution Oct ILC Physics WG general meeting Without γγ  hadron overlay Invariant mass (GeV)  w/o BG overlay  w/ BG overlay Cut on the angler distribution Different jet clustering Durham  kT jet algorithm (as same as CLIC CDR)

kT jet clustering Oct ILC Physics WG general meeting Invariant mass (GeV) Dijet reconstruction with γγ  hadron BG Use Durham w/o BG overlay Optimize R parameter for kT algorithm R=1.0~1.3 looks suitable  Check with forward particle before jet reconstruction

Jet reconstruction with PFO cut Oct ILC Physics WG general meeting Dijet reconstruction with γγ  hadron BG  w/o BG  w/ BG kT  w/ BG kT (cosθ<0.98)  W/ BG inv. M (cosθ<0.98) Check with small statistics Slightly improve the PFO cosθ cut Set R=1.1 for kT algorithm

H  WW* channel Oct ILC Physics WG general meeting H  WW * (one on-shell W) from Higgs decay H  WW *  qqqq fully hadronic decay channel is considered h W1W1 W2W2 1.Apply forced four jet clustering Employ kT algorithm with R=1.0 2.Jet paring for W 1, W 2 (W 1 is on-shell with J 1, J 2 ) Select best candidate with minimizing χ 2

Reconstructed masses Oct ILC Physics WG general meeting MH Mw1Mw

Conclusion We concentrate the studies for DBD – 1TeV – Detector simulation has been finalized – Reconstruction is now still on-going – Schedule is quite tight but need to finalize by LCWS12 Oct ILC Physics WG general meeting