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Calculations of Higgs x-sections at N k LO

Calculations of Higgs x-sections at N k LO. p. diff. observables Higgs HqT (NLO+NNLL) Resbos (NLO+NLL). Hard scattering. Higgs. …. gg H Higlu ggHTotal Fehip hnnlo resbos. VBF VV2H (NLO) VBFNLO (NLO). decay. Hdecay Prophecy4f FeynHiggs. W/Z H V2HV. bkg. p. gg diphox

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Calculations of Higgs x-sections at N k LO

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  1. Calculations of Higgs x-sections at NkLO p diff. observables Higgs HqT (NLO+NNLL) Resbos (NLO+NLL) Hard scattering Higgs … ggH Higlu ggHTotal Fehip hnnlo resbos VBF VV2H (NLO) VBFNLO (NLO) decay Hdecay Prophecy4f FeynHiggs W/Z H V2HV bkg p gg diphox resbos g/jet jetphox ttH hQQ pdf jet jet nlojet++ Cteq 2009 Mstw 2008 Uncertainties pdfs A.-C. Bourgaux, M. Escalier, L. Fayard

  2. Whystudyingagain cross-section ? LHC to improve potential discovery… …but LHC accident : 14 TeV10 TeV Consequence expected on cross-sections 2/14

  3. Tools and parameters used • Higlu (NLO), • HNNLO (NNLO, no mt correction), • FEHiP, HggTotal (NNLO+F(mt)) Anastasiou • HqT Factorisation (µF) and renormalisation (µR) scales : mF=mR in [mH/2 ; 2mH ] to limit computations Pdf: mstw2008 CTEQ6L1/M for Higlu default parameters used, while concluding for a common prescription: mt = 172.7 GeV for FEHiP, 172 GeV for Higlu 178 GeV for HNNLO

  4. Integrated x-sections (100-800 GeV) • HNNLO mt ∞ No correction • HIGLU mt exact Opening of the on-shell phase-space • FEHiP mt ∞ + correction:

  5. Integrated x-sections with HggTotal Available : http://www.phys.ethz.ch/~babis/Software/ Includes electroweack corrections, Different choice for scales: mR=mF=0.5*mH

  6. s*BR(H  gg) with HNNLO s×Br(H  gg) Br(H  gg) (Br tables of HNNLO seem to be computed from Hdecay)

  7. differential x-sections Motivations: -take into consideration acceptance of detector and change of ecm need angular and pT distributions of photons -Higgs pT is a powerful discriminating variable, need good knowledge of distributions especially at low pT where resummation is important to avoid fixed order Monte Carlo behavior

  8. differential x-sections with HNNLO 5 (jet) 1 3 H 4 6 (jet) 2 gg fusion Higgs 2 photons γ LO _ pT34 pT3 &pT4 y34η3 & η4 NLO pT5 pT34 pT3 &pT4 y34η3 & η4 NNLO pT5 pT34 pT3 & pT4 pT6 y34η3 & η4

  9. photong mH=100 GeV mH=800 GeV For high masses, the photon is more central normalized: stable observable / pert order mH=100 GeV ATL-COM-PHYS-2009-161 Qian, Liu, Mansoulie, Purdham, Strandberg, Thun

  10. photong mH=100 GeV fixed order calculation : LO bounded at pt=mH/2  NLO and NNLO unstables in this region normalized: ATL-COM-PHYS-2009-161

  11. mH=100 GeV mH=800 GeV Higgs normalized: stable observable / pert order mH=100 GeV ATL-COM-PHYS-2009-161 Detector acceptance will limit the rapidity range that can be measured

  12. Higgs compatible with statistical error mH=100 GeV ATL-COM-PHYS-2009-161

  13. Higgs PT, @ LO and NLO, with HqT mH=125 GeV Normalized : ≠ from HNNLO Correction to pT(H) : appendix

  14. mrst2004 resummation for low pTfix order for high pT HqT HNNLO

  15. Influence of mR , mF LO For highpT : dependance on scalesremainsalmost constant : calculationisactually LO For lowpT : dependance on scalesdecreasesbetween LO and NLO NLO mH/2

  16. Influence of resummation scale mRS (@ LO) mRS=mH Matched calculation is closer to fix order when resumation scale is lower

  17. Influence of mRS @ LO linearscale: logscale: @ NLO

  18. Acceptances with FEHiP, PYTHIA and MC@NLO

  19. Conclusion Gluon fusion: soon under control, VBF: great work in progress from Nansi (vv2h, mass and scales dependances), W/Z H: will be investigated and compared with Djouadi computation at NNLO, tṫ H: will be investigated to close available programs study. Up to now signal investigated, what about background? gjet: yet investigated by Pauline (NLO) jet-jet : NLOjet++ could be investigated (NLO) Differential cross-section  feedback to statistic team (Nansi, Francesco, Louis)

  20. Appendix

  21. PT of Higgs : HqT • Construction of the curve : • Resummed : divergent terms only « resummed »=exp(Sudakov factor) • Asymptotic : limit of perturbative order when PT0 : divergent terms only • Fix order : all perturbative developpement terms, including divergent terms • Matched = Resummed + Fix order - Asymptotic

  22. Availabletools

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