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PHANTOM Update

PHANTOM Update. Ezio Maina. U. of Torino. Physics at TeV Colliders Workshop - Les Houches 2007. Phantom Ballestrero, Belhouari,Bevilacqua,E.M. Dedicated event generator Complete 2 →6 O(α 6 )+O(α 4 α s 2 ) p-p, p- pbar, e + e -- Complete set of reactions up to pp → 4l2j, ee → 2l4j

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PHANTOM Update

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  1. PHANTOM Update Ezio Maina U. of Torino Physics at TeV Colliders Workshop - Les Houches 2007

  2. PhantomBallestrero, Belhouari,Bevilacqua,E.M. • Dedicated event generator • Complete 2→6 O(α6)+O(α4αs2) • p-p, p-pbar, e+e-- • Complete set of reactions up to pp→ 4l2j, ee → 2l4j • At LHC: q1q2→f1f2 f3 f4 f5f6 O(α6)+O(α4αs2) gg → f1f2 f3 f4 f5f6, gq→gq f1f2 f3 f4, qq→gg f1f2 f3 f4 • Exact matrix elements. No production⊗decay or EVBA • Fast • One-shot: generates unweighted events for all processes simultaneously • Efficient: good mapping of phase-space • Multichannel + Vegas q1q2→q1q2 q3 q4 lv covered in Phase1.0 Accomando,Ballestrero,E.M. hep-ph/0504009

  3. qqVV prod VV scattering Higgs top VV couplings

  4. Exact vs VVqq-Prod⊗Decay uu→uuqqμν Single process qq=u-dbar,c-sbar mh=500GeV MADEVENT: qqWV⊗Decay Could produce exact result Tuned comparison

  5. VV scattering with PHANTOM • Light Higgs ➙ VV weakly coupled Higgs Found ➙ check VV scattering Are SM predictions verified? • Heavy (No) Higgs ➙ VV strongly coupled Higgs Not Found ➙ check VV scattering What restores Unitarity?

  6. Models of EWSB Electroweak Chiral Lagrangian Butterworth,Cox,Forshaw PRD65(02)96014 Fabbrichesi,Vecchi hep-ph/0703236 many others • Expand LL → LL Amp in partial waves M=∑j aj (s) Pj(cos(ϑ)) • SS†=1 ⇒ |aj(s)|≤1 • Low Energy Th. M(VV→VV)∝s/v2 No H Unitarization: one example aj = a0j /(1-ia0j) a0j∝s Small s ⇒ LET Large s ⇒ aj→1 NOT UNIQUE!! Works well in ππ

  7. Models of EWSB 2 Additional dynamics,dimensions ……. • Higgs low energy “remnant” of High Energy Strong Dynamics • Severely constrained by EW Precision Tests • Additional states may appear as resonances (Model dependent) • Reduced HVV couplings ➙ Partial restoration of Unitarity up to the High Energy scale Model Independent Low Energy parametrization of composite Higgs models Giudice,Grojean,Pomarol,Rattazzi hep-ph/0703164 Barbieri,Bellazzini,Rychkov,Varagnolo arXiv:0706.0432

  8. qq→4qlv(EW) M(VW)>800GeV +pT+E+η+Mij cuts Small sensitivity to MH in SM range ⇒ SM predictions well defined. Not just counting exp Accomando,Ballestrero,Bolognesi,E.M.,Mariotti JHEP 0603(2006)093 hep-ph/0512219

  9. qq→4qμ+μ--(EW) M(VZ)>800GeV +pT+E+η+Mij cuts Accomando,Ballestrero,Belhouari,Maina PRD 75:113006,2007 hep-ph/0603167 100 fb-1 |ηV|< 2

  10. Looking for Mr. V Boson Butterworth, Ellis, Raklev hep-ph/0702150 Jet in W+jet W jets 70<M<90 GeV pT > 250 GeV Alternatives?

  11. qq→4qlvO(α6)+O(α4αs2) Ballestrero, Bevilacqua,E.M. WVjj ✔ Wjjjj ✘

  12. Closer to the real world FAMOS CMS Note 2007/005 Preliminary Torino+ Milano CMS Group+TH Bkg:Alpgen+Madevent 430 fb-1 needed for S/B1/2=5 in 4qev

  13. Conclusions • Studying EWSB through VV scattering is hard • Semileptonic channels essential • New techniques for reconstructing hadronic V’s needed Plans • Complete qq→4qlv • Alternative models of EWSB

  14. Backup slides

  15. Boson-Boson scattering and Unitarity

  16. Selection 4qμν CMS Note

  17. Selection 4qeν CMS Note

  18. Selection 4qeν continued

  19. Efficiency

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