PHANTOM Update

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

description

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 - PowerPoint PPT Presentation

Transcript of PHANTOM Update

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PHANTOM Update

Physics at TeV Colliders Workshop - Les Houches 2007

Ezio Maina

U. of Torino

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PhantomBallestrero, Belhouari,Bevilacqua,E.M.

Dedicated event generator Complete 2→6 O(α6)+O(α4αs

2) p-p, p-pbar, epbar, e++ee----

Complete set of reactions up to pp → 4l2j, ee → 2l4j At LHC: q1q2→f1f2 f3 f4 f5f6 O(α6)+O(α4αs

2)

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

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qqVV prod VV scattering

Higgs

top

VV couplings

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Exact vs VVqq-Prod Decay ⊗uu→uuqqμν Single processqq=u-dbar,c-sbar mh=500GeV

MADEVENT: qqWV Decay⊗

Tuned comparison

Could produce exact result

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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?

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Models of EWSBElectroweak Chiral LagrangianButterworth,Cox,Forshaw PRD65(02)96014Fabbrichesi,Vecchi hep-ph/0703236 many others

Expand LL → LL Amp in partial waves M=∑j aj (s) Pj (cos(ϑ)) SS†=1 |a⇒ j(s)|≤1Low Energy Th. M(VV→VV) s/v∝ 2 No H

Unitarization: one exampleaj = a0j /(1-ia0j) a0j s Small s LET Large s a∝ ⇒ ⇒ j→1

NOT UNIQUE!!Works well in ππ

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Models of EWSB 2

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 modelsGiudice,Grojean,Pomarol,Rattazzi hep-ph/0703164Barbieri,Bellazzini,Rychkov,Varagnolo arXiv:0706.0432

Additional dynamics,dimensions …….

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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

qq→4qlv(EW) M(VW)>800GeV +pT+E+η+Mij cuts

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qq→4qμ+μ-- (EW) M(VZ)>800GeV +pT+E+η+Mij cutsAccomando,Ballestrero,Belhouari,Maina PRD 75:113006,2007 hep-ph/0603167

100 fb-1

|ηV|< 2

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Looking for Mr. V BosonButterworth, Ellis, Raklev hep-ph/0702150

70<M<90 GeV

pT > 250 GeV

Alternatives?

W jets Jet inW+jet

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qq→4qlv O(α6)+O(α4αs2)

Ballestrero, Bevilacqua,E.M.

WVjj Wjjjj ✔ ✘

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Closer to the real worldCMS Note 2007/005 PreliminaryTorino+ Milano CMS Group+TH

FAMOS

Bkg:Alpgen+Madevent

430 fb-1 needed for S/B1/2=5 in 4qev

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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

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Backup slides

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Boson-Boson scattering and Unitarity

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Selection 4qμνCMS Note

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Selection 4qeν CMS Note

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Selection 4qeν continued

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Efficiency