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Boson Boson Scattering at LHC with PHASE

Boson Boson Scattering at LHC with PHASE. What can we observe at LHC?. Higgs!. Higgs discovery. Unitarity. Unitarization: eg:Butterworth,Cox,Forshaw PRD65(02)96014 different ways of constructing amplitudes which are unitary from low order amp. At the LHC. Incoming V’s are always

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Boson Boson Scattering at LHC with PHASE

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  1. Boson Boson Scattering at LHC with PHASE E. Maina - VV at LHC with Phase - Les Houches 2005

  2. What can we observe at LHC? E. Maina - VV at LHC with Phase - Les Houches 2005

  3. Higgs! E. Maina - VV at LHC with Phase - Les Houches 2005

  4. Higgs discovery E. Maina - VV at LHC with Phase - Les Houches 2005

  5. Unitarity E. Maina - VV at LHC with Phase - Les Houches 2005

  6. Unitarization: eg:Butterworth,Cox,Forshaw PRD65(02)96014different ways of constructing amplitudes which are unitary from low order amp E. Maina - VV at LHC with Phase - Les Houches 2005

  7. At the LHC Incoming V’s are always off-shell E. Maina - VV at LHC with Phase - Les Houches 2005

  8. Large interferences Kleiss-Stirling, PLB182(86)75 • The HE off-shell behaviour is worse than on-shell When the V’s are off-shelll emission from f-lines must be included (a;b)= linear combination of a and b E. Maina - VV at LHC with Phase - Les Houches 2005

  9. PHASE hep-ph/0504009PHact Adaptive Six-fermion Event-GeneratorE. Accomando, A. Ballestrero, E. Maina- Univ. Torino • Dedicated event generator • All • One-shot • Efficient: good coverage of phase-space • Interfaced with showering/hadronization • Problems • Large number of processes • Large number of diagrams/process • Large number of channels/enhanced regions E. Maina - VV at LHC with Phase - Les Houches 2005

  10. PHACT PLB350(95)225 E. Maina - VV at LHC with Phase - Les Houches 2005

  11. E. Maina - VV at LHC with Phase - Les Houches 2005

  12. E. Maina - VV at LHC with Phase - Les Houches 2005

  13. Processes in PHASE1.0 Adding ud<-->cs and e<-->mu ---> 1K processes All particles outgoing E. Maina - VV at LHC with Phase - Les Houches 2005

  14. An interesting example: 1046 diagrams It includes: • ZZ --> W+W- Higgs --> WW • ZW- --> ZW- • W-Z --> ZW- • W-W- --> W-W- • W- --> W-W+W- with 2 Higgs --> WW channels • W- --> ZZW- Higgs --> ZZ Homework: check it out E. Maina - VV at LHC with Phase - Les Houches 2005

  15. Future Improvements • 2q --> 4qlnu @ O(as2aw4) First result later • 2q --> 4ql+l- in integration test ZW&ZZ final states semilept • 2q --> 2q4l all ingredients ready ZW&ZZ final states lept • 2g --> 4qlnu @ O(as2aw4) & @ O(as4aw2) Main TOP channel! Amp O(as2aw4) ready Good control of tails is essential • 2g --> 2q4l E. Maina - VV at LHC with Phase - Les Houches 2005

  16. With C. Mariotti and S. Bolognesi, E. Accomando, S. Ballestrero(Torino) First look • pT(q,l+/-)> 10 GeV • E(q,l+/-)>20GeV • M(q,q)>20GeV • Abs(eta(q))<6.5 • Abs(eta(l+/-))<3 • Abs(eta(jc))<3 • eta(jf)>2 • eta(jb)<-2 Reject • 160<M(blnu)<190GeV • 160<M(bqq)<190GeV Require • 70<M(qq)<90GeV E. Maina - VV at LHC with Phase - Les Houches 2005

  17. Top rejection W mass PHASE vs PYTHIA mH=500GeV No Higgs PYTHIA has only LL in EVBA approximation E. Maina - VV at LHC with Phase - Les Houches 2005

  18. VV scattering Cannot be separated from all other EW contributions Expect: • central high pT JJ and lnu from W’s • high energy, high pT forward and backward spectator J Background: • tt • VV+jets • V+jets E. Maina - VV at LHC with Phase - Les Houches 2005

  19. S/B from EW processes in PHASE at parton level Main bkg: tt(EW!), single t, VVV If more than one qq pair is close to MW,Z best match is chosen. Flavour info used. • pT(q,l+/-)> 10 GeV • E(q,l+/-)>20GeV • M(q,q)>20GeV • Abs(eta(q))<6.5 • Abs(eta(l))<3 Reject • 160<M(blnu)<190GeV • 160<M(bqq)<190GeV Require • 70<M(qq)<90GeV • 70<M(lnu)<90GeV • M(jf-jb)MW,MZ E. Maina - VV at LHC with Phase - Les Houches 2005

  20. Spectator vs decay partons E. Maina - VV at LHC with Phase - Les Houches 2005

  21. V(qcqc) spectrum Flavour info No flavour info E. Maina - VV at LHC with Phase - Les Houches 2005

  22. S/B kinematics E. Maina - VV at LHC with Phase - Les Houches 2005

  23. Neural Net Selection of Signal mH=500GeV NoHiggs E. Maina - VV at LHC with Phase - Les Houches 2005

  24. Internal gluon QCD correctionswith G. Bevilacqua (Torino) Includes qq-->tt No external g All PHASE1.0 processes 70<M(jcjc)<90GeV First results: no real analysis E. Maina - VV at LHC with Phase - Les Houches 2005

  25. Conclusions • A new 6f Event Generator is available for VV scattering, Higgs in VBF, top(soon), VVV physics • First results in VV scattering and Higgs production • Extracting Signal is hard WORK is in PROGRESS • New processes • More realistic simulations: FAMOS, CMKIN E. Maina - VV at LHC with Phase - Les Houches 2005

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