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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 - PowerPoint PPT Presentation
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E. Maina - VV at LHC with Phase - Les Houches 2005
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Boson Boson Scattering at LHC with PHASE
E. Maina - VV at LHC with Phase - Les Houches 2005
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What can we observe at LHC?
E. Maina - VV at LHC with Phase - Les Houches 2005
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Higgs!
E. Maina - VV at LHC with Phase - Les Houches 2005
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Higgs discovery
E. Maina - VV at LHC with Phase - Les Houches 2005
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Unitarity
E. Maina - VV at LHC with Phase - Les Houches 2005
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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
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At the LHC
Incoming V’s are always off-shell
E. Maina - VV at LHC with Phase - Les Houches 2005
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Large interferences Kleiss-Stirling, PLB182(86)75
The HE off-shell behaviour is worse than on-shell€
VL (q12 = m2 + 4 sΔ1)VL (q2
2 = m2 + 4 sΔ2) ⏐ → ⏐ X
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
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PHASE hep-ph/0504009
PHact Adaptive Six-fermion Event-GeneratorE. Accomando, A. Ballestrero, E. Maina- Univ. Torino
€
q1q2 ⏐ → ⏐ q3q4q5q6l1l2
€
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
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PHACT PLB350(95)225
E. Maina - VV at LHC with Phase - Les Houches 2005
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E. Maina - VV at LHC with Phase - Les Houches 2005
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E. Maina - VV at LHC with Phase - Les Houches 2005
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Processes in PHASE1.0
All particles outgoingAdding ud<-->cs and e<-->mu ---> 1K processes
E. Maina - VV at LHC with Phase - Les Houches 2005
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An interesting example:
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
1046 diagrams
E. Maina - VV at LHC with Phase - Les Houches 2005
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Future Improvements
2q --> 4qlnu @ O(as2aw
4) 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(as
2aw4) & @ O(as
4aw2)
Main TOP channel! Amp O(as2aw
4) ready
Good control of tails is essential 2g --> 2q4l
E. Maina - VV at LHC with Phase - Les Houches 2005
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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)<190GeVRequire 70<M(qq)<90GeV
With C. Mariotti and S. Bolognesi, E. Accomando, S. Ballestrero(Torino)
E. Maina - VV at LHC with Phase - Les Houches 2005
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PHASE vs PYTHIA
PYTHIA has only LL in EVBA approximation
mH=500GeV No Higgs
Top rejectionW mass
E. Maina - VV at LHC with Phase - Les Houches 2005
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VV scattering
Expect: central high pT JJ and lnu from W’s high energy, high pT forward and backward spectator J
Background:
Cannot be separated from all other EW contributions
tt VV+jets V+jets
E. Maina - VV at LHC with Phase - Les Houches 2005
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S/B from EW processes in PHASE at parton level
Main bkg: tt(EW!), single t, VVV
pT(q,l+/-)> 10 GeVE(q,l+/-)>20GeVM(q,q)>20GeVAbs(eta(q))<6.5Abs(eta(l))<3
Reject160<M(blnu)<190GeV160<M(bqq)<190GeVRequire70<M(qq)<90GeV70<M(lnu)<90GeV M(jf-jb)MW,MZ
If more than one qq pair is close to MW,Z
best match is chosen. Flavour info used.
E. Maina - VV at LHC with Phase - Les Houches 2005
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Spectator vs decay partons
E. Maina - VV at LHC with Phase - Les Houches 2005
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V(qcqc) spectrum
No flavour info Flavour info
E. Maina - VV at LHC with Phase - Les Houches 2005
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S/B kinematics
E. Maina - VV at LHC with Phase - Les Houches 2005
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Neural Net Selection of Signal
mH=500GeV NoHiggs
E. Maina - VV at LHC with Phase - Les Houches 2005
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Internal gluon QCD correctionswith G. Bevilacqua (Torino)
Includes qq-->tt No external g
First results: no real analysis 70<M(jcjc)<90GeV
All PHASE1.0 processes
E. Maina - VV at LHC with Phase - Les Houches 2005
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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 productionExtracting Signal is hard
WORK is in PROGRESS
New processes More realistic simulations: FAMOS, CMKIN