[email protected]€¦ · example using gosam+ninja with sherpa: h t t computed more than 10 years...
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Gionata Luisoni
Max Planck Institute for Physics Munich
In collaboration with:
H. Van Deurzen, P.Mastrolia, E.Mirabella, G.Ossola, T.Peraro
15/01/2014 MPI ATLAS-PhenoGroup meeting
G. Luisoni
Outline Computational setup
H t t + 1 jet @ NLO Conclusions & Outlook
15/01/2014 MPI ATLAS-PhenoGroup meeting
G. Luisoni
Computational setup
15/01/2014 MPI ATLAS-PhenoGroup meeting
Tree amplitude Subtraction scheme Phase space integral
Virtual corrections
G. Luisoni
Computational setup
15/01/2014 MPI ATLAS-PhenoGroup meeting
Multipurpose MC event generator:
• Amplitude generation w. subtraction • Phase space integration • Shower • Hadronization • MPI / Minimum bias / …
Automatic 1-loop amplitude calculator:
• Amplitude with Feynman diagrams • Reduction via
• OPP/Laurent expansion • tensor integral
• Interface via BLHA to several MCs
G. Luisoni
pp H t t + 1 jet @ NLO Example using GoSam+Ninja with Sherpa:
H t t computed more than 10 years ago Relevant for determination of Higgs-top Yukawa coupling Two different masses: mH, mT --> challenging computation
15/01/2014 MPI ATLAS-PhenoGroup meeting
[Dittmaier et al.; Reina et al.]
H t t + 1 jet
Processes #Diagrams # Groups Timing (col.+hel. summed)
320 18 3
1895 1575
223 ms 1505 ms
16 32
# Hel.
[van Deurzen, G.L., Mastrolia, Mirabella, Ossola, Peraro]
G. Luisoni
pp H t t + 1 jet @ NLO Two different choices of scales:
Physical setup: LHC 8 TeV anti-kt: R=0.5 pT>15 GeV |η| < 4.0 PDFs: cteq6L1 @ LO CT10 @ NLO
15/01/2014 MPI ATLAS-PhenoGroup meeting
with: ;
;
Very stable results with different scales!
G. Luisoni
pp H t t + 1 jet @ NLO
15/01/2014 MPI ATLAS-PhenoGroup meeting
Two different choices of scales:
G. Luisoni
pp H t t + 1 jet @ NLO Higgs pseudorapidity
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G. Luisoni
pp H t t + 1 jet @ NLO Higgs transverse momentum
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G. Luisoni
pp H t t + 1 jet @ NLO Higgs transverse momentum
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G. Luisoni
pp H t t + 1 jet @ NLO
15/01/2014 MPI ATLAS-PhenoGroup meeting
Top-antitop observables
G. Luisoni
pp H t t + 1 jet @ NLO Top-antitop-Higgs observables
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G. Luisoni
Conclusions & Outlook GoSam+Sherpa
Used for first computation of Htt+1 jet
Preliminary analysis using two different dynamical scales
Significant reduction of scale uncertainties
NLO contribution can distort shapes
Codes and libraries are available
Outlook:
More refined analysis in terms of:
observables / cuts / shower / hadronization / merging
Specific requests?
15/01/2014 MPI ATLAS-PhenoGroup meeting
G. Luisoni
PS: Ninja
15/01/2014 MPI ATLAS-PhenoGroup meeting
Tested recently on several processes:
Reduced timing Increased stability
[Van Deurzen, Luisoni, Mastrolia, Mirabella, Ossola, Peraro]
* Different CPU.