MC(4BSM) Overview. Kentarou Mawatari,

Transcription

1 MC(4BSM) Overview Kentarou Mawatari, 1. History of MC4BSM 2. BSM workflow at the LHC 3. Beyond LO+PS 4. Summary and outlook disclaimer (Who am I?) I m a pheno person. I m a heavy user of MC tools, but not a real developer I d stayed for 5 years in Brussels and worked with MAD people, so 1 /30

2 1. History of MC4BSM 2 /30

3 10th anniversary of MC4BSM! 06 Fermilab 07 Princeton 08 CERN 09 UC Davis 10 NBI, Copenhagen 12 Cornell 13 DESY, Hamburg 14 IBS, Daejeon 15 Fermilab 16 UCAS, Beijing 17??? 3 /30

4 MC4BSM before the LHC 4 /30

5 The first MC4BSM (2006) agenda 5 /30

6 MC4BSM in the LHC era 6 /30

7 The 10th MC4BSM (2016) Agenda 4 days (8:30-18:30) more than 100 participants LHC results beyond LHC beyond LO tutorials 17 tools + more 7 /30

8 MC4BSM survey 1. Who are theorists/experimentalists? 2. Who are young? Who are PhD students? 3. How many tools among 17 have you ever heard? 4. How many tools among 17 have you ever used? Herwig, Pythia, Sherpa, GAMBIT, Grace, FDC, MadGraph, Whizard, CompHEP, CalcHEP, Gosam, Fastjet, Checkmate, FastLim, FeynRules, MadAnalysis, Delphes 8 /30

9 Why do we need MC event generators? need to produce fully exclusive events to be compared with data. 9 /30

10 Why do we need MC event generators? Martini, KM, Sengupta [PRD, ] [Bernon, Goudelis, Kraml, KM, Sengupta, JHEP ] 10/30

11 Do we need MC for the γγ resonance search? ATLAS [ ] 11/30

12 Do we need MC for the γγ resonance search? ATLAS Higgs diphoton [ ] None of searches can be done without MC. 12/30

13 2. BSM workflow at the LHC 13/30

14 MC generators 10 years ago Durham University HERWIG and PYTHIA Peter Richardson IPPP, Durham University MC4BSM 20 th March 1 14/30

15 MC generators 10 years ago Built In Models SUSY SUSY+RPV RS Gravitons Z /W Technicolor Left-Right Models Compositeness Excited fermions Leptoquarks Fourth generation HERWIG PYTHIA MC4BSM 20 th March 7 15/30

16 MC generators 10 years ago Conclusions The existing HERWIG and PYTHIA programs will remain the workhorses of event simulation in the near future. Unlikely to be any new models implemented in them directly. New processes should use the Les Houches. The simulation in the new C++ generators will be different and hopefully allow more models to be studied. MC4BSM 20 th March 24 16/30

17 BSM workflow: about 10 years ago take a BSM model (symmetry, particle contents, ), i.e. Lagrangian derive the Feynman rules draw Feynman diagrams for our interesting 2 2 processes compute the amplitude (squared) implement it into a generator manually generate events parton-shower/hadronisation detector simulation analysis Herwig, Pythia 17/30

18 model files DM physics tool DM annihilation DM-N cross section LHE file HEP file LHCO file BSM workflow: now at NLO take a BSM model (symmetry, particle contents, ), i.e. Lagrangian derive the Feynman rules draw Feynman diagrams for our interesting any processes compute the amplitude (squared) implement it into a generator manually generate events parton-shower/hadronisation detector simulation analysis Matrix-element generator Shower MC 18/30

19 LHE (Les Houches Events) file e.g. p p > X2(750) + j 19/30

20 MC4BSM2016 tools take a BSM model (symmetry, particle contents, ), i.e. Lagrangian derive the Feynman rules FeynRules draw Feynman diagrams for our interesting any processes compute the amplitude (squared) generate events parton-shower/hadronisation Herwig, Pythia, Sherpa Grace, MadGraph, Whizard, CompHEP, CalcHEP, FDC, Gosam micromegas MadDM detector simulation analysis Fastjet, Delphes GAMBIT, Checkmate, FastLim, MadAnalysis 20/30

21 3. Beyond LO+PS 21/30

22 PS alone vs. ME+PS merging Dreiner, Kraemer, Tattarsall [ ] 22/30

23 PS alone vs. ME+PS merging Dreiner, Kraemer, Tattarsall [ ] Improving QCD predictions and reducing MC uncertainties. 23/30

24 Matrix elements vs. Parton showers ME Fixed order calculation computationally expensive (limited number of particles) Valid when partons are hard and well separated PS Resums logs to all orders computationally cheap (No limit on particle multiplicity) Valid when partons are collinear and/or soft Let s merge them! But without double counting 24/30

25 NLO+PS Born virtual NLO ME + PS without double counting real Degrande, Fuks, Hirschi, Proudom, Shao [ ] 25/30

26 ME+PS [ ] 26/30

27 ME+PS ATLAS [ ] 27/30

28 Amazing precision SM backgrounds Standard Model Production Cross Section Measurements Status: June 2016 σ [pb] 80 µb 1 total (x2) 60 µb ATLAS Preliminary inelastic Theory µb 1 n j < p T < 2 TeV n j < m jj < 5TeV p T > 25 GeV n j 0 Run 1,2 s =7,8,13TeV LHC pp s =7TeV Data fb 1 LHC pp s =8TeV Data 20.3 fb p T > 100 GeV n j 0 n j 1 n j 0 n j 2 n j 1 n j 1 n j 3 n j 2 n j 2 n j 4 n j 3 n j 3 n j 4 n j 5 n j 4 n j 6 n j 5 n j 6 total n j 4 n j 5 n j 6 n j 7 n j 8 t-chan Wt s-chan 2.0 fb 1 WZ ZZ WW WZ ZZ WW WZ ZZ? total ggf H WW H ττ VBF H WW Zγ W γ Zγ LHC pp s =13TeV Data fb n j 7 n j 7 H γγ H ZZ 4l W ± W ± WZ pp Jets R=0.4 γ fid. W fid. Z fid. t t fid. t tot. VV tot. γγ fid. H fid. Vγ fid. t twt tz t tγ tot. tot. fid. Zjj EWK fid. Zγγ n j = 0 tot. Wγγ VVjj n j = 0 EWK tot. fid. 28/30

29 4. Summary and outlook 29/30

30 Summary and outlook Congratulation on the 10th anniversary of MC4BSM! Impressive progresses during the last 10 years. - We can simulate any processes in any BSM models at the tree level by ME+PS merging. - NLO+PS matching/merging MC tools provide more reliable predictions, and are becoming the new standard. - Fully automatic NLO-QCD computations for SM processes as well as for several BSM processes, e.g. simplified SUSY and DM models, are already publicly available. What is the next? What should we do toward MC4BSM2026? 30/30