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MadGraph Samples for LHC physics
Aim of the project
Produce a database of validated LHC parton-level (and possibly hadron-level) MC events with MadGraph and the corresponding codes for large scale production. Main SM backgrounds and signals should be included, as well as representative BSM samples.
Motivation
MC's samples will play a fundamental role in the path to making discoveries at the LHC. Latest generation of the MC's have improved on several important aspects: from a more accurate simulation of events with multi-jet final states (with ME/PS matching) to full flexibility on new physics models implementation.
The increasein the MC powers is paralleled by the larger complexity of the codes both at the computational and user level, leading to the need of a continuous and reliable support from the MC developers. Normally, many issues arise in the dey-to-day use of such codes, some of which become essential in the final experimental analyses.
We propose to provide samples and codes for key SM and BSM processes at the LHC.
For each process we plan to publish:
- Small-size (<1M) parton-level and hadron level (Pythia) sample.
- Associated (frozen) code for large scale production over the grid.
The samples and the associated codes would be therefore validated by the MC authors and directly used by experimentalists or as a reference (comparison) with dedicated analysis generations.
A public set of samples to be used as a common reference by all the LHC community (exp and th) could be very useful for other reasons. For instance, they could form a base for future comparisons between experiments or make the interactions with theorists (both model builders and MC developers) easier.
People
- MadGraph Team (including Steve Mrenna)
- Roberto Chierici & Paolo Bartalini (CMS)
- Interested: Jon Butterworth & Osamu Jinnouch (ATLAS)
Tools
- MadGraph/ MadEvent v4 :
- SM
- BSM (SUSY, topBSM, 2HDM, UED,...)
- ME/PS matching within Pythia
- GridDevelopment: How to use the grid packs
- MatchChecker
Modus Operandi
We have identified three phases:
- Agreement on the definition of the most important samples (all)
- List of processes
- Trigger or acceptance cuts
- SM Parameters
- Benchmark points and models for BSM
- MC codes and samples generation and validation (mg team + anybody interested)
- Large scale samples generation with (full) detector simulation (CMS+ATLAS)
Matching validation will be performed with MatchChecker.
Definition of the most important samples
A sample is defined by specifying:
- Model
- Initial state and final state particles
- Couplings (EW, and QCD)
- Phase space region
Information for MG/ME generation is collected in the banner through which a the sample can be fully reproduced.
SM parameters
- Masses -> latest best values. LO parameters for EW.
- PDF set and alphaS : cteq?
- Scales: for matched samples these are automatically set by the code.
Standard Model Samples
| QCD Jets | |||||||
| Process | Stars | Couplings | Binning | Phase space region | Matching | Event files | Remarks |
| jets (2) | 3. | QCD only | HT bins (100-250 !GeV, 250-500 !GeV, 500-1000 !GeV, 1000-inf !GeV) | abs(eta(j))<5, Ptj>20 !GeV | 0,1,2,3,4+ | light jets are u,d,c,s,b,g; Need to veto the first gluon splitting into bb in the PS | |
| bb~ + jets | 3. | QCD only | HT bins (100-250 !GeV, 250-500 !GeV, 500-1000 !GeV, 1000-inf !GeV) | abs(eta(j))<5, Ptj>20 !GeV | 0,1,2,3+ | massive b; Need to veto the first gluon splitting into bb in the PS | |
| bb~ bb~+ jets | 1. | QCD only | none | 0,1+ | massive b |
| Vector Boson | |||||||
| Process | Stars | Couplings | Binning | Phase space region | Matching | Event files | Remarks |
| W (-> l v)+ jets | 3 | EW=2 + QCD | none | all | 0,1,2,3,4+ | W=W+,W- ; l=(e,mu,tau) | |
| Z /a (-> l+l-)+ jets | 3 | EW=2 + QCD | none | m(l+l-)>50 !GeV | 0,1,2,3,4+ | photon is included ; l=(e,mu,tau) | |
| Z /a (-> l+l-)+ jets | 3 | EW=2 + QCD | none | 50>m(l+l-)>10 !GeV, HT>30 !GeV | 0,1,2,3,4+ | photon is included ; l=(e,mu,tau) | |
| Z (-> vv)+ jets | 3 | EW=2 + QCD | none | pt(Z)>50 !GeV | 0,1,2,3,4+ | ||
| V (-> l l')+ QQ~ | 1 | EW=2+QCD | none | all | no | V=W+,W-,Z ; l=(e,mu,tau,v), (Z->vv included) Q=b, c | |
| a + jets | 3 | EW=1 + QCD | HT bins (40-100 !GeV, 100-200 !GeV, 200-inf !GeV) | pt(a)>20 !GeV, abs(eta(a))<2.5, !DeltaR(a,jet)>0.3 | 0,1,2,3,4+ | ||
| a + QQ~ + jets | 1 | EW=1 + QCD | none | pt(a)>20 !GeV, abs(eta(a))<2.5, !DeltaR(a,jet)>0.3 | 0,1,2+ | photon; Q=b |
| Vector Bosons | |||||||
| Process | Stars | Couplings | Binning | Phase space region | Matching | Event files | Remarks |
| VV(-> 4l)+ jets | 3 | EW=2+QCD | none | m(l+l-)>10 !GeV; m(lv)>30 !GeV | 0,1+ | V=W+,W-,Z l=(e,mu,tau,v) | |
| VV (-> 4l) + QQ~ | 1 | EW=1 + QCD | none | all | no | V=W+,W-,Z l=(e,mu,tau,v), Q=b | |
| aV(-> 2l)+ jets | 1 | EW=2+QCD | none | pt(a)>20 !GeV, !DeltaR(a,jet)>0.3 | 0,1+ | V=W+,W-,Z l=(e,mu,tau,v) | |
| a a + jets | 1 | EW=2+QCD | none | pt(a)>20 !GeV, abs(eta(a))<2.5, !DeltaR(a,jet)>0.3 | 0,1,2+ | photon | |
| a a + QQ~ + jets | 1 | EW=1 + QCD | none | pt(a)>20 !GeV, abs(eta(a))<2.5, !DeltaR(a,jet)>0.3 | no | photon; Q=b | |
| V V V | 3 | EW=3 | none | all | no | V=W+,W-,Z | |
| a a a | 3 | EW=3 | none | pt(a)>20 !GeV, abs(eta(a))<2.5, !DeltaR(a,jet)>0.3 | no |
| Top | |||||||
| Process | Stars | Couplings | Binning | Phase space region | Matching | Event files | Remarks |
| tt + jets ' | 3 | QCD only | none | all | 0,1,2,3+ | top decays into everything. Done with DECAY | |
| tt + bb~ | 3 | QCD only | none | all | no | top decays into everything. Done with DECAY | |
| tjb | 3 | EW=4, QCD=1 | none | all | no | t-channel, b massive, leptonic top decay | |
| tj | 3 | EW=4, QCD=0 | none | all | no | t-channel, leptonic top decay | |
| tb | 3 | EW=4, QCD=0 | none | all | no | s-channel, b massive, leptonic top decay | |
| tW | 3 | EW=5, QCD=1 | none | all | no | tW-channel, inclusive top and W decays | |
| tWb | 3 | EW=5, QCD=2 | none | all | no | tW-channel, b-massive, doub-res diagram subtraction, inclusive top and W decays |
| Higgs | ||||||||
| Process | Stars | Couplings | Binning | Phase space region | Matching | Event files | Remarks | |
| Higgs + jets | 3 | QCD only | none | all | 0,1,2,3+ | HEFT, mh=115,125,135,145,160,180,200 !GeV | ||
| Higgs + 2 jets | 3 | EW only | none | all | no matching | mh=115,125,135,145,160,180,200 !GeV includes V (->jj) + Higgs | ||
| tt~ + Higgs | 3 | QCD=2,EW=1 | none | all | 0,1+ | mh=115,125,135,145,160,180,200 !GeV | ||
| V (-> l l') + Higgs + jets | 3 | EW=3 + QCD | none | all | 0,1,2 | mh=115,125,135,145,160,180,200 !GeV |
New Physics Samples
- MSSM : we use the Snowmass benchmark points
- UserModel : Z' into leptons
- TopBSM : New resonances in the ttbar invariant mass spectrum
- TwoHiggsDoublet : Alternative EWSB scenarios
Some LHE files and cards used for validation
Please note that these files need to be passed through the Pythia package found on the MG/ME download page. For all jet multiplicities below the highest multiplicity wanted, IEXCFILE=1 must be specified in the pythia_card.dat. For the highest multiplicity wanted, IEXCFILE=0 must be specified.
W+ > l+ vl
| Sample | events | xqcut | LHE file | Banner |
| W+ 0jet | 100k | 10 | lhe_file | banner |
| W+ 1jet | 100k | 10 | lhe_file | banner |
| W+ 2jet | 100k | 10 | lhe_file | banner |
| W+ 3jet | 100k | 10 | lhe_file | banner |
| W+ 4jet | 100k | 10 | lhe_file | banner |
---
W- > l- vl~
| Sample | events | xqcut | LHE file | Banner |
| W- 0jet | 100k | 10 | lhe_file | banner |
| * W- 1jet* | 100k | 10 | lhe_file | banner |
| W- 2jet | 100k | 10 | lhe_file | banner |
| W- 3jet | 100k | 10 | lhe_file | banner |
| W- 4jet | 100k | 10 | lhe_file | banner |
---
Z/a > l+ l-
| Sample | events | xqcut | M(l+l-) | LHE file | Banner |
| Z/a 0jet | 100k | 10 | 50 | lhe_file | banner |
| Z/a 1jet | 100k | 10 | 50 | lhe_file | banner |
| *Z/a 2jets | 100k | 10 | 50 | lhe_file | banner |
| Z/a 3jets | 100k | 10 | 50 | lhe_file | banner |
| Z/a 4jets | 5x 20k | 10 | 50 | lhe_file1, lhe_file2, lhe_file3, lhe_file4, lhe_file5 | banner |
Z > v v~
| Sample | events | xqcut | LHE file | Banner |
| Z + 1jet | 100k | 10 | lhe_file | banner |
| Z + 2jets | 100k | 10 | lhe_file | banner |
| Z + 3jets | 100k | 10 | lhe_file | banner |
| Z + 4jets | 100k | 10 | lhe_file | banner |
ttbar+ jets:
Please specify QCUT=30 (or as indicated below) in the pythia_card.dat.
| Sample | events | xqcut | QCUT | LHE file | Banner |
| ttbar+ 0 jet | 100k | 20 | 30 | lhe_file | banner |
| ttbar+ 1 jet | 100k | 20 | 30 | lhe_file | banner |
| ttbar+ 2jets | 100k | 20 | 30 | lhe_file | banner |
| ttbar+ 3jets | 100k | 20 | 30 | lhe_file | banner |
MC samples generation and validation
People involved in the generation/validation should report progress in the DevelopmentArea (you have to be registered in the team to access this page).
Sample codes for the grid
LHC @ 10 !TeV - Gridpacks used for production
Please note that all cross-sections in the following do include the correct BR already. Typically, the results is given for all the lepton families included.
Non matched processes
| GridPack | xsec |
| V+QQ, i.e. Z,W+ or W- + bb~ or cc~ (massive) | |
| gridpack | 289 pb |
| W+ and W- + c quark (massive) | |
| gridpack | 1487 pb |
| single top s-channel | |
| Including leptonic top decay, $\mu_R=\mu_F=m_{top}$ | |
| gridpack | 1.66 pb |
| single top t-channel pp>tj (p=u,d,s,c,b,g) | |
| Including leptonic top decay, $\mu_R2=\mu_F2=m_{top}2+Q2$, initial state b-quark | |
| gridpack | 43.7 pb |
| single top t-channel pp>tbj (p=u,d,s,c,g) | |
| Including leptonic top decay, $\mu_R2=\mu_F2=m_{top}2+Q2$, massive b-quark | |
| gridpack | 27.6 pb |
| single top W associate pp>tW (p=u,d,s,c,b,g) | |
| Inclusive top and W decays, $\mu_R=\mu_F=m_{top}$, initial state b-quark | |
| gridpack | 27.5 pb |
| single top W associate pp>tbW (p=u,d,s,c,g) | |
| Inclusive top and W decays, $\mu_R=\mu_F=m_{top}$, double resonant diagrams (ttbar) subtracted, massive b-quark | |
| ar.gz gridpack | 17.1 pb |
Matched processes
| GridPack | Efficiency (xqcut,qcut) | xsec after matching |
| ttbar +0,1,2,3 | ||
| Including integration grids and with (inclusive) top decay using DECAY. Generation time for 1000 events: about 1h30 on a 3.00 GHz P4 desktop machine. | ||
| mini-soup (4 flavors) with decay | ~33% (20,30) | 317 pb |
| mini-soup (5 flavors) with decay | ~33% (20,30) | 317 pb |
| W into leptons + 0,1,2,3,4j (5 flavors) | ||
| running time: ~30-40 min for 1000 events | ||
| mini-soup | ~45%(10,15) | ~40nb |
| Z/a into leptons + 0,1,2,3,4j (5 flavors) with mll>50 GeV | ||
| running time: ~90 min for 1000 events | ||
| mini-soup | ~40%(10,15) | ~3.7 nb |
| Z/a into leptons + 0,1,2,3,4j (5 flavors) with 10<mll<50 GeV and Sum over jet pt's>30 GeV | ||
| running time: ~90 min for 1000 events | ||
| mini-soup | to be tested (xqcut=5,qcut=10?) | to check |
| Z into nunu + 0,1,2,3,4j (5 flavors) | ||
| running time: ? | ||
| mini-soup | to be tested | ~11.1 nb |
| VV into leptons + 0,1j (5 flavors) | ||
| running time: ? | ||
| mini-soup | to be tested | 11.8 pb |
| QCD: 2,3,4j (5 flavors) | ||
| pay attention to the change of xqcut (and then Qcut has to be changed) between Slice 1,2 and 3,4: qcut=30 for slice 1,2 and 60 for 3,4. This is done in order to increase the efficiency | ||
| (100,250) GeV | ~34%(20,30) | ~15 microbarn |
| (250,500) GeV | ~20% (20,30) | ~400 nanobarn |
| (500,1000) GeV | ~30%(40,60) | ~14 nanobarn |
| (1000,...) | ~20%(40,60) | ~370 picobarn |
| b-enriched :bb+0,1,2,3;b+1,2,3,b~+1,2,3 | ||
| pay attention to the change of xqcut (and then Qcut has to be changed) between Slice 1,2 and 3,4: qcut=30 for slice 1,2,3 and 60 for 4. This is done in order to increase the efficiency | ||
| (100,250) GeV | ~28% (20,30) | ~450 nanobarn |
| (250,500) GeV | ~15% (20,30) | ~15 nanobarn |
| (500,1000) GeV | ~10% (20,30) | ~700 picobarn |
| (1000,inf) GeV | ~15% (40,60) | ~13 picobarn |
| a+1,2,3,4 j (5 flavor) | ||
| cross section are given before matching | ||
| (40,100) GeV | ~11% (5,10) | ~ 368.7 nb |
| (100,200) | ~?% (5,10) | ~103.6 nb |
| (200,inf) | ~?% (10,15) | ~10.49 nb |
LHC @ 14 !TeV - Gridpacks used for production
Please note that all cross-sections in the following do include the correct BR already. Typically, the results is given for all the lepton families included.
Non matched processes
| GridPack | xsec |
| single top s-channel | |
| Including leptonic top decay, $\mu_R=\mu_F=m_{top}$ | |
| gridpack | 2.65 pb |
| single top t-channel pp>tj (p=u,d,s,c,b,g) | |
| Including leptonic top decay, $\mu_R2=\mu_F2=m_{top}2+Q2$, initial state b-quark | |
| gridpack | 82.8 pb |
| single top t-channel pp>tbj (p=u,d,s,c,g) | |
| Including leptonic top decay, $\mu_R2=\mu_F2=m_{top}2+Q2$, massive b-quark | |
| gridpack | 55.6 pb |
| single top W associate pp>tW (p=u,d,s,c,b,g) | |
| Inclusive top and W decays, $\mu_R=\mu_F=m_{top}$, initial state b-quark | |
| gridpack | 62.4 pb |
| single top W associate pp>tbW (p=u,d,s,c,g) | |
| Inclusive top and W decays, $\mu_R=\mu_F=m_{top}$, double resonant diagrams (ttbar) subtracted, massive b-quark | |
| gridpack | 41.5 pb |
Matched processes
| GridPack | Efficiency (xqcut,qcut) | xsec after matching |
| ttbar +0,1,2,3 | ||
| Including integration grids and with (inclusive) top decay using DECAY. Generation time for 1000 events: about 1h30 on a 3.00 GHz P4 desktop machine. | ||
| 4-flavor | ~27% (20,30) | ~750 pb |
| 5-flavor | ~27% (20,30) | ~750 pb |
| W into leptons + 0,1,2,3,4j (5 flavors) | ||
| running time: ~30-40 min for 1000 events | ||
| gridpack.tar.gz | ~40% (10,15) | 60 nb |
| Z/a into leptons + 0,1,2,3,4j (5 flavors) with mll>50 GeV | ||
| running time: ~90 min for 1000 events | ||
| gridpack.tar.gz | ~45% (10,15) | ~7 nb |
| Z/a into leptons + 0,1,2,3,4j (5 flavors) with 10<mll<50 GeV and Sum over jet pt's>30 GeV | ||
| running time: ~90 min for 1000 events | ||
| to come | to be tested (xqcut=5,qcut=10?) | to check |
| Z into nunu + 0,1,2,3,4j (5 flavors) | ||
| running time: ? | ||
| mini-soup | to be tested | ~19.5 nb |
| VV into leptons + 0,1j (5 flavors) | ||
| running time: ? | ||
| mini-soup | to be tested | 19.3 pb |
| QCD: 2,3,4j (5 flavors) | ||
| (100,250) GeV | ~30% (20,30) | ~24 mb |
| (250,500) GeV | ~18% (20,30) | ~770 nb |
| (500,1000) GeV | ~12% (20,30) | ~36 nb |
| (1000,inf) GeV | ~9% (20,30) | ~1 nb |
| b-enriched :bb+0,1,2,3;b+1,2,3,b~+1,2,3 | ||
| (100,250) GeV | ~50% (20,30) | ~900 nb |
| (250,500) GeV | ~30% (20,30) | ~50 nb |
| (500,1000) GeV | ~20% (20,30) | ~4 nb |
| (1000,inf) GeV | ~20% (20,30) | ~0.15 nb |
| a+1,2,3,4 j (5 flavor) | ||
| cross section are given before matching | ||
| (40,100) | ~11% (5,10) | ~574 nb |
| (100,200) | ~18% (5,10) | ~174 nb |
| (200,inf) | ~27% (10,15) | ~19 nb |
Productions with 1 multiplicity / sample
tt~ +jets:
- tt~ : without integration grids and with integration grids and with integration grids and (inclusive) top decay (4-flavor)
- tt~ + j : without integration grids and with integration grids and with integration grids and (inclusive) top decay (4-flavor)
- tt~ + jj : without integration grids and with integration grids and with integration grids and (inclusive) top decay (4-flavor)
- tt~ + jjj : without integration grids and with integration grids and with integration grids and (inclusive) top decay (4-flavor)
| Process | * EXCL. Xsec (Qcut=30)* | * INCL. xsec (Qcut=30)* | Efficiency of the matching |
| tt~ | 309 pb | / | 52% (excl) |
| tt~+ 1 jet | 222 pb | / | 28% (excl) |
| tt~+ 2 jets | 100 pb | / | 14% (excl) |
| tt~+ 3 jets | / | 63 pb | 14% (incl) |
Differences of cross sections between 4 and 5 flavor are too small to be taken into account here. Notes
- xqcut used: 20 GeV -> Qcut=30 GeV to be used in pythia_card.dat
- for the 0,1,2 jets multiplicities, use IEXCFILE=1
W+ + light jets only (udscg)
Notes
- xqcut used: 10 GeV -> Qcut=15 GeV to be used in pythia_card.dat
- for all multiplicities EXCEPT the highest, use IEXCFILE=1
| Process | GridPack | * EXCL. Xsec (Qcut=15)* | * INCL. xsec (Qcut=15)* |
| (w+>leptons) +0 jet | gridpack.tar.gz | 22.5 nb | / |
| (w+>leptons) +1 jets | gridpack.tar.gz | 8.1 nb | / |
| (w+>leptons) +2 jets | gridpack.tar.gz | 2.8 nb | / |
| (w+>leptons) +3 jets | gridpack.tar.gz | 1 nb | 1.6 nb |
| (w+>leptons) +4 jets | to come | ||
W- + light jets only (udscg)
| Process | GridPack | * EXCL. Xsec (Qcut=15)* | * INCL. xsec (Qcut=15)* |
| (w->leptons) +0 jet | gridpack.tar.gz | 16.5 nb | |
| (w->leptons) +1 jets | gridpack.tar.gz | 5.7 nb | |
| (w->leptons) +2 jets | gridpack.tar.gz | nb | |
| (w->leptons) +3 jets | gridpack.tar.gz | nb | |
| (w->leptons) +4 jets | to come | ||
Notes
- xqcut used: 10 GeV -> Qcut=15 GeV to be used in pythia_card.dat
- for all multiplicities EXCEPT the highest, use IEXCFILE=1
Other notes
For the pythia step treatement the following parameter could be usefull:
- MSTP(81)=0 !use virtuality-ordered showers
- MSTP(5)=109 ! tune to use the Underlying Events for PDF CTEQ6L1
Typical run time
Reference machine is a recent macbook running Leopard, intel CPU 2.16 GHz Dual Core 2 (but only one CPU is used of course), 4Mb of L2 cache and 1Go of RAM. The process is (W+>e+ve)+jets at the LHC, with all parameters and cuts set to their default values. The warming up time is for a rather slow 24*1GHz cluster (FYNU cluster at UCL). The compiled gridpack sizes are for static linking only, dynamic linking should decrease them a lot. Also, the run time is not expected to scale linearly with the number of essay diagrams, in particular for complicated processes. Generating 10K W+2j events could take only 2h, not 12h!
| Process | total # diag. | # subproc | Warming up time | Gridpack size | Compilation Time | Compiled gridpack size | Time to generate 1000 events |
| (W+>e+ve)+0j | 2 | 2 | 2min | 0.9Mb | 10s | 1.1 Mb | 5s |
| (W+>e+ve)+1j | 12 | 6 | 5min | 1.0Mb | 30s | 1.7 Mb | 1min40 |
| (W+>e+ve)+2j | 188 | 50 | 20min | 2.8 Mb | 2min10 | 8.5 Mb | 69min |
| (W+>e+ve)+3j | 1848 | ? | 112min | 14 Mb | 6min | 22 Mb | ? |
