Joseph Lykken Fermilab

Transcription

1 Joseph Lykken Fermilab LHC Theory Initiative Fellows Meeting, 30 April 2008

2 Monte Carlo Tools for Beyond the Standard Model Physics 3rd workshop: MARCH 10-11, 2008 (CERN) Note: both days will be full days. Participants who don't want to miss anything should plan on arriving Mar 9 and leaving Mar 12. Organizing committee: Georges Azuelos, Christophe Grojean, Jay Hubisz, Borut Kersevan, Joe Lykken, Fabio Maltoni, Konstantin Matchev, Filip Moortgat, Steven Mrenna, Maxim Perelstein, Peter Skands, James Wells : mc4bsm.at.phys.ufl.edu 2nd workshop: MARCH 21-24, 2007 (PRINCETON) Organizing committee:jay Hubisz, Konstantin Matchev, Steven Mrenna, Maxim Perelstein, Peter Skands. 1st workshop: MARCH 20-21, 2006 (FERMILAB) Organizing Committee: Marcela Carena, Mu Chun Chen, Bogdan Dobrescu, Chris Hill, Jay Hubisz, Joe Lykken, Konstantin Matchev, Stephen Mrenna, Maxim Perelstein, Jose Santiago, Peter Skands.

3 MC4BSM: This series of mini-workshops aims to gather together theorists and experimentalists interested in developing and using Monte Carlo tools for Beyond the Standard Model Physics in an attempt to be prepared for the analysis of data focusing on the Large Hadron Collider. Since a large number of excellent tools already exist for the study of low energy supersymmetry and the MSSM in particular, this workshop will instead focus on tools for alternative TeV-scale physics models. The main goals of the workshop are: To survey what is available. To provide feedback on user experiences with Monte Carlo tools for BSM. To identify promising models (or processes) for which the tools have not yet been constructed and start filling up these gaps. To propose ways to streamline the process of going from models to events, i.e. to make the process more user-friendly so that more people can get involved and perform serious collider studies outside of the MSSM.

4 MC4BSM: summer 1996 There was a Snowmass Study in the summer of 1996 Howie Baer and I were the SUSY theory conveners The only SUSY event generator available was ISASUSY (Steve Mrenna s SPYTHIA appeared later that year) Only the ISAJET Mafia really knew how to do SUSY simulations Frank Paige (future ATLAS SUSY convener) and Ian Hinchliffe (future ATLAS physics coordinators) spent all of Snowmass generating LHC msugra events This became the basis for the SUSY chapter in the ATLAS physics TDR

5 MC4BSM: summer 1996 My job at Snowmass was to look at SUGRA models with nonuniversal gaugino masses In principle ISASUSY could handle this, but only if you were happy with α s (M Z ) = 0.14 So I ended up hacking the code. There was no way to validate anything that anyone was doing, and the SM backgrounds were order of magnitude wrong If the SSC had turned on in 1998, we would have been in big trouble

6 MC4BSM: spring 2008 The number, quality and maturity of publically available simulation tools has grown enormously:

7 Supersymmetry CALCHEP: MSSM tree-level matrix element generator. Phase space integration and event generation. Extensions possible. COMPHEP: MSSM tree-level matrix element generator. Phase space integration and event generation. Extensions possible. CPSUPERH: Higgs phenomenology in the MSSM with explict CP Violation. FEYNHIGGS: MSSM Higgs sector including explicit CP-violation (masses, couplings, branching ratios, and cross sections). HERWIG: Event generator for the MSSM (with and without RPV). Interface to ISAJET. ILCSLEPTON: NLO cross-sections for slepton production in e + e and e e collisions. HDECAY: MSSM Higgs decay widths including loop effects. ISAJET: MSSM event generator. MSSM mass and coupling spectrum, decay widths. Checks against experimental constraints. MICROMEGAS: MSSM (work on CPV in progress) and NMSSM dark matter relic density. NMHDECAY: NMSSM mass spectrum plus couplings and decay widths of all Higgs bosons. Checks against experimental constraints. O MEGA: MSSM tree-level matrix element generator. Extensions possible. PROSPINO: SUSY-NLO cross sections at hadron colliders. PYTHIA: MSSM event generator. RPV decays. Extensions to R-hadrons and NMSSM available. SDECAY: MSSM decay widths including loop effects. SHERPA: MSSM event generator. SOFTSUSY: MSSM mass and coupling spectrum. SPHENO: MSSM mass and coupling spectrum, decay widths, and e + e cross sections. SUSPECT: MSSM mass and coupling spectrum. SUSY-MADGRAPH: MSSM Matrix Elements. SUSYGEN3: MSSM event generator (with and without RPV).

8 CMSSW GeneratorInterfaces Generator View CVS Documentation Responsible Status Pythia6 Pythia6Interface View Twiki Filip Moortgat, Hector Naves ready Herwig6 Herwig6Interface View Twiki Fabian Stoeckli ready ALPGEN AlpgenInterface View Twiki Maurizio Pierini, Maria Spiropulu ready MadGraph MadGraphInterface View Twiki Maria Hansen, Dorian Kcira ready CompHEP CompHEPInterface View Twiki Sergey Slabospitsky, Dimitri Konstantinov in progress MCatNLOInterface View Twiki Fabian Stoeckli ready TopRex TopRexInterface View Twiki Sergey Slabospitsky advanced ( but no doc) StaGen StaGenInterface View Twiki? Sergey Slabospitsky advanced (but no doc) Charybdis CharybdisInterface View Twiki Sergey Slabospitsky, Halil Gamsizkan advanced (but no doc) Hydjet HydjetInterface View Twiki Camelia Mironov in progress Pyquen PyquenInterface View Twiki Camelia Mironov in progress EvtGen EvtGenInterface View Twiki Aniello Nappi, Roberto Covarelli in progress Phantom MadGraphInterface View Twiki Sara Bolognesi ready ResBos ResBosInterface View Twiki NN?? Cosmic Muon Generator CosmicMuonGenerator View Twiki Philipp Biallass ready Beam Halo Muon Generator BeamHaloGenerator View Twiki Emmanuelle Perez advanced (but no doc) Beam Gas Generator BeamGasGenerator? View Twiki NN?? Pythia8 Pythia8Interface View Twiki Mikhail Kirsanov in progress Herwig++ Herwig++Interface View Twiki? Oliver Oberst?? ExHume? ExHumeInterface View Twiki Antonio Vilela Pereira ready Pomwig PomwigInterface View Twiki Antonio Vilela Pereira ready EDDE EDDEInterface View Twiki Andrei Sobol et al. in progress Stephen Mrenna MC4BSM in CMS

9 General-Purpose Event Generators HERWIG! Angular-ordered shower, cluster hadronization! v6 Fortran, now Herwig++ PYTHIA! Virtuality/kT-ordered shower, string hadronization! v6 Fortran, v8 C++ SHERPA! Virtuality-ordered shower, string/cluster hadronization MC4BSM3! C Bryan Webber

10 MC4BSM: spring 2008 The wave of the future in physics tools is modularity Instead of one do-it-all program, you use a chain of programs written and supported by different groups of people This increases the overall quality, gives much more flexibility to the user, allows cross-validation, and increases the pool of experts It also decreases greatly the time gap between the invention of a new theoretical model and the ability of an experiment to compare the model with data

11 modular event simulation: an example You invent a theory and write down its Lagrangian. Use FeynRules to get the Feynman rules. MadGraph reads this output and computes the matrix elements for interesting processes. MadEvent generates unweighted events from this. Bridge figures out how to decay the exotics. Pythia takes all this in SUSY Les Houches format and generates fully showered (using a VINCIA plug-in) and hadronized LHC event n-tuples. CMSSW puts these through a full simulation of the CMS detector. ROOT makes plots that you compare to data.

12 MC4BSM: democracy Perhaps the biggest change is that now anybody can play this game. The level of seriousness (and thus realism) is limited mostly by how much work you are willing to do. Graduate students can and have already made important contributions (e.g. Bridge, MadEvent, Sherpa,...)

13 MC4BSM: opportunity There is a lot to do for LHC. Short-term: almost nothing is validated at the level of detail required to claim discoveries at LHC! Real validation only happens when new users appear and get their hands dirty. Long-term: everything having to do with QCD needs to be improved.

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