Peter Skands Theoretical Physics, CERN / Fermilab Monte Carlo Tools for Beyond the Standard Model Physics Nordic Workshop on LHC and Beyond, June 2008, Nordita, Stockholm

Peter Skands MC Tools for Beyond the Standard Model Physics - 2 BSM Work Flow Particle Content Charges Lagrangian Couplings Mass Spectrum Mixings Matrix Elements Phase Space Cross Sections Decay Widths Parton-Level Event Generation Collider Phenomenology Hadron-Level Event Generation Constraints Discoveries Old Philosophy: few models, few tools New Philosophy: many models, many tools General-purpose tools still main workhorses, but increasingly interfaced to special-purpose ones. Stockholm LHEF Py, Hw, Sh HEPM C SLHA + BSM-LHEF LanHEP, FeynRules Many Dark Matter p Decay Flavour Physics g μ -2 Baryon Asymmetry EWEW

Peter Skands MC Tools for Beyond the Standard Model Physics - 3Overview ►Tools Fields and Charges  Spectra Lagrangian  Model files Hard Matrix Elements ►Interfaces and Reviews ►New Physics in Herwig and Pythia Disclaimer: previous slide was the only colourful slide. Rest of talk will be dry, but hopefully useful

Peter Skands MC Tools for Beyond the Standard Model Physics - 4 Models from a Tools Perspective ►A QFT Model Set of fields, gauge groups, and charges  Lagrangian  + boundary conditions:  some couplings zero, others equal / related.  Definition of model at tree level  Parameters, Feynman rules Got Any Good Quantum Numbers?  Time-evolution causes states with degenerate conserved quantum numbers to mix  mixing ►Radiative corrections needed when … Large scale hierarchies are present  E.g., boundary conditions imposed at “GUT” scale, measurement done “at” LHC scale  absorb enhanced higher-order corrections by redefining couplings: RGE running Degeneracies are present (where small corrections make big difference)  E.g., KK excitations highly degenerate at tree-lvl in UED, lifted at one-loop lvl. Large sensitivity is present  E.g., m h = m Z at tree-lvl MSSM. Scalar mass quadratically sensitive to rad. corrs.

Peter Skands MC Tools for Beyond the Standard Model Physics - 5 Tools: Fields and Charges  Spectra ►Top-Down A model = set of fields and charges + boundary conditions  Boundary conditions usually imposed at a “high” scale (e.g., GUT)  Small set of parameters at boundary-condition scale  RGE running  Larger set of (related) parameters “at” LHC scale To compute observables you need  Spectrum of pole masses + Mixing matrices + RGE-improved couplings for each interaction ►Tools (RGE packages): MSSM (extensions beyond CMSSM in progress):  Isasusy (Baer et al)  Spheno (Porod)  SoftSusy (Allanach)  Suspect (Djouadi et al)  + more specialized for Higgs: CPSuperH, FeynHiggs, NMSSMTools Other BSM / more general SUSY: no general tool ! Put in masses and couplings by hand

Peter Skands MC Tools for Beyond the Standard Model Physics - 6 Tools: Fields and Charges  Spectra ►Bottom-Up A model = set of effective (tree-level) operators  In principle with arbitrary coefficients (some zero? up to you!)  Dimensional analysis: e.g., 4-fermion = dimension 6  C i /Λ i 2  “no” RGE running; all parameters effective weak-scale ones anyway  May still need to take into account radiative corrections to masses and SM couplings Include additional explicit fields  Example: general MSSM with all couplings defined at weak scale ►Tools: You don’t need an RGE package any more  If only operators between SM fields  “anomalous couplings” (modify your SM tool)  If too involved or more fields, feed effective Lagrangian to LanHEP or FeynRules … You may still need to compute rad. corrections to masses and mixings  E.g., FeynHiggs takes a weak-scale SUSY spectrum as input and outputs a weak- scale spectrum as well, but now including several loop-corrections to the Higgs masses and mixing.  No general package. In general done model by model in papers.

Peter Skands MC Tools for Beyond the Standard Model Physics - 7 Tools: Lagrangian  “Model Files” ►LanHEP Model defined in terms of tables of (weak-scale) parameters, particles, and interaction vertices with explicit Lorentz structure C code with command-line interface:  Output: CompHEP and FeynArts formats Existing models:  MSSM, with RPV, with CPV, with gravitino and sgoldstinos, NMSSM  Leptoquarks, 2HDM, Anomalous V couplings, Octet pseudoscalars, Higgsless model, Inert doublet model, excited fermions, technicolor, with technihadrons, Little Higgs, UED. Project on loop-calculations in progress  SloopS  FeynArts and FormCalc used for calculations  LanHEP used to generate counterterms From A. Semenov, MC4BSM, March 2008

Peter Skands MC Tools for Beyond the Standard Model Physics - 8 Tools: Lagrangian  Feynman rules ►LanHEP Model defined in terms of tables of parameters, particles, and interaction vertices with explicit Lorentz structure C code with command-line interface:  Several checks on charge conservation, hermiticity, … Output: CompHEP and FeynArts formats Existing models:  MSSM, with RPV, with CPV, with gravitino and sgoldstinos, NMSSM  Leptoquarks, 2HDM, Anomalous V couplings, Octet pseudoscalars, Higgsless model, Inert doublet model, excited fermions, technicolor, with technihadrons, Little Higgs, UED. Project on loop-calculations in progress  SloopS  FeynArts and FormCalc used for calculations  LanHEP used to generate counterterms From A. Semenov, MC4BSM, March 2008

Peter Skands MC Tools for Beyond the Standard Model Physics - 9 ►FeynRules Mathematica package:  Model defined in terms of an extension of the FeynArts-format  Readily adaptible to loop calculations Output: CompHEP/CalcHEP, FeynArts, MadGraph, Sherpa formats  Package highly integrated with MadGraph Existing models:  SM + scalars, 3-site model, Higgs effective theory, Hill-Model  Large Extra Dimensions + Color octet scalars to appear soon  Brand new code, but powerful interface and generic features: expect more soon. Tools: Lagrangian  “Model Files” From C. Duhr, MC4BSM, March 2008

Peter Skands MC Tools for Beyond the Standard Model Physics - 10 Tools: Hard Matrix Elements ►Traditional Generators (Herwig, Pythia) All-in-one matrix elements + decays + showers + hadronization + …  Convenient, but limited set of models / processes  Fortran versions already interface external codes. C++ versions even more so Expect SUSY, Z’, some XD, …, but use ME tools for the rest (see below)  External interfaces also facilitate matrix-element / parton-shower matching ►Matrix-Element Generators AlpGen: for SM with large numbers of legs (up to 2  6)  Ideal for multi-particle backgrounds (incl. hard extra jets, spin correlations, etc)  + a small amount of BSM: modified couplings, Z’ (next release: W’), alpOSET CompHEP/CalcHEP, (Herwig++), MadGraph, Sherpa, Whizard  Slower than AlpGen, but more generic  easier to include arbitrary BSM  Powerful combination with LanHEP (CH) and FeynRules (CH/MG/SH).  CH: Powerful combination MicrOmegas: dark matter  SH: Powerful combination with CKKW matched showers All of these interface Hw/Py via Les Houches Accords  Can also add matrix elements with additional QCD jets to get ME/PS matched signal simulations (More on matching: black- board seminar next week)

Peter Skands MC Tools for Beyond the Standard Model Physics - 11 Special Effects ►Black Holes CatFish (Cavaglia et al.) Charybdis (Richardson et al.) TrueNoir (Landsberg) ►NLO SUSY calculations ILCSlepton (Freitas, NLO SUSY cross sections in ee for CMSSM) Prospino (Plehn et al., NLO SUSY cross sections in pp for CMSSM) SuperIso (Mahmoudi et al., NNLO b  sγ & NLO isospin asym. in B  K * ) SusyBSG (Slavich, NLO b  sγ incl. mFLV) SUSY-HIT (Muhlleitner et al., NLO sparticle and Higgs decays in CMSSM) ►Dark Matter DarkSusy (Edsjö et al.) MicrOmegas (Belanger et al.) More... ? Devil is in the details I’m not an expert on BH ►Other SUSY Tools Parameter Fitting: Fittino (Bechtle, Wienemann) Parameter Fitting: Sfitter (Lafaye et al.) Flavour Violation: Fchdecay (Guasch et al.) Higgs Corrections: FeynHiggs (Heinemeyer et al.)

Peter Skands MC Tools for Beyond the Standard Model Physics - 12Overview ►Tools ►Interfaces and Reviews ►New Physics in Herwig and Pythia

Peter Skands MC Tools for Beyond the Standard Model Physics - 13 Interfaces and Accords ►Les Houches Accord (LHA) and Les Houches Event Files (LHEF) LHA (obsolete): Boos et al., hep-ph/  Fortran common block interface to transfer parton-level event records between parton-level (ME) generators and gen.-purpose ones for showering, hadronization, …  Many existing interfaces still based on this, e.g., matching with AlpGen LHEF: Alwall et al., hep-ph/  File-based (xml) extension of LHA  more universal. Now universal standard. ►Susy Les Houches Accord (SLHA) and SLHA2 SLHA 1: PS et al., hep-ph/  File-based (ascii) transfer of SUSY parameters, spectra, and decay tables. Universal standard.  Also contains useful discussion of convention choices in SUSY SLHA 2: Allanach et al., arXiv: [hep-ph]  Generalization to flavour violation, CP violation, R-parity violation, NMSSM ►BSM-LHEF BSM-LHEF: Alwall et al., arXiv: [hep-ph]  Specific extension of LHEF for SUSY/BSM (more later) So far “spoken” by MadGraph, CalcHEP, and Pythia, more to come

Peter Skands MC Tools for Beyond the Standard Model Physics - 14 SLHA1  SLHA2 ►“old-style” SUSY : SLHA1: No flavour violation (not even CKM), no CP violation, no R-parity violation ►Flavour violation  Mixing: ~uL, ~dL, … are no longer mass eigenstates Main Issue: PDG (no-mixing limit): u_L c_L t_ u_R c_R t_ d_L s_L b_ d_R s_R b_2 Down squarks: PDG code d_ d_ d_ d_ d_ d_6 Up squarks: PDG Code u_ u_ u_ u_ u_ u_6 Several such issues addressed by SLHA2. Spectrum of states change  meaning of PDG codes change. Be aware of this. + 6x6 mixing matrices describing (~qL,~qR) composition of each state arXiv: [hep-ph]

Peter Skands MC Tools for Beyond the Standard Model Physics - 15 Useful Tools Reviews & Workshops ►Les Houches Guidebook to Generators for LHC Dobbs et al., hep-ph/  Focus on SM generators (backgrounds)  Useful mini-reviews of each generator / physics topic.  Comprehensive update (Richardson, PS) planned for later in 2008  Updated descriptions of all event generators  Updated brief reviews on PDFs, Matching, and a new review on Underlying Event BSM Tools Repository:  ►SUSY SUSY “Bestiary of Public Codes”: Allanach, arXiv: [hep-ph] ►Workshops SUSY and the Tools for New Physics, Munich, June 30 – Jul 4, 2008 MC4BSM (focus on non-SUSY):  probably in US ~ March 2009  37 tools At last counting

Peter Skands MC Tools for Beyond the Standard Model Physics - 16Overview ►Tools Fields and Charges  Spectra Lagrangian  Model files Hard Matrix Elements ►Interfaces and Reviews ►New Physics in Herwig and Pythia

Peter Skands MC Tools for Beyond the Standard Model Physics - 17 BSM in Herwig++ From M. Gigg, MC4BSM, March 2008 Gigg, Richardson [arXiv:hep-ph/ ] In progress: RS, MSSM, MUED, NMSSM, Little Higgs (Based on HELAS)

Peter Skands MC Tools for Beyond the Standard Model Physics - 18 BSM in Pythia ►As Torbjörn will emphasize, there are 2 Pythia generators, 6 and 8 Pythia 6 (Fortran): in process of being phased out but still maintained Pythia 8 (in C++): new developments (see Torbjörn’s talk) ►Pythia 6: Large library of BSM processes  Z’, W’ (incl SM interference and matching to Z’/W’ + jet)  2HDM (h 0, H 0, H ±, A 0 ) – with freely specifiable CP- and flavour-conserving couplings  Z R, W R, H ++ in Left-Right Symmetric Model  4 th generation fermions (can be recycled for other models with t’ / b’ / tau’ states)  Excited fermions  Leptoquarks  Compositeness and Anomalous Couplings  Excited fermions  Technicolor strawman model, recently updated to include techni-"a" meson a_tc, analog a0(980)  MSSM, with some CPV, RPV decays. Well-developed SLHA interface.  Released last week (4.6.18): minimal UED  Well-developed interfaces to AlpGen, MadGraph, CompHEP, CalcHEP. Example file on web shows how to input an LHEF file for showering and hadronization. IUED(1) = Main UED ON(=1) / OFF(=0) switch (D=0) IUED(2) = Number of large extra dimensions into which only the graviton propagates (D=6) IUED(3) = Number of quark flavour KK excitations (D=5) RUED(0) = Curvature 1/R of the UED (D=1000.0) RUED(1) = Cutoff scale Lambda (D=5000.0) g + g -> g* + g* 312 g + q -> g* + q*_D/q*_S 313 q_i + q_j -> q*_Di + q*_Dj -> q*_Si + q*_Sj 314 g + g -> q*_D + q*_Dbar -> q*_S + q*_Sbar 315 q + qbar -> q*_D + q*_Dbar -> q*_S + q*_Sbar 316 q_i + q_barj -> q*_Di + q*_Sbarj 317 q_i + q_barj -> q*_Di + q*_Dbarj -> q*_Si + q*_Sbarj 318 q_i + q_j -> q*_Di + q*_Sj 319 q_i + q_bari -> q*_Dj + q*_Dbarj +

Peter Skands MC Tools for Beyond the Standard Model Physics - 19BSM-LHEF From M. Herquet, MC4BSM, March 2008 Basic Philosophy: include all relevant model information together with the actual events  include model info in LHEF “header”

Peter Skands MC Tools for Beyond the Standard Model Physics - 20BSM-LHEF From M. Herquet, MC4BSM, March 2008

Peter Skands MC Tools for Beyond the Standard Model Physics - 21 BSM-LHEF in Action BLOCK QNUMBERS # NH heavy neutrino 1 0 # 3 times electric charge 2 2 # number of spin states (2S+1) 3 1 # colour rep (1: singlet, 3: triplet, 8: octet) 4 0 # Particle/Antiparticle distinction (0=own anti) … … a parton-level LHEF event record including particle, generated by CalcHEP Event listing (standard) I particle/jet K(I,1) K(I,2) K(I,3) K(I,4) K(I,5) P(I,1) P(I,2) P(I,3) P(I,4) P(I,5) 1 !p+! !p+! ================================================================================================================================== 3 !d! !d! !dbar! !d! !NH! !NH! !e+! !ubar! !d! !e+! !ubar! !d! Modify Pythia LHEF example (main81.f) to read this file FeynRules/MadGraph also automatically puts QNUMBERS and SLHA in LHEF header information Alwall, Boos, Dudko, Gigg, Herquet, Pukhov, Richardson, Sherstnev, PS arXiv: [hep-ph]

Peter Skands MC Tools for Beyond the Standard Model Physics - 22 BSM in Pythia 8 ►See Torbjörn’s talk Pythia 8 now mature and going beyond Pythia 6 Some big BSM pieces still missing:  SUSY (PS), technicolor (Mrenna), (UED?) ►Currently implementing: General MSSM SUSY Cross Sections (using SLHA2)  Including general flavour violation (sometimes called non-minimal FLV)  Includes CKM as well as off-diagonal squark and slepton mass matrix terms  Including CP violating phases  Collaboration (counter-checking) with M. Klasen and B. Fuks (XSUSY) Plan to have sparticle cross sections implemented within the year  Including decays: via BSM-LHEF (flat phase space) also within the year.  Including decays with ME weighting  realistic timescale (?) mid BSM-LHEF should obviously be included as well  Partly with SUSY-decay implementation, full implementation after SUSY completed