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Determination of SUSY Parameters at LHC/ILC

Determination of SUSY Parameters at LHC/ILC. Hans-Ulrich Martyn RWTH Aachen & DESY. Outline. Why and how to explore supersymmetry Discovery and measurements at LHC Precision measurements at ILC Reconstructing supersymmetry Dark matter and colliders Scenarios off mainstream

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Determination of SUSY Parameters at LHC/ILC

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  1. Determination of SUSY Parameters at LHC/ILC Hans-Ulrich Martyn RWTH Aachen & DESY

  2. Outline • Why and how to explore supersymmetry • Discovery and measurements at LHC • Precision measurements at ILC • Reconstructing supersymmetry • Dark matter and colliders • Scenarios off mainstream • Summary and outlook SUSY parameter determination at LHC/ILC

  3. Ellis et al 06 Why supersymmetry Most attractive extension of Standard Model • ensures naturalness of hierarchy scales • unification of fundamental gauge forces • provides cold dark matter candidate • stabilisation of light Higgs mass corrections • local SUSY incorporates gravity • additional sources of CP violation • maximal symmetry of fermions & bosons EW data consistent with weak-scale SUSY LHC experiments outcome extremely important, huge impact on future projects - ILC, VLHC, superB, super… discovery - revolution in particle physics SUSY parameter determination at LHC/ILC

  4. Hidden sector MSSM sector Flavour blind mediators MSSM • Building blocks SM  MSSM • duplication of particles  sparticles • 105 new parameters in MSSM R-parity conserving • Biggest mystery - symmetry breaking invoke hidden sector • Plethora of mediation mechanisms: gravity, gauge, gaugino, anomaly, string inspired, …  reduced set of parameters • what are dominant effects producing couplings of hidden sector andMSSMfields:tree-level, loop-induced, ..., ? SUSY parameter determination at LHC/ILC

  5. , tanβ,Af Soft parameters GUT scale  low scale MSSM  Observables mSUGRA: m0, m1/2, A, tanβ, sign  string inspired models GMSB AMSB ….. masses, decay widths, spin, couplings, mixings, quantum numbers, cross-sections RPV, CPV, LFV … neutralinos/charginos sleptons squarks Higgs (h,H,A) at present RGE MGUT, MX, MS, HO corrections, renormalisation scheme..., ? SUSY parameter determination at LHC/ILC

  6. , tanβ,Af Soft parameters GUT scale  low scale MSSM  Observables mSUGRA: m0, m1/2, A, tanβ, sign  string inspired models GMSB AMSB ….. masses, decay widths, spin, couplings, mixings, quantum numbers, cross-sections RPV, CPV, LFV … neutralinos/charginos sleptons squarks Higgs (h,H,A) in future all obstacles solvable with sufficient precision data -- need new techniques at hadron colliders SUSY parameter determination at LHC/ILC

  7. LHC 2007 commissioning @ 0.9 TeV 2008 start operation @ 14 TeV goal: few fb-1 per experiment 2010 reliable results on new physics, discoveries? huge discovery potential up to scales of m ~ 2.5 TeV ILC 2006 reference design 2009 technical design 2010 + … ready for decision 7 - 8 years construction polarised e+e-, e-e-, γγ high-precision measurements up to kinematic limit 0.5 - 1 TeV Experimental facilities pp 14 TeV e+e- 1 TeV SUSY parameter determination at LHC/ILC

  8. LHC Dominant production of strongly interacting squarks, gluinos Many states produced at once, long decay chains complicated final states ILC Production of non-colored sleptons, neutralinos, charginos Select exclusive reactions, bottom-up approach, model independent analysis Exploring supersymmetry Considerable synergy between LHC and ILC combined analyses, concurrent running SPS 1a’ mSUGRA benchmark favourable for LHC & ILC SUSY parameter determination at LHC/ILC

  9. Discovering SUSY at LHC • Signatures from gluino/squark decay chain: high pT multi-jets, isolated leptons, large missing energy • Inclusive search Meff=∑1,4ETi + ETmiss QCD background reliably calculable? W, Z, tt production  Anastasiou SUSY parameter determination at LHC/ILC

  10. Early discovery of SUSY at LHC? • Is there New Physics? What is the scale? Science community expects fast and reliable answers, e.g. planning for future facilities • Understanding detector and ETmisss spectrum crucial! • Discovery potential vs luminosity SUSY parameter determination at LHC/ILC

  11. Reconstructing masses at LHC Exploit variety of invariant mass distributions, low & high end points Construct kinematic constraints on sparticle masses  precise mass differences  seriously limited by poor neutralino mass strong slR - χ1 correlation Nojiri, SUSY06 SUSY parameter determination at LHC/ILC

  12. Reconstructing masses at LHC • End point method: waste of statistics and information • Mass relation method: exact kinematics using complete events • bbll channel • 5 masses: each event define 4-dim hypersurface in 5-dim mass space • 5 events sufficient to solve mass equations • many events: overconstraint fit, solve for masses, improved resolution • All sparticle masses known:  reconstruction LSP momentum Kawagoe, Nojiri, Polesello 2004 SUSY parameter determination at LHC/ILC

  13. Shape of decay distribution carry spin information Problems: pick up correct combination quark + near lepton, tell ql+ from anti-ql+ Solution: lepton charge asymmetry Assumptions: more squarks than antisquarks squarks/sleptons dominantly left or right neutralino spin ½ Distinct from other models, e.g. UED spinless Spin, L/R sfermion? SUSY parameter determination at LHC/ILC

  14. Finding sparticles with help of ILC • Light neutralinos and chargino found at ILC  Prediction of masses of heavy neutralinos and chargino may not be accessible at ILC • New particle can be identified at LHC via ‘edge’ in the di-lepton mass spectrum LHC/ILC interplay: Phys.Rept.426 (2006) 47 SUSY parameter determination at LHC/ILC

  15. LHC analysis access to high mass states, sleptons and gauginos via cascades resolution limited by strong correlations with neutralino LSP mass differences much more accurate Correct interpretation? neutralino sneutrino KK photon SPS 1a’ spectrum from LHC       Aguilar-Saavedra et al 2006 SUSY parameter determination at LHC/ILC

  16. Masses at ILC • Energy spectrum, end points δm ~ 0.1 GeV • Threshold excitation curve characteristic βdependence, steep rise δm ~ 0.05 - 0.2 GeV flat energy spectrum SUSY parameter determination at LHC/ILC

  17. Stau production flat energy spectrum distorted to triangular shape fit upper end point  mstau Coannihilation region small Δm = mstau-mχ  3 GeV accessible difficult measurement due to huge γγ bkg important to get DM constraint very problematic for LHC Masses -stau E+ E- mstau = 173 GeV δm ~ 0.3 GeV Point D’ mstau = 218 GeV Δm = 5 GeV δm ~ 0.15 GeV h-um 04 SUSY parameter determination at LHC/ILC

  18. Masses - gauginos Neutralino production Chargino production Many reactions to get the mass of the lightest neutralino very accurately! δm ~ 0.05 GeV SUSY parameter determination at LHC/ILC

  19. Masses - cascade decays Decay chains à la LHC kinematics of cascade decay provides access to intermediate slepton 2-fold ambiguity for mass solutions  extremely narrow mass peak δm/m ~ 5∙10-5 Similarly: selectron reconstruction Berggren 05 SUSY parameter determination at LHC/ILC

  20. Masses & mixings Chargino sector Mass matrix masses from threshold excitation Mixings polarised cross sections σL,R[11] and σL,R[12] disentangle ambiguities and determine mixing angles cos 2ΦLR Choi et al 2000 SUSY parameter determination at LHC/ILC

  21. Masses & mixings Stop production lightest squark in many scenarios, difficult to detect at LHC Mixing polarised cross sections Minimal mass reconstructed from kinematics, momentum correlations, using mχ peak at mstop SPS 5 Bartl et al 97 Finch et al 04 SUSY parameter determination at LHC/ILC

  22. Spin Threshold production and Angular distribution all masses known: reconstruction polar angle Θ (2-fold ambiguity) Unambiguous spin assignment model inependent, distinct from e.g. UED L/R quantum numbers via polarisation R sfermions prefer right-handed electrons e-R L sfermions prefer left-handed electrons e-L Choi et al 2006 SUSY parameter determination at LHC/ILC

  23. Couplings Basic element of SUSY identical gauge and Yukawa couplings SU(2) gauge g = Yukawa ĝ U(1) gauge g’ = Yukawa ĝ’ Slepton production Freitas et al, 04 SUSY parameter determination at LHC/ILC

  24. Coherent LHC+ILC analysis complementary spectrum completed superior to sum of individual analyses accuracy increased by 1-2 orders of magnitude Challenge: experimental accuracy matched by theory? SPS 1a’ spectrum from LHC+ILC       Aguilar-Saavedra et al 2006 SUSY parameter determination at LHC/ILC

  25. How to proceed? • We want to understand the relation between the visible sector, observables, and the fundamental theory  SUSY provides a predictive framework • How precise can we predict masses, x-sections, branching ratios, couplings, … ? • many relations between sparticle masses at tree-level, much worse at loop-level • choice of renormalisation scheme? • Which precision can be achieved on parameters of the MSSM Lagrangian? • Lagrangian parameters not directly measurable • parameters not always directly related to a particular observable, e.g. µ,tan ß • fitting procedure, … • Can we reconsruct the fundamental theory at high scale? • unification of couplings, soft masses, … ? • which SUSY breaking mechanism, origin of SUSY breaking? Goals of the SPA Project SUSY parameter determination at LHC/ILC

  26. SPA convention and project • Supersymmetry Parameter Analysis Supported by ~100 theorists & experimentalists • SPA Convention renormalisation schemes / LE parameters / observables • Program repository theor. & expt. analyses / LHC+ILC tools / Susy Les Houches Accord scheme translation, RGE & spectrum calculators, event generators, fitting, … • Theoretical and experimental tasks short- and long-term sub-projects, SUSY calc. vs expt., LO  NLO  NNLO, …, new channels & observables, combine LHC+ILC data • Reference point SPS1a’ derivative of SPS1a, consistent with all LE and cosmological data • Future developments CP-MSSM, NMSSM, RpV, effective string theory, etc.  Hollik, Robens You are invited to join! http://spa.desy.de/spa/EPJC 46 (2006) 43 SUSY parameter determination at LHC/ILC

  27. Extracting Lagrange parameters Global fit of all available ‘data’ to most up-to-date HO calculations input: masses, edges, x-sects, BRs from LHC & ILC ~120 values incl. realistic error correlations theory: no errors (no reliable estimate available) output: ~20 parameters tools Fittino(Bechtle, Desch, Wienemann), SFitter(Lafaye, Plehn, D.Zerwas) Results SPS 1a’ high precision LHC alone not able to constrain most parameters  Arkani-Hamed SUSY parameter determination at LHC/ILC

  28. High-scale extrapolation • Gauge couplings α-1 grand unification ~2σ / giU~2% ε3 at ~8σ level SUSY parameter determination at LHC/ILC

  29. 1/Mi[GeV-1] Mj2 [103 GeV2] Mj2 [103 GeV2] mSUGRA GMSB MM Q [GeV] Q [GeV] Q [GeV] High-scale extrapolation • Universality of gaugino & scalar mass parameters in mSUGRA • Evolution in GMSB distinctly different from mSUGRA • Bottom-up evolution of Lagrange parameters provides high sensitivity to SUSY breaking schemes  Porod SUSY parameter determination at LHC/ILC

  30. Testing mSUGRA mSUGRA fit excellent Universality can be tested in bottom-up approach non-coloured sector at permil to percent level colored sector needs improvement LHC+ILC: Telescope to Planck scale physics SUSY parameter determination at LHC/ILC

  31. Cold dark matter in Universe ΩDM≈ 22% ΩDMh2= 0.105 ± 0.008 WMAP Understanding nature of cold dark matter requires direct detection DM particle in astrophysical expt precise measurement of DM particle mass & spin at colliders compare relic density calculation with observation Ωχ h2~ 3 ∙10-27cm3s-1/<σv> requires typical weak interaction annihilation cross section Candidates: neutralino, gravitino, sneutrino, axino, … Formation: freeze out of thermal equilibrium in generalΩχ » 0.2, annihilation mechanism needed thermal production late decays metastable stau Dark matter & colliders  Kraml, Allanach SUSY parameter determination at LHC/ILC

  32. Baltz 06 Neutralino dark matter SPS 1a’‘bulk region’ annihilation through slepton exchange χχ тт, bb σχχdepends on light slepton masses & couplings LHC: precision ~20% (very high lumi) assuming mSUGRA, ‘a posteriori’ estimate/fix of unconstrained parameters, e.g. mixings LHC + ILC: precision ~1-2% matches WMAP/Planck expts  Reliable prediction for direct neutralino - proton detection cross section SUSY parameter determination at LHC/ILC

  33. LHC multiple solutions μ wino bino Higgsino M1 ILC resolves Neutralino dark matter LCC2‘focus point region’ heavy sfermions, light gauginos annihilation ΧΧ WW, ZZ σχχdepends on M1, M2, μ, tanβ LHC: study gluino decays, not enough constraints to solve neutralino matrix LHC + ILC: ~10% precision on relic abundance parasitic LHC peak at Ωχ~ 0 SUSY parameter determination at LHC/ILC

  34. Gravitino dark matter Gravitino mass set by SUSY breaking scale F of mediating interaction m3/2 =F/√3∙MP Planck scale MP =2.4∙1018 GeV In general free parameter depending on scenario supergravity, gaugino, gauge mediation m3/2 = TeV … eV Most interesting: gravitino LSP, stau NLSP m3/2 = few GeV - few 100 GeV Dominant decay gravitational coupling, lifetime sec - years Gravitino not detectable in astrophysical expts SUSY parameter determination at LHC/ILC

  35. Gravitino dark matter Detecting metastable staus & gravitinos identify & record stopping stau  stau mass wait until decay  stau lifetime measure τ recoil spectra  gravitino mass rare radiative decays  gravitino spin γ- τ correlations in LHC detectors not appropriate stau mass ok, no lifetime or decay spectra moderate rate, high background, busy timing externalabsorber/calorimeter needed ILC ideal environment high rate, adjustable via cms energy low duty cycle ~0.5%, excellent calorimetry Hamaguchi et al 04, Feng, Smith 04, DeRoeck et al 05, H-UM 06 SUSY parameter determination at LHC/ILC

  36. trap Gravitino dark matter GDM ε scenario mo=m3/2=20 GeV, M1/2=440 GeV ILC case studyL=100 fb-1 @ 500 GeV(<1 year data taking) • Prolific stau production • Lifetime measurement • Decay spectrum  Access to Planck scale / Newton’s constant • SUSY breaking scale • Unique test of supergravity: gravitino = superpartner of graviton H-U M, EPJC 48 (2006) 15 SUSY parameter determination at LHC/ILC

  37. Off mainstream scenarios • Scenario SPS 1a’ is just a benchmark, a test bed • Nature may be very different from SPS 1a’, mSUGRA, or … • Other possibilities • complex parameters, CP phases baryogenesis • lepton flavour violation neutrino masses • R-parity violation unstable LSP, neutrino masses • alternative SUSY breaking mediation anomaly, gauge, gaugino, … mixed scenarios of SUSY breaking • additional matter/gauge fields NMSSM, UMSSM, ESSM, … • additional dimensions • split SUSY • and many more … • Different signatures at LHC / ILC SUSY parameter determination at LHC/ILC

  38. SPS 1a S/√L CP phases CPV in SUSY may explain baryon asymmetry CP phases affect CP-even quantities generate CP-odd observables(triple products) EDM constraints for 1st, 2nd generation sfermions and charginos/neutralinos mSUGRA Φμ< 0.1-0.2 Stop decay widths μ, At strong phase dependence Φ(At) of stop  chargino + b Neutralino sector in selectron production μ, M1 pure Χi0 exchange in t and u channel transversely polarised e-e- beams cross section CP even azimuthal asymmetry CP odd pse_L∙(se1x se2) complementary to Bartl et al m=380 GeV 2 σ @ L=100 fb-1  Kernreiter, Rolbiecki SUSY parameter determination at LHC/ILC

  39. LFV in slepton pair production Seesaw mechanism to generate neutrino masses mν LR extension: νR singlet fields and superpartners added to MSSM sensitivityσLFV ~ 0.1-1 fb  Majorana mass scale MR~1013-1014 GeV  radiative decay Br(μeγ)~10-13 Massive neutrinos affect RGEs of sleptons flavour off-diagonal terms with large Yukawa couplings for 3rd generation kink in evolution of L3, H2 M(νR3) = (5.9±1.6) 1014 GeV μe τμ SPS 1a Lepton Flavour Violation Deppisch et al 04  Deppisch SPS 1a’ Blair et al 05 SUSY parameter determination at LHC/ILC

  40. Split SUSY SUSY breaking scale split between scalar & gaugino sectors Spectrum light Higgs, neutralinos, charginos, gluino squarks, sleptons, H, A extremely heavy Signaturesstrongly dependent on gluino lifetime long-lived gluino, R-hadrons LHC displaced vertices stable R0 missing ET stable R+ balanced pT Chargino/neutralino sector LHC & ILC conventional phenomenology for searches/masses anomalous Yukawa couplings from gaugino-Higgsino mixing Both LHC & ILC needed to establish SUSY Lagrangian at common scalar mass scale m˜ Arkani-Hamed, Dimopoulos Kilian et al 04  Provenza SUSY parameter determination at LHC/ILC

  41. Summary & outlook Experiments at LHC will tell if weak-scale supersymmetry is realised in nature Methods and techniques have been developed to discover and explore supersymmetry. Close contacts between experiment and theory are needed to go beyond basic discovery  SPA project provides a platform for discussions Both accelerators, the LHC and a future ILC, are necessary to understand the sparticle spectrum in detail and to unravel in a model-independent way the fundamental supersymmetry theory High-precision measurements of low-energy Lagrange parameters offer the unique possibility to perform reliable extrapolations towards the GUT / Planck scale and to test the concepts of unification of the laws of physics SUSY parameter determination at LHC/ILC

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