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Jan Kalinowski

SUSY 2. Jan Kalinowski. Outline. Constructing the MSSM SUSY must be broken SUSY: experimrental status Prospects for the LHC. 4 x neutralino. ~. H 0 H 0 H ±. 1. 2 x chargino. ~. 2. ~. MSSM: particles and sparticles. SM. SUSY. squarks (L&R) sleptons (L&R) sneutrinos (L&?).

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Jan Kalinowski

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  1. SUSY 2 Jan Kalinowski

  2. Outline • Constructing the MSSM • SUSY must be broken • SUSY: experimrental status • Prospects for the LHC Supersymmetry, part 2

  3. 4 x neutralino ~ H0 H0 H± 1 2 x chargino ~ 2 ~ MSSM: particles and sparticles SM SUSY squarks (L&R)sleptons (L&R)sneutrinos (L&?) quarks (L&R)leptons (L&R) neutrinos (L&?) Spin-1/2 Spin-0 gluino BinoWino0Wino± gluon Z0W± AfterMixing Spin-1 BW0 Spin-1/2 h0 H0 A0 H± Spin-0 Extended higgs sector (2 doublets) Supersymmetry, part 2

  4. If both present rapid proton decay Exact SUSY Superpotential But most general gauge-invariant and renormalisable admits also • Minimal choice (MSSM) : R-parity = (-1)2S+3B+L conserved • Consequences: • SUSY particles produced in pairs • SUSY particles decay into SM + odd number of SUSY particles • All SUSY particles will eventually decay into LSP • LSP stable • some must have survived from Big Bang • weakly interacting massive particle • candidate for cold dark matter • LSP neutral • typical collider signature:missing energy Supersymmetry, part 2

  5. Exact SUSY Exact SUSY => no new parameters • SUSY implies relations between masses and couplings: • gauge coupling = Yukawa coupling crucial for hierarchy problem • scalars and fermions from the same multiplet have equal masses SUSY must be broken Supersymmetry, part 2

  6. SUSY must be broken • Spontaneous breaking of global SUSY requires <0|H|0> > 0 • V>0 implies that Fi or Dacannot simultaneously vanish for any values of the fields • F-term breaking requires a singlet chiral superfield • not possible within the MSSM • D-term breaking via xa • does not work in the MSSM since gives charge and color-breaking minima Supersymmetry, part 2

  7. SUSY must be broken Other problems withspontaneous susy breaking • Mass sum rule • not all superpartners could be heavier than SM particles • difficult to get phenomenologically acceptable masses • Difficult to give masses to gauginos • ….. Problems can be overcome with additional fields in ”hidden sector” Supersymmetry, part 2

  8. Hidden sector MSSM sector Flavour blind mediators SUSY must be broken • Invoke a hidden sector where SUSY breaking occurs • In the hidden sector the F and/or D terms of some non-MSSM develop VEV phenomenology depends mainly on mechanism for communicating SUSY breaking rather than on SUSY-breaking mechanism itself Supersymmetry, part 2

  9. Unconstrained MSSM No particular SUSY breaking mechanism assumed L. Girardello, M. Grisaru ’82 No additional mass terms for chiral fermions Relations between dimensionless couplings unchanged Most general case: 105 new parameters Question: what is the scale of SUSY breaking parameters (including mu)? Phenomenology suggest the weak scale Supersymmetry, part 2

  10. Why weak-scale SUSY ? • Naturalness=> new TeV scale that cutts off quadratically divergent a contributions from SM particles • predicts a light Higgs Mh< 130 GeV as suggested by data Mh< 149 GeV @ 95% • Predicts gauge coupling unification Erler, 0907.0883 Supersymmetry, part 2

  11. Why weak-scale SUSY ? • accomodates heavy top quark and provides radiative EWSB • dark matter candidate: neutralino, sneutrino, ... Supersymmetry, part 2

  12. Unconstrained MSSM No particular SUSY breaking mechanism assumed L. Girardello, M. Grisaru ’82 No additional mass terms for chiral fermions Relations between dimensionless couplings unchanged Most general case: 105 new parameters – masses, mixing angles, CP phases • Good phenomenological description if universal breaking terms • Scenarios for SUSY breaking => predictions in terms of small set of parameters • Experimental determination of SUSY parameters => patterns of SUSY breaking Supersymmetry, part 2

  13. different scenarios mSUGRA SPS1a GMSB SPS7 AMSB SPS9 Supersymmetry, part 2

  14. SUSY breaking needed to break SU(2)xU(1) Higgs in the MSSM Supersymmetry, part 2

  15. Higgs sector Mh<MZ Supersymmetry, part 2

  16. FeynHiggs Heinemeyer, Weiglein ’05 upper bound on light Higgs Supersymmetry, part 2

  17. Higgs couplings to gauge bosons: tree level; including loops change to fermions: Supersymmetry, part 2

  18. LHWG-Note 2005-01 limits on Higgs from LEP search at LEP exclusion limits depend on scenario e.g. if CP violated all h,H,A mix Supersymmetry, part 2

  19. Electroweak precision tests: SM vs. MSSM SM: MH varied MSSM: susy parameters varied Supersymmetry, part 2

  20. gauge invariance sfermions Squark mixing off-diagonal terms ~ partner fermion mass => mixing important for 3rd generation sfermions Supersymmetry, part 2

  21. gauginos Higgsinos and EW gauginos mix Mass matrices are given in terms of => MSSM predicts mass relations between charginos and neutralinos Supersymmetry, part 2

  22. Prospects at the LHC Supersymmetry, part 2

  23. Establishing SUSY • discovery – signals for new physics, possibly SUSY? • measurements – masses, cross sections, couplings • parameter studies – MSSM Lagrangian, SUSY breaking? Basic objects at the LHC • jets, isolated leptons and photons, displaces vertices • energies and transverse momenta • missing transverse momentum Search strategies • inclusive • canonical searches – jet multiplicity, isolated leptons, • large missing energy, ... • counting, identifying an excess • exclusive • specific processes – measure energy and combinations • of invariant mass spectra • determine SUSY masses and couplings • (modulo reasonable assumptions) Search path at the LHC Supersymmetry, part 2

  24. LHC: signal and background BG from W, Z and tt: 107-109 events per 10 fb-1 SUSY signal: 103-105 events per 10 fb-1 need strong rejection ~10-4 Exploit kinematics to maximum extent: mass reconstruction method Supersymmetry, part 2

  25. CMS Inclusive searches Require: at least two jets with pT> EcandETmiss > Ec, Ec to maximise S/pB pT >20 GeV for any lepton M(l, ETmiss) > 100 GeV to reduce W+jets ST > 0.2 to reduce dijet background ATLAS TDR L=10 fb-1 Supersymmetry, part 2

  26. After inclusive searches Observe excess in inclusive ETmiss + jets, + 1 lepton, + 2 leptons, ... • ETmiss => undetectable particles in the final state • Meff + xsection => strongly interacting heavy particles • jets => colored particles • excess of SS leptons => some of them Majorana • OS-SF leptons => lepton flavor conserved • ... • First glimpses of new physics emerge: global analyses show • that physics beyond SM exisitsI • what its mass scale is One may even attempt to fit all these to determine the SUGRA model parameters. However, better to use partial reconstruction of exclusive final states to determine precise combinations of masses from kinematic endpoints of distributions Supersymmetry, part 2

  27. Exclusive measurements • Complicated cascade decays • Many intermediates • Typical signal • Jets • Squarks and Gluinos • Leptons • Sleptons and weak gauginos • Missing energy • Undetected LSP • Model dependent Mass/GeV Start from the bottom of the decay chain “typical” susy spectrum(mSUGRA) ATLAS Point5 Supersymmetry, part 2

  28. edge 68.13 +/- 1 GeV Exploiting further pT of Z => Exclusive measurements Key decays are ATLAS Point4 Supersymmetry, part 2

  29. write Solve for iand EA full reconstruction of the LSP 4-momentum Reconstructing the LSP Alternative method to measure masses: look at individual decays Nojiri, Polesello and Tovey, arXiv:hep-ph/0312317 Kawagoe, Nojiri and Polesello, Phys.Rev. D71 (2005) 035008 SUSY states are quite narrow, approx. on-shell the 4-momentum of A not measured, but: and then reconstruct masses of A, B, C and D Supersymmetry, part 2

  30. BIs this really SUSY? • Bor Kaluza-Klein states ? End of first few fb-1 of data taking Scenario: • After careful calibration … • ATLAS and CMS observe excess of events • Missing transverse energy • Leptons • Jets • Edges in invariant mass distributions • determine masses • AAre we ready to claim SUSY discovery? Supersymmetry, part 2

  31. Revisit “Typical” sparticle spectrum Left Squarks-> strongly interacting -> large production -> chiral couplings LHC point 5 20 = neutralino2–> (mostly) partnerof SM W0 Right slepton(selectron or smuon) -> Production/decay produce lepton -> chiral couplings mass/GeV 10–> Stable -> weakly interacting 10 = neutralino1–> Stable -> weakly interacting Some sparticles omitted Revisit ”typical” SUSY spectrum Supersymmetry, part 2

  32. Left Squarks-> strongly interacting -> large production -> chiral couplings 20 = neutralino2–> (mostly) partnerof SM W0 Right slepton(selectron or smuon) -> Production/decay produce lepton -> chiral couplings 10–> Stable -> weakly interacting 10 = neutralino1–> Stable -> weakly interacting Revisit ”typical” SUSY spectrum SUSY mass/GeV Supersymmetry, part 2

  33. Revisit “Typical” KK-particle spectrum ? What if KK spectrum similar? First KK-quark-> strongly interacting -> large production UED q1 First KK-Z–> partnerof SM Z0 First KK- lepton(electron or muon) -> Production/decay produce lepton mass/GeV Z1 l1 g1 10–> Stable -> weakly interacting First KK-photon–> Stable -> weakly interacting Supersymmetry, part 2

  34. eg. lepton charge asymmetries UED SUSY Smillie, Webber hep-ph/0507170 efficiency depends on sparticle masses KK-like masses SPS1a-like masses Measure spin Barr hep-ph/0405052 SUSY/KK differ in spins in the decay chain need sensitivity to the particle spin Supersymmetry, part 2

  35. Cosmological connection • Extremely tempting to assume that EWSB and Dark Matter . ., ncharacterised by the same energy scale • Likely that new physics contains a stable particle that can be n n, copiously produced at the LHC There are counterexamples, but if above true => large cross sections for jets + missing , energy events at the LHC => LHC will provide data for astrophysics => infer DM properties from masses and cross sections Relic density WXh2 ~ 3 x 10-27 cm3s-1 / <sv> requires typical weak interaction annihilation cross sections How well <sv> can be predicted from LHC depends on model for NP Supersymmetry, part 2

  36. Focus point Co-annihilation Bino LSP Higgs funnel WMAP and SUSY DM bino • neutralino being a pure • bino: NN -> fermion pairs • higgsino: NN -> WW,ZZ • wino: NN-> WW,ZZ higgsino Arkani-Hamed, Delgado, Giudice wino DM models seem fine tuned Supersymmetry, part 2

  37. LCC benchmark points American LCC + Snowmass05 benchmark points Peskin, LCWS’06 Supersymmetry, part 2

  38. LCC points The LHC will start testing cosmology a LC in a foreseeable future would greatly help Supersymmetry, part 2

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