Tevatron for LHC

1. Tevatron for LHC & other SUSY Exotics SUSY Tracey Berry Royal Holloway IOP, 31st January 2007

2. Why Exotics? Despite success of SM motivation for Exotics is strong … • Gauge hierarchy problem: why is the EW scale so small? • Dark matter problem: what is the nature most of the matter in the Universe? • Unification hypothesis: do the forces unify at a high scale? ….. E.g. implies there is something new/exotic we haven’t yet found..

3. What new physics ? • Supersymmetry • CHAMPs • Z’ • Extra Dimensions • Black Holes … in this talk, but many others……….. Aim: outline methods used at the Tevatron & plans for the LHC searches • What new physics can we expect/hope (!) to see ? …. • May be something totally unknown!

4. Supersymmetry • Supersymmetry (SUSY) fundamental continuous symmetry connecting fermions and bosons Qa|F> = |B>, Qa|B> = |F> • SUSY stabilises Higgs mass against loop corrections at EW scale • Possible explanation of dark matter – Lightest Supersymmetric Particle (LSP) • SUSY modifies running of SM gauge couplings ‘just enough’ to give Grand Unification at single scale. • SUSY gives rise to partners of SM states with opposite spin-statistics but otherwise same Quantum Numbers. spin-1/2 matter particles (fermions) <=> spin-1 force carriers (bosons) • Expect SUSY partners to have same masses as SM states - Not observed •  SUSY must be a broken symmetry • Different mechanisms of SUSY breaking lead to different models MSSM, mSugra, GMSB, AMSB

5. p p ~ ~ ~ ~ ~ A H0 H± H0u H0d H+u H-d c01 ~ ~ ~ h q ~ c02 l g ~ ~ ~ ~ q ne u d e ne u d e ~ ~ ~ ~ c m s nm c s m nm ~ ~ ~ ~ t b t nt q l t b t nt l ~ ~ ~ g W± g Z W± Z ~ g g ~ ~ ~ ~ ~ ~ ~ G c04 c03 c02 c ±1 c01 c ±2 G SUSY Signatures Q: What do we expect SUSY events @ hadron colliders to look like? A: Typical decay chain: • Strongly interacting sparticles (squarks, gluinos) dominate production. • Heavier than sleptons, gauginos etc. cascade decays to LSP. • Potentially long decay chains and large mass differences • Many high pT objects observed (leptons, jets, b-jets). • If R-Parity conserved: LSP (lightest neutralino in mSUGRA) stable • and sparticles pair produced. • Large ETmiss signature

6. SUSY @ Tevatron SUSY searches key goal of Tevatron experiments • Hadron collider  large cross-section for producing strongly interacting sparticles • Jets + ETmiss searches But small kinematic reach: • Limited pT separation from SM hadronic backgrounds • Short decay chains give limited signal multiplicity (jets, leptons) • Alternative: lower backgrounds • Trilepton searches • Alternative: rare decays • Bsmm Cross Section (pb) T. Plehn et al.

7. Run II: Jets + ETmiss Observe 40 Expect 56 ± 3 ± 14 • E.g. CDF Selection: • 3 jets with ET>120 GeV, 70 GeV and 25 GeV • Missing ET>90 GeV • HT=∑ jet ET > 280 GeV • Missing ET not along a jet direction: • Background: • W/Z+jets with Wl or Z • Top • QCD multijets • Mismeasured jet energies lead to missing ET • No excess observed • Exclude regions of squark / gluino mass plane (mSUGRA projection) • Missing ET not along a jet direction: • Avoid jet mismeasurements • Background: • W/Z+jets with Wl or Z • Top • QCD multijets • Mismeasured jet energies lead to missing ET • No excess observed • Exclude regions of squark / gluino mass plane (mSUGRA projection)

8. LHC: Jets + ETmiss • Inclusive searches with Jets + n leptons + ETmiss channel. • Map statistical discovery reach in mSUGRA m0-m1/2 parameter space. • Sensitivity only weakly dependent on A0, tan(b) and sign(m). 5s “Golden channel at the LHC” 5s ATLAS • Syst.+ stat. reach harder to assess: focus of current & future work.

9. Run II: Trileptons • Striking 3 isolated l signature • Low background • Easy to trigger • Alternative approach at Tevatron: reduce hadronic background with multi-lepton requirement • Sensitive to gaugino (chargino/neutralino) production • Analyses depend on SUSY model: • Low tan: • 2e+e/m • 2m+e/m • High tan (BR(t ) enhanced): • 2e+isolated track (1-prong t) • Other requirements (typical): • Large ETmiss • mll>15 GeV, mll = mZ • Njet < 2 Golden channel at TeVatron If Rp conserved • Also under study for LHC (large m0 / Focus Point scenarii)

10. Run II Trileptons Predicted Central 0.44±0.06 Plug 0.34±0.1 Total Observed 0 700-1000 pb-1 ee+l, em+l mm+l, me+l ee+track, mm+track Predicted 0.64±0.18 Total Observed 1 • CDF then combine the trilepton and dilepton SUSY search results: to obtain limits on m(chargino) & s.Br in various SUSY models MSSM with W/Z decays 122 GeV/c^2, s.Br = 0.42 pb. tanb=3, m>0 enhanced BR of chargino & neutralino to e & m 129 GeV/c2, s.Br = 0.25 pb. 162 < M1/2 230 GeV/c2. 162 < M1/2 240 GeV/c2., M0=70 Limit on mass of the chargino of 122 GeV/c^2, corresponding on sigma times Br of 0.42 pb. MSSM with W/Z decays - where we have artificially set the masses of the lightest chargino equal to the mass of the second to lightest neutralino equal to twice the mass of the lightest neutralino (LSP), and the Branching ratio of the lightest chargino(second to lightest neutralino) into leptons equal to the BR of the W(Z) boson into leptons. enhanced BR of chargino and neutralino to e & m & sensitive to masses (sigma times Br) of 157 GeV/c^2(0.1 pb). • The Standard Model backgrounds are evaluated from Monte Carlo samples, while the rate of jets faking leptons is obtained from jet samples at different Et thresholds collected in the data.

11. CDF Like-sign Dileptons Background: Wg, Diboson, ttbar, Drell-Yan, fakes • Search for 2 high-momentum same-sign leptons Predicted 33.7± 3.5 events Observe 44 • Tighter sample: Z veto and MET>15 GeV requirement Predicted 7.9 ± 1.0 Observed 13 CDF observe an excess of events! This search is sensitive to New Physics with three or more leptons, such as SUSY trilepton signatures, or signals with Majorana particles, e.g gluino pair production signatures with decays into leptons.

12. Bsmm Trileptons 2,10, 30fb-1 @ Tevatron Run II: Bsmm • SM BR heavily suppressed: • SUSY enhancements ~ tan6(b)/mA4 • Complementary to trilepton searches: important at high tan b • Preselection (CDF): • Two muons with pT>1.5 GeV/c • Displaced dimuon vertex • Search for excess in Bs (also Bd) mass window • Background estimated using a linear extrapolation from the sidebands, and normalised to data B+-+K+ Results compatible with SM backgrounds: • 1(0) CMU(CMX) events observed, • 0.88± 0.30(0.39 ± 0.21) CMU(CMX) exp. • Combined Limit: • BR(Bs->mm)<1.0 x 10-7 at 95%C.L. • Future Run II limit ~2x10-8 (8 fb-1) Inclusive search

13. p p ~ c01 ~ ~ ~ ~ q c02 g lR q q l l LHC: Exclusive Studies • Prospects for kinematic measurements at LHC: measure weak scale SUSY parameters (masses etc.) using exclusive channels. • Different philosophy to TeV Run II (better S/B, longer decay chains) g aim to use model-independent measures. • Two neutral LSPs escape from each event • Impossible to measure mass of each sparticle using one channel alone • Use kinematic end-points to measure combinations of masses. • Old technique used many times before (n mass from b decay spectrum, W (transverse) mass in Wgln). • Difference here is we don't know mass of neutral final state particles.

14. ~ ~ c01 c02 ~ l l l LHC: Dilepton Edge • When kinematically accessible c02 canundergo sequential two-body decay to c01 via a right-slepton (e.g. LHC Point 5). • Results in sharp OS SF dilepton invariant mass edge sensitive to combination of masses of sparticles. • Can perform SM & SUSY background subtraction using OF distribution e+e- + m+m- - e+m- - m+e- • Position of edge measured with precision ~ 0.5% (30 fb-1). ~ ~ • m0 = 100 GeV • m1/2 = 300 GeV • A0 = -300 GeV • tan(b) = 6 • sgn(m) = +1 e+e- + m+m- - e+m- - m+e- e+e- + m+m- Point 5 ATLAS ATLAS 30 fb-1 atlfast 5 fb-1 SU3 Physics TDR

15. ~ qL ~ ~ c02 ~ c01 q l l l ~ qL ~ ~ c02 c01 q h lq edge llq edge b b 1% error (100 fb-1) 1% error (100 fb-1) LHC: Endpoint Measurements • Dilepton edge starting point for reconstruction of decay chain. • Make invariant mass combinations of leptons and jets. • Gives multiple constraints on combinations of four masses. • Sensitivity to individual sparticle masses. bbq edge llq threshold 1% error (100 fb-1) 2% error (100 fb-1) TDR, Point 5 TDR, Point 5 TDR, Point 5 TDR, Point 5 ATLAS ATLAS ATLAS ATLAS

16. Sparticle Expected precision (100 fb-1) qL 3% 02 6% lR 9% 01 12% ~ ~ ~ ~ LHC: Sparticle Masses ~ ~ c01 lR ATLAS ATLAS • Combine measurements from edges from different jet/lepton combinations to obtain ‘model-independent’ mass measurements. Mass (GeV) Mass (GeV) ~ ~ c02 qL ATLAS ATLAS LHCC Point 5 Mass (GeV) Mass (GeV) • Also measurements of spin (Barr)

17. 100 GeV Staus 100 GeV Higgsino-like Chargino 100 GeV Gaugino-like Chargino Limits in AMSB: champ = c ±1 • M(c±1)>174 GeV/c2 ~ ~ Champs CHArged Massive stable Particles: -electrically charged -massive speed<<c -lifetime long enough to decay outside detector Event Selection: -2 muons Pt> 15 GeV, isolated -Speed significantly slower than c

18. Tevatron Resonance Searches Different techniques used by CDF and D0 • CDF: Search for a resonance in a particular channel e.g. ee, mm or gg • ee, mm: 200pb-1: Higgs, Sneutrino (Spin-0); Z’ (Spin-1), Randall-Sundrum Graviton (Spin-2) • ee: 448 pb-1: Z’, Littlest Higgs Z, Contact Interactions, AFB • ee:819 pb-1: Z’, RS Graviton • gg: 1 fb-1: RS Graviton • Combined channels later: e.g. ee+gg for RS model 95% C.L. lower limits on contact interaction mass scales. D0: Performed specific model dependent searches Randall-Sundrum Graviton: ee+gg 1 fb-1, mm ~250 pb-1 Tev-1 ED model search: ee: 200pb-1 95% C.L. lower limits on the littlest Higgs Z' models

19. Run II: Dielectron Resonances • Dielectron channel: studied invar. mass and AFB show no evidence of excess • Limits on Z’ (peak) from 650 GeV (Zl) – 850 GeV (SM) Are there resonances in the contact interactions or a broad increase? 95% C.L. lower limits on contact interaction mass scales. • Used same data (448 pb-1) to set limits on… 95% C.L. lower limits on the littlest Higgs Z' models

20. G Extra Dimensional Models Original models were proposed as a solution to the hierarchy problem Why is gravity weak compared to gauge fields? MEW (1 TeV) << MPlanck (1019 GeV)? Since then, many new models have been introduced to solved other problems: Dark Matter, Dark Energy, SUSY Breaking, etc Arkani-Hamed, Dimopoulos, Dvali,Phys Lett B429 (98) ADD • (Many) Large flat Extra-Dimensions (LED) could be as large as a few m • In which G can propagate, SM particles restricted to 3D brane Randall, Sundrum,Phys Rev Lett 83 (99)b RS Planck TeV brane • Small highly curved extra spatial dimension • (RS1 – two branes) Gravity localised in the ED -1 Dienes, Dudas, Gherghetta,Nucl Phys B537 (99) SM chiral fermions SM Gauge Bosons W, Z, g, g TeV sized EDs • Bosons could also propagate in the bulk • Fermions are localized at the same (opposite) orbifold point: destructive (constructive) interference between SM gauge bosons and KK excitations G W, Z • All SM particles propagate in “Universal” ED • often embedded in large ED UED e, m Not covered here, but can lead to interesting SUSY-like signatures!

21. Branching Fraction g W u Z RS model • Model parameters: • Gravity Scale: • 1st graviton excitation mass: m1 • = m1Mpl/kx1, & mn=kxnekrc(J1(xn)=0) • Coupling constant: c= k/MPl • 1 = m1 x12 (k/Mpl)2 Resonance position width k = curvature, R = compactification radius 400 600 800 1000 = Mple-kRc Experimental Signature for Model RS 5D curve space with AdS5 slice: two 3(brane)+1(extra)+time! K/MPl Mll (GeV) d/dM (pb/GeV) 10-2 10-4 10-6 10-8 10-10 KK excitations can be excited individually on resonance 700 GeV KK Graviton at the Tevatron k/MPl = 1,0.7,0.5,0.3,0.2,0.1 from top to bottom Coupling proportional to p-1 for KK levels above the fundamental level (n>=1) for n=0 graviton couples with the gravitational strenght 1 0.5 0.1 0.05 0.01 1 extra warped dimension • Couplings of each individual KK excitation are determined by the scale, = Mple-kRc ~ TeV massesmn = kxne-krc (J1(xn)=0) LHC Signature:Narrow, high-mass resonance states in dilepton/dijet/diboson channels 1500 GeV GKK and subsequent tower states 1000 3000 5000 Mll (GeV) Davoudiasl, Hewett, Rizzo hep-ph0006041

22. Tevatron RS Searches • Graviton decaying to ee or gg (mm) • Backgrounds: • Drell-Yan ee, direct  production • Jets: fake e, 0, • Data consistent with background • Limits on coupling (k/MPl ) vs m(1st KK- mode) D0 performed combined ee+gg (diem search) CDF performed ee & gg search, then combine CDF implemented a special trigger: “SUPER PHOTON_70” To keep high efficiency at high mass: Had/Em inefficient at high ET asEM E saturates, so is miscalculated. PHOTON 70 has noHAD/EM cut • Theoretically preferred Lp<10TeV, otherwise the model would no longer be interesting for solving the hierarchy problem – assures no new hierarchy appears between mEW and Lp

23. LHC: RS Discovery Limits • At ATLAS best channels to search in are G(1)e+e- and G(1)gg due to the energy and angular resolutions of the LHC detectors • G(1)e+e- best chance of discovery due to relatively small bkdg, from Drell-Yan* m1 = 1.5 TeV • Search for gg(qq) g G(1)g e+e- ATLAS study using test model with k/MPl=0.01 (narrow resonance). • Signal seen for mass in range [0.5,2.08] TeV for k/MPl=0.01. • Measure spin (distinguish from Z’) using polar angle distribution of e+e-. • Measure shape with likelihood technique. • Can distinguishspin 2 vs. spin 1 at 90% CL for mass up to 1.72 TeV. 100 fb-1 100 fb-1 ATLAS Experimental resolution ATLAS 100 fb-1 m1 = 1.5 TeV A resonance could be seen in many other channels: mm, gg, jj, bbbar, ttbar, WW, ZZ, hence allowing to check universality of its couplings. 100 fb-1 ATLAS ATLAS L.Randall and R.Sundrum, Phys.Rev.Lett. 83 (1999) 3370-3373; Phys.Rev.Lett.83 (1999) 4690-4693

24. CMS RS Discovery Limits G1μ+μ- G1ee G1 Solid lines = 5s discovery Dashed = 1s uncert. on L Theoretical Constraints LHC completely covers the region of interest • c>0.1 disfavoured as bulk curvature becomes to large (larger than the 5-dim Planck scale) • Theoretically preferred Lp<10TeV assures no new hierarchy appears between mEW and Lp Theoretical Constraints c>0.1 disfavoured as bulk curvature becomes to large (larger than the 5-dim Planck scale) Theoretically preferred Lp<10TeV

25. TeV-1 Extra Dimension Model • I. Antoniadis, PLB246 377 (1990) • Multi-dimensional space with orbifolding • (5D in the simplest case, n=1) • The fundamental scale is not planckian: • MD ~ TeV • Gauge bosons can travel in the bulk •  Search for KK excitations of Z,g.. • Fundamental fermions (quarks/leptons) can be • localized at the same (M1) or • opposite (M2) points of orbifold •  destructive (M1) or constructive (M2) • interference of the KK excitations • with SM model gauge bosons New Parameters R=MC-1 : size of the compact dimension MC : corresponding compactification scale M0 : mass of the SM gauge boson Characteristic Signature: KK excitations of the gauge bosons appearing as resonances with masses : Mn = √(M02+n2/R2) where (n=1,2,…) & also interference effects! G. Azuelos, G. Polesello EPJ Direct 10.1140 (2004) ppZ1KK/1KKe+e- • Look for l+l- decays of g and Z0 KK modes. • Also in decays (mT) of W+/- KK modes. • Or evidence of g* via dijet s or bb, tt s me+e- (GeV) Mn = M0 In M1 case the KK gauge states couplings to SM fermions are the same as the SM ones but scaled by a factor of √2 Fermion-gauge boson couplings can be exponentially suppressed for higher KK-modes

26. Tevatron/LHC: TeV-1 ED Searches D0 performed the first dedicated experimental search for TeV-1 ED at a collider ppZ1KK/1KKe+e- predicted background L = 200pb-1 • 2 high pT isolated electrons • Bckg: irreducible: Drell-Yan • Also ZZ/WW/ZW/ttbar SM Drell-Yan TeV-1 ED signal hc=5.0 TeV-2 Lower limit on the compactification scale of the longitudinal ED: MC>1.12 TeV at 95% C.L. 5 discovery limit of ppZ1KK/1KKe+e- (M1 model) With L=30/80 fb-1 CMS will be able to detect a peak in the e+e- invar. mass distribution if MC<5.5/6 TeV. Better Limit: from precision electroweak data MC≥4 GeV World Combined Limit MC>6.8 TeV at 95% C.L, dominated by LEP2 measurements

27. ATLAS expectations for e and μ: 2 leptons with Pt>20GeV in |h|<2.5, mll>1TeV Reducible backgrounds from tt, WW, WZ, ZZ PYTHIA + Fast simu/paramaterizedreco + Theor. uncert. For (ee+mm)using this method, the reach is ~8 TeV for L=100 fb-1 ~10.5 TeV for 300 fb-1 MC (R-1)<5.8 TeV :100 fb-1 TeV-1 ED Discovery Limits g(1)/Z(1)→e+e-/m+m- ATLAS have studied 3 methods to determine the discovery limits for this signature: model independent & dependent • Model independent search for the resonance peak– lower mass limit • 2 sided search window – search for the interference • Model dependent – fit to kinematics of signal 2 leptons with Pt>20GeV in |h|<2.5, mll>1TeV Event kinematics* can be fully defined by the 3 variables x1PA • Acceptance for leptons: |h|<2.5 x2PB 13.5 TeV with 300 fb-1 G. Azuelos, G. Polesello EPJ Direct 10.1140 (2004) • A simple number counting technique compared to the reach obtained in a detailed study of the invMss spectrum Even for lowest resonances of MC (4 TeV), no events would be observed for the n=2 resonances of Z and g at 8 TeV (Mn = √(M02+n2/R2)), which would have been the most striking signature for this kind of model. G. Azuelos, G. Polesello (Les Houches 2001 Workshop Proceedings), Physics at TeV Colliders, 210-228 (2001) Can use resonance and interference to search – model dependent and independent….

28. Search Region Selection 6s Observable width is combination of intrinsic new physics & detector resolution Detector resolutions influence the choice of search windows Similar issues at the LHC RS Graviton Search ee+gg channel mm channel TeV-1 ED Search k/MPl=0.05 k/MPl=0.05 ee channel: experimental resolution is smaller than the natural width of the Z(1)mm channel: exp. momentum resol. dominates the width ee+gg: EM energy determined using calorimeters mm: pT measured in tracker Asymmetric windows only lower mass bound used (due to long high-mass tail)   Symmetric windows width 6 x detector resolution Add resolution equations?

29. G g,q jet,V g,q G g,q f,V g,q f,V Broad increase in s due to closely spaced summed over KK towers Run I CDF Run I l=+1 Mll ADD Collider Signatures • Real Gravitonemission in association with a vector-boson Signature: jets + missing ET, V+missing ET s depends on the number of ED Jets+ missingET, γ+ missingET • Virtual Graviton exchange Signature: deviations in s and asymmetries of SM processes e.g. qq l+l-,   & new processes e.g. gg  l+l- Excess above di-lepton continuum s independent of the number of ED* in Hewett convention

30. q q q qqgGKK dominate sub-process for n>2 q g q g q g g q q GKK GKK GKK qggGKK q q q q q q q g q g g GKK GKK g GKK gggGKK g g g g g g g g g g g GKK g GKK GKK sfalls as 1/MDn+2 for all sub-processes g q g g _ Gkk g Gkk q Present ADD Emission Limits LEP and Tevatron results are complementary For n>4: g+MET For n<4: LEP limits best CDF limits best jet+MET

31. ADD Discovery Limit: G Emission Real graviton production J. Weng et al. CMS NOTE 2006/129 ppg+GKK MD= 1– 1.5 TeV for 1 fb-1 2 - 2.5 TeV for 10 fb-1 3 - 3.5 TeV for 60 fb-1 • G  high-pT photon + high missing ET • Main Bkgd: Zg  nng, At low pT the bkgd, particularly irreducible Zg  nng is too large require pT>400 GeV Rates for MD≥ 3.5TeV are very low – too low for 5s discovery Also W e(m,t)n, Wg en, g+jets, QCD, di-g, Z0+jets ppjet+GKK gggG, qgqG & qqGg Dominant subprocess • Signature: jet + G  jet with high transverse energy (ET>500 GeV)+ high missing ET (ETmiss>500 GeV), • vetos leptons: to reduce jet+W bkdg mainly • Bkgd.: irreducible jet+Z/W jet+ /jet+l jZ(nn) dominant bkgd, can be calibrated using ee and mm decays of Z. Discovery limits L.Vacavant, I.Hinchcliffe, ATLAS-PHYS 2000-016 J. Phys., G 27 (2001) 1839-50 J. Phys., G 27 (2001) 1839-50 MDMIN (TeV)

32. D0 ee+gg ADD LED g e+ e- GRW [1] HLZ[2] Hewett[3] L (pb-1) Final state n=2 n=3 n=4 n=5 n=6 n=7 Λ=+1/λ=-1 200 CDF ee 1.10 - 1.31 1.10 0.999 0.929 0.879 0.987/0.959 246 D0 μμ 1.07 1.09 1.27 1.07 0.97 0.90 0.85 0.96/0.93 275 D0 ee+γγ 1.48 1.74 1.76 1.48 1.33 1.24 1.17 1.32/1.21 RunI+RunII World Best Limit (cos*) spectrum to extract limits D0 perform a combined fit of the invariant mass and angular information SM events expected to be distributed uniformly in cosq* And to maximise reconstruction efficiency they perform combined ee+gg (diEM) search: reduces inefficiencies from • Parameterises in terms of h=/ Ms4 s = sSM+ hsINT+ h2 sKK + sBG • g ID requires no track, but g converts (ee) • e ID requires a track, but loose track due to imperfect track reconstruction/crack SM Interference ED term Background • 3D templates used to set limits Signal events are accumulated at low cosq* & high mass low mass, high cosq* most stringent collider limits on LED to date! Add a feynman diagram? Use all the information of the event – can gain in sensitivity

33. ADD Discovery Limit: G Exchange ppGKKmm • Two opposite sign muons in the final state with Mmm>1 TeV • Irreducible background from Drell-Yan, also ZZ, WW, WW, tt (suppressed after selection cuts) • PYTHIA with ISR/FSR + CTEQ6L, LO + K=1.38 Virtual graviton production 1 fb-1: 3.9-5.5 ТеV for n=6..3 10 fb-1: 4.8-7.2 ТеV for n=6..3 100 fb-1: 5.7-8.3 ТеV for n=6..3 300 fb-1: 5.9-8.8 ТеV for n=6..3 Fast MC Belotelov et al., CMS NOTE 2006/076, CMS PTDR 2006 V. Kabachenko et al. ATL-PHYS-2001-012

34. LHC: Black Hole Signatures Dimopoulos and Landsberg PRL87 (2001) 161602 Mp=1TeV, n=2, MBH = 6.1TeV • In large ED (ADD) scenario, when impact parameter smaller than Schwartzschild radius Black Hole produced with potentially large x-sec (~100 pb). • Decays democratically through Black Body radiation of SM states – Boltzmann energy distribution. ATLAS w/o pile-up ATLAS w/o pile-up • Discovery potential (preliminary) • Mp < ~4 TeV  < ~ 1 day • Mp < ~6 TeV  < ~ 1 year • Studies continue …

35. Strategy to Search for New Physics • Aim in searches for New Physics is to find a deviation from the expected/ SM. • To do this first need to know what the SM looks like in the new detector… i.e. • first it will be important to understand the detector: • Calibration…. • To quote Ian Hinchcliffe from 2005… We first need to study

36. Summary! • Exotics searches well underway at Tevatron • Statistics increasing rapidly now • New searches commencing soon at LHC • Many more exotics searches not covered here… Leptoquarks, Technicolor, more SUSY and ED searches…. • Good prospects for exciting discoveries • Exciting times ahead!

37. Distinguishing Z(1) from Z’, RS G • Spin 1 Z(1) signal can be distinguished from a spin-2 narrow graviton resonance using the angular distribution of its decay products. • Z(1) can also be distinguished from a Z’ with SM-like couplings using the distribution of the forward-backward asymmetry: due to contributions of the higher lying states, the interference terms and the additional √2 factor in its coupling to SM fermions. The Z(1) can be discriminated for masses up to about 5 TeV with L=300fb-1. 4 TeV resonances 4 TeV resonances Z(1) or Z’ or RS Graviton? ATLAS G. Azuelos, G. Polesello EPJ Direct 10.1140 (2004) G. Azuelos, G. Polesello EPJ Direct 10.1140 (2004)

38. TeV-1 ED Discovery Limits WKK decays G. Polesello, M. Patra EPJ Direct C 32 Sup.2 (2004) pp.55-67 For L=100 fb-1 a peak in the lepton-neutrino transverse invariant mass (mTln) W1  e R-1=4 TeV • Isolated high-pT lepton >200 GeV + missing ET > 200 GeV • Invmass (l,n) (mln)> 1 TeV, veto jets • Bckg: irreducible bkdg: Wen, Also pairs: WW, WZ, ZZ, ttbar R-1=5 TeV R-1=6 TeV SM Sum over 2 lepton flavours Peak detected if the compactification scale (MC= R-1) is < 6 TeV SM =√2peTpnT(1-cosDf) mTen (GeV) If no signal is observed with100 fb-1 a limit of MC > 11.7 TeV can be obtained from studying the mTendistribution below the peak: G. Polesello, M. Patra EPJ Direct, ATLAS 2003-023 - Can’t get such a limit with Wmn since momentum spread - can’t do optimised fit which uses peak edge If a peak is detected, a measurement of the couplings of the boson to the leptons and quarks can be performed for MC up to ~ 5 TeV.

39. * since there are large uncertainties in the calculations of the bkdgs: requires b-jet energy scale can be accurately computed. TeV-1 ED g* Discovery Limits Gluon excitation decays Can also Detect KK gluon excitations (g*) by reconstructing their hadronic decays (no leptonic decays). This is more challenging than Z/W which have leptonic decay modes M=1 TeV Detect g* by (1) deviation in dijet s (2) decays into heavy quarks M=1 TeV± 200 GeV SM SM • For ttbar one t is forced to decay leptonically M=1 TeV With 300 fb-1 Significance of 5 achieved for: bbar channel: R-1 = 2.7 TeV * M=2 TeV ttbar channel: R-1 = 3.3 TeV M=2 TeV However, it is not in general possible to obtain a mass peak well separated from the bkdg.  it is unlikely that an excess of events in the g*bbar channel could be used as evidence of the g* resonance, since there are large uncertainties in the calculations of the bkdgs. For M=1TeV the peak displacements could be used as evidence for new physics if the b-jet energy scale can be accurately computed. This could be used to confirm the presence of g* in the case that an excess in the dijet s is observed.

40. CDF SS Dilepton Events the two highest-E_T events, which are electron-electron, and of an e-μ event. • This event has more than 100GeV Met. There are lots of piled-up interactions. the third electron does not come from the same interaction vertex. Two electrons above 100 GeV each. In the same event we have a photon of 15GeV, Met of 25GeV and a third electron of 5GeV that does not pass the calorimeter isolation e-mu

41. Run II Trileptons Expected Signal Background Observed Events • The Standard Model backgrounds are evaluated from Monte Carlo samples, while the rate of jets faking leptons is obtained from jet samples at different Et thresholds collected in the data.

42. SUSY at the LHC • Directproductioncross-sectionssmall • ButcouldbetheonlywaytoobserveSUSYifqgareheavy!(“focuspoint”) • Inotherregionstrileptonssignalenhancedfromsquark-gluinocascade ~ ~ • Ecm of 14 TeV available!! • Between 1-2 fb-1 in the first year of data taking! • In typical mSugra scenario, squarks and gluinos dominate => signatures with jets + MET • Very quick discovery ! (all plots from Ian Hinchliffe, SUSY05)

43. How fast can SUSY be found? • Plot shows reach in SUSY model space • Solid region is not allowed • Hatched region is already ruled out by LEP • Contours label squark and gluion masses and luminosity • Example- 0.1 fb-1 discovers gluino mass 1 TeV • This is 1 year at 1/1000 of the design luminosity!

44. Tevatron Experiments: CDF & D0 Hermitic calorimeter (central & plug)/muon coverage Precision tracking and silicon vertex detectors  Excellent particle ID =1.0 =0 Muon System Central Calorimeters || < 1 || < 1.5 || < 1 =2.0 =3.0 Plug Calorimeter 1<||<3 Solenoid COT Time-of-Flight Silicon Tracker

45. Rare decay, SM branching frac ~10-9 • Loop diagrams with sparticles (or direct decay if RPV) enhance orders of magnitude hep-ph/0507233 Previous limit: Indirect constraint: BS Important at high tan • Look for excess of µµ events in Bs and Bd mass windows • Background estimation: linear extrapolation from sidebands • Results compatible with SM backgrounds Br(Bs)<1.0×10-7 @ 95%CL --- Closing in on SUSY! --- Else Lytken, Moriond QCD 2006 45

46. CMU-CMX Channel: Expect Observed Prob Bs0.39±0.21 0 68% Bd0.59±0.21 0 55% CMU-CMU Channel: Expect Observed Prob Bs0.88±0.30 1 67% Bd1.86±0.34 2 63% Look in the Bs and Bd Signal Window LR > 0.99 Else Lytken, Moriond QCD 2006 46

47. Projection Z’->ee

48. RS1 Model Parameters A resonance could be seen in many other channels: mm, gg, jj, bbbar, ttbar, WW, ZZ, hence allowing to check universality of its couplings:  e Relative precision achievable (in %) for measurements of s.B in each channel for fixed points in the MG,Lp plane. Points with errors above 100% are not shown. Also the size (R) of the ED could also be estimated from mass and cross-section measurements. Allenach et al, hep-ph0211205 Allenach et al, JHEP 9 19 (2000), JHEP 0212 39 (2002) BR(G→) = 2 * BR(G→ee)

49. ATLAS and CMS Experiments Large general-purpose particle physics detectors CMS ATLAS Total weight 7000 t Overall diameter 25 m Barrel toroid length 26 m End-cap end-wall chamber span 46 m Magnetic field 2 Tesla Total weight 12 500 t Overall diameter 15.00 m Overall length 21.6 m Magnetic field 4 Tesla Detector subsystems are designed to measure: energy and momentum of g ,e, m, jets, missing ET up to a few TeV

50. Angular distributions RS1 Model Determination How could a RS G resonance be distinguished from a Z’ resonance? Potentially using Spin information: G has spin 2: ppGee has 2 components: ggGee & qqGee: each with different angular distributions: MG=1.5 TeV 100 fb-1 e+e- MC = 1.5 TeV LHC Spin-2 could be determined (spin-1 ruled out) with 90% C.L. up to MG = 1720 GeV with 100 fb-1 Note: acceptance at large pseudo-rapidities is essential for spin discrimination (1.5<|eta|<2.5) Allanach et al, hep-ph 0006114 Stacked histograms Spin-2 nature of the G(1) can be measured : For masses up to 2.3 TeV (c=0.1) there is a 90 % chance that the spin-2 nature of the graviton can be determined with a 95 % C.L.