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Beyond the SM: Tevatron Results & Potential

Way. Beyond the SM: Tevatron Results & Potential. Greg Landsberg Prague LHC Workshop July 10, 2003. Outline. Life Beyond the Standard Model New Physics’ Many Faces The Tevatron Lessons Run II Stats Beyond SUSY More Fun in Extra Dimensions Conclusions. …is boringly precise:.

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Beyond the SM: Tevatron Results & Potential

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  1. Way Beyond the SM: Tevatron Results & Potential Greg Landsberg Prague LHC Workshop July 10, 2003

  2.  Greg Landsberg, Beyond the SM @ the Tevatron  Outline • Life Beyond the Standard Model • New Physics’ Many Faces • The Tevatron Lessons • Run II Stats • Beyond SUSY • More Fun in Extra Dimensions • Conclusions

  3. …is boringly precise: …but not at all boring: SM accommodates, but does not explain: EWSB CP-violation Fermion masses Higgs self-coupling is positive, which leads to a triviality problem that bounds mH from above The natural mH value isL, where L is the scale of new physics; if SM is valid up to GUT scale, an extreme ((v/mGUT)2) fine-tuning is required RGE equations MH < 211 GeV @ 95% CL (Combined EW fit) MH > 113.5 GeV @ 95% CL (LEP2, up to 209 GeV) Gravitational Force EM/Hypercharge Force Inverse Strength Weak Force Direct Strong Force MPl MGUT v 102 1019 1016 E [GeV]  Greg Landsberg, Beyond the SM @ the Tevatron  Life Within the Standard Model

  4.  Greg Landsberg, Beyond the SM @ the Tevatron  New Physics’ Many Faces • Supersymmetry • mSUGRA like • Gauge MSB • Gaugino MSB • Anomaly MSB • Strong Dynamics • Technicolor • Top See-Saw • Compositeness • Exotics • Leptoquarks • Extra gauge bosons • Extra Dimensions • Large/Infinite Volume Extra Dimensions • Warped Extra Dimensions • Universal Extra Dimensions • Something COMPLETELY unexpected

  5.  Greg Landsberg, Beyond the SM @ the Tevatron  Searches for New Physics • Electroweak/Heavy Flavor/QCD Physics: • Most properties are well known • Mainly precision measurements • Higgs physics: • Most signatures are known • A few free parameters • Well-defined search strategy • Searches for New Physics: • Do not even know what it is and where it is • Little doubt exists that it must be there, maybe just around the corner • Only vague ideas about signatures • Many channels, many possibilities of statistical fluctuations • Might not be possible to use ‘cousin channels’ as a discovery proof (e.g., RPV SUSY) • An ultimate challenge and an ultimate prize!

  6.  Greg Landsberg, Beyond the SM @ the Tevatron  Searches at the Tevatron • The Tevatron energy might or might not be in the right range for new physics discovery • Perhaps with the exception of minimal technicolor models, the LHC is really the machine for ultimate test • Instead of giving you a review of full capabilities of the Tevatron in all possible channels we use for searches, I’ll give you my personal view on the most promising discovery channels at the Tevatron • Consider both targeted and signature-based searches to cover all the bases • A few hints from Run I: eeggMET, em + X “top” events, etc. • Importance of b’s and t’s • New physics in top production and decay • “Grand finale” model-independent searches a la Sleuth [DØ, PRD 62, 92004 (2000); PRL 86, 3712 (2001); PRD 64, 012004 (2001)]

  7.  Greg Landsberg, Beyond the SM @ the Tevatron  The Tevatron Lessons • The upgraded Tevatron with 10% higher energy still has not crossed new energy threshold, so it’s unlikely that NP would appear as “spectacular events,” such as copious SUSY or black hole production • Need to be patient • It’s likely that NP will manifest itself first as a marginal event excess in a number of related channels • Need for optimal combination of various channels to reach the discovery significance (cf. Higgs) • It’s likely that NP will be overwhelmed by the SM backgrounds in the channels of interest • Need reliable background calculation tools and advanced methods of background suppression, while retaining high sensitivity for the signal • It’s given that with the complexity of modern detectors, particle ID is based on a large number of variables • Need for advanced multivariate particle ID techniques • It’s possible that NP searches would require special triggers • Need for fast triggering methods in a complex environment

  8. DØ CDF  Greg Landsberg, Beyond the SM @ the Tevatron  Run II Detectors • Significantly upgraded experiments with three major subdetectors: • Hermetic Calorimeters • Central Tracker • Muon Detectors • Multiple detectors – multiple handles: • EM: calorimetry, preshowers, (tracking, ionization) • Muons: central and outer tracks, • ionization, calorimetry • t’s: tracking, calorimetery • Jets: tracking, calorimetry

  9.  Greg Landsberg, Beyond the SM @ the Tevatron  Tevatron Reach for New Physics • A rule of thumb: for pair production of heavy objects cross section drops by a factor of 2 for every 20 GeV in the object mass: • 2 fb-1  effective x30 in accumulated statistics (higher energy, efficiency) • 10 fb-1  effective x150 in accumulated statistics • Constant S/√B (statistics-limited case): • Run IIa: 20 GeV x log230 or 100 GeV increase in the mass reach • Run IIb: 20 GeV x log2150 or 145 GeV improvement in the mass reach • Nowadays mass limits are ~100 GeV thus Run IIa will double the phase space probed; Run IIb will add only additional 20% • If I were to bet if the Tevatron is going to see NP, I’d bet on Run IIa; if we do not see any evidence with ~2 fb-1, it’s likely that the Tevatron is simply not in the right energy range to probe it • Note: if the error on the background is systematics-limited, the reach compared to Run I does not improve at all, as S/B = S/(aB)  const: • Some backgrounds can be measured from data; thus guaranteeing B ~ 1/√∫Ldt, but not all of them! • Desperate need for NkLO (k ≥ 1) Monte Carlo for accurate SM background description!

  10. In a perfect world… MC is as glamorous as your detector (often not built yet!) You can bet on it! Who needs the data?!! In the real world… Only a schematic description Lack of non-Gaussian effects The GIGO effect  Greg Landsberg, Beyond the SM @ the Tevatron  Tevatron Lesson: the Monte Carlo Do not rely on MC – it will look quite different from the actual data taken with the new detectors; we witnessed this in both Run I and Run II

  11.  Greg Landsberg, Beyond the SM @ the Tevatron  Fast Monte Carlo – A Good Compromise? • Parametric fast MC: • Is flexible and tunable with real data • Easily interfaced with modern event generators • Able to generate large samples of events on a short time scale

  12.  Greg Landsberg, Beyond the SM @ the Tevatron  Run II Stats • 1/8 of the expected Run IIa statistics (2 fb-1) have been delivered already; most of it in the last few months • Data taking efficiency is ~90% for both the CDF and DØ collaborations • EPS’03 and LP’03 results will break the new level of statistics, exceeding those in Run I • While the future of the Tevatron upgrade became uncertain recently, we are proceeding with an aggressive upgrade schedule with the shutdown planned in about 2 years to replace the silicon detectors

  13.  Greg Landsberg, Beyond the SM @ the Tevatron  Search for Exotics at the Tevatron • It’s a long shot, as signatures are often not clear and physics motivation is frequently questionable • “To find Exotica, call 1-800-EXOTICA” - WNUA , Chicago • Technicolor models have been restricted significantly by LEP (both direct searches and precision measurements) • Run II should confirm or exclude simplest versions of technicolor and topcolor models • Additional gauge bosons and leptoquarks: • Come in many SM extensions, particularly in GUTs; however, they do not solve SM problems per se • Significantly constrained by the LEP precision electroweak data • Massive Slow-Moving Particles • Limited motivation (need high degeneracy or exotic particles) • Both collaborations utilize TOF and dE/dx to perform searches

  14.  Greg Landsberg, Beyond the SM @ the Tevatron  Searches for Extra Gauge Bosons • Example: Z’ searches • Current limits ~700 GeV • Run II sensitivity ~1 TeV • Not a significant extension of the parameter space E6 Z’ couplings M > 620 GeV (DØ) M > 665 GeV (CDF) ∫Ldt ~ 40 pb-1 SM-like Z’ couplings

  15.  Greg Landsberg, Beyond the SM @ the Tevatron  Searches for Leptoquarks • A lot of excitement 6 years ago, due to reported HERA high-Q2 event excess • Interest largely evaporated since the LQ interpretation of HERA result was shown to be wrong by the Tevatron • Nevertheless, searches are under way, and expected Run II sensitivity extends to 300-350 GeV for scalar LQ’s DØ Run II: MLQ2 > 157 GeV CDF Run II: MLQ1 > 230 GeV ∫Ldt = 30 pb-1

  16. Caveat: the large hierarchy of scales picture is based solely on the log extrapolation of gauge couplings by some 14 decades in energy How valid is that? 1998: abstract mathematics meets phenomenology: extra spatial dimensions have been first used to: “Hide” the hierarchy problem by making gravity as strong as other gauge forces in (4+n)-dimensions (Arkani-Hamed, Dimopoulos, Dvali) Explore modification of the RGE in (4+n)-dimensions to achieve low-energy unification of the gauge forces(Dienes, Dudas, Gherghetta) Burst of ideas to follow: 1999: possible rigorous solution of the hierarchy problem by utilizing metric of curved anti-deSitter space (Randall, Sundrum) 2000: “democratic” (universal) extra dimensions, equally accessible by all the SM fields(Appelquist, Chen, Dobrescu) 2001: “contracted” extra dimensions – use them and then lose them (Arkani-Hamed, Cohen, Georgi) All these models result in rich low-energy phenomenology Gravitational Force Real GUT Scale Inverse Strength EM/Hypercharge Force Virtual Image Weak Force MPl=1/GN Strong Force L ~ 1 TeV M’Pl MZ MS M’GUT MGUT logE  Greg Landsberg, Beyond the SM @ the Tevatron  More Fun in Extra Dimensions

  17.  Greg Landsberg, Beyond the SM @ the Tevatron  Math Meets Physics • Math physics: some dimensionalities are quite special • Example: Laplace equation in two dimensions has logarithmic solution; for any higher number of dimensions it obeys power law instead • Some of these peculiarities exhibit themselves in condensed matter physics, e.g. diffusion equation solutions allow for long-range correlations in 2D-systems (cf. flocking) • Modern view in topology: one dimension is trivial; two and three spatial dimensions are special (properties are defined by the topology); any higher number is not • Do we live in a special space, or only believe that we are special? • One of the most innovating and exciting recent ideas, yet barely tested experimentally!

  18. EWSB from extra dimensions: Hall, Kolda [PL B459, 213 (1999)](lifted Higgs mass constraints) Antoniadis, Benakli, Quiros [NP B583, 35 (2000)](EWSB from strings in ED) Cheng, Dobrescu, Hill [NP B589, 249 (2000)](strong dynamics from ED) Mirabelli, Schmaltz [PR D61, 113011 (2000)](Yukawa couplings from split left- andright-handed fermions in ED) Barbieri, Hall, Namura [hep-ph/0011311](radiative EWSB via t-quark in the bulk) Flavor/CP physics from ED: Arkani-Hamed, Hall, Smith, Weiner [PRD 61, 116003 (2000)](flavor/CP breaking fields on distant branes in ED) Huang, Li, Wei, Yan [hep-ph/0101002](CP-violating phases from moduli fields in ED) Neutrino masses and oscillations from ED: Arkani-Hamed, Dimopoulos, Dvali, March-Russell [hep-ph/9811448](light Dirac neutrinos from right-handed neutrinos in the bulk or light Majorana neutrinos from lepton number breaking on distant branes) Dienes, Dudas, Gherghetta [NP B557, 25 (1999)](light neutrinos from right-handed neutrinos in ED or ED see-saw mechanism) Dienes, Sarcevic [PL B500, 133 (2001)](neutrino oscillations w/o mixing via couplings to bulk fields) Many other topics from Higgs to dark matter  Greg Landsberg, Beyond the SM @ the Tevatron  Using the Extra Dimension Paradigm

  19. SM fields are localized on the (3+1)-brane; gravity is the only gauge force that “feels” the bulk space What about Newton’s law? Ruled out for flat extra dimensions, but not for sufficiently small compactified extra dimensions: Compact Dimension Flat Dimension  Greg Landsberg, Beyond the SM @ the Tevatron  The ADD Model • Gravity is fundamentally strong force, bit we do not feel that as it is diluted by the volume of the bulk • G’N = 1/MD2; MD  1 TeV • More precisely, from Gauss’s law: • Amazing as it is, but no one has tested Newton’s law to distances less than  1mm (as of 1998) • Thus, the fundamental Planck scale could be as low as 1 TeV for n > 1

  20. Real Graviton Emission Monojets at hadron colliders g g g q GKK GKK g q Single VB at hadron or e+e- colliders V GKK V V GKK GKK GKK V Virtual Graviton Emission Fermion or VB pairs at hadron or e+e- colliders f f V GKK GKK f f V  Greg Landsberg, Beyond the SM @ the Tevatron  Collider Signatures for Large ED • Kaluza-Klein gravitons couple to the momentum tensor, and therefore contribute to most of the SM processes • For Feynman rules for GKK see: • Han, Lykken, Zhang, PR D59, 105006 (1999) • Giudice, Rattazzi, Wells, Nucl. Phys. B544, 3 (1999) • Since graviton can propagate in the bulk, energy and momentum are not conserved in the GKK emission from the point of view of our 3+1 space-time • Depending on whether the GKK leaves our world or remains virtual, the collider signatures include single photons/Z/jets with missing ETor fermion/vector boson pair production • If the energy is above Planck scale, copious black hole production is inevitable

  21. In the case of pair production via virtual graviton, gravity effects interfere with the SM (e.g., l+l- at hadron colliders): Therefore, production cross section has three terms: SM, interference, and direct gravity effects The sum in KK states is divergent in the effective theory, so in order to calculate the cross sections, an explicit cut-off, MS, is required An expected value of the cut-off is  MD, as this is the scale at which the effective theory breaks down, and the string theory needs to be used to calculate production Direct emission and virtual effects are complementary methods of probing ADD model Unfortunately, a number of similar papers calculating the virtual graviton effects appeared simultaneously Hence, there are three major conventions on how to write the effective Lagrangian: Hewett, Phys. Rev. Lett. 82, 4765 (1999) Giudice, Rattazzi, Wells, Nucl. Phys. B544, 3 (1999); revised version, hep-ph/9811291 Han, Lykken, Zhang, Phys. Rev. D59, 105006 (1999); revised version, hep-ph/9811350 Fortunately (after a lot of discussions and revisions) all three conventions turned out to be equivalent and only the definitions of MS are different:  Greg Landsberg, Beyond the SM @ the Tevatron  Virtual Graviton Effects

  22.  Greg Landsberg, Beyond the SM @ the Tevatron  Tevatron Searches • High-mass, low |cosq| tail is a characteristic signature of LED [Cheung, GL, PRD 62 076003 (2000)] • 2-dimensional method resolves this tail from the high-mass, high|cosq| tail due to collinear divergencies in the SM diphoton production • Best limits on the effective Planck scale come from the DØ Run I data: • MS(Hewett) > 1.1/1.0 TeV (l = +1/-1) • LT(GRW) > 1.2 TeV • MS(HLZ) > 1.0-1.4 TeV (n=2-7) • Similar limits already set with Run II data • New 120 pb-1 analysis out next week! • Sensitivity in Run II and at the LHC (HLZ, from [Cheung, GL, PRD 62 076003 (2000)]) 50 pb-1

  23. qq/gg  q/gGKK jets + MET final state Z(nn)+jets is irreducible background Challenging signature due to large instrumental backgrounds from jet mismeasurement, cosmics, etc. DØ pioneered this search in Run I and set limits [PRL 90, 251802 (2003)] MD > 0.7-1.0 TeV CDF just announced similar preliminary limits qq  gGKK g+MET final state CDF search [PRL 89, 281801 (2002)] set limits between 500 and 600 GeV  Greg Landsberg, Beyond the SM @ the Tevatron  Hadron Colliders: Graviton Emission Theory: [Giudice, Rattazzi, Wells, Nucl. Phys. B544, 3 (1999) and corrected version, hep-ph/9811291] [Mirabelli, Perelstein, Peskin, PRL 82, 2236 (1999)]

  24. Intermediate-size extra dimensions with TeV-1 radius Introduced by Antoniadis [PL B246, 377 (1990)] in the string theory context; used by Dienes/Dudas/ Gherghetta [PL B436, 55 (1998)] to allow for low-energy unification SM gauge bosons can propagate in these extra dimensions Expect ZKK, WKK, gKK resonances Effects of the virtual exchange of the Kaluza-Klein modes of vector bosons at lower energies Gravity is not included in this model Antoniadis/Benaklis/Quiros [PL B460, 176 (1999)] – direct excitations; require LHC energies  Greg Landsberg, Beyond the SM @ the Tevatron  TeV-1 Extra Dimensions [ABQ, PL B460, 176 (1999)] IBQ ZKK

  25.  Greg Landsberg, Beyond the SM @ the Tevatron  Current Limits on TeV-1 ED From Cheung/GL [PRD 65, 076003 (2002)]

  26.  Greg Landsberg, Beyond the SM @ the Tevatron  Tevatron Tests in Run II • We expect the dijet and DY production to be the most sensitive probes of TeV-1 extra dimensions • The 2D-technique similar to the search for ADD effects in the virtual exchange yields the best sensitivity in the DY production [Cheung/GL, PRD 65, 076003 (2002)] • Similar (or slightly better) sensitivity is expected in the dijet channel; detailed cuts and NLO effects need to be studied • Run IIb could yield sensitivity similar to the current limits from indirect searches at LEP • These tests are complementary in nature to those via loop diagrams at LEP From Cheung/GL [PRD 65, 076003 (2002)]

  27. Randall-Sundrum (RS) scenario [PRL 83, 3370 (1999); PRL 83, 4690 (1999)] Gravity can be localized near a brane due to the non-factorizable geometry of a 5-dimensional space + brane (RS) – no low energy effects +– branes (RS) – TeV Kaluza-Klein modes of graviton ++ branes (Lykken-Randall) – low energy collider phenomenology, similar to ADD with n=6 –+– branes (Gregory-Rubakov-Sibiryakov) – infinite volume extra dimensions, possible cosmological effects +–+ branes (Kogan et al.) – very light KK state, some low energy collider phenomenology x5 SM brane Davoudiasl, Hewett, Rizzo PRD 63,075004 (2001) Drell-Yan at the LHC  Greg Landsberg, Beyond the SM @ the Tevatron  Randall-Sundrum Scenario G Planck brane

  28. Neither gravity experiments, nor cosmology provide interesting limits on most of the RS models Existing limits come from collider experiments, dominated by precision electroweak measurements at LEP As the main effect involves direct excitation of the GKK, energy is the key Given the existing constraints and the theoretically preferred parameters, there is not much the Tevatron can do to test RS models Extra degree of freedom due to the compact dimension results in a light scalar field – the radion Again, Tevatron sensitivity is very limited LHC is the place to probe RS models  Greg Landsberg, Beyond the SM @ the Tevatron  Current Constraints

  29.  Greg Landsberg, Beyond the SM @ the Tevatron  Run II Searches • CDF pioneered RS graviton searches in the dilepton and dijet modes • Limited increase in sensitivity with larger statistics

  30.  Greg Landsberg, Beyond the SM @ the Tevatron  Universal Extra Dimensions • The most “democratic” ED model: all the SM fields are free to propagate in extra dimension(s) with the size Rc = 1/Mc ~ 1 TeV-1[Appelquist, Cheng, Dobrescu, PRD 64, 035002 (2001)] • Instead of chiral doublets and singlets, introduce vector-like quarks and leptons • Gravitational force is not included in this model • The number of universal extra dimensions is not fixed: • It’s feasible that there is just one (MUED) • The case of two extra dimensions is theoretically attractive, as it breaks down to a chiral SM and has additional nice features, such as guaranteed proton stability, etc. • Every particle acquires KK modes with masses Mn2 = M02 + Mc2, n = 0, 1, 2, … • Kaluza-Klein number (n) is conserved at the tree level, i.e. n1 n2 n3 … = 0; consequently, the lightest KK mode cold be stable (and is an excellent dark matter candidate [Cheng, Feng, Matchev, PRL 89, 211301 (2002)]) • Hence, KK-excitations are produced in pairs, similar to SUSY particles • Consequently, current limits (dominated by precision electroweak constraints, particularly on the T-parameter) are sufficiently low (Mc~ 300 GeV for one ED and of the same order, albeit more model-dependent for >1 ED)

  31. Naively, one would expect large clusters of nearly degenerate states with the mass around 1/RC, 2/RC, … Cheng, Feng, Matchev, Schmaltz: not true, as radiative corrections tend to be large (up to 30%); thus the KK excitation mass spectrum resembles that of SUSY! Minimal UED model with a single extra dimension, compactified on an S1/Z2 orbifold Odd fields do not have 0 modes, so we identify them w/ “wrong” chiralities, so that they vanish in the SM Q, L (q, l) are SU(2) doublets (singlets) and contain both chiralities  Greg Landsberg, Beyond the SM @ the Tevatron  UED Phenomenology [Cheng, Matchev, Schmaltz, PRD 66, 056006 (2002)] MC = 1/RC = 500 GeV

  32.  Greg Landsberg, Beyond the SM @ the Tevatron  UED Spectroscopy • First level KK-states spectroscopy Decay: B(g1→Q1Q) ~ 50% B(g1→q1q) ~ 50% B(q1→qg1) ~ 100% B(t1→W1b, H1+b) ~ B(Q1→QZ1:W1:g1) ~ 33%:65%:2% B(W1→nL1:n1L) = 1/6:1/6 (per flavor) B(Z1→nn1:LL1) ~ 1/6:1/6 (per flavor) B(L1→g1L) ~ 100% B(n1→g1n) ~ 100% B(H1→gg1, H±*g1) ~ 100% Production: q1q1 + X → MET + jets (~shad/4); but: low MET Q1Q1+ X→ V1V’1 + jets → 2-4 l + MET (~shad/4) [CMS, PRD 66, 056006 (2002)]

  33. Reasonably high rate up to M ~ 500 GeV Q1Q1, q1q1 Run II, s = 2 TeV [Rizzo, PRD 64, 095010 (2001)]  Greg Landsberg, Beyond the SM @ the Tevatron  Production Cross Section

  34.  Greg Landsberg, Beyond the SM @ the Tevatron  Sensitivity in the Four-Lepton Mode • Only the gold-plated 4-leptons + MET mode has been considered in the original paper • Sensitivity in Run IIb can exceed current limits • Much more promising channels: • dileptons + jets + MET + X (x9 cross section) • trileptons + jets + MET + X (x5 cross section) • Detailed simulations is required: important to see this process implemented in a MC • One could use SUSY production with adjusted masses and branching fractions as a temporary fix L is per experiment; (single experiment) [Cheng, Matchev, Schmaltz, PRD 66, 056006 (2002)]

  35.  Greg Landsberg, Beyond the SM @ the Tevatron  Almost No Extra Dimensions • Novel idea: build a multidimensional theory that is reduced to a four-dimensional theory at low energies [Arkani-Hamed, Cohen, Georgi, Phys. Lett. B513, 232 (1991)] • An alternative EWSB mechanism, the so-called Little Higgs (a pseudo-goldstone boson, responsible for the EWSB) [Arkani-Hamed, Cohen, Katz, Nelson, JHEP 0207, 034 (2002)] • Limited low-energy phenomenology: one or more additional vector bosons; a charge +2/3 vector-like quark (decaying into V/h+t), necessary to cancel quadratic divergencies), possible additional scalars (sometimes even stable!), all in a TeV range • Unfortunately, the Tevatron reach is very poor; LHC would be the machine to probe this model • However: keep an eye on it – this is currently the topic du jour in phenomenology of extra dimensions; new signatures are possible!

  36.  Greg Landsberg, Beyond the SM @ the Tevatron  (Instead of) Conclusions • ED are one of the most exciting novelideas, yet barely tested experimentally: • ADD: virtual graviton effects, direct graviton emission, string resonances • TeV-1 dimensions: VKK, virtual effects • RS: graviton excitations, SM particle excitation, radion, direct graviton emission • Universal extra dimensions: rich SUSY-like phenomenology • Like in SUSY searches, Run II would double the parameter space probed, which makes this subject one of the most exciting exotic channels to explore • Both CDF and DØ collaborations pursue this avenue very actively

  37.  Greg Landsberg, Beyond the SM @ the Tevatron  Grand Finale: Have We Missed Anything? • SLEUTH (formerly known as SHERLOCK) [DØ, PRD 62, 92004 (2000); PRL 86, 3712 (2001); PRD 64, 012004 (2001)] is an attempt to use multivariate techniques to answer the above question • Generalizes search for high-pT physics by identifying global variables, correlated with the pT of a process, and then looking for “reasonable” contiguous areas in the resulting multivariate space yielding maximum excess of data above the SM background • Unusual, data-driven approach; an interesting method to answer the question of whether there was an evidence for new physics in the data posteriori • Takes into account the fact that search for excesses was performed in many different variables and channels by adjusting the probability accordingly; consequently, trades decreased significance for increased generality • Used by DØ to reanalyze Run 1 data in a semi-model-independent way and quantify the degree of the agreement between the data and the SM predictions in some 30 previously studied channels

  38. ~ ~ P(s) = -1.23s→ P = 0.89,i.e. 89% of hypothetical experimentswould have seen more “interesting” results in these 32 channels than DØ  Greg Landsberg, Beyond the SM @ the Tevatron  DØ Run 1 Sleuth Results • Sleuth is a nice tool to use before closing the door and shutting off the lights: have we forgotten or missed anything • It crucially relies on background understanding and won’t help at this (most time-consuming) step • Not very competitive with direct search for a known signature (e.g. mass peak)

  39. [Atwood, Bar-Shalom, Sony, PRD 62, 056008 (2000)], used HLZ formalism Look at the dijet production cross section as a function of t = s/s Reach at the Tevatron ~1.5 TeV (2 fb-1), at the LHC ~10 TeV (30 fb-1) – comparable to that in the dilepton/diphoton channels Also, tt invariant mass and pT at the Tevatron or LHC (Run IIa reach: ~1.2 TeV; LHC: ~6 TeV) [Rizzo, hep-ph/9910255 (1999)] Tevatron, SM MS = 0.75 TeV MS = 2 TeV MS = 4 TeV MS = 6 TeV MS = 1.5 TeV LHC, SM  Greg Landsberg, Beyond the SM @ the Tevatron  ADD and Dijet Production ^

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