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Searching For Large Extra Dimensions at D 

Searching For Large Extra Dimensions at D . Ryan J. Hooper (University of Notre Dame) On behalf of the D  Collaboration. Extra dimensions Overview of Run 1 results Run 2 expectations Current Run 2 data The diEM channel The di m channel Summary. Extra Dimensions.

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Searching For Large Extra Dimensions at D 

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  1. Searching For Large Extra Dimensions at D Ryan J. Hooper (University of Notre Dame) On behalf of the D Collaboration • Extra dimensions • Overview of Run 1 results • Run 2 expectations • Current Run 2 data • The diEM channel • The dim channel • Summary Ryan J. Hooper -- DPF, May 24-28, 2002

  2. Extra Dimensions • String Theory yearns for n=6,7 extra dimensions • Compactified with radius R ~ 10-32m • Astrophysical and table top experiments: • Ruled out n=1 and put significant constraints on n=2 • Placed limits on R < 0.15mm • “Large” Extra Dimensions (LED) • Arkani-Hamed, Dimopoulos, Dvali (ADD) hep-th/9809124 • Graviton is only particle that propagates in extra dimensions • Effective Planck scale (MS) down to TeV ranges • A solution to the hierarchy problem • Kaluza-Klein modes of the graviton (GKK) can enhance effects at colliders Ryan J. Hooper -- DPF, May 24-28, 2002

  3. g g g q GKK GKK g q V GKK V V GKK GKK GKK V Extra Dimensions at D • At D we look for direct GKK production • Strong n dependence • 1/(MS)n+2 • Gluon or vector boson + ET • ET from graviton escaping detection • We look at virtual GKK exchange as well • Weaker n dependence • h = F/MS4 • F = 1 (GRZ) = log(MS2/M2) for n=2, 2/(n-2) n>2 (HLZ) = 2l/p; l = ±1 (Hewett) USED FOR THIS TALK! • Two lepton or two vector boson final states Ryan J. Hooper -- DPF, May 24-28, 2002

  4. D Run 1: Direct GKK Search • P-pbar gluon + GKK • Final state jet + ET • Recent monojet result • ~79pb-1 of Run 1 data • ET > 150 GeV • Leading Jet: ET > 150 GeV • |h| < 1.0 • Gives complementary limit to LEP results for n > 4 Ryan J. Hooper -- DPF, May 24-28, 2002

  5. e,g q,g q* q,g e,g D Run 1: Virtual GKK Search • Final states are dileptons or diphotons • In Run 1 looked at dielectrons + diphotons • For better sensitivity combine e and g to form “diEM” • Invariant mass vs. |cos(q*)| • LEDs at high mass and low |cos(q*)| • Results • 127pb-1 of data • ET > 45 GeV • |h| < 2.5 • ET < 25 GeV • LEP: MS > ~ 0.5-1.2 TeV MS > 1.1 TeV for l= +1 MS > 1.0 TeV for l= -1 Ryan J. Hooper -- DPF, May 24-28, 2002

  6. D Run 2 Expectations • Run 1: 0.13fb-1 • In Run 2 • CM energy 1.96 TeV vs. 1.8 TeV in Run 1 • Run 2a: 2fb-1 doubling MS sensitivities over Run 1 • Run 2b: 15fb-1 tripling MS sensitivities over Run 1 • Upgraded D detector • Our current Run 2 LED analysis follows the Run 1 virtual GKK analysis previously mentioned • Also add the dimuon channel Ryan J. Hooper -- DPF, May 24-28, 2002

  7. D Run 2: DiEM Zs Central + Central • The Z is a good place to “calibrate” high PT objects • Using ~10pb-1 of data • We see Z to diEM • Cuts: • Standard D EM ID • ET > 20 GeV • ET < 30 GeV • |h| < 1.1 or 1.5 < |h| < 2.5 Central + End Cap Ryan J. Hooper -- DPF, May 24-28, 2002

  8. D Run 2: LEDs DiEM Channel D Run 2 Preliminary • We see 2 high mass events Monte Carlo Data Ryan J. Hooper -- DPF, May 24-28, 2002

  9. EM1 EM2 ET = 115.4 GeV  = 0.10  = 5.27 No track match ET = 109.7 GeV  = -2.10  = 2.19 No track match M(diEM) = 376 GeV; cosq* = 0.79; MET = 8.2 GeV; D Run 2: DiEM Channel D Run 2 Preliminary • Highest mass diEM candidate No extra dimensions yet…but let’s not forget the electron’s heavier brother! Ryan J. Hooper -- DPF, May 24-28, 2002

  10. D Run 2: Dim Resonances Green Histograms = Opposite sign muons Blue Histograms = Same sign muons • Once again lets use well known physics to “calibrate” • ~10pb-1 of data • Cuts: • DMuon ID • Both muons |h| < 1.6 • Pt tracks > 2.5 GeV • For Z plot: Track Pt > 15 GeV Z D Run 2 Preliminary J/y Upsilon Ryan J. Hooper -- DPF, May 24-28, 2002

  11. D Run 2: LEDs Dim Channel • We see a few high mass events D Run 2 Preliminary Monte Carlo Data Ryan J. Hooper -- DPF, May 24-28, 2002

  12. Summary • Extra dimensions can bring the effective Planck scale down to TeV energies • D in Run 1: • Direct GKK production results complementary to LEP limits for n > 4 • Virtual GKK exchange limits of MS > 1.1 TeV for l = +1 • and MS > 1.0 TeV for l = -1 • D in Run 2: • With 2fb-1, sensitivity to MS should double vs. Run 1 • Virtual GKK exchange in diEM and dim • We currently have J/y, Upsilon and Z resonances • See some higher mass events • Should have first physics results by ICHEP Ryan J. Hooper -- DPF, May 24-28, 2002

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