Ryan J. Hooper -- DPF, May 24-28, 2002
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Searching For Searching For Large Extra Dimensions at Large Extra Dimensions at
DD
• Extra dimensionsExtra dimensions• Overview of Run 1 resultsOverview of Run 1 results• Run 2 expectationsRun 2 expectations• Current Run 2 dataCurrent Run 2 data
– The diEM channelThe diEM channel– The diThe di channel channel
• SummarySummary
Ryan J. Hooper (University of Notre Dame)Ryan J. Hooper (University of Notre Dame)On behalf of the DOn behalf of the D Collaboration Collaboration
Ryan J. Hooper -- DPF, May 24-28, 2002
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• String Theory yearns for n=6,7 extra dimensionsString Theory yearns for n=6,7 extra dimensions– Compactified with radius R ~ 10Compactified with radius R ~ 10 -32-32mm– Astrophysical and table top experiments: Astrophysical and table top experiments:
– Ruled out n=1 and put significant Ruled out n=1 and put significant constraints on n=2constraints on n=2– Placed limits on R < 0.15mmPlaced limits on R < 0.15mm
• ““Large” Extra Dimensions (LED)Large” Extra Dimensions (LED)– Arkani-Hamed, Dimopoulos, Dvali (ADD) hep-th/9809124Arkani-Hamed, Dimopoulos, Dvali (ADD) hep-th/9809124– Graviton is only particle that propagates in extra dimensionsGraviton is only particle that propagates in extra dimensions– Effective Planck scale (MEffective Planck scale (MSS) down to TeV ranges) down to TeV ranges
– A solution to the hierarchy problemA solution to the hierarchy problem– Kaluza-Klein modes of the graviton (GKaluza-Klein modes of the graviton (GKKKK) can enhance effects at colliders) can enhance effects at colliders
Extra DimensionsExtra Dimensions
nnSPl RMM 22
Ryan J. Hooper -- DPF, May 24-28, 2002
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• At DAt D we look for direct G we look for direct GKKKK production production– Strong n dependenceStrong n dependence
• 1/(MS)n+2
– Gluon or vector boson + EGluon or vector boson + ETT
– EETT from graviton from graviton
escaping detectionescaping detection
• We look at virtual GWe look at virtual GKKKK
exchange as wellexchange as well– Weaker n dependence Weaker n dependence
– F/MF/MSS44
– F = 1 (GRZ)F = 1 (GRZ) = log(M= log(MSS
22/M/M22) for n=2, 2/(n-2) n>2 (HLZ)) for n=2, 2/(n-2) n>2 (HLZ)
= 2= 2//; ; = ±1 (Hewett) = ±1 (Hewett) USED FOR THIS TALK!USED FOR THIS TALK! – Two lepton or two vector boson final statesTwo lepton or two vector boson final states
Extra Dimensions at DExtra Dimensions at D
82
4 SM
GKK
gq
q GKK
gg
g
GKK
GKK
GKKGKK
V
VV V
Ryan J. Hooper -- DPF, May 24-28, 2002
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DD Run 1: Direct G Run 1: Direct GKKKK Search Search• P-pbar P-pbar gluon + G gluon + GKKKK • Final state jet + EFinal state jet + ETT
• Recent monojet resultRecent monojet result– ~79pb~79pb-1-1 of Run 1 data of Run 1 data– EETT > 150 GeV > 150 GeV
– Leading Jet: ELeading Jet: ETT > 150 GeV > 150 GeV– ||– Gives complementary limitGives complementary limit
to LEP results for n > 4to LEP results for n > 4
Ryan J. Hooper -- DPF, May 24-28, 2002
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• Final states are dileptons or diphotonsFinal states are dileptons or diphotons• In Run 1 looked at dielectrons + diphotonsIn Run 1 looked at dielectrons + diphotons
– For better sensitivity For better sensitivity combine e and combine e and to form “diEM” to form “diEM”
• Invariant mass vs. |cos(Invariant mass vs. |cos()|)|• LEDs at high mass LEDs at high mass
and low |cos(and low |cos()|)|
• ResultsResults– 127pb127pb-1-1 of data of data– EETT > 45 GeV > 45 GeV– ||| < 2.5| < 2.5– EETT < 25 GeV < 25 GeV
• LEP: MLEP: MSS > ~ 0.5-1.2 TeV > ~ 0.5-1.2 TeV
DD Run 1: Virtual G Run 1: Virtual GKKKK Search Search
MMSS > 1.1 TeV > 1.1 TeV for for
MMSS > 1.0 TeV > 1.0 TeV for for
q,g q,g
e,
e,
Ryan J. Hooper -- DPF, May 24-28, 2002
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DD Run 2 Expectations 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 DD 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
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DD Run 2: DiEM Zs Run 2: DiEM Zs» The Z is a good place to “calibrate” high PT objects» Using ~10pb-1 of data» We see Z to diEM» Cuts:» Standard DStandard D EM ID EM ID» EETT > 20 GeV > 20 GeV» EETT < 30 GeV < 30 GeV» ||| < 1.1 or | < 1.1 or
1.5 < |1.5 < || < 2.5| < 2.5
Central + End Cap
Central + Central
Ryan J. Hooper -- DPF, May 24-28, 2002
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DD Run 2: LEDs DiEM Channel Run 2: LEDs DiEM Channel We see 2 high mass eventsWe see 2 high mass events
Monte Carlo Data
D Run 2 Preliminary
Ryan J. Hooper -- DPF, May 24-28, 2002
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» Highest mass diEM candidate
No extra dimensions yet…but let’s not forget the electron’s heavier No extra dimensions yet…but let’s not forget the electron’s heavier brother!brother!
DD Run 2: DiEM Channel Run 2: DiEM Channel
D Run 2 Preliminary
M(diEM) = 376 GeV; cos* = 0.79; MET = 8.2 GeV;
EM2EM1
ET = 109.7 GeV = -2.10 = 2.19No track match
ET = 115.4 GeV = 0.10 = 5.27No track match
Ryan J. Hooper -- DPF, May 24-28, 2002
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DD Run 2: Di Run 2: Di Resonances Resonances» Once again lets use well known physics to “calibrate”» ~10pb-1 of data» Cuts: » DD Muon ID » Both muons || < 1.6 » Pt tracks > 2.5 GeV
» For Z plot:Track Pt > 15 GeV
D Run 2 Preliminary
Green Histograms = Opposite sign muons
Blue Histograms = Same sign muons
J/
Upsilon
Z
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• We see a few high mass eventsDD Run 2: LEDs Di Run 2: LEDs Di Channel Channel
D Run 2 Preliminary
Monte Carlo Data
Ryan J. Hooper -- DPF, May 24-28, 2002
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SummarySummary• Extra dimensions can bring the effective Planck Extra dimensions can bring the effective Planck
scale down to TeV energies scale down to TeV energies • DD in Run 1: in Run 1:
• Direct GDirect GKKKK production results complementary to LEP limits production results complementary to LEP limits for n > 4for n > 4
• Virtual GVirtual GKKKK exchange limits of M exchange limits of MSS > 1.1 TeV for > 1.1 TeV for = +1 = +1 • and Mand MSS > 1.0 TeV for > 1.0 TeV for = -1= -1
• DD in Run 2: in Run 2:• With 2fbWith 2fb-1-1, sensitivity to M, sensitivity to MSS should double vs. Run 1 should double vs. Run 1• Virtual GVirtual GKKKK exchange in diEM and di exchange in diEM and di• We currently have J/We currently have J/, Upsilon and Z resonances, Upsilon and Z resonances• See some higher mass events See some higher mass events
• Should have first physics results by ICHEPShould have first physics results by ICHEP
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