Search for Extra Dimensions at ATLAS

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Search for Extra Dimensions at ATLAS
PASCOS 2003 T.I.F.R, Mumbai, 3-8 January 2003
Ambreesh Gupta University of Chicago
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Spectrum of ATLAS Studies

• Large Extra Dimensions
• KK Graviton Direct Production ? Missing ET
• KK Graviton Virtual Production ? Drell-Yan
• TeV-1 Extra Dimensions
• KK Gauge Bosons ? Multi-TeV Resonance
• Randall-Sundrum Models
• KK Graviton ? TeV Resonance
• Radion ? Higgs Like Signature
• Other Scenario
• (E)LED MSSM ? RGE and Di-Jet cross section
• LED singlet neutrino 2HDM-II ? H???

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Large Extra Dim. Graviton Direct Production

• The apparent weakness of gravity could be due
• to diffusion of its field in extra dimension.
• Gravitons will appear as tower of massive
• Kaluza Kline states from 4D point of view.
• G(k) as external leg gt Missing Energy in 4D.
• ATLAS studies for sensitivity on scale MD and
  number
• of extra dimension ? .

L. Vacavant and I. Hinchliffe, J. Phys. G Nucl.
Part. Phys. 27 (2001) 1839
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Large Extra Dim. Graviton Direct Production

• Disentangle ? and MD
• - Run at two different energies
• e.g 10 TeV and 14 TeV gt
• need 50 fb-1.

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Large Extra Dim. Graviton Virtual Exchange

• Signal Deviation in DY cross section,
  Asymmetries.
• ATLAS studies with the photon and lepton pair
  production.

V. Kabachenko, A. Migakov, A Zenin,
ATL-PHYS-2001-012

• Large enhancement in
• di-lepton cross section.
• (similarly in di-photon)

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Large Extra Dim. Graviton Virtual Exchange
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TeV-1 Size Extra Dimension KK Gauge Boson

• Kaluza-Kline excitation of SM
• Gauge possible in presence of
• small extra dimension R 1 TeV-1
• Indirect constraint from LEP
• R gt 4 TeV-1.
• ATLAS studies
• - Study the di-lepton resonance from
  ?(1)/Z(1)
• - Implemented in PYTHIA ( M.E from T. Rizzo)

G. Azuelos and G. Polesello, hep-ph/0204031.
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TeV-1 Size Extra Dimension KK Gauge Boson
Reach Possible to detect resonance up to 5.8 TeV
In absence of peak a 95 CL of 13.5 TeV can be
achieved
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TeV Scale Gauge Coupling Unification

• KK excitation of Gauge boson affect the
  evolution of
• gauge couplings.
• LHC studies
• - Signal Modified Di-Jet cross section

C. Balzas, B. Laforge, hep-ph/0110217
Reach 5? signal measurable for scale 5-10 TeV
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Randall-Sundrum Model Narrow Resonance

• Geometric property of space-time is
• used to solve the hierarchy problem.
• Kaluza-Kline excitations could be
• observed as well separated narrow resonance.
• Atlas study on signal sensitivity and spin
  determination.
• Signal G(k) ? ee-, ??-, ?? (WW, ZZ, tt)
• - Model implemented in HERWIG.
• - Studies done for the electron channel
  (also ??-, ??)
• - One year of high luminosity run 100 fb-1.

B.C Allanach, K. Odagiri, A. Parker and B.
Webber, JHEP 9 (2000) 19.
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Randall-Sundrum Model Narrow Resonance
mG 1.5 TeV
5? sensitivity up to 2.1TeV of graviton mass.
Spin-1 ruled out with 90 CL up to 1.7 TeV of
graviton mass.
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Randall-Sundrum Model Radions

• In order to stabilize the size of extra dimension
  
• an additional scalar ?, the Radion, is
  proposed.
• The Radion has couplings similar to SM Higgs, and
  
• mixes with it.
• ATLAS studies for various Radion decay modes.

Goldberger and Wise, PRL 83 (1999) 4922.
G. Azuelos, D. Cavalli, H. Przysiezniak, L.
Vacavant, hep-ph/0204031.
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Randall-Sundrum Model Radions

• ? ? ??, ZZ ? 4l
• - SM Higgs study re- interpreted
• for 100 fb-1 data.
• ? ? hh ? ??bb
• - Study similar to MSSM. Negligible
  background.
• ? ? hh ? ????
• - High Backgrounds.

Reach 4.6, 5.7 TeV for m? 300, 600 GeV.
Reach 1.1 TeV with m? 600 GeV
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Summary

• LHC will be able to probe a number of Models.
  Studies
• done on
• - Large Extra Dimension.
• - Warped Extra Dimensions.
• - TeV-1 Size Extra Dimension.
• Studies in progress for blackholes and trans
  planckian
• scattering, universal extra dimension,