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Search for Extra Dimensions at ATLAS

Search for Extra Dimensions at ATLAS

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Search for Extra Dimensions at ATLAS

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

  2. 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

  3. 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 => 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

  4. Large Extra Dim.: Graviton Direct Production • Disentangle  and MD • - Run at two different energies • e.g 10 TeV and 14 TeV => • need 50 fb-1.

  5. 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)

  6. Large Extra Dim.: Graviton Virtual Exchange

  7. 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 > 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.

  8. 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

  9. 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

  10. 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)  e+e-, +-,  (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.

  11. 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.

  12. 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.

  13. 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

  14. 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,…