1. Sreerup Raychaudhuri TIFR Extra Dimensions and Collider Physics Workshop on Synergy between High Energy and High Luminosity Frontiers Tata Institute of Fundamental Research, Mumbai January 10, 2011

2. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Extra Compact Dimensions Ancient Age 1914-1975 Mediæval Age 1970-1998 Modern Age 1998- Attempts to unify gravitation with electromagnetism : Kaluza-Klein theory Compact dimensions lead to Yang-Mills theories Largely abandoned In 1950’s and 1960’s Relativistic string theory requires D = 26 or D = 10 Compactification on Calabi-Yau manifolds or orbifolds led to gauge theory Discovery of D-branes and AdS-CFT Large extra dimensions proposed to solve hierarchy problem Warped extra dimensions as a more natural solution: use of AdS-CFT ideas Universal extra dimensions : ‘bosonic’ supersymmetry

3. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Compact Dimensions RCRC two-dimensional one-dimensional

4. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Large Extra Dimensions Antoniadis, Arkani-Hamed, Dimopoulos, Dvail 1998 SM fields are confined to the brane Only graviton can access the bulk brane bulk

5. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Kaluza-Klein tower of states

6. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Each graviton KK mode couples very weakly with SM matter, but collective effect of many modes builds up to electroweak strength realvirtual

7. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Graviton-induced processes : DØ

8. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR M S (TeV) Constraining the string scale :

9. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Laboratory Black Holes b If impact parameter b < R S Schwarzschild radius for M = 2 m p, a micro-black hole is formed Decay by Hawking radiation with lifetime ~ 10 -25 s Spectacular spherically-distributed signals Cross section (semiclassical) : At least 10 5 micro black holes at the 14-TeV LHC with 10 fb -1 Einstein gravity gives 10 -28 pb

10. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Probability of accretion:

11. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Warped Extra Dimension Randall, Sundrum 1999 Planck brane TeV brane AdS 5 ‘throat’ Metric contracts exponentially along AdS 5 ‘throat’  Gravitons acquire TeV masses

12. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Warp factor controls the entire RS phenomenology: Kaluza-Klein tower of states Each graviton couples as: Graviton KK modes behave like WIMPs…

13. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Decay modes of RS gravitons

14. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Sum over propagators

15. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Graviton resonances in Drell-Yan dileptons

16. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR

18. ATLAS dilepton CMS dielectron inaccessible 5 X CDF

19. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR ATLAS Allanach et al (2000) Resonant production of G 1 Final state : dielectrons

20. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR RS Variants Warp factor: Must choose KR C = 11.7 Dynamic generation of hierarchy : Goldberger-Wise Replace KR C = T(x) ; potential in T(x) is flat Introduce a bulk scalar with 4 couplings 11.7

21. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Residue is a light scalar – the radion

22. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Invoke AdS-CFT correspondence: bulk RS model is equivalent to a composite SM on the TeV brane Keep only Higgs fields localised to TeV brane and let all other SM fields go into the bulk Each will have KK modes, just as the graviton has in RS Strongest signal will be from the g 1 decaying to t t FCNC Tevatron

23. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Universal Extra Dimension Appelquist, Cheng, Dobrescu 2001 ; metric is flat

24. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR

27. Collider bound: R -1 > 728 GeV Dark Matter constraint:

28. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR Bounds from non-discovery are easy, but ….

29. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR

30. many other possibilities…

31. Extra Dimensions and Collider Physics Sreerup Raychaudhuri, TIFR SUMMARY If SUSY is the Standard BSM theory, Extra Dimensions have become the Standard non-SUSY theory Three main paradigms: ADD, RS, UED Each has interesting collider phenomenology LHC has the potential to discover all of the models …unless they decouple Next few years may be exciting! Thank You