1 / 17

Extra Dimensions of Space-Time

Extra Dimensions of Space-Time. Motivation:. String theory suffers conformal anomaly that makes theory inconsistent --> get rid of it Conformal anomaly ~ (D-26) for a bosonic string ~ (D-10) for a fermionic string.

leola
Download Presentation

Extra Dimensions of Space-Time

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Extra Dimensionsof Space-Time Motivation: String theory suffers conformal anomaly that makes theory inconsistent --> get rid of it Conformal anomaly ~ (D-26) for a bosonic string ~ (D-10) for a fermionic string • Is it possible that we actually leave in D > 4? • Do we have experimental evidence for D=4, D> 4?

  2. Why don’t we see extra dimensions

  3. Kaluza-Klein Approach compact space Pseudo-Euclidean space Minkowski space Metrics Fields Eigenfunctions of Laplace operator on internal space K d Masses K-K modes Radius of the compact space Couplings

  4. Multidimensional Gravity Action K-K Expansion Newton constant Plank Mass Reduction formula

  5. Low Scale Gravity 10 10 10 Modified Newton potential

  6. Brane World Compact Dimensions Non-compact dimensions Kink soliton R Energy density brane Localization on the brane (Potential well) D4-brane New D4-brane SM Bulk Space-time of Type I superstring

  7. graviton The ADD Model metric SM K-K gravitons Interactions with the fields on the brane The # of KK gravitons with masses Emission rate

  8. Particle content of ADD model • (4+d)-dimensional picture: • (4+d)-dimensional massless graviton + matter • 4-dimensional picture • 1 massless graviton (spin 2) + matter • KK tower of massive gravitons (spin 2) • (d-1) KK spin 1 decoupling fields • KK tower of real scalar decoupling fields • KK tower of scalar fields (zero mode – radion) The SM fields are localized on the brane, while gravitons propagate in the bulk The “gravitational” coupling is

  9. HEP Phenomenology New phenomena: graviton emission & virtual graviton exchange • KK states production bg LHC

  10. HEP Phenomenology II • Virtual graviton exchange q - Spin=2 q SM Angular distribution

  11. Randall-Sandrum Models D4-brane D4-brane Plank TeV Bulk Positive tension Negative tension Metric Matter warp factor graviton radion Perturbed Metric

  12. Randall-Sandrum Model cont’d Brane 2 Brane 1 Wrap factor • Massless graviton • massive K-K gravitons • massless radion Hierarchy Problem ! • Massless graviton • massive K-K gravitons • massless radion

  13. HEP Phenomenology The first KK graviton mode M ~ 1 TeV • Drell-Yan process • Excess in dijet process Exclusion plots for resonance production Excluded Excluded Run I Dj D-Y Run II D-Y Tevatron LHC

  14. HEP Phenomenology II The x-section of D-Y production First KK mode First and subsequent KK modes Tevatron (M ~ 700 GeV) LHC (M ~ 1500 GeV)

  15. HEP Phenomenology III Angular dependence LHC LHC

  16. ED Conclusion • ADD Model • The MEW/MPL hierarchy is replaced by • For M small enough it can be checked at • modern and future colliders • For d=2 cosmological bounds on M are high (> 100 TeV), • but for d>2 are mild • Preictions of modification of the Newton’s law may be checked • RS Model • The MEW/MPL hierarchy is solved without new hierarchy • A large part of parameter space will be studied in future • collider experiments • With the mechanism of radion stabilization the model is viable • Cosmological scenarios are consistent (except the cosmological • constant problem)

  17. What comes beyond the Standard Model ? SM

More Related