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Cosmology in Warped Extra Dimensions

Cosmology in Warped Extra Dimensions. Kenji Kadota, Theoretical Physics Institute, Univ. of Minnesota. Dark Matter ( K.K., ‘Sterile Neutrino Dark Matter in Warped Extra Dimensions’ arXiv:0711.1570 [ hep-ph] ) 1) Motivation 2) Setup: Bulk fields in warped 5D

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Cosmology in Warped Extra Dimensions

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  1. Cosmology in Warped Extra Dimensions Kenji Kadota, Theoretical Physics Institute, Univ. of Minnesota • Dark Matter ( K.K., ‘Sterile Neutrino Dark Matter in Warped Extra Dimensions’ arXiv:0711.1570[hep-ph] ) 1) Motivation 2) Setup: Bulk fields in warped 5D 3) Sterile Neutrino properties a) Coupling to the radion (AdS/CFT interpretation) b) Sterile Neutrino Mass c) Abundance 4) Examples II) Baryon Asymmetry of the Universe ( T. Gherghetta, K.K., M. Yamaguchi ‘Warped Leptogenesis with Dirac Neutrino Masses’ arXiv:0705.1749[hep-ph]) III) Conclusion/Discussion

  2. Motivation • No absolutely stable collisionless particles in a simple Randall-Sundrum model ( c.f. Flat Extra-Dimension: KK parity KK Dark Matter Dines et al ‘99, Appelquist et al ‘00,Cheng et al ‘02, Servant et al ‘02, Agashe & Servant ‘04, ‘05) • Particles with the life-time longer than the age of the Universe  Sterile (chargeless, right-handed) Neutrino Advantages of 5D compared with 4D for sterile neutrino dark matter scenario • Fine-tuning ameliorated (thanks to warp factor and small wave function overlaps) • Production mechanism (radion decay) Can be either Cold or Warm Dark Matter

  3. Warm DM: Free-streams erasing the inhomogeneities • Warm dark matter: bigger free-streaming than that of cold dark matter • Missing satellite problem (satellite: small galaxies, the mass 10-3 of Milky Way galaxy) • Cusp/core problem Simple warm dark matter model accounting for all the dark matter in the universe is excluded. ‘Simple’ warm dark model: Sterile neutrino produced from the active-sterile neutrino mixing (Dodelson-Widrow ‘94) Lyman-alpha forrest: lower limit 10 keV X-ray: upper bound 8 keV Our scenario: Radion decay produces sterile neutrinos We assume negligible mixing production, negligible Yukawa coupling (c.f. • Large lepton asymmetry : Shi&Fuller ‘99 • Additional singlet scalar : Kusenko ‘06 • Inflaton : Shaposhnikov and Tkachev ‘06 • Subdominant warm dark matter: Palazzo, Cumberbatch, Solsar, Silk ‘07)

  4. Cosmology in Warped Extra Dimensions • Dark Matter ( K.K., ‘Sterile Neutrino Dark Matter in Warped Extra Dimensions’ arXiv:0711.1570[hep-ph] ) 1) Motivation 2) Setup: Bulk fields in warped 5D 3) Sterile Neutrino properties a) Coupling to the radion (AdS/CFT interpretation) b) Sterile Neutrino Mass c) Abundance 4) Examples II) Baryon Asymmetry of the Universe ( T. Gherghetta, K.K., M. Yamaguchi ‘Warped Leptogenesis with Dirac Neutrino Masses’ arXiv:0705.1749[hep-ph]) III) Conclusion/Discussion

  5. Setup: 5D Warped space-time SM fields+ Three right-handed Neutrinos (one of which is sterile dark matter N) All fields in the bulk Brane stabilized by Goldberg-Wise ‘99

  6. Bulk fields

  7. Cosmology in Warped Extra Dimensions • Dark Matter ( K.K., ‘Sterile Neutrino Dark Matter in Warped Extra Dimensions’ arXiv:0711.1570[hep-ph] ) 1) Motivation 2) Setup: Bulk fields in warped 5D 3) Sterile Neutrino properties a) Coupling to the radion (AdS/CFT interpretation) b) Sterile Neutrino Mass c) Abundance 4) Examples II) Baryon Asymmetry of the Universe ( T. Gherghetta, K.K., M. Yamaguchi ‘Warped Leptogenesis with Dirac Neutrino Masses’ arXiv:0705.1749[hep-ph]) III) Conclusion/Discussion

  8. 5D Randall-Sundrum 1. Coordinate z along AdS 2. Planck brane at z=R 3. TeV brane at z=R’ 4. Radion 5. Planck brane localized field 6. TeV brane localized field 7. At finite temperature, two stationary solutions: RS geometry & AdS-Schwarzschild space 4D Strongly coupled CFT with gravity 1. Energy Scale in CFT 2. Cutoff of CFT =1/R 3. CFT spontaneously breaks conformal invariance 4. Pseudo-Goldstone boson of broken conformal invariance 5. Elementary fields coupled to CFT 6. Composites of CFT 7. Confinement & Deconfinement phases Holographic Interpretation (Maldacena ‘97, Gubser et al ‘98, Witten ‘98, Arkani-hamed et al ‘00, Rattazzi et al ‘01)

  9. Radion Couplings J: Global current whose breaking leads to Goldstone boson f: symmetry breaking scale

  10. Cosmology in Warped Extra Dimensions • Dark Matter ( K.K., ‘Sterile Neutrino Dark Matter in Warped Extra Dimensions’ arXiv:0711.1570[hep-ph] ) 1) Motivation 2) Setup: Bulk fields in warped 5D 3) Sterile Neutrino properties a) Coupling to the radion (AdS/CFT interpretation) b) Sterile Neutrino Mass c) Abundance 4) Examples II) Baryon Asymmetry of the Universe ( T. Gherghetta, K.K., M. Yamaguchi ‘Warped Leptogenesis with Dirac Neutrino Masses’ arXiv:0705.1749[hep-ph]) III) Conclusion/Discussion

  11. Sterile Neutrino Mass SterileWe assume negligible Yukawa (i.e. no mixing)Negligible Dirac mass

  12. Cosmology in Warped Extra Dimensions • Dark Matter ( K.K., ‘Sterile Neutrino Dark Matter in Warped Extra Dimensions’ arXiv:0711.1570[hep-ph] ) 1) Motivation 2) Setup: Bulk fields in warped 5D 3) Sterile Neutrino properties a) Coupling to the radion (AdS/CFT interpretation) b) Sterile Neutrino Mass c) Abundance 4) Examples II) Baryon Asymmetry of the Universe ( T. Gherghetta, K.K., M. Yamaguchi ‘Warped Leptogenesis with Dirac Neutrino Masses’ arXiv:0705.1749[hep-ph]) III) Conclusion/Discussion

  13. Sterile neutrino abundance • Boltzmann equation To account for all the current dark matter,

  14. Cosmology in Warped Extra Dimensions • Dark Matter ( K.K., ‘Sterile Neutrino Dark Matter in Warped Extra Dimensions’ arXiv:0711.1570[hep-ph] ) 1) Motivation 2) Setup: Bulk fields in warped 5D 3) Sterile Neutrino properties a) Coupling to the radion (AdS/CFT interpretation) b) Sterile Neutrino Mass c) Abundance 4) Examples II) Baryon Asymmetry of the Universe ( T. Gherghetta, K.K., M. Yamaguchi ‘Warped Leptogenesis with Dirac Neutrino Masses’ arXiv:0705.1749[hep-ph]) III) Conclusion/Discussion

  15. Examples Lyman-alpha: lower limit 10 keV Sterile Neutrino dark matter model in 4D typically suffers from fine-tunings , which is relaxed in 5D.

  16. Cosmology in Warped Extra Dimensions Kenji Kadota, Theoretical Physics Institute, Univ. of Minnesota • Dark Matter ( K.K., ‘Sterile Neutrino Dark Matter in Warped Extra Dimensions’ arXiv:0711.1570[hep-ph] ) 1) Motivation 2) Setup: Bulk fields in warped 5D 3) Sterile Neutrino properties a) Coupling to the radion (AdS/CFT interpretation) b) Sterile Neutrino Mass c) Abundance 4) Examples II) Baryon Asymmetry of the Universe ( T. Gherghetta, K.K., M. Yamaguchi ‘Warped Leptogenesis with Dirac Neutrino Masses’ arXiv:0705.1749[hep-ph]) III) Conclusion/Discussion

  17. <<TeV (e.g, 10-9TeV) Mass splitting due to the Majorana mass confined on Planck brane Lepton number violation leads to the small mass splittings

  18. TeV Scale Warped Leptogenesis (T. Gherghetta, K.K. & M. Yamahuchi, arXiv:0705.1749[hep-ph]) ~TeV Enough baryon asymmetry even at TeV scale! (c.f. T~1010GeV for standard leptogenesis.)

  19. Discussion/Conclusion Future work in progress: Phase transitions (e.g. entropy dilution etc), Thermal corrections etc (Warm, Cold) Dark Matter in Warped Extra Dimensions • No absolutely stable collisionless/chargeless particles • Long-lived Sterile neutrino Produced by radion decay Fine-tunings ameliorated TeV Scale Warped Leptogenesis • Global symmetry breaking term (Majorana mass) confined on Planck brane while RH Neutrino localized around TeV brane Small mass splitting for big CP asymmetry at TeV scale

  20. Radion coupling to Fermion

  21. TeV Scale Warped Leptogenesis ~TeV Enough baryon asymmetry even at TeV scale

  22. CDM/WDM (Abazajian et al ‘01,’06)

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