Cosmology in Warped Extra Dimensions

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 arXiv0711.1570hep-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
• arXiv0705.1749hep-ph)

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 ShiFuller 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 arXiv0711.1570hep-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
• arXiv0705.1749hep-ph)

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 arXiv0711.1570hep-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
• arXiv0705.1749hep-ph)

8
Holographic Interpretation (Maldacena 97,
Gubser et al 98, Witten 98, Arkani-hamed et al
00, Rattazzi et al 01)

• 5D Randall-Sundrum
• 1. Coordinate z along AdS
• 2. Planck brane at zR
• 3. TeV brane at zR
• 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

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 arXiv0711.1570hep-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
• arXiv0705.1749hep-ph)

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 arXiv0711.1570hep-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
• arXiv0705.1749hep-ph)

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 arXiv0711.1570hep-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
• arXiv0705.1749hep-ph)

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 arXiv0711.1570hep-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
• arXiv0705.1749hep-ph)

17
Mass splitting due to the Majorana mass confined
on Planck brane

• ltltTeV
• (e.g, 10-9TeV)

Lepton number violation leads to the small mass
splittings
18
TeV Scale Warped Leptogenesis (T. Gherghetta,
K.K. M. Yamahuchi, arXiv0705.1749hep-ph)
TeV
Enough baryon asymmetry even at TeV scale! (c.f.
T1010GeV 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)