1. Topics in Higgs Portal Dark Matter
Seungwon Baek (KIAS)
Yonsei, March 21, 2013
based on ,
in collaboration with P. Ko, W.I. Park, E. Senaha

2. Outline Evidences for dark matter Relic density Direct detection
Indirect detection
Higgs portal singlet fermionic/vector DM
Collider phenomenology (Higgs search)
EW precision tests
Vacuum stability
Perturbativity
Conclusions

3. Dark Matter
Ordinary matter contribute only 4% of the total energy of the universe
The bulk of the universe is made up of dark matter and dark energy

4. Evidences for Dark Matter
Rotation curve
The observed stars and galaxies move faster than luminous objects can support. F. Zwicky (1933)

5. Evidences for Dark Matter
The Bullet Cluster
Two clusters of galaxies moving away from each other after collision. Clowe, et. al. (2006)
Red region (visible)ordinary matter (hot gas)
Blue region (invisible)more gravity (dark matter)
However, Lee & Komatsu (2010) claims it is incompatible with ΛCDM model

6. Evidences for Dark Matter
Cosmic Microwave Background Radiation (CMBR)
CMBR is almost perfect black body radiation with T=2.728K
Isotropic with anisotropy at the level of 10^(-5)
CMB power spectrum shows

7. Dark Matter All the evidences for DM are via gravitational interaction
We do not know the nature of DM
If DM is WIMP, it allows the particle physics explanation, direct/indirect detection, and its creation at LHC

8. WIMP miracle

9. Relic density Boltzmann eq. Introduce Y Conservation of entropy
Bertone, et. al
Boltzmann eq.
Introduce Y
Conservation of entropy
The Boltzmann eq. becomes

10. Now introduce a variable x:
For heavy WIMP, we can expand
Then in terms of

11. Now we can solve the Boltzmann eq.
The current relic density
The freeze-out temperature

12. WIMP DM Searches

13. Direct Detection
The event # of WIMP-nucleon scattering per unit time, per unit detector mass
Jungman, et.al. (1996)
scattering angle in the CM frame

14. The FF is a Fourier tranf. of the nucleus distribution function:
micrOmegas (2009)
Fermi distribution function

15. Effective operators for direct detection
v=10^(-3), q(max)=100MeV
Cross section is calculated q=0 limit
For SI (spin-independent) cross section (Majorana DM)

16. Effective operators for direct detection
For Dirac DM
Scalar DM
Vector DM
+: WIMP, -: anti-WIMP

17. WIMP-quark scattering

18. Indirect Detection Proportional to DM annihilation rate
Galactic center, Center of Sun(Earth) may be good place to look for DM annihilation signals.
Observed flux
spectrum of photon (neutrino)

19. Evidences for Dark Matter
Cosmic Ray Searches
PAMELA satellite observed striking increase in the positron spectrum

22. Indirect Detection
, ,
If confirmed, it may be a clear signal for 130 GeV DM.

23. Hidden Sector DM and Higgs Portal
One possible WIMP DM scenario is the framework of “Hidden Sector” DM
DM may be singlet under the SM gauge grouphidden
Hidden sector is generic in SUSY or superstring models

24. Hidden Sector DM and Higgs Portal
The renormalizable Higgs can mediate the interaction between the SM and hidden sector SM
HS(DM)

25. DM physics
GIM-type cancellation occurs in the DM annihilation and scattering cross section
0 for degenerate Higgs

26. Direct detection
XENON100(2012)

27. Direct detection Exclusion plot by XENON100 gX: DM-X coupling
Cancellation is quite effective

28. DM relic density
Thermal relic density
Singlet Fermionic DM
Vector DM

29. DM relic density
SFDM
VDM
P-wave annihilation
S-wave annihilation

30. Comparison with the EFT approach
For heavy m2, H2 can be integrated out. And EFT is a good approximation.
S. Kanemura et.al 2010, A. Djouadi, et.al. 2011, O. Lebedev, H. M. Lee, Y. Mambrini, 2011, L. Lopez-Hororez, Schwetz, Zupan 2012

31. Comparison with the EFT approach
SFDM scenario is ruled out in the EFT
We may lose information in DM pheno.
A. Djouadi, et.al. 2011

32. Comparison with the EFT approach

33. Comparison with the EFT approach

34. Higgs Phenomenology
Higgs sector is extendedHiggs phenomenology is different from the SM one SM
HS(DM)

35. Higgs Phenomenology Invisible decay of Higgs at tree is allowed
Reduction of Higgs signal strength Hi X

36. Higgs Phenomenology Signal strength (reduction factor)
ri<1. If some ri>1, our scenario is excluded
Atlas 2013

37. EW precision tests
New contribution to the EW precision obs. Barger, et.al. 2008

38. EW precision tests
The S,T,U parameters give strong constraints on the mixing angle α

39. EW precision tests

40. Higgs phenomenology
It will be difficult to produce the 2nd Higgs at the LHC.

41. Higgs phenomenology

42. Direct detection

43. Direct detection

44. Vacuum stability (EW)
Requiring the global min. of the Higgs potential is at the EW vacuua constrains the parameters of the Higgs portal
violates this condition

46. Triviality and vacuum stability bound on mH
125GeV
The Higgs potential may become unstable before Mpl.

47. Higgs portal model can provide negative contribution to the SM-like Higgs.
Lebedev 2012, J. Elias-Miro, et.al 2012

48. Conclusions DM with Higgs portal
provides cancellation to reduce the direct search bound
improves the stability of Higgs potential
changes the Higgs search at colliders
is constrained by EWPT and the discovery of SM-Higgs boson
It will be difficult to produce the 2nd Higgs.