Detection of Neutralino WIMP

1
Detection of Neutralino WIMP
decay and

• Yeong Gyun Kim
• (Korea Univ.)

• Evidence for Dark Matter
• Dark Matter Candidates
• Direct Detection of Neutralino WIMP
• Indirect Detection Neutrino Telescopes
• Conclusions

2

• Evidence for Dark Matter

• What is Dark Matter ?

stuff that neither emits nor absorbs detectable
EM radiation
the existence can be inferred by its
gravitational effects on visible celestial body

• Motion of Galaxies in Clusters

• Galactic Rotation Curves

• Gravitational Lensing

• Temperature fluctuation of CMBR
  

3

• Motions of galaxies in clusters

• Observed the Coma cluster of galaxies in 1933

• Found the galaxies move too fast to be confined
• in the cluster by the gravitational attraction of
  visible
• matter alone.

Dark Matter in cluster
Fritz Zwicky (1898-1974)
The central 1Mpc of Coma cluster in optical
4

• Galactic Rotation Curves

• In 1970s, they found flat rotation curves.

Dark Matter in galaxy
Vera Rubin (1928-)
5

• Cosmic Microwave Background Anisotropies

WMAP satellite
6

• Matter/Energy density in the Universe

• Baryonic Dark Matter

• Non-Baryonic Dark Matter

• Dark Energy (Cosmological constant)

7
II. Dark Matter Candidates (what is Dark
Matter made of ?)

• Baryonic Dark Matter candidates

• MACHOs (MAssive Compact Halo Objects)

Jupiter, brown dwarfs, white dwarfs, neutron
stars, black hole.

• Hydrogen gas, Dusts.

• Non-Baryonic Dark Matter candidates

• Neutrinos

• Axion

• WIMPs (Weakly Interacting Massive Particles)

Neutralinos, Kaluza-Klein states, .

• Wimpzillas (superheavy DM)

• .

8

• Relic density of WIMPs

WIMP Weakly Interacting Massive Particle

• Time evolution of the number density of WIMPs

H Hubble constant
thermally averaged annihilation cross section
of WIMP
equilibrium number density
9
Freeze out at
If
10

• Minimal Supersymmetric Standard Model (MSSM)

• SM fields plus an extra Higgs doublet
• and their superpartners

• SU(3) x SU(2) x U(1) gauge symmetry and
• Renormalizability

• R-parity conservation (to avoid fast proton
  decay)

( B baryon number, L lepton number S
spin )
1 for ordinary particles -1 for their
superpartners
LSP is STABLE !

• Soft Supersymmetry Breaking

11

• Neutralino mass matrix

In the basis
Bino, Wino mass parameters
Higgsino mass parameter
ratio of vev of the two neutral Higgs

• Lightest Neutralino LSP in many cases (WIMP
  !! )

12

• Neutralino Annihilation channels

etc.
13

• Overview of the allowed regions of mSUGRA
  parameter
• space by the Relic density of Neutralino WIMP

1. Bulk region
(hep-ph/0106204, Battaglia et al.)
at low m0 and m1/2 t-channel slepton exchange
2. Stau co-annihil. region
at low m0 where neutralino-stau
coannihilation
3. Focus point region
at large m0 where mu is small a sigificant
higgsino comp.
4. A-annihilation region
at large
where
14
III. Direct detection of Neutralino WIMP

• Local Dark Matter density

• Maxwellian velocity distribution

• Local Flux of Dark Matter

15

• Principles of WIMP detection

• Elastic scattering of a WIMP on a nucleus inside
  a detector

• The recoil energy of a nucleus with mass

For

• This recoil can be detected in some ways

• Electric charges released (ionization detector)

• Flashes of light produced (scintillation
  detector)

• Vibrations produced (phonon detector)

16

• Experimental Results

(CDMS collab. astro-ph/0405033)
17

• Low energy effective Lagrangian for
  neutralino-quark int.

scalar interaction
spin-dep. interaction

• The other terms are velocity-dependent
  contributions and can be
• neglected in the non-relativistic limit for the
  direct detection.

• The axial vector currents are proportional to
  spin operators
• in the non-relativistic limit.

18

• Spin-dependent Neutralino-Nucleus cross-section

reduced mass
where
(J the spin of the nucleus)
the quark spin content of the nucleon

the expectation values of the spin content of
the nucleus depends on the target nucleus
for
for
19

• Scalar Neutralino-Nucleus cross-section

where
A the atomic weight, Z the nuclear electric
charge

20

vs.

• In most instances,

the scalar (spin-independent) cross section
scales with the atomic weight, in contrast to
the spin-dependent cross section.

• The scalar interaction almost always dominates
  for nuclei with A gt 30.

For , either interaction can dominate,
depending on the SUSY parameters.
has predominantly spin-independent
interactions.
21
decays in MSSM

• In the Standard Model

• the decay proceeds through Z penguin and
• W exchange box diagrams.

• the decay is helicity suppressed due to
• angular momentum conservation.

• Current Experimental Limit (90 CL)

(CDF)
(D0)
22

• In the MSSM (Babu,Kolda 2000)

• Fermion mass eigenstates can be different from
• the Higgs interaction eigenstates.

• This generates Higgs-mediated FCNCs.

23

vs.

• Both observables increase as

increases.

• Smaller Higgs masses give larger observable
  values.

24

• Minimal Supergravity Model

• Unification of the gauge couplings at GUT scale

• Universal soft breaking parameters at GUT scale

m universal scalar mass M universal gaugino
mass A universal trilinear coupling

• Radiative EW symmetry breaking

Free parameters ( m,M,A,
)
25
These conditions imply that

at EW scale
at EW scale

Bino-like
Heavy
26
mSUGRA model ( A0 and m,M lt 1TeV )
(S.Baek, YGK, P.Ko 2004 )
Higgs and sparticle mass and
bounds included.

27
mSUGRA model ( A0 and m,M lt 1 TeV )
(S.Baek, YGK, P.Ko 2004 )
Required that Neutralino is LSP
Higgs and sparticle masses and

bounds included.

28

• Non-universal Higgs mass Model (NUHM)

• Parameterize the non-universality in the Higgs
  sector
• at GUT scale

• The above modifications of mSUGRA boundary
  cond.
• lead to the change of and at EW
  scale.

29
mSUGRA
NUHM
30
mSUGRA
NUHM
31
Non-Universal Higgs Mass Model
32
Non-Universal Higgs Mass Model

33
Non-Universal Higgs Mass Model
34
Non-Universal Higgs Mass Model

35

• A specific D-brane Model (D.G. Cerdeno et al.
  2001)

• the gauge groups of the standard model come
  from different sets of Dp branes.

• In this model, scalar masses are not completely
• universal and gaugino mass unificaion is
  relaxed.

• the string scale is around GeV rather than
  GUT scale.

Free parameters
36
A D-brane Model
37
A D-brane Model

38
See D.G.Cerdenos talk this afternoon for more
detailed analysis, including Non-universal
scalar and gaugino masses
39
IV. Indirect detection of Neutralino WIMP (
Neutrino telescopes SuperK, AMANDA, ANTARES,
IceCube)

• Neutralino WIMPs in the galactic halo can be
  captured by the SUN and Earth through
  Neutralino-nucleus scattering

• The accumulated Neutralino WIMPs annihilate into
  SM particles,
• which ultimately yields energetic neutrino flux

• The neutrino flux can be detected in neutrino
  telescopes
• via conversion

40
Super-K Super Kamiokande detector
50,000 ton water Cherenkov detector, located in
the Kamioka-Mozumi mine in Japan with 1000 m rock
overburden.
Set upper limits on WIMP-induced upward muon flux
from the Sun and Earth etc. (103 / km2 yr)
41
AMANDA Antiartic Muon and Neutrino Detector
Array
A deep under-ice Cherenkov neutrino telescope.
Uses 3 km thick ice layer at the geographical
South Pole.
AMANDA-II detector is in operation with 677
PMTs at 19 strings since 2000.
AMADA-II will be integrated to IceCube.
42
ANTARES Astronomy with a Neutrino Telescope
and Abyss
environmental RESearch
A deep underwater neutrino telescope.
In construction of a 12-string detector in the
Mediterranean Sea at 2400 m depth
43

• The number of Neutralino WIMP in the Sun (or
  Earth)

the capture rate of WIMPs onto the Sun (or
Earth)
the total annihilation cross section times
relative velocity per volume

• The present annihilation rate (at 4.5 Gyr,
  age of solar system)

for
for
When accretion is efficient, the annihilation
rate depends on the capture rate C, but not on
the annihilation cross section.
44

• The Capture rate C depends on the elastic
  scattering cross
• section of Neutralino with matter in the Sun (or
  Earth).

• The capture rate for the Earth primarily depends
  on
• the spin-independent DM scattering cross
  section.
• (only a negligible fraction of the Earths
  mass is in nuclei with spin)

• For the capture rate of the Sun, both
  spin-independent
• and spin-dependent DM scattering cross section
  can be important.
• (spin-dependent interaction with hydrogen
  nuclei)

The neutrino-induced muon flux strongly depends
on Neutralino-nucleus scattering cross section.
45
Muon Flux vs.
mSUGRA model ( A0 and m,M lt 1TeV )
(S.Baek, YGK, P.Ko PRELIMINARY)
from the Sun
from the Earth
46
vs.

(S.Baek, YGK, P.Ko PRELIMINARY)
47
vs.

in Non-Universal Higgs Model
(S.Baek, YGK, P.Ko PRELIMINARY)
from the Sun
from the Earth
48
Muon Flux vs.
Non-Universal Higgs Mass Model
(S.Baek, YGK, P.Ko PRELIMINARY)
from the Sun
from the Earth

49
Muon Flux vs.
Non-Universal Higgs Mass Model
(S.Baek, YGK, P.Ko PRELIMINARY)
from the Sun
from the Earth

50
Muon Flux vs.
A D-brane Model
(S.Baek, YGK, P.Ko PRELIMINARY)
from the Earth
from the Sun
51
V. Conclusions

• We considered the direct detection and indirect
  detection of neutralino WIMPs
• in the galactic halo, including the current
  upper bound of
• in mSUGRA, Non-Universal Higgs mass and a
  D-brane model.

• We have shown that current upper limit on the
  branching ratio puts
• strong constraint on the model parameter space
  which could lead to quite large
• spin-independent neutralino-proton scattering
  cross section and
• neutrino-induced muon flux from the Sun and
  Earth.