Transcript ASBS2 - University of Arizona

Supersymmetric Dark Matter
Shufang Su • U. of Arizona
K. Olive, astro-ph/0301505
Composition of the Universe
We know how much, but no idea what it is.
» 0.02 baryon
» 0.7
0.1 - 0.3
Non-baryonic
dark matter
Dark Energy
, quintenssence,…
S. Su Dark Matter
Baryonic dark matter (lum» 0.003)
 Hot dark matter: Neutrino
 Cold dark matter
− WIMP
− axions
 Other possibilities
− self-annihilating DM
− self-interacting DM
− warm DM
− fuzzy CDM
− …
2
WIMP CDM
 requirements
 Stable
− lifetime ¸ 10 Gyr
 Non-baryonic
 Neutral: color (strong interaction) and electric
− strong upper limits on the abundance of anomalously
heavy isotopes
 Cold: non-relativistic
 Yield correct density WIMP
− weak interacting:  » 0.01, mW » 100 GeV
  » 0.1
S. Su Dark Matter
3
Standard Model
I
II
III
Quarks
u
c
t
SM is a very dsuccessful
s theoretical
b
framework that describes all
Leptons
e


experimental observations to date
e


§,Z
Gauge boson
W
g

Not
for
cosmology
observations
(force carrier)
− Dark Matter
electro
weak
strong
2
=g /4
− Cosmology constant
-magnetic …
− Baryon asymmetry
» 0.01
» 0.03
» 0.1
Higgs
S. Su Dark Matter
H
4
Standard Model
I
II
III
u
d
c
s
t
b
Leptons
e
e




Gauge boson
(force carrier)

W§,Z
g
Higgs
H
Quarks
CDM requirements
 Stable
 Non-baryonic
 Neutral
 Cold
 Correct density
No good candidates for CDM in SM
S. Su Dark Matter
5
Supersymmetry
 SM is an effective theory below some energy scale 
Hierarchy problem: MEW100 GeV , Mplank 1019 GeV ?
Naturalness problem: mass of a fundamental scalar (like
Higgs) receive huge quantum corrections:
H
H
(mH2)physical  (mH2)0
-(1019
GeV)2
+
2
(1019 GeV)2
-
 Supersymmetry
SM particle
Spin differ by 1/2
2
(100 GeV)2
precise cancellation
up to 1034 order
superpartner
Naturalness  ms-particle » O(100-1000) GeV
S. Su Dark Matter
6
Gauge Coupling Unification
SM
SUSY
S. Su Dark Matter
7
Minimal Supersymmetric Standard Model (MSSM)
SM particle
Squarks
Spin differ by 1/2
»
u
»
d
»
c
»
s
t»
»
b
»


»

sleptons
»
e
»
e
»


»

Gauginos
»0
»
Higgsino
»
S. Su Dark Matter
B
»
W§,W0
»
(Hu+,Hu0)
,
»
(Hd0,
»
g
»
Hd-)
superpartner
CDM requirements
 Stable
 Non-baryonic
 Neutral
 Cold
m > 45 GeV
 Correct density
weak interaction
8
MSSM DM Candidates
 Possible DM candidates
− sneutrino ~

~0,W
~ 0,H
~ 0) !  0
~ 0,H
− neutralino (B
d
u
i
 Stable ?
General MSSM, including B,L-violating operators
• dangerous  introduce proton decay p ! K+ d
P
u
u
odd -~ odd
s

-s
+
u K
• R-parity
SM particle: even + superparticle: odd − no proton decay
− lightest supersymmetric particle (LSP) stable
LSP  SM particle, LSP  super particle
Good candidate of DM: could be ~
 or 10
S. Su Dark Matter
9
Sneutrino Dark Matter
~

Z
~

/l/q
/l/q
~

/l ~

~
f

~

W/Z
/l ~

W/Z
rapid annihilation, hAvi large
 light sneutrino: 45-200 GeV  low abundance
 heavy sneutrino: 550 – 2300 GeV  0.1    1
− disfavored on theoretical ground
− excluded by nuclear recoil direct detection: m~ ¸ 20 TeV
Sneutrino CDM in MSSM is excluded
S. Su Dark Matter
10
Neutralino
~0
B ,
~
W0,
Superpartner of
gauge bosons
~
Hd0,
~
Hu0
Superpartner of
Higgs bosons
 Properties
− fermion
− neutral
− heavy: m > 45 GeV
~
~ ~
~
 (B0, W0, Hd0, Hu0)  neutralinos i0, i=1…4 mass eigenstates
 Interactions: weak interacting / gauge coupling
~
f

f
H

S. Su Dark Matter

W,Z


11
Lightest Neutralino CDM
Now let us focus on neutralino as a candidate for CDM
 Neutralino mass matrix
Input parameter: M1, M2, , tan
~
~
~
~
i0=i B0+ i W0+i Hd0 +i Hu0 , m1 m2  m3  m4 , 1 being LSP
For small mixing: mZ ¿ M1, M2, 
~
M1< M2, ||: B0
~
M2< M1, ||: W0
~
~
||< M1, M2: Hu0 § Hd0
S. Su Dark Matter
Bino-LSP
Wino-LSP
Higgsino-LSP
12
MSSM Parameters
 Interactions involve the whole set of MSSM parameters
> 100 new parameters (SM: 19 parameters)
 other experimental constraints
Simplest assumption (unification)
CMSSM (constrained MSSM)
m0
M1/2
A0
tan
sign 
common scalar mass
common gaugino mass
common trilinear scalar
S. Su Dark Matter
GUT scale
||,b replaced by mZ,LSP
tan
Low energy

MSSM
parameters
13
Relic Density
>H
Decoupling:
=nhvi ¼ H
n/s
<H
Thermal relic density
 ! X+Y
− early time
n ¼ neq
− late time
(n/s)today » (n/s)decoupling
− at freeze-out
T » m/20
Approximately, relic / 1/hvi
S. Su Dark Matter
14
Neutralino Relic Density (I)
 10
 t-channel
(dominate)
f
~
f
 10
 s-channel
 10
~
 10
W
+
f
Z,H
~
 10
 10
/l/q
/l/q
~
absent for B0
W
Important near pole
m » mZ,H/2
Relic Density: =hAvi n » H
Special cases:
− Co-annihilation: mLSP ¼ mNLSP
− Annihilation near a pole: e.g. m » mZ,H/2
S. Su Dark Matter
<v> = a+bx+…
x=T/m
16
Neutralino Relic Density (II)
 0.3
No EWSB
CMSSM
m=mZ,h/2
0.1  
h2
bulk
S. Su Dark Matter
stau LSP
17
Phenomenological Constraints
Other constraints
− Higgs mass
mh > 114.4 GeV
− b ! s  : » 10-4
exclude small m1/2
important for  <0

muon g-2
me~=99GeV
b ! s 
S. Su Dark Matter
b
s
− muon g-2
th-exp=(26 § 16)£ 10-10
m= mZ,h/2 region
already excluded
18
~
Bulk region and -l coannihilation region
mh
m » m~
~ in equilibrium
+X ! +Y
~ decays into  eventually
~ ~~
Co-annihilation:, ,

bulk
if ignore co-annihilation
hvi » 1/m2,  / m/hvi
 upper bound on m
S. Su Dark Matter
mB~ » 200 GeV
19
Funnel-Like Region
Large tan : m » mA,H/2
~
 10
~
 10
A,H
/l/q
/l/q
A,H: heavy Higgses
SM:
h0
MSSM: h0,H0,A,H§
 / 1/hvi
hvi » 1/(4m2 – mA,H2)2 too big

 too small
S. Su Dark Matter
20
Focus Point Region
(100 GeV)2
conventional wisdom
focus point
a few are
TeVvery
, natural
naturalness  mfunnel
, ||
 TeV
Co-annihilation,
and
focus
pointm0regions
fine-tuned
0, M1/2
Highly depend on the otherm0input
m0 term negligible
termparameters
not negligible
|| À M1
~
DM Bino-like: 10 ¼ B0
S. Su Dark Matter
|| » M1
DM Bino-Higgsino mixture
22
Direct Detection of DM
 Direct detection via neutralino-nucleon scattering
,Z
/ 1/mq2~
− Bino DM: no diagram 1
require small m0
− Bino-Higgsino DM
large m0 detectable
 DM low velocity, non-relativistic
− Spin-dependent:  i  q i q
Mspin / pq h Spi/ JN + nq h Sni/ JN
− Spin-independent:   q- mq q / mW
Mscalar / Z fp+ (A-Z) fn
S. Su Dark Matter
23
Neutralino-Nucleon Scattering (II)
2 £ 10-10 pb  SI  6 £ 10-8 pb
2 £ 10-7 pb  SD  10-5 pb
S. Su Dark Matter
25
DAMA and CDMS
CDMS
DAMA
Edelweiss
NUHM
• DAMA finds signal in
annual modulation as
earth passes through
WIMP wind
• CDMS and Edelweiss
excludes much of the
favored region
CMSSM
S. Su Dark Matter
pb = 10-36 cm2
26
Indirect Detection
DM annihilation products from the Sun, Earth, galaxy
require hard annihilation products (not good for Bino DM)
  from the core of the Earth and Sun
Under-ice, underwater neutrino telescopes
 e+ from the local solar neighborhood
Anti-matter/ anti-particle experiments


  from the Galactic center
Atmospheric Cherenkov telescopes, space-based  ray detectors
S. Su Dark Matter
28
Comparison of pre-LHC SUSY Searches
− DM searches are complementary to collider searches
− When combined, entire cosmologically attractive region
will be explored before LHC ( » 2007 )
S. Su Dark Matter
29
Conclusion
 DM is the one of the strongest phenomenological
motivation for new physics
 Fruitful interplay of particle physics, cosmology,
and astrophysics
 A fascinating time: we know how much,
but have no idea what it is
 Many, many experiments
 MSSM neutralino LSP is a good candidate for CDM
 In SUSY, DM searches are promising, highly
complementary to collider searches
S. Su Dark Matter
30