1. Shufang Su • U. of Arizona
SuperWIMP Dark matter
Gravitino from Slepton and Sneutrino Decays
Shufang Su • U. of Arizona
J. Feng, F. Takayama, S. Su
Hep-ph/

2. Outline SWIMP dark matter and gravitino LSP-
SWIMP dark matter and gravitino LSP
Late time energy injection and BBN
Slepton and sneutrino NLSP
Dominant two body EM decay l ! l+G
Subdominant 3-body hadronic decay
Viable parameter space
Conclusion ~
S. Su SWIMP

3. Why gravitino not considered as CDM usually?-
thG  v-1  (gravitional coupling)-2
(comparig to WIMP of weak coupling strength)
v too small
thG too big, overclose the Universe ~
However, gravitino can get relic density by other means
SuperWIMP
S. Su SWIMP

4. WIMP  SWIMP + SM particle-
FRT hep-ph/ ,
WIMP
104 s  t  108 s
SWIMP SM
Gravitino LSP
LKK graviton
106
S. Su SWIMP

5. SWIMP and SUSY WIMP SWIMP: G (LSP) WIMP: NLSP mG» mNLSP ~ SUSY case-
SWIMP: G (LSP) WIMP: NLSP mG» mNLSP ~
SUSY case ~
Ellis et. al., hep-ph/
104 s  t  108 s
NLSP  G + SM particles ~
Neutralino/Chargino NLSP
Slepton NLSP
BBN EM
had
Brhad  O(0.01)
Brhad  O(10-3)
S. Su SWIMP

6. Different approach to gravitino superWIMP- ~
NLSP  G + SM particles
my talk
Takayama’s talk
SWIMP close universe
SWIMP maybe insiginificant
nNLSP  NLSP/mNLSP  1/mSUSY
thNLSP  v-1  m2SUSY
 nNLSP  mSUSY
NLSP: slepton,sneutrino
NLSP: slepton, sneutrino,
neutralino
fix SWIMP = 0.23
SWIMP = mG/mNLSP thNLSP ~
S. Su SWIMP

7. Late time energy injection and BBN-
/10-10 = 6.1 0.4 ?
EM,had=EM,had BEM,had YNLSP
EM, had energy injection:
» mNLSP-mG
Fields, Sarkar, PDG (2002)
S. Su SWIMP

8. EM and Had BBN constraints-
EM BBN constraints
had BBN constraints
EM BBN
Cyburt, Ellis, Fields and Olive,
PRD 67, (2003)
Kawasaki, Kohri and Moroi,
astro-ph/
S. Su SWIMP

9. Slepton NLSP lifetime and EM injection-
l  G + l,  ! G +  ~
Decay lifetime (sec)
EM energy injection EM (GeV)
S. Su SWIMP

10. Hadronic decay branching ratio-
l  lZG,WG ,  ! ZG, lWG ~
meson contribution
mNLSP
S. Su SWIMP

11. Viable Parameter space-
200 GeV ·  m · 400 » 1500 GeV
mG ¸ 200 GeV
 m · 80 » 300 GeV ~
negligible EM BBN constraints
S. Su SWIMP

12. Conclusions SuperWIMP is possible candidate for dark matter-
SuperWIMP is possible candidate for dark matter
SUSY models: gravitino LSP (SWIMP) slepton NLSP (WIMP)
Constraints from BBN: EM injection and hadronic injection
need updated studies of BBN constraints on hadronic/EM injection
Favored mass region: (enlarged if SWIMP<0.23)
Sneutrino:  m  GeV  m  100 GeV
Charged R: 200 GeV ·  m · 1500 GeV, mG ¸ 200 GeV
 500 GeV  mR
Rich collider phenomenology (no direct/indirect DM signal)
Charged slepton: highly ionizing track
Sneutrino: missing energy ~ ~ ~ ~ ~
S. Su SWIMP

13. SM energy distribution
Decay life time  mpl
SM energy distribution
 mG
 SUSY breaking scale SM
NLSP ~ G SM
NLSP ~ SM
NLSP ~ G ~ G
NLSP SM SM
NLSP ~ G ~ G
S. Su SWIMP