Transcript ASBS2 - University of Arizona

SuperWIMP Dark matter
in SUSY with a Gravitino LSP
Shufang Su • U. of Arizona
See also, Jonathan Feng’s talk,
SuperWIMPs and Slepton Traps
J. Feng, F. Takayama, S. Su
hep-ph/0404198, 0404231
Why is the gravitino not usually considered as DM?
In supergravity, for mG~ » GeV – TeV
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
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WIMP  SWIMP + SM particle
FRT hep-ph/0302215, 0306024
WIMP
104 s  t  108 s
SWIMP
SM
 Gravitino LSP
 LKK graviton
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Outline
SWIMP dark matter and gravitino LSP
Constraints
- Late time energy injection and BBN
NLSP  gravitino +SM particle
slepton, sneutrino, neutralino
- approach I: fix SWIMP=0.23
- approach II: SWIMP=(mSWIMP/mNLSP) thNLSP
Collider phenomenology
Conclusion
Updates since Jan SLAC LC workshop
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SWIMP and SUSY WIMP
 SUSY case
~ (LSP)
SWIMP: G
WIMP: NLSP mG~ » mNLSP
Ellis et. al., hep-ph/0312262; Wang and Yang, hep-ph/0405186.
104 s  t  108 s
~
NLSP  G + SM particles
neutralino/chargino NLSP
slepton/sneutrino NLSP
Brhad  O(0.01)
Brhad  O(10-3)
EM
BBN
had
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Constraints
~
NLSP  G + SM particles
/10-10 = 6.1 0.4
 Dark matter density G~ · 0.23
- approach I: fix SWIMP=0.23
- approach II: SWIMP=(mSWIMP/mNLSP) thNLSP
 CMB photon energy distribution
 Big bang nucleosynthesis
Late time EM/had injection could
change the BBN prediction of
light elements abundances
Fields, Sarkar, PDG (2002)
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BBN constraints on EM/had injection
 Decay lifetime NLSP
 EM/had energy release
had
EM
EM (GeV)
» mNLSP-mG~
EM,had=EM,had BrEM,had
YNLSP
EM
Cyburt, Ellis, Fields and Olive, PRD 67, 103521 (2003) Kawasaki, Kohri and Moroi, astro-ph/0402490
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YNLSP: approach I
 approach I: fix G~ = 0.23
200 GeV ·  m · 400 » 1500 GeV
, EM,had=EM,had BEM,had
mG~ 
¸ NLSP
200 GeV
slepton and sneutrino
YNLSP m
· 80 » 300 GeV
apply CMB and BBN constraints on (NLSP, EM/had )
 viable parameter space
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Approach II: slepton and sneutrino
G~ = (m~G/mNLSP) thNLSP
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Collider Phenomenology
SWIMP Dark Matter
 no signals in direct / indirect dark matter searches
 SUSY NLSP: rich collider phenomenology
NLSP in SWIMP: long lifetime  stable inside the detector
 Charged slepton highly ionizing track, almost background free
Distinguish from stau NLSP and gravitino LSP in GMSB
 GMSB: gravitino m » keV warm not cold DM
 collider searches: other sparticle (mass)
 (GMSB) ¿ (SWIMP): distinguish experimentally
Feng and Smith, in preparation.
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Sneutrino and neutralino NLSP
 sneutrino and neutralino NLSP missing energy
signal: energetic jets/leptons + missing energy
 Is the lightest SM superpartner sneutrino or neutralino?
 angular distribution of events (LC)
vs.
 Does it decay into gravitino or not?
 sneutrino case: most likely gravitino is LSP
 neutralino case: most likely neutralino LSP
 direct/indirect dark matter search
positive detection  disfavor gravitino LSP
 precision determination of SUSY parameter: th~,~
~,~  0.23  favor gravitino LSP
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● Decay life time
● SM energy distribution
 Mpl
 m~G
SM
NLSP
~
G
SM
NLSP
 SUSY breaking scale
SM
NLSP
~
G
~
G
SM
NLSP
SM
NLSP
~
G
~
G
Capture particle:
Goity, Kossler and Sher,
hep-ph/9305244
Supergravity at colliders
Buchmuller et. al.
hep-ph/0402179
SWIMPs and slepton traps
Feng and Smith
In preparation…
See Feng’s talk
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Conclusions
SuperWIMP is possible candidate for dark matter
SUSY models
SWIMP: gravitino LSP WIMP: slepton/sneutrino/neutralino
Constraints from BBN: EM injection and hadronic injection
need updated studies of BBN constraints on hadronic/EM injection
Favored mass region
 Approach I: fix ~G=0.23
 Approach II: G~ = (mG~/mNLSP) thNLSP
Rich collider phenomenology (no direct/indirect DM signal)
 charged slepton: highly ionizing track
 sneutrino/neutralino: missing energy
Other implications …
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