Transcript ASBS2 - University of Arizona

Gravitino Dark matter
the darkest dark matter
 Coupling / 1/mpl
 no signal for direct/indirect DM searches
 can not be produced at colliders
New proposal:
not very exciting
superWIMP DM
 naturally obtain 
 solve BBN 7Li anomaly
 Could be tested at colliders
Shufang Su • U. of Arizona
Aspen Winter Conference 2005
Gravitino
 Gravitino: superpartner of graviton
 Obtain mass when SUSY is spontaneously broken mG~ » F/mpl
 Stable when it is LSP - candidate of Dark Matter
mG~ ¿ mSUSY
mG~ » mSUSY
» keV
» GeV – TeV
warm Dark Matter
cold Dark Matter
S. Su
Gravitino Dark Matter
3
Gravitino: warm dark matter
mG~ ¿ mSUSY
(GMSB)
 h2 » (mG~/keV) (100/g*)
 mG~ » keV : warm Dark Matter
 mG~  keV : problematic !
gravitino dilution necessary
 stringent bounds on reheating temp.
Moroi, Murayama and Yamaguchi, PLB303, 289 (1993)
S. Su
Gravitino Dark Matter
4
Gravitino cold dark matter
mG~ » mSUSY » GeV – TeV
LSP
~
, ~
l
thermalLSP  v-1
 (weak
coupling)-2
~
G
WIMP
~
G  LSP + SM
BBN constraints:
TRH  105 – 108 GeV
Kawasaki, Kohri and Moroi,
asrtro-ph/0402490, astro-ph/0408426
Conflict with thermal leptogenesis:
TRH  3 £ 109 GeV
S. Su
(supergravity)
~
, ~
l
~
G
LSP
thermalLSP  v-1
superWIMP
DM
 (gravitational coupling)-2
● v too small
● thG~ too big
overclose the Universe
unless TRH  1010 GeV
Buchmuller, Bari, Plumacher, NPB665,
445 (2003)
Gravitino
Dark
Matter
Bolz, Brandenburg and Buchmuller,
NPB 606, 518 (2001)
5
WIMP  SWIMP + SM particle
FRT hep-ph/0302215, 0306024
WIMP
104 s  t  108 s
SWIMP
SM
 Gravitino LSP
 LKK graviton
106
S. Su
Gravitino Dark Matter
6
SuperWIMP 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
S. Su
Gravitino Dark Matter
7
Constraints
~
NLSP  G + SM particles
/10-10 = 6.1 0.4
 Dark matter density G~ · 0.23
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)
S. Su
Gravitino Dark Matter
8
BBN constraints on EM/had injection
 Decay lifetime NLSP around a year
 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
S. Su
Gravitino Dark Matter
9
slepton and sneutrino NLSP
G~ = (m~G/mNLSP) thNLSP
J. Feng, F. Takayama, S. Su
hep-ph/0404198, 0404231
NLSP, EM,had=EM,had BEM,had YNLSP
apply CMB and BBN constraints on (NLSP, EM/had )
 viable parameter space
S. Su
Gravitino Dark Matter
10
superWIMP in mSUGRA
Ellis et. al., hep-ph/0312262
BBN EM constraints only
Usual WIMP allowed region
superWIMP allowed region
Stau NLSP
S. Su
Gravitino Dark Matter
11
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.
S. Su
Gravitino Dark Matter
12
Guaranteed signal at colliders
Feng, SS, Takayama, in preparation
Model independent approach: DM  < v>ann  production
Birkedal, matchev, Perelstein, PRD 70, 077701 (2004).
 Usual WIMP: missing energy + jet or photon
irreducible SM background
 superWIMP: promising event rates at LHC/LC.
preliminary
preliminary
S. Su
Gravitino Dark Matter
13
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
S. Su
Gravitino Dark Matter
14
● Decay life time
● SM particle energy/angular
distribution
…
 mG~
 mpl
SM
NLSP
~
G
SM
NLSP
 LFV
SM
NLSP
…
~
G
~
G
SM
NLSP
SM
NLSP
~
G
~
G
Buchmuller et. al., hep-ph/0402179
Hamaguchi and Ibarra, hep-ph/0412229
Feng et. al., Hep-ph/0405248
Slepton trapping:
Hamaguchi et. al. hep-ph/0409248
Feng and Smith, hep-ph/0409278
S. Su
Gravitino Dark Matter
15
Slepton trapping
Feng and Smith, hep-ph/0409278
 Slepton could live for a year, so
can be trapped then moved
to a quiet environment to observe
decays
 LHC: 106 slepton/yr possible, but
most are fast. By optimizing trap
location and shape, can catch »
100/yr in 1000m3 water
 LC: tune beam energy to produce
slow sleptons, can catch 1000/yr in
1000m3 water
S. Su
Gravitino Dark Matter
16
Courtesy of J. Feng
Conclusions
Gravitino could be warm DM: m » keV
Gravitino could be cold DM: m » few hundred GeV
 thermal production: TRH 1010 GeV
 Non-thermal production: superWIMP
WIMP  superWIMP + SM particle
SuperWIMP: gravitino LSP WIMP: slepton/sneutrino/neutralino
Constraints from BBN: EM injection and hadronic injection
viable parameter space
Rich collider phenomenology (no direct/indirect DM signal)
 charged slepton: highly ionizing track
 sneutrino/neutralino: missing energy
Slepton trapping
S. Su
Gravitino Dark Matter
17