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Shufang Su • U. of Arizona
superWIMP Dark matter the darkest dark matter Coupling / 1/mpl (very suppressed) no signal for direct/indirect DM searches can not be produced at colliders Shufang Su • U. of Arizona not very exciting naturally obtain solve BBN 7Li anomaly could be tested at colliders Work collaborated with J. Feng, F. Takayama
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Outline WIMP and superWIMP dark matter Gravitino LSP as superWIMP
- WIMP and superWIMP dark matter Gravitino LSP as superWIMP 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 Slepton trapping Conclusion S. Su SWIMP
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Dark Matter (DM) DM h2=0.112 § 0.009 Non-baryonic Stable Neutral Cold
Can not be any of the known particles microscopic identity of DM ? WIMP and superWIMP appear in particle physics models motivated independently by attempts to solve EWSB relic density are determined by Mpl and Mweak naturally around the observed value no need to introduce and adjust new energy scale S. Su SWIMP
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Universe cools: n=nEQe-m/T
WIMP - Thermal equilibrium $ ff Boltzmann equation expansion ff ff Universe cools: n=nEQe-m/T WIMP =n hvi v.s. H WIMP » h anv i-1 mWIMP» Mweak an » weak2 Mweak-2 naturally around the observed value e.g. neutralino LSP Freeze out, n/s » const early time H n ¼ neq late time H (n/s)today » (n/s)decoupling at freeze-out ¼ H TF » m/25 Approximately, relic / 1/hvi S. Su SWIMP
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superWIMP WIMP superWIMP + SM particles 104 s t 108 s SM
- WIMP superWIMP + SM particles FRT hep-ph/ , 104 s t 108 s SWIMP WIMP SM superWIMP e.g. Gravitino LSP LKK graviton WIMP neutral charged 106 S. Su SWIMP
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Gravitino Gravitino: superpartner of graviton
- 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 » keV warm Dark Matter ~ mG » mSUSY » GeV – TeV cold Dark Matter ~ S. Su SWIMP
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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 SWIMP
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Gravitino cold dark matter
- mG » mSUSY » GeV – TeV (supergravity) ~ G ~ , l LSP G ~ , l LSP superWIMP DM thermalLSP v-1 (weak coupling)-2 thermalLSP v-1 (gravitational coupling)-2 WIMP G LSP + SM BBN constraints: TRH 105 – 108 GeV Conflict with thermal leptogenesis: TRH 3 £ 109 GeV ~ v too small thG too big overclose the Universe unless TRH 1010 GeV ~ Kawasaki, Kohri and Moroi, asrtro-ph/ , astro-ph/ Bolz, Brandenburg and Buchmuller,NPB 606, 518 (2001) Buchmuller, Bari, Plumacher, NPB665, 445 (2003)
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Superpartner of graviton
superWIMP : an example - change light element abundance predicted by BBN Strong constraints ! SUSY case WIMP superWIMP + SM particles NLSP: slepton/sneutrino neutralino/chargino Gravitino LSP Superpartner of graviton WIMP superWIMP SM particle 1 mpl2 Decay lifetime planck mass S. Su SWIMP
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superWIMP and SUSY WIMP
- neutralino/chargino NLSP slepton/sneutrino NLSP BBN EM had Brhad O(0.01) Brhad O(10-3) S. Su SWIMP
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Constraints ~ NLSP G + SM particles Dark matter density G · 0.23
- ~ NLSP G + SM particles Dark matter density G · 0.23 ~ Approach I Approach II SWIMP close universe SWIMP maybe insiginificant nNLSP SWIMP/mSWIMP1/mSWIMP 1/mSUSY thNLSP v-1 m2SUSY nNLSP mSUSY NLSP: slepton,sneutrino neutralino : excluded NLSP: slepton, sneutrino, neutralino fix G = 0.23 ~ G = mG/mNLSP thNLSP ~ S. Su SWIMP
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Constraints (cont’) CMB photon energy distribution
- CMB photon energy distribution - early decay: = 0 thermalized through e e, eX eX , e e - late decay: 0 statistical but not thermodynamical equilibrium || · 9 £ 10-5 Fixsen et. al., astro-ph/ Hagiwara et. al., PDG S. Su SWIMP
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Constraints (cont’) ? Big bang nucleosynthesis /10-10 = 6.1 0.4
Fields, Sarkar, PDG (2002) S. Su SWIMP
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BBN constraints on EM/had injection
- Decay lifetime NLSP EM/had energy release EM,had=EM,had BrEM,had YNLSP Cyburt, Ellis, Fields and Olive, PRD 67, (2003) EM EM (GeV) » mNLSP-mG ~ Kawasaki, Kohri and Moroi, astro-ph/ had EM S. Su SWIMP
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Decay lifetime Decay lifetime (sec) ~ ~ l G + l, ! G +
- Decay lifetime (sec) l G + l, ! G + ~ B G + /Z/h ~ S. Su SWIMP
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EM.had and BrEM, had EM, had » mNLSP-mG
EM/had branching ratio BrEM, had ~ neutralino slepton Sneutrino EM mode BrEM 1 had Brhad O(1) O( ) S. Su SWIMP
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YNLSP: approach I approach I: fix G = 0.23 ~ slepton and sneutrino
- approach I: fix G = 0.23 ~ slepton and sneutrino 200 GeV · m · 400 » 1500 GeV mG ¸ 200 GeV ~ m · 80 » 300 GeV apply CMB and BBN constraints on (NLSP, EM/had ) viable parameter space NLSP, EM,had=EM,had BEM,had YNLSP S. Su SWIMP
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YNLSP: approach II approach II: G = (mG/mNLSP) thNLSP ~
- approach II: G = (mG/mNLSP) thNLSP ~ Approximately right-handed slepton sneutrino (left-handed slepton) neutralino “bulk” “focus point/co-annihilation” S. Su SWIMP
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Approach II: slepton and sneutrino
- G = (mG/mNLSP) thNLSP ~ S. Su SWIMP
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Approach II: bino - G = (mG/mNLSP) thNLSP ~ S. Su SWIMP
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superWIMP in mSUGRA Usual WIMP allowed region superWIMP allowed region
- BBN EM constraints only Stau NLSP Ellis et. al., hep-ph/ Usual WIMP allowed region superWIMP allowed region S. Su SWIMP
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Distinguish from stau NLSP and gravitino LSP in GMSB
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 S. Su SWIMP
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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 ~ S. Su SWIMP
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SM particle energy/angular distribution … mG
Decay life time SM particle energy/angular distribution … mG mpl … ~ SM NLSP Probes gravity in a particle physics experiments! BBN, CMB in the lab Precise test of supergravity: gravitino is a graviton partner ~ G SM NLSP SM NLSP ~ G ~ G SM NLSP SM NLSP ~ G ~ G How to trap slepton? Hamaguchi, kuno, Nakaya, Nojiri, hep-ph/ Feng and Smith, hep-ph/ S. Su SWIMP
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Slepton trapping Feng and Smith, hep-ph/ - 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. Catch 100/yr in 1 kton water LC: tune beam energy to produce slow sleptons, can catch 1000/yr in 1 kton water S. Su SWIMP
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Conclusions SuperWIMP is possible candidate for dark matter
- SuperWIMP is possible candidate for dark matter SUSY models SWIMP: gravitino LSP WIMP: slepton/sneutrino/neutralino Constraints from BBN: EM injection and hadronic 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 slepton trapping WIMP superWIMP + SM particle ~ ~ ~ S. Su SWIMP
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Frequently asked question
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Something about lepton
- G +, ~ mesons, induce hadronic cascade meson decay before interact with BG hadrons longer than typical meson (, K) lifetime (E/m)£ 10-8 s S. Su SWIMP
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