a. khmelnitsky- is gravitino still a warm dark matter candidate?
TRANSCRIPT
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8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
Is gravitino still a warm dark matter candidate?
A. Khmelnitsky
Faculty of Physics, M.V.Lomonosov Moscow State University
Institute for Nuclear Research of the Russian Academy of Sciences, Moscow
15th International Seminar on High Energy Physics,Quarks-2008
Sergiev Posad, Russia, May 23-29, 2008
with D. Gorbunov and V. Rubakov
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8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
CDM Issues
Cold Dark Matter Consistent with Bulk of Cosmological Data
BUT
Some Discrepancies are Observed
Missing Satellites:CDM Predicts too Many Satellite Dwarf GalaxiesCuspy Galactic Density ProfilesToo Low Angular Momenta of Spiral Galaxies
Possible Hints towards Warm Dark MatterWDM: Sizeable Primordial Velocity Dispersions of DMParticles
Another way to quantify: Phase space density
http://find/http://goback/ -
8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
CDM Issues
Cold Dark Matter Consistent with Bulk of Cosmological Data
BUT
Some Discrepancies are Observed
Missing Satellites:CDM Predicts too Many Satellite Dwarf GalaxiesCuspy Galactic Density ProfilesToo Low Angular Momenta of Spiral Galaxies
Possible Hints towards Warm Dark Matter
WDM: Sizeable Primordial Velocity Dispersions of DMParticles
Another way to quantify: Phase space density
http://find/http://goback/ -
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Motivation and Recipe Light gravitinos as WDM Results and Summary
CDM Issues
z=2
z=1
z=0 CDM WDM1 WDM2
Simulation of structure formation in CDM and WDMscenarios with various masses of DM particles(P. Bode, J. P. Ostriker and N. Turok, 2001)
M i i d R i Li h i i WDM R l d S
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8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
CDM Issues
Cold Dark Matter Consistent with Bulk of Cosmological Data
BUT
Some Discrepancies are Observed
Missing Satellites:CDM Predicts too Many Satellite Dwarf GalaxiesCuspy Galactic Density ProfilesToo Low Angular Momenta of Spiral Galaxies
Possible Hints towards Warm Dark Matter
WDM: Sizeable Primordial Velocity Dispersions of DMParticles
Another way to quantify: Phase space density
http://find/http://goback/ -
8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
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8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
CDM Issues
Cold Dark Matter Consistent with Bulk of Cosmological Data
BUT
Some Discrepancies are Observed
Missing Satellites:CDM Predicts too Many Satellite Dwarf GalaxiesCuspy Galactic Density ProfilesToo Low Angular Momenta of Spiral Galaxies
Possible Hints towards Warm Dark Matter
WDM: Sizeable Primordial Velocity Dispersions of DMParticles
Another way to quantify: Phase space density
Motivation and Recipe Light gravitinos as WDM Results and Summary
http://find/http://goback/ -
8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
Phase space density
Measurable quantity
Q= v2
radial3/2
Q 5 103 M/pc3
(km/s)3
Estimates typical value of halo particles distribution function
Q m4 n
13p23/2
n
p23/2= fhalo(p, r)d
3p
5/2
fhalo(p, r)p2d3p
3/2
fhalo(p, r)
Thus
fhaloQ
33/2m4
Motivation and Recipe Light gravitinos as WDM Results and Summary
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8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
Warmness Condition
In course of evolution particles leave dense regions ofphase-space Q f decreases by a factor of = 102 103
But only a fraction of dark matter particles should have highphase space density
dSph/DM 105
WDM: Fraction of particles has primordial phase spacedensity
f Q
33/2 m4
Motivation and Recipe Light gravitinos as WDM Results and Summary
http://find/http://goback/ -
8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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Motivation and Recipe Light gravitinos as WDM Results and Summary
Warmness Condition
In course of evolution particles leave dense regions ofphase-space Q f decreases by a factor of = 102 103
But only a fraction of dark matter particles should have highphase space density
dSph/DM 105
WDM: Fraction of particles has primordial phase spacedensity
f Q
33/2 m4
Motivation and Recipe Light gravitinos as WDM Results and Summary
http://find/http://goback/ -
8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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p g g y
Warmness Condition
In course of evolution particles leave dense regions ofphase-space Q f decreases by a factor of = 102 103
But only a fraction of dark matter particles should have highphase space density
dSph/DM 105
WDM: Fraction of particles has primordial phase spacedensity
f Q
33/2 m4
Motivation and Recipe Light gravitinos as WDM Results and Summary
http://find/http://goback/ -
8/3/2019 A. Khmelnitsky- Is gravitino still a warm dark matter candidate?
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p g g y
Light gravitinos as Warm Dark Matter
Two production channels
Scattering processes:
Total present mass density:
scG
M
100 GeV
2 1keV
mG
TR
1 TeV
Gravitino mass in keV range Low reheat temperature
Decay processes:
Motivation and Recipe Light gravitinos as WDM Results and Summary
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g g y
Production in decays
Decay rate:
M5
6m2G
M2Pl
Total present mass density:
decG 8104
gb +
15
16gf
gMSSM
g
3/2 1keVmG
M
100 GeV
3
Largest contribution comes from heaviest superparticlesSuperparticles mass in 100 GeV range
Motivation and Recipe Light gravitinos as WDM Results and Summary
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Gravitino from decays spectrum
%Fermi-Dirac
rr
TR = 4M
'TR M
%
Fermi-Dirac
'Gravitino from decays
Feature at low reheat temperature
Gravitino from decays are colder than thermal:
Mean momentum is lowerPhase space density is higher
Motivation and Recipe Light gravitinos as WDM Results and Summary
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Two scenarios are considered
M Mq,Mg TR Mq,Mg; M M,M
Motivation and Recipe Light gravitinos as WDM Results and Summary
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Two scenarios are considered
M Mq,Mg TR Mq,Mg; M M,M
Allowed region is too small
Motivation and Recipe Light gravitinos as WDM Results and Summary
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Results and Conclusion
We find that gravitino is warm dark matter provided that
its mass is in range
1keV mG 25 keV
TR is at most in the TeV range
superparticles whose mass M is below the reheat temperatureobeys
M 350 GeV
Gravitino as warm dark matter candidate will soon be eitherruled out or supported by the LHC experiments.
Motivation and Recipe Light gravitinos as WDM Results and Summary
http://find/http://goback/ -
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Results and Conclusion
We find that gravitino is warm dark matter provided that
its mass is in range
1keV mG 25 keV
TR is at most in the TeV range
superparticles whose mass M is below the reheat temperatureobeys
M 350 GeV
Gravitino as warm dark matter candidate will soon be eitherruled out or supported by the LHC experiments.
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