Document 7153937

Report
Dark Matter, LSP wino dark matter, satellite data, moduli and nonthermal cosmological history, and LHC
Gordy Kane
May 2009
PAMELA Physics Workshop
 Over two decades ago recognized that one way to “see” dark matter
was via products of annihilation of pairs of DM particles in the galaxy
 Traditionally the lightest superpartner, LSP, a very good DM
candidate
 Annihilate into everything, but positrons, antiprotons, gammas
should be easier to see over backgrounds so look for those
Recently reported possible satellite signals and relevant data:
PAMELA, Fermi/GLAST, etc
Dark matter! Not only learn what DM is – could also be the discovery
of supersymmetry (if indeed LSP) – may also point toward
underlying theory – probes cosmological history of universe! -Worth lot of effort to untangle the situation, test interpretations –
does an LSP give a satisfactory description of the data?
maybe
OUTLINE OF TALK
 Survey of DM approaches
 PAMELA data light wino LSP?
-- issues
-- description of data
 Dark matter relic density from non-thermal-equilbrium
cosmological history of the universe – but still “wimp miracle”!
 High scale underlying theory of this phenomenology, moduli
 Comments on LHC implications
 Concluding remarks
Describing the data with dark matter annihilation
(a) thermal cosmological history, and describe all data with one
component MLSP > 2 TeV
-- stable, < v> ≈3x10-26 cm3 s-1 – need enhancement
Arkani-Hamed, Weiner et al – heavy hidden sector DM
Bergstrom, Edjso, Zaharijas 0905.0333
Meade, Papucci, Strumia, Volansky 0905.0480 “non-conventional DM”
-- decaying DM, lifetime
1026 second
Arvanitaki, Dimopoulos et al, 0904.2789 – DM is singlet of SO(10) 16, like RH
Shirai, Takahashi, Yanagida – wino LSP with mass 3 TeV
Typically positron ratio rises significantly above 100 GeV
(b) non-thermal cosmological history
-- < v> ≈ 3x10-24 cm3 s-1 , wino LSP, M 200 GeV
WINO LSP VERY WELL MOTIVATED FOR DARK MATTER
-- two decades
-- anomaly mediated supersymmetry breaking (Randall, Sundrum…)
-- “split” supersymmetry (Arkani-Hamed, Dimopoulos, …)
-- Z’ mediation (Wang, Langacker, Yavin, Paz, Verlinde … )
-- M theory compactified on G2 manifold (Acharya, Kane, …)
-- MSSM scan – (Hewett, Rizzo et al)
Wino LSP DM annihilation provides most positrons, most energetic
positrons compared to other forms of LSP
My perspective today:
-- study whether wino LSP provides a satisfactory description of
PAMELA, Fermi etc data
-- no comments on other approaches
CAN A WINO LSP DESCRIBE THE PAMELA DATA?
Grajek, Kane, Phalen, Pierce, Watson 0812.4555, plus Ran Lu, Cheng Peng recently
• Rate? – density too small with thermal equilibrium
cosmology, standard propagation parameters, though wino
annihilates well into e+ [better than bino, higgsino etc]
wino
w+ e+ , + , quarks
~+
w
wino
w
– But in comprehensive theories, e.g. Planck scalestring theories
that have TeV physics, stabilized moduli, consistency with other
data, etc, non-thermal cosmological history is probably the
default
– We normalize to local relic density (use 0.3 GeV/cm3) – This is the
right procedure if LSPs of non-thermal origin, e.g. moduli decay
Also, for DM annihilation, energy dependent “boost factors” are
better motivated than none – actually inevitable – improves the
agreement with data for wino LSP
Lavalle, Salati, Brun, Donato, Fornengo, Taillet et al 0809.5268 etc
[“boost factor” is not good terminology here since average not increased]
Antiprotons – Naively expect signal but not apparent in PAMELA
data – however,
• antiprotons from quark fragmentation, so soft – lose energy
poorly so soft antiprotons get to detector
• present in old data, so old data was background + “signal”
• old data fitted as if just background, result used as
background in recent analyses
Gammas? Fermi/Glast data ?
Synchrotron radiation – OK for some magnetic field parameters
OTHER ISSUES
• Profile of galaxy DM – use NFW everywhere – results a little better if
profile a little softer, and that is probably preferred by astrophysics
-- relevant for antiprotons and gammas, not much for positrons
• Run Galprop, vary 6-7 parameters – not yet scan since computing
time long – did > 200 simulations so far, will have >103 in a month
• Mwino = 200 GeV so far, trying other values – only parameter of
underlying physics
• Region below 10 GeV poorly described – little wino DM signal
there, so only relevant to be sure no systematic problem – assume
solar modulation
• Direct detection very small for wino, very sensitive to higgsino mix
Density enhancement of positron
1
10-1
L = 4 kpc
28
K0 = 4 10 cm2 s-1
 = 0.54
vconv = 5 km s-1 kpc-1
vAlfven = 32 km s-1
=1
f=1
10-2
10
102
Antiproton Flux Ratio With Density Enhancement
signal(enhanced)+background
signal+background
background
p/(p+ p)
10-4
L = 4 kpc
28
K 0 = 410 cm2 s-1
 = 0.54
v conv = 5 km s-1 kpc-1
v Alfven = 32 km s-1
=1
f=1
Modulation Field  = 800 MV
10-5
1
10
102
Kinetic Energy (GeV)
3
10
Note signal
persists to low
energies as
expected for
light quark
fragmentation
B/C Ratio
GALPROP
0.35
HEAO Data
0.3
B/C Ratio
0.25
0.2
0.15
0.1
0.05
10-1
L = 4 kpc
28
K0 = 410 cm2 s-1
 = 0.54
vconv = 5 km s-1 kpc-1
vAlfven = 32 km s-1
=1
f=1
1
10
Kinetic Energy (GeV/nuc)
102
3
10
0807.1508
[UB /(Urad + UB )=0.1]
Synchrotron radiation constraint
Allowed for masses with wino line
below limit, e.g. green line
FERMI DATA?
Note wino LSP
works well up to
about 100 GeV
note hint of two
components
THUS a wino LSP with mass 200 GeV is a promising candidate to
describe PAMELA data including constraints, and Fermi data with
additional component or modified Galprop primary spectra beyond
100 GeV
IMPROVED EXPERIMENTAL TESTS COMING
VERY SOON
• PAMELA higher energy positrons 100-200 GeV – must see “turnover”
(or flattening if one bin) if wino LSP (M 200 GeV)
• PAMELA higher energy electrons – important to separate e+ from e−
• Fermi/GLAST – gammas
SOON
• LHC
• AMS-02
THEORY ISSUES:
 MUST HAVE NON-THERMAL COSMOLOGY TO GET RELIC DENSITY IF
WINO LSP – PROBLEM? GOOD?
[wino annihilation cross section 3x10-24 cm3 s-1 but thermal history
implies cross section about 100x larger]
-- Non-thermal cosmology – generic in any string theory with stabilized
moduli, TeV scale, any high scale supersymmetric theory? –
(Acharya, GK, Piyush Kumar, Scott Watson in preparation)
-- similarly for supersymmetric flat directions, Q-balls (Fujii Hamaguchi),
axinos, saxions, kination (Salati …, Chung, Everett…)
-- speculative version of moduli decay Moroi-Randall ph/9906527
-- existence proof: M-theory compactified on G2 manifold  wino LSP,
relic density about right from first principles -- 0804.0863 (Acharya,
Kane, Kumar, Shao, Watson) has detailed calculations, can calculate
moduli masses and widths, thermal DM diluted by entropy from
moduli decay  DM from moduli decay
CONSISTENT FRAMEWORK COSMOLOGICALLY
o Consider theories with stabilized moduli and weak scale, wino LSP
o Moduli coupling Planck suppressed  long lifetime  10-3 sec
o They dominate universe before decay, after freezeout, before BBN
o Decays produce many LSPs, entropy, dilute thermal LSPs
o LSPs annihilate
“Non-thermal
2
nLSP  3HnLSP    v nLSP
wimp miracle”
so LSPs will annihilate down to
3H /  v
but now at decay temperature rather than at freezeout temperature
o Assuming large initial abundance and large annihilation cross
section, results independent of initial abundance
Relic density
1 165MeV mLSP 3x107 GeV 2
 LSP h 
rh
10 Tmod
200GeV
v
2
rh
Tmod
 30MeV , Trh  100MeV
increases by ratio
of reheat temp at
decay to that at
freezeout
Dark matter at LHC
Is what is seen at LHC same as in indirect data?
Test wino hypothesis
Get more info to calculate the relic density
For G2-MSSM squarks heavy so predict no signal here, but see winos in gluino decay
LHC phenomenology of light wino LSP well known
Early 1999, 2000
• Moroi-Randall
• Feng Moroi Randall Strassler
• Ghergetta, Giudice, Wells
Recent
• Moroi, Yanagida et al ph/0610277
• Acharya et al 0801.0478
LSP nearly degenerate, so hard to see – missing
energy from “escaping” chargino, LSP
• Chargino,
• mass difference  200 MeV, so decay has 1-2 soft pions
• Find via gluino, its decays as trigger – Mgluino ranges from
about 2 to about 9 Mwino in models
• in our (Acharya, Bobkov, Kane, Kumar, Shao) string
construction with M theory compactified on a manifold of G2
holonomy, the LSP was wino, and gluino decay was mainly to
C1, N2 (not N1) so can look for tracks in vertex detector – also
gluino pair gives four tops so easy to trigger on
LHC implications of TeV LSPs or decaying DM?
-- no LHC signal in some cases
-- indirect (and very model dependent) in others, need certain
superpartner spectrum or other matter to get annihilation or
decay products to describe PAMELA, not contradict something
-- sometimes new collider phenomenology – new light vector
bosons with mass  1 GeV, decay into electrons so get “lepton
jets” – model of Arkani-Hamed, Weiner et al
 “Lepton jets”
Delayed decays possible, also missing energy along lepton jet
IF THE PAMELA EXCESS IS INDEED DUE TO A LIGHT WINO LSP
THE IMPLICATIONS ARE REMARKABLE
• Would have learned that the dark matter, about a fifth of the
universe, is (mainly) the W superpartner, and its approximate mass
• Discovery of supersymmetry!
-- guarantees can study superpartners at LHC
• Would have learned that the universe had a non-thermal
cosmological history, one we can probe
• Suggests moduli dominated “UV completion” – M-Theory “G2 –
MSSM” construction a concrete example
Tests, information from more data soon and then from LHC, AMS02
Gamma Ray Emission With Dark Matter
signal+background
10-2
background
E 2  [MeV 2 cm-2 s-1 MeV -1]
FERMI
10-3
10-4
L = 4 kpc
28
K0 = 410 cm2 s-1
 = 0.54
v conv = 5 km s-1 kpc-1
v Alfven = 32 km s-1
=1
f=1
o
o
o
o
0  l  360 , 10  |b|  20
10-5
1
10
Energy (GeV)
102
3
10
Positron Flux Ratio With Density Enhancement
signal+background
background
PAMELA
-
e +/(e +e +)
0.1
L = 4 kpc
28
K 0 = 4  10 cm2 s-1
 = 0.54
v conv = 5 km s-1 kpc-1
v Alfven = 32 km s -1
=1
f=1
Modulation Field  = 800 MV
-3
Ne - =3.6  10 at E = 34.5 GeV
0.01
1
10
Energy (GeV)
100
1000
Positron and Electron With Density Enhancement
signal+background
background
E
-
E 3(e +e+) (GeV 2m-2s-1sr -1)
e
E -1.40 - 270 GeV
-9
Additional flux:  = 1.8  10 (( e )
e
GeV
30% Positron
100
FERMI(statistical error)
FERMI(systematical error)
L = 4 kpc
28
K 0 = 4  10 cm2 s-1
 = 0.54
v conv = 5 km s-1 kpc-1
v Alfven = 32 km s -1
=1
f=1
Modulation Field  = 800 MV
-3
Ne - =3.6  10 at E = 34.5 GeV
10
100
Energy (GeV)
1000
10
Be/ 9Be Ratio
GALPROP
0.4
ISOMAX Data
10
9
Be/ Be Ratio
0.35
0.3
0.25
L = 4 kpc
28
K 0 = 4 10 cm2 s-1
 = 0.54
v conv = 5 km s-1 kpc-1
vAlfven = 32 km s-1
=1
f=1
0.2
0.15
0.1
10-2
10-1
1
10
Kinetic Energy (GeV/nuc)
102
3
10
Energy-dependent and particle-dependent annihilation enhancements from
density fluctuations
• Galaxies are built from little galaxies – density fluctuations inevitable
• Keep average local density, but <n2> <n>2 and annihilations n2
• Positrons lose energy rapidly so mainly come from nearer us
• Antiprotons lose energy poorly, come from farther away
• Different distances feel profile differently, different amount of clumps
On the antimatter signatures of the cosmological dark matter subhalos.
Julien Lavalle . Dec 2008. arXiv:0812.3576 [astro-ph]
Galactic secondary positron flux at the Earth T. Delahaye, F. Donato, N.
Fornengo, J. Lavalle, R. Lineros, P. Salati, R. Taillet arXiv:0809.5268 [astro-ph]
Antimatter cosmic rays from dark matter annihilation: First results from an Nbody experiment. J. Lavalle (Turin U. & INFN, Turin) , E. Nezri, E. Athanassoula
(Provence U.) , F.-S. Ling (Brussels U.) , R. Teyssier (Saclay)
Phys.Rev.D78:103526,2008. arXiv:0808.0332 [astro-ph]
Clumpiness of dark matter and positron annihilation signal: computing the
odds of the galactic lottery. Julien Lavalle (Marseille, CPPM) , Jonathan
Pochon (Annecy, LAPP) , Pierre Salati, Richard Taillet (Savoie U. & Annecy,
LAPTH) . astro-ph/0603796
B/C Ratio
GALPROP
0.35
HEAO Data
0.3
B/C Ratio
0.25
0.2
0.15
0.1
0.05
10-1
L = 4 kpc
K0 = 4.31028 cm2 s-1
 = 0.45
vconv = 5 km s-1 kpc-1
vAlfven = 31 km s-1
=1
f=1
1
10
Kinetic Energy (GeV/nuc)
102
3
10
Consistent motivated picture
 PAMELA positrons wino LSP
 Large wimp v 3x10-24 cm3sec-1
 DM non-thermal in origin
 Moduli dominate universe after inflation, matter dominated
 Gravity mediated susy
 M3/2 10-100 TeV moduli masses
 Moduli decay before BBN
 Spectrum:
-- scalars M3/2
-- higgsinos from Giudice-Masiero term M3/2
-- gauginos including LSP light
[field whose F-term dominates susy is not the field whose vev gives the
gauge coupling – maybe consequence of approximate R symmetry]
G2 – MSSM is a concrete example of a UV completion of these generic arguments!

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