dark matter shining by galactic gamma rays and its possible implications for the lhc

Wim de Boer, Karlsruhe

HEP2008, Chile, Jan. 8, 2008 1

Dark Matter shining by Galactic gamma rays and its possible implications for the LHC

From EGRET excess of diffuse Galactic gamma rays• Determination of WIMP mass• Determination of WIMP halo (= standard halo + DM ring)

Confirmation:• Rotation curve• Canis Major/Monoceros stream• Gas flaring

PREDICTIONS• for LHC (if SUSY)• for direct searches• for solar neutrinos

Ingredientsto this analysis

Gamma ray spectrafor BG + DMAParticle Physics

Cosmology

Astrophysics

23%DM, thermalhistory of WIMPs Annihilation cross sectionTidal disruption of dwarfs

CosmicsGamma rays

AstronomersRotation curveTidal streamsGas flaring


HEP2008, Chile, Jan. 8, 2008 2

• 95% of the energy of the Universe is non-baryonic 23% in the form of Cold Dark Matter

• Dark Matter enhanced in Galaxies and Clusters of Galaxies but DM widely distributed in halo-> DM must consist of weakly interacting and massive particles -> WIMP’s

• Annihilation with <σv>=2.10-26 cm3/s, if thermal relic

From CMB + SN1a + surveys

DM halo profile of galaxycluster from weak lensing

If it is not darkIt does not matter

What is known about Dark Matter?


HEP2008, Chile, Jan. 8, 2008 3

Colliding Clusters Shed Light on Dark Matter

http://www.sciam.com/

August 22, 2006

Observations with bullet cluster:

•Chandra X-ray telescope shows distribution of hot gas•Hubble Space Telescope and others show distribution of Dark Matter from gravitational lensing•Distributions are clearly different after collision-> •dark matter is weakly interacting!


HEP2008, Chile, Jan. 8, 2008 4

Do we have Dark Matter in our Galaxy?

RotationcurveSolarsystem

rotation curveMilky Way

1/r


HEP2008, Chile, Jan. 8, 2008 5

Simple 3-Komponent Galaxy: p+e+Wimps

Interactions:

p+e <->H electromagnetic x-sectionp+p -> X strong x-section: 10-25 cm2

p+W -> p+W x-section:<10-43 cm2 (direct DM searches)W+W -> X x-section: 10-33 cm2 (Hubble expansion)


HEP2008, Chile, Jan. 8, 2008 6

Expansion rate of universe determines WIMP annihilation cross section

Thermal equilibrium abundance

Actual abundance

T=M/22Co

mo

vin

g n

um

ber

d

ensi

ty

x=m/TGary Steigmann/ Jungmann et al.

WMAP -> h2=0.1130.009 -> <v>=2.10-26 cm3/s

DM increases in Galaxies:1 WIMP/coffee cup 105 <ρ>. DMA (ρ2) restarts again..

T>>M: f+f->M+M; M+M->f+fT<M: M+M->f+fT=M/22: M decoupled, stable density(wenn Annihilationrate Expansions- rate, i.e. =<v>n(xfr) H(xfr) !)

Annihilation into lighter particles, likequarks and leptons -> 0’s -> Gammas!Only assumption in this analysis:WIMP = THERMAL RELIC!


HEP2008, Chile, Jan. 8, 2008 7

Example of DM annihilation (SUSY)

Dominant + A b bbar quark pairSum of diagrams should yield<σv>=2.10-26 cm3/s to getcorrect relic density

Quark fragmentation known!Hence spectra of positrons,gammas and antiprotons known!Relative amount of ,p,e+ known as well.

f

f

f

f

f

f

Z

Z

W

W 0

f~

A Z

≈37 gammas


HEP2008, Chile, Jan. 8, 2008 8

IF DM particles are thermal relics from early universethey can annihilate with cross section as large as <v>=2.10-26 cm3/s which implies an enormous rate of gamma raysfrom π0 decays (produced in quark fragmentation) (Galaxy=1040 higher rate than any accelerator)

Expect significant fraction of energetic Galactic gamma rays to come from DMA in this case.Remaining ones from pCR+pGAS-> π0+X , π0->2γ

(+some IC+brems)This means: Galactic gamma rays have 2 componentswith a shape KNOWN from the 2 BEST studied reactionsin accelerators: background known from fixed target exp. DMA known from e+e- annihilation (LEP)

Conclusion sofar


HEP2008, Chile, Jan. 8, 2008 9

R

Sundisc

Basic principle for indirect dark matter searches

R

Sun

bulge

disc

From rotation curve:

Forces: mv2/r=GmM/r2

or M/r=const.for v=cons.and(M/r)/r2

1/r2

for flat rotation curve

Expect highest DM densityIN CENTRE OF GALAXY

Divergent for r=0?NFW profile1/rIsotherm profile const.

IF FLUX AND SHAPE MEASURED INONE DIRECTION, THEN FLUX ANDSHAPE FIXED IN ALL (=180) SKY DIRECTIONS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

R1

THIS IS AN INCREDIBLE CONSTRAINT, LIKE SAYING I VERIFYTHE EXCESS AND WIMP MASS WITH 180 INDEPENDENT MEAS.


HEP2008, Chile, Jan. 8, 2008 10

Instrumental parameters:

Energy range: 0.02-30 GeVEnergy resolution: ~20%Effective area: 1500 cm2

Angular resol.: <0.50

Data taking: 1991-1994

Main results: Catalogue of point sourcesExcess in diffuse gamma rays

EGRET on CGRO (Compton Gamma Ray Observ.)

Data publicly available from NASA archive


HEP2008, Chile, Jan. 8, 2008 11

Two results from EGRET paper

Enhancement in ringlike structure at 13-16 kpc

Called “Cosmic enhancement

Factor”Excess

101 Eγ GeV


HEP2008, Chile, Jan. 8, 2008 12

Background + signal describe EGRET data!

Blue: background uncertainty

Background + DMA signal describe EGRET data!

Blue: WI MP mass uncertainty

50 GeV

70

I CI C


HEP2008, Chile, Jan. 8, 2008 13

Analysis of EGRET Data in 6 sky directions

A: inner Galaxy (l=±300, |b|<50)B: Galactic plane avoiding AC: Outer Galaxy

D: low latitude (10-200)

E: intermediate lat. (20-600)F: Galactic poles (60-900)

A: inner Galaxy B: outer disc C: outer Galaxy

D: low latitude E: intermediate lat. F: galactic poles

Total 2 for all regions :28/36 Prob.= 0.8 Excess above background > 10σ.


HEP2008, Chile, Jan. 8, 2008 14

Fits for 180 instead of 6 regions180 regions:80 in longitude 45 bins4 bins in latitude 00<|b|<50

50<|b|<100

100<|b|<200

200<|b|<900 4x45=180 bins >1400 data points. Reduced 2≈1 with 7% errorsBUT NEEDED IN ADDITION to 1/r2 profile, substructurein the form of 2 doughnut-likerings in the Galactic disc!

ONE RING COINCIDES WITHORBIT FROM CANIS MAJORDWARF GALAXY which loosesmass along orbit by tidal forces

OTHER RING coincides with H2 ring


HEP2008, Chile, Jan. 8, 2008 15

2002,Newberg et al. Ibata et al, Crane et al. Yanny et al.

1/r2 profile and rings determined from inde-pendent directions

xy

xz

Expected Profile

v2M/r=cons.and

(M/r)/r2

1/r2

for const.rotation

curveDivergent for

r=0?NFW1/r

Isotherm const.

Dark Matter distribution

Halo profile

Observed Profile

xy

xz

Outer Ring

Inner Ring

bulge

tota

lDM

1/r2 halodisk

Rotation Curve

Normalize to solar velocity of 220 km/s


HEP2008, Chile, Jan. 8, 2008 16

Halo density on scale of 300 kpc

Sideview Topview

Cored isothermal profile with scale 4 kpc Total mass: O(1012) solar masses


HEP2008, Chile, Jan. 8, 2008 17

Halo density on scale of 30 kpc

Sideview Topview

Enhancement of inner (outer) ring over 1/r2 profile 6 (8).Mass in rings 0.3 (3)% of total DM


HEP2008, Chile, Jan. 8, 2008 18

How does DM substructure formfrom tidal disruption of dwarf

galaxies?


HEP2008, Chile, Jan. 8, 2008 19

The Milky Way and its satellite galaxies

Canis Major

Tidal force ΔFG 1/r3


HEP2008, Chile, Jan. 8, 2008 20

Tidal streams of dark matter from CM and Sgt

CM

Sgt

Sun

From David Law, Caltech


HEP2008, Chile, Jan. 8, 2008 21

Canis Major Dwarf orbits from N-body simulationsto fit visible ring of stars at 13 and 18 kpc

Canis Major leaves at 13 kpc tidal stream of gas(106 M☉ from 21 cm line), stars (108 M☉ ,visible), dark matter (1010 M☉, EGRET)

Movie from Nicolas Martin, Rodrigo Ibatahttp://astro.u-strasbg.fr/images_ri/canm-e.html


HEP2008, Chile, Jan. 8, 2008 22

N-body simulation from Canis-Major dwarf galaxy

prograde retrograde

Ob

serv

ed

sta

rsR=13 kpc,φ=-200,ε=0.8

Canis Major (b=-150)


HEP2008, Chile, Jan. 8, 2008 23

Gas flaring in the Milky Way

no ring

with ring

P M W Kalberla, L Dedes, J Kerp and U Haud, http://arxiv.org/abs/0704.3925

Gas flaring needs EGRET ring with mass of 2.1010M☉!


HEP2008, Chile, Jan. 8, 2008 24

Enhancement of inner (outer) ring over 1/r2 profile 6 (8).Mass in rings 0.3 (3)% of total DM

Inner Ring coincides with ring of dust and H2 -> gravitational potential well!

H2

4 kpc coincides with ring ofneutral hydrogen molecules!H+H->H2 in presence of dust->grav. potential well at 4-5 kpc.


HEP2008, Chile, Jan. 8, 2008 25

Objections against DMA interpretation

Rotation curves in outer galaxy measured with different method than inner rotation curve. Can you combine? Also it depends on R0.

Answer: first points of outer RC have same negative slope as inner RC so no problem with method. Change of slope seen for every R0.

R0=8.3 kpc

R0=7.0v

R/R0

Innerrotationcurve

Outer RC

Black hole at centre: R0=8.00.4 kpc

Sofue &Honma


HEP2008, Chile, Jan. 8, 2008 26

Bergstrom et al. astro-ph/0603632, Abstract:

we investigate the viability of the model using the DarkSUSY package to compute the gamma-ray and antiproton fluxes. We are able to show that their (=WdB et al) model is excluded by a wide margin from the measured flux of antiprotons.

Problem with DarkSUSY (DS):1) Flux of antiprotons/gamma in DarkSUSY: O(1) from DMA. However, O(10-2) from LEP data Reason: DS has diffusion box with isotropic diffusion -> DMA fills up box with high density of antiprotons2) Priors of DARKSUSY.(and other propagation models as well): a) static galactic magnetic fields are negligible b) gas is smoothly distributed c) propagation in halo and disk are the sameALL priors likely wrong and can change predictions for DM searches by ORDER OF MAGNITUDE (and still ok with all observations!)

Do antiproton data exclude interpretation of EGRET data?


HEP2008, Chile, Jan. 8, 2008 27

it is shown that Galactic cosmic rays can be effectively confined throughmagnetic reflection by molecular clouds,Chandran, 1999

Another propagation model including static magnetic fields and gas clouds and anisotropic diffusion

Galactic magnetic field (A0)

Fast propagation along regular field lines will reduceantiproton flux from DMA, while grammage and lifetimeare determined by trapping in magnetic fields


HEP2008, Chile, Jan. 8, 2008 28

Escape time of cosmic rays andgrammage (distance x density)

10Be (t1/2 = 1.51 Myr) is cosmicclock: lifetime of cosmics 107 yrs.

In GALPROP: by large haloIn CHANDRAN: by long trapping.

B/C=secondary/prim.determines grammage (smaller than disc!)In GALPROP: by large haloIn CHANDRAN: by reflectingmolecular clouds

B/C determines grammage

10Be/9Be determines escape time


HEP2008, Chile, Jan. 8, 2008 29

CHANDRAN model GALPROP model

Preliminary results from GALPROP with isotropic and anisotropic propagation

Summary: with fast propagation perp. to disc (e.g. by convection,fast diffusion or static magnetic fields) one reduces contributionof charged particles from DMA by large factor and can be consistent with B/C and 10Be/9Be


HEP2008, Chile, Jan. 8, 2008 30

What about Supersymmetry?

Simplest model: mSUGRA with 5 parameters:m0, m1/2, tan β, A0, sign µ


HEP2008, Chile, Jan. 8, 2008 31

EGRET excess interpreted as DM consistent with WMAP, Supergravity and electroweak constraints

Bulk

Too largeboostfactorfor EGRETdata

StauLSP

h<114

LSP largely Bino DM may be supersymmetric partner of CMB

Charginos, neutralinos and gluinos light

WMAP

EGRET

Stau coannihilation

mA resonance


HEP2008, Chile, Jan. 8, 2008 32

mSUGRA cross sections

tot [pb]

tan=50 A0=0

Main production channels:Contributions of different production channelsnormalized to the total SUSY cross section

Total mSUGRA cross section(LO) K

NLO =1.3-1.7

MET+ Njets+ Nleptons


HEP2008, Chile, Jan. 8, 2008 33

mSUGRA topologies

<MET>

Heff= MET+ET jets

+ETleptons

mSUGRA averaged observables in m0-m

1/2 plane

<Njets> ET>30 GeV

<N>muons PT>10 GeV/c

<PT>

highest muon <E

T > highest jet

Different event topology in different regions according to masses and couplings..

tan=50 A0=0CMS FAMOS


HEP2008, Chile, Jan. 8, 2008 34

Detector performanceDetector performance

Inclusive trigger efficiencies in mSUGRA plane L1 Stream

143

292e 17

Jet+MET 88+45Jets1(1,2,3,4) 177,86,70

.......

LL thresholds, GeV

12e

HLT Stream LL thresholds, GeV197

e 292e 17

Jet+MET 180+123Jets1(1,2,3,4) 657,247,113

.........

12

L1 with respect to MC HLT with respect to L1

Main trigger streams for SUSY


HEP2008, Chile, Jan. 8, 2008 35

Celestial bodies collect DM in their cores by their high density.Annihilation can result in flux of HIGH energy neutrinos from sun (from b-decays or from Z-decays).

Neutrinos can be detected by large detectors,like Super-Kamiokande, Amanda, Ice-Cube, Baksanby the charged current interactions with nuclei,which yields muons in the detectors.

Indirect DM detection from solar neutrinos

EG

RET

SUN


HEP2008, Chile, Jan. 8, 2008 36

WIMPs elastically scatter off nuclei => nuclear recoilsMeasure recoil energy spectrum in target

Direct Detection of WIMPs

0

0

H,Z

EGRET?CDMS

XENON10

If SUSY particle spectrumknown, elastic scattering X-section can be calculated


HEP2008, Chile, Jan. 8, 2008 37

Clustering of DM

An artist picture of what we should see if oureyes were sensitive to 3 GeV gamma rays and wewere flying with 220 km/s through the DM halo


HEP2008, Chile, Jan. 8, 2008 38

8 physics questions answered SIMULTANEOUSLY if WIMP = thermal relic

• Astrophysicists: What is the origin of “GeV excess” of diffuse

Galactic Gamma Rays?• Astronomers: Why a change of slope in the galactic rotation

curve at R0 ≈ 11 kpc? Why ring of stars at 13 kpc? Why ring of molecular hydrogen at 4 kpc? Why S-shape in gas flaring? • Cosmologists: How is DM annihilating?A: into

quark pairs

How is Cold Dark Matter distributed?• Particle physicists: Is DM annihilating as expected in

Supersymmetry?

A: DM substructure

A: DM annihilation

A: standard profile + substructure

A: Cross sections perfectly consistent with mSUGRA for light gauginos, heavy squarks/sleptons


HEP2008, Chile, Jan. 8, 2008 39

Summary

>>10σ EGRET excess shows intriguing hint that:

WIMP is thermal relic with expected annihilation into quark pairs

SPATIAL DISTRIBUTION of annihilation signal is signature for DMAwhich clearly shows that EGRET excess is tracer of DM by fact thatone can construct rotation curve and tidal streams from gamma rays.

DM becomes visible by gamma rays from fragmentation(30-40 gamma rays of few GeV pro annihilation from π0 decays)

Results rather model independent, since only KNOWN spectral shapes of signal and background used, NO model dependent calculations of abs.fluxes.Different shapes or unknown experimental problems may change the gamma ray flux and/or WIMP mass, BUT NOT the distribution in the sky.

DM interpretation strongly supported independently by gas flaring

DM interpretation perfectly consistent with Supersymmetry

dark matter shining by galactic gamma rays and its possible implications for the lhc

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