wim de boer, karlsruhe susy09, northeastern univ., boston, june 5, 2009 1 indirect dark matter...

Wim de Boer, Karlsruhe

SUSY09, Northeastern Univ., Boston, June 5, 2009 1

Indirect Dark Matter Searches in theLight of ATIC, FERMI, EGRET and PAMELA

Annihilation products fromdark matter annihilation:

Gamma rays(EGRET, FERMI)

Positrons (PAMELA)

Antiprotons (PAMELA)

e+ + e- (ATIC, FERMI, HESS, PAMELA)

Neutrinos (Icecube, no results yet)

e-, p drown in cosmic rays?



Expansion rate of universe determines thermal relic annihilation cross section

Thermal equilibrium abundance

Actual abundance

T=M/22Co

mo

vin

g n

um

ber

d

ensi

ty

x=m/TG. Steigman

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

DM increases in Galaxies:1 100 GeV 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 annihilation rate expansion rate, i.e. =<v>n(xfr) H(xfr) !)

Only assumption:WIMP = STABLE THERMAL RELIC!



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



Resurs Dk1 Satellite

300 - 600

km

Bottom Scintillator

Transition Radiation Detector

(removed for tech.reasons)

Time of Flight Counters

Silicon Tracker and Permanent Magnet

Si-W Electromagnetic Calorimeter

Neutron Detector

Anticoincidence Shield

1.2 m

20.5 cm2sr

~450 kg

~10 T

The PAMELA Satellite Experiment (launched July 2006)



Positron fraction

PAMELA, positron and antiproton measurements

Positrons: excess

Galprop Pamela

Nature 458:60,2009,arXiv:0810.4995

Antiprotons: NO excess

Antiproton/proton ratio

+prelim. new data, Boezio, Pamela-WS 2009(O. Adriani et. al., PRL (2009)[0810.4994])



ATIC Balloon experiment, Nature 2008

Kaluza-Klein DM decays to lepton pairs ->peak in electron spectrum with tail from energy losses

Baltz, Hooper, hep-ph/0411053Baltz, Zurek, 0902.0593

KK x-section Y4

so mainly decay to leptons and u-quarks



FERMI measures GeV gamma rays + electrons

e+

e–



Alexander Moiseev Pamela workshop May 11, 2009

FERMI electron spectrum: NO BUMP at 600 FERMI electron spectrum: NO BUMP at 600 GeVGeV

Simulating the LAT response to a spectrum with an “ATIC-like” feature:

This demonstrates that the Fermi LAT would have been able to reveal “ATIC-like” spectral feature with high

confidence if it were there. Energy resolution is not an issue with such a wide feature



HESS MAGIC

Cherenkov telescopes measure TeV gamma rays



HESS, May 2009

Electron spectrum falls off above 1 TeV



Interpretations

Many possibilities: Background from hadronic showers with large electromagnetic component -> ap->0

astrophysical sources pulsars -> apulsar

positron acceleration in SNR -> asec

locality of sources -> aSNR

dark matter annihilation -> aDMA leptophilic? bound states? Kaluza-Klein



Cosmic ray spectra

Lipari, PAMELA Workshop, 2009

1 TeV

E-2.7

E-3.3

E-3.0

e- mainly from SNR e+ mainly p+p e

p+p 3p+p+X

3 orders of magn.

<2 orders of magn.



G.F. 5000 cm2 srExposure > 3 yrs

dP/P2 ~ 0.004 2.5 TV, p rejection = 10-5 (ECAL +TRD); Δx=10µm; Δt=100ps



20102009



AMS to be launched in 2010

AMS

Space Shuttle



AMS on ISS



The AMS superconducting Magnet at CERN (2008)

18

Coils

He Tank



19

Magnet inside vacuum tank



Current Status (May 2009)

The magnet is at 1.7 KThe system is fully leaktight to superfluid

heliumThe magnet is being commissioned

and other detector components will beintegrated in 2009. Flight to ISS 2010.

Note: all components have been integrated in2008 in

spare vacuum vessel and have been thoroughly

tested. They worked as expected.



The Alpha Magnetic Spectrometer on ISS

AMS



AMS proton contamination

S. Haino, INFN Perugia



What a little dash of protons can do!

Moskalenko & Strong

PAMELA claims p rejection of 10-5. CAUTION! This is not verified using independent technique in flight.

Gregory Tarle at PPC09, 20.5.09



M. Schmanau, Karlsruhe

AMS Geant

FERMI GeantAMS TRD Testbeam

GEANT proton/electron separation

Hard to simulate p+p->p+0+X (diff. scatt.)Looks very much like electron. Only TRD can distinguish.Especially dangerous for photon detectors with “converter”

Ferro, Sobol,Totem-Note 2004-5

single diffractive x-section

pp/ppbar exp.

10 mb

100 1000 GeV √s



DM interpretation of FERMI e-data

TeV DM decaying to low scaleParticle, which can onlydecay leptonically/

TeV DM forms bound state to get large boost factor via Sommerfeld enhancement

Models e.g. by Arkani-Hamed,Finkbeiner,Slatyer,WeinerarXiv:0810.0713 Nomura and Thaler,arXiv:0810.5397

Fit by Bergstrom et al.arXiv:0905.0333

See also talk by G. Kane, tuesdayon wino DM with non-thermal history



3-component e- sources: spiral arm, disc, local

3-component structureexplains e-spectrum,Pamela anomalyand why nothing in pbar

Shaviv et al., arXiv:0902.0376,2009sp

iral

arm

near sources

positrons

disc

e loose energy rapidly (dE/dt E2), hence they are “local”



The pulsar situation

Yuksel, Kistler, Stanev, 2008 (cf. Aharonian, Atoyan and Völk, 1995; Kobayashi et al., 2004)

Geminga pulsar estimates

Vela pulsar (supernova remnant)



D. Grasso et al., arXiv:0905.0636

Pulsars

More in talk byProfumo on monday

Note: rotating strongB-field-> synch. rad->+B->(e+ + e-) -> N ->N+B->N(e+ + e-)So pulsars strong sourcefor (e+ + e-), NO pbar.Escape fraction unknown..



P. Blasi, arXiv:0903.2794

Secondary positron acceleration in SNR

Idea:

secondary particles are produced in SNR and might as well beaccelerated there ->. source of HE secondary positronsand electrons

e+e-

prim. e-



How much DMA signal can still be in pbar?

Answer: in isotropic propagation models very little.

In anisotropic prop. models significant pbar contribution from DMA allowed!

F. Donato, D. Maurin, P. Brun, T. Delahaye and P. Salati, Phys.Rev.Lett.102:071301,2009



Present models: isotropic propagation

Is this right?

Isotropic propagation leads to “propagation enhancement”:of charged particles: trapping of chargedparticles in “leaky” Galaxy for a long time->

Flux of gamma rays from DMA Flux of antiprotons in such propagation models,

Although we KNOW from LEP that fragmentationgives many more photons than antiprotons

NO!

CONVECTION = negligible with isotropic propagation in contrast to observation



NATURE 452, 17. April 2008, “Blown away by cosmic rays”, D.Breitschwerdt

NGC 253

Fit to ROSAT data,Everett et al.arXiv:0710.3712v1

Cosmic Rays (CR) form a plasma. If blowing in a given direction,it will take other particles with it, thus exerting pressure.This CR pressure drives all halo particles to intergalactic space,thus reducing strongly the flux of charged particles from DMA.

Convection of few 100 km/s not allowed in GALPROP, since particles will not return to disc and produce secondaries.



propagation including convection

Present models use isotropic propagation, i.e. same diffusion constant in halo and disc.

This does not allow for significant convection, since CR‘s do not return to disc->too little secondary productionfrom CR hitting gas in discHOWEVER, significant convection observed by ROSATCRs propagation can be

described by diffusion and convection, very much like a drop of ink inside streaming water (with water velocity=convection velocity)

Radiaactive clocks like 10Be determine time from source to Sun (107 yrs) Need slow diffusion in disc, but particlesin halo drift to outer spacewith convectionWith convection little flux of charged particles from DMA, since particles drift away.



Best evidence for convection from absence of Best evidence for convection from absence of 511 keV emission from the Galactic disc 511 keV emission from the Galactic disc

INTEGRAL/SPI observed bright 511 keV emission from the bulge of the Milky Way (1.3 x 1043 positrons injected per second), but almost nothing from disc

Sources of low energy positrons (low energy, else they do not annihilate): •Radioactive nuclei from SNIa and other stellar objects, see Prantzos,arXiv:0809.2491

Explanation:DiffusionE so MeV positrons do not diffuse.

Convection independentof energy, so they candisappear by convectionfrom disc to halo. Hereno electrons to annih.



“ROSAT” convection GALPROP convection

Propagation including “ROSAT” convection

Summary: preferred propagation perp. to disk can reducecontribution of charged particles from DMA by large factor and can be consistent with B/C and 10Be/9Be

(Bergstrom, Edsjo, Gustafsson and Salati, JCAP, astro-ph/0602632)

propagationenhancement:

DM: GC



Secondary production (B/C) and cosmic clocks (10Be/9Be)

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

In diffusion dom.: by large haloIn convection dom.: by slow diff.

B/C=secondary/prim.determines grammage (smaller than disk!)In diffusion dom.: by large haloIn convection dom.: by slow diffusion in disk.

B/C determines grammage

10Be/9Be determines escape time



Diffuse gamma rays

Great advantage of pointing to the source and propagation is „straightforward“ without dependence on magnetic field and diffusion.

Astrophysical point sources can be pinpointed and subtracted.

For newest FERMI data on DMA:see Winer on Wednesday, June 10



PublishedFERMI dataon VELA pulsar:agrees within errorswith EGRET at 3 GEVastro-ph/0812.2960

20% EGRET

Diffuse gamma rays from FERMI

100%

Why diffuse spectrum disagrees 100% with EGRET at 3 GeVwhile VELA spectrum agrees with EGRET at 3 GeV within 20%?



Indirect Dark Matter Signals in 2008

•511 keV emission from the galactic bulge

•The HEAT positron excess

•EGRET’s galactic gamma ray spectrum

•EGRET’s extragalactic gamma ray spectrum

•The WMAP hazeDan Hooper – SUSY07 Indirect Searches For Particle Dark Matter



Shape of Haze perfectly consistent with EGRET excessMagnitude of Haze has large uncertainties from B-fieldtowards Galactic centre and spectral shape of electrons.

The WMAP Haze

Egret DM

WM

AP

HASLAM408 MHz

Haze: Hooper, Dobler and Finkbeiner, arXiv:0705.3655

CR s

ynH

aze



AMS will tell

12345

Contrib. ap->0 apulsar

asec

alocal aDMA

Parameters

X-sectionspectrum, distance, fluxspectrum, distance, fluxspectrum, distance, fluxspectrum,flux

Comments

correct shape/x-sect. existsexistsexists, Non-standard(leptophilic,long range,strong boost)

Future constraints

AMS-2 e+ fract. at HEe+ fract. at HEe+ fract. at HELHC, FERMI-GammasAMS-02,Pamela

Summary on contributions to e+,e-

My expectation: combination of 1 and 4Contribution from DMA to charged particles very dependenton propagation model. Strong leaky box enhancement by present propagation models not necessarily true, if convection taken into account. Best evidence for convection: ROSAT x-rays andlow disc intensity of 511 keV positron annihilation line from INTEGRAL



Summary

Charged particles do not point to source, so many indistinguisable sources possible. Also propagation uncertainties large.

|Data>= ap->0 |Background> + aDMA |DMA>+ asec |SNR> + alocal |SNR(x)> + apulsar |Pulsar>

At present all coeff. between 0 and 1 possible.Need additional data to distinguish:a)LHC will constrain aDMA

b)FERMI gamma rays will tell about astrophysical sources and DMA via diffuse gamma rays (propagation “straightforward”)c)Positron fraction will distinguish between alocal

and (asec ,apulsar)



Summary

Intriguing hint of anomalous positron production. Exciting, if true, but would like to see experimental verification by AMS with TRD! Rise explained by “locality”. of e sources (disk, spiral arm, local (Shaviv)) Expect decrease in positron fraction above 100 GeV contr. to pulsars“locality” would explain harder FERMI electron spectrum, but alsohere proton rejection issue, since relying on MC. Wait for AMS.Prel. diffuse gamma ray spectrum from FERMI disagrees much stronger with EGRET than published VELA spectrum. Wait and see.

GALPROP model has 2 deficiencies: diffusion isotropic and too little convectionIf convection a la ROSAT (see NATURE,April 2008) is included , thena)small gradient from diffuse gamma rays solved (EGRET)b)explain absence of MeV positrons from SN in disk (INTEGRAL) c)charged particle yield from DMA reduced up to order of magnitude. UNLIKELY to see DMA in charged particles with conv.



Background estimation by extrapolation dangerous

Diffractive scattering and/or hadronic showers with strongelectromagnetic component may give hadronic background in electron peak, NOT seen by extrapolation.

FERMI

Only way to MEASURE hadronicbackground is using a TRD/RICH.in addition to calorimeter.

AMS-02 will hopefully do it!!



S. Haino, INFN Perugia

R. Battiston, Pamela Workshop, 2009



PAMELA e+ selection with Calorimeter

Thanks to Piergiorgio Picozza, Spokesman, PAMELA Collaboration

Flight data:Rigidity: 20-30 GeV

Test beam data:Momentum: 50 GeV/c

neg.

pos.

pp

e



Evidence for convection

1. ROSAT X-Ray maps of hot gas in halo driven by CR pressure

2. Integral absence of positron annihilation in disk

3. Small gradient in EGRET diffuse gamma rays

(in diffusive model MOST cosmic ray interactions with gas towards center of Galaxy, thus producing there MANY more diffuse gamma rays by inelastic collisions then in outer Galaxy. Strong gradient NOT observed! (Breitschwerdt, Dogiel, Völk, A&A (2002)) CRs crossing disk in center reduced by convection!!

wim de boer, karlsruhe susy09, northeastern univ., boston, june 5, 2009 1 indirect dark matter...

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