IN V E STIG A TIN G N E U TR A L IN O D A R K M A TTE R :IN V E STIG A TIN G N E U TR A L IN O D A R K M A TTE R :IN V E STIG A TIN G N E U TR A L IN O D A R K M A TTE R :IN V E STIG A TIN G N E U TR A L IN O D A R K M A TTE R :

A D A G IO S A N D PR E STO SA D A G IO S A N D PR E STO SA D A G IO S A N D PR E STO SA D A G IO S A N D PR E STO S

A lessandro B ottino A lessandro B ottino A lessandro B ottino A lessandro B ottino U niversità di Torino/IN F NU niversità di Torino/IN F NU niversità di Torino/IN F NU niversità di Torino/IN F N

TheTheTheThe D ark Side of the D ark Side of the D ark Side of the D ark Side of the U niverseU niverseU niverseU niverse 2006 2006 2006 2006 M adrid , M adrid , M adrid , M adrid , JuneJuneJuneJune 20202020----24, 2006 24, 2006 24, 2006 24, 2006

Contents

• W hereW hereW hereW here do do do do w ew ew ew e stand stand stand stand w ithw ithw ithw ith neutralinoneutralinoneutralinoneutralino dark dark dark dark m atterm atterm atterm atter ????

• H intsH intsH intsH ints forforforfor relicrelicrelicrelic neutralinosneutralinosneutralinosneutralinos in in in in presentpresentpresentpresent resultsresultsresultsresults

fromfromfromfrom direct/direct/direct/direct/indirectindirectindirectindirect searchessearchessearchessearches ? ? ? ?

• The The The The rolerolerolerole of of of of astrophysicalastrophysicalastrophysicalastrophysical uncertaintiesuncertaintiesuncertaintiesuncertainties

• PerspectivesPerspectivesPerspectivesPerspectives

Com biningCom biningCom biningCom bining data of W M A P (3 data of W M A P (3 data of W M A P (3 data of W M A P (3 yearsyearsyearsyears data) data) data) data) w ithw ithw ithw ith

sm allsm allsm allsm all----scalescalescalescale CM B dataCM B dataCM B dataCM B data

largelargelargelarge----scale scale scale scale structurestructurestructurestructure surveyssurveyssurveyssurveys

w eakw eakw eakw eak gravitationalgravitationalgravitationalgravitational lensinglensinglensinglensing

highhighhighhigh----redshiftredshiftredshiftredshift SupernovaeSupernovaeSupernovaeSupernovae

((((D .N .D .N .D .N .D .N . SpergelSpergelSpergelSpergel etetetet al., al., al., al., astroastroastroastro----phphphph/0603449) /0603449) /0603449) /0603449)

one can one can one can one can obtainobtainobtainobtain

12.008.0 2 ≤Ω≤ hCDM

W ithin supersym m etric theories w ith RW ithin supersym m etric theories w ith RW ithin supersym m etric theories w ith RW ithin supersym m etric theories w ith R ----parity conservation, parity conservation, parity conservation, parity conservation,

the the the the neutralinoneutralinoneutralinoneutralino provides one of the m ost interesting realizations provides one of the m ost interesting realizations provides one of the m ost interesting realizations provides one of the m ost interesting realizations

of a of a of a of a cold dark m atter particlecold dark m atter particlecold dark m atter particlecold dark m atter particle (W IM P) w ith (W IM P) w ith (W IM P) w ith (W IM P) w ith

appropriate appropriate appropriate appropriate relic abundance relic abundance relic abundance relic abundance

sizeable sizeable sizeable sizeable ratesratesratesrates for d irect and indirect m easurem entsfor d irect and indirect m easurem entsfor d irect and indirect m easurem entsfor d irect and indirect m easurem ents

A convenient susy schem e is an A convenient susy schem e is an A convenient susy schem e is an A convenient susy schem e is an effective effective effective effective –––– MMMM inim al in im al in im al in im al

SSSSupersym m etric extension of the upersym m etric extension of the upersym m etric extension of the upersym m etric extension of the SSSStandard tandard tandard tandard MMMM odel at the odel at the odel at the odel at the

electrow eak scale electrow eak scale electrow eak scale electrow eak scale ---- w hat w e m ainly consider in this talk w hat w e m ainly consider in this talk w hat w e m ainly consider in this talk w hat w e m ainly consider in this talk

CDMΩ≈Ωχ

Notice that no gaugino-mass unification is assumed

N eutralinoN eutralinoN eutralinoN eutralino relicrelicrelicrelic abundanceabundanceabundanceabundance

R elic A bundance for Cold Candidates (W IM Ps)

intann

2392

v

cm103

><×≈Ω

−

σχh

≡>< intannvσ therm altherm altherm altherm al averageaverageaverageaverage of of of of integrated from the decoupling tim e to the present integrated from the decoupling tim e to the present integrated from the decoupling tim e to the present integrated from the decoupling tim e to the present

epoch.epoch.epoch.epoch.

Cosm ologicalCosm ologicalCosm ologicalCosm ological boundboundboundbound::::

238intann

max2

CDM2

cm103.2v

13.0)(−×≥>

CosmologicalCosmological boundbound on on mmχχ

GeV 6 ≥χm

mχ (GeV)

analyticapproximation

for (Ωχ h2)min

Ωχh2

upper bound

on ΩCDM h2

A.BA.BA.BA.B., Donato, ., Donato, ., Donato, ., Donato, FornengoFornengoFornengoFornengo, , , , ScopelScopelScopelScopelhephephephep----phphphph/0304080/0304080/0304080/0304080

CosmologicalCosmological boundbound on on mmχχ

GeV 6 ≥χm

mχ (GeV)

analyticapproximation

for (Ωχ h2)min

Ωχh2

upper bound

on ΩCDM h2

A.BA.BA.BA.B., Donato, ., Donato, ., Donato, ., Donato, FornengoFornengoFornengoFornengo, , , , ScopelScopelScopelScopelhephephephep----phphphph/0304080/0304080/0304080/0304080

physicalphysicalphysicalphysicalregionregionregionregion

M uchM uchM uchM uch lighterlighterlighterlighter neutralinosneutralinosneutralinosneutralinos are are are are allow edallow edallow edallow ed in in in in N extN extN extN ext----totototo----M inim alM inim alM inim alM inim al

Supersym m etricSupersym m etricSupersym m etricSupersym m etric extensionsextensionsextensionsextensions of the Standard M odelof the Standard M odelof the Standard M odelof the Standard M odel ::::R . F lores, R . F lores, R . F lores, R . F lores, K .A .K .A .K .A .K .A . O live and D . O live and D . O live and D . O live and D . Thom asThom asThom asThom as, , , , PhysPhysPhysPhys. . . . L ett.L ett.L ett.L ett. B 263 (1991) 425B 263 (1991) 425B 263 (1991) 425B 263 (1991) 425

S.A . A bel, S . Sarkar and I.B . W hittingham , hepS.A . A bel, S . Sarkar and I.B . W hittingham , hepS.A . A bel, S . Sarkar and I.B . W hittingham , hepS.A . A bel, S . Sarkar and I.B . W hittingham , hep----ph/9209292ph/9209292ph/9209292ph/9209292

D .G . Cerdeno, C . H ugonie, D .E . L opezD .G . Cerdeno, C . H ugonie, D .E . L opezD .G . Cerdeno, C . H ugonie, D .E . L opezD .G . Cerdeno, C . H ugonie, D .E . L opez ----F ogliani, C . F ogliani, C . F ogliani, C . F ogliani, C . M unozM unozM unozM unoz and A .M . and A .M . and A .M . and A .M . TeixeraTeixeraTeixeraTeixera

hephephephep----phphphph/0408102/0408102/0408102/0408102

J. J. J. J. G unionG unionG unionG union , D . , D . , D . , D . H ooperH ooperH ooperH ooper, and B . , and B . , and B . , and B . M cE lrathM cE lrathM cE lrathM cE lrath , , , , hephephephep----phphphph/0509024/0509024/0509024/0509024

SaHaHaWaBa~~~~~

5)2(

04)1(

03)3(

21 ++++=χ

M SSM M SSM M SSM M SSM isisisis extendedextendedextendedextended bybybyby addingaddingaddingadding a new a new a new a new gaugegaugegaugegauge singletsingletsingletsinglet ch iralch iralch iralch iral superm ultipletsuperm ultipletsuperm ultipletsuperm ultiplet

---- specia l specia l specia l specia l featuresfeaturesfeaturesfeatures: : : :

a very light CPa very light CPa very light CPa very light CP ----odd H iggs boson odd H iggs boson odd H iggs boson odd H iggs boson

a 5a 5a 5a 5 ----com ponents neutralino (the com ponents neutralino (the com ponents neutralino (the com ponents neutralino (the usualusualusualusual 4 4 4 4 com ponentscom ponentscom ponentscom ponents + a + a + a + a singlinosinglinosinglinosinglino))))

A lsoA lsoA lsoA lso direct detection direct detection direct detection direct detection ratesratesratesrates forforforfor relicrelicrelicrelic neutralinosneutralinosneutralinosneutralinos are are are are sizeablysizeablysizeablysizeably enhancedenhancedenhancedenhanced

N oticeN oticeN oticeN otice: the W IM P : the W IM P : the W IM P : the W IM P relicrelicrelicrelic density density density density m ightm ightm ightm ight bebebebe m uchm uchm uchm uch higherh igherh igherh igher thanthanthanthan

the standard one the standard one the standard one the standard one in in in in cosm ologicalcosm ologicalcosm ologicalcosm ological m odelsm odelsm odelsm odels w hichw hichw hichw hich im plyim plyim plyim ply anananan enhancem entenhancem entenhancem entenhancem ent

in the in the in the in the expansionexpansionexpansionexpansion rate of the rate of the rate of the rate of the U niverseU niverseU niverseU niverse at the W IM P at the W IM P at the W IM P at the W IM P decouplingdecouplingdecouplingdecoupling tim etim etim etim e

ThisThisThisThis isisisis the case the case the case the case forforforfor::::

---- Cosm ological m odels Cosm ological m odels Cosm ological m odels Cosm ological m odels w ithw ithw ithw ith a a a a kinationkinationkinationkination phasephasephasephase

(Salati, (Salati, (Salati, (Salati, astroastroastroastro----phphphph/0207396; R osati, /0207396; R osati, /0207396; R osati, /0207396; R osati, hephephephep ----phphphph/0309124)/0309124)/0309124)/0309124)

- D arkD arkD arkD ark----energy m odels based on energy m odels based on energy m odels based on energy m odels based on scalarscalarscalarscalar----tensor gravitytensor gravitytensor gravitytensor gravity

(Catena, F ornengo, M asiero, P ietroni and R osati, (Catena, F ornengo, M asiero, P ietroni and R osati, (Catena, F ornengo, M asiero, P ietroni and R osati, (Catena, F ornengo, M asiero, P ietroni and R osati, astroastroastroastro----phphphph/0403614)/0403614)/0403614)/0403614)

---- R andallR andallR andallR andall----SundrumSundrumSundrumSundrum DDDD ----branebranebranebrane m odelm odelm odelm odel

((((R andallR andallR andallR andall and and and and SundrumSundrumSundrumSundrum , P R L 83 (4690) 1999) , P R L 83 (4690) 1999) , P R L 83 (4690) 1999) , P R L 83 (4690) 1999)

F or F or F or F or constraints using cosm ic antiprotonsconstraints using cosm ic antiprotonsconstraints using cosm ic antiprotonsconstraints using cosm ic antiprotons,,,, see Schelke, Catena, see Schelke, Catena, see Schelke, Catena, see Schelke, Catena,

F ornengoF ornengoF ornengoF ornengo, M asiero and , M asiero and , M asiero and , M asiero and P ietroni, hepP ietroni, hepP ietroni, hepP ietroni, hep ----ph/0605287ph/0605287ph/0605287ph/0605287

enhancem ent of the relic abundance in a scalarenhancem ent of the relic abundance in a scalarenhancem ent of the relic abundance in a scalarenhancem ent of the relic abundance in a scalar----tensor gravity m odeltensor gravity m odeltensor gravity m odeltensor gravity m odel

C atenaC atenaC atenaC atena , , , , F ornengoF ornengoF ornengoF ornengo, M asiero, , M asiero, , M asiero, , M asiero, P ietroniP ietroniP ietroniP ietroni and R osati: astroand R osati: astroand R osati: astroand R osati: astro–––– ph/0403614ph/0403614ph/0403614ph/0403614

3nRY =

D etection of D etection of D etection of D etection of relicrelicrelicrelic particlesparticlesparticlesparticles

WIMP direct WIMP direct measurementsmeasurements

annual-modulationeffect

χ χ

nuclear-recoil measurement

χ χγ,e+ dp,

PairPair annihilationannihilation in the in the halohalo

AnnihilationsAnnihilations takingtaking placeplace in the in the HaloHalo

χ + χ→

keep directionality

ν, ν

γ (continuum)

γ line (Zγ)

−

e+

searches for rare

components in cosmic raysp

2density) Wimp( ratesdetection ∝

D

if halo is clumpy, strong enhancement in signal

Bengtsson, Salati, SilkSilk, StebbinsBerezinsky, A.B., Mignola

for signals due to produced by WIMP self-annihilationsin the galactic halo

-- propagation and diffusion of the charged particles in the halo

-- evaluation of the secondary productions (background)

Detection Detection Detection Detection ratesratesratesrates dependdependdependdepend sensitivelysensitivelysensitivelysensitively on the on the on the on the followingfollowingfollowingfollowing propertiespropertiespropertiesproperties::::phase-space distribution function for the WIMPs in the galactic halo

-- deviations of the smooth component from the isothermal sphere

-- possible existence of streams and clumps

dpe ,,+

The elastic cross section is bounded

- from below by the cosmological upper

limit

- from above by the susy model

This generates a “funnel”

at low mass

Neutralino – nucleon cross sectionColor code

from now on:

● Ωχh2 < 0.095

×××× Ωχh2 > 0.095

Sensitivity lines for a NaI detector with a low energy threshold and a large exposure for various WIMP distribution functionsIn the galactic halo

AB, Donato, Fornengo and Scopel, hep-ph/0304080

The elastic cross section is bounded

- from below by the cosmological upper

limit

- from above by the susy model

This generates a “funnel”

at low mass

Neutralino – nucleon cross sectionColor code

from now on:

● Ωχh2 < 0.095

×××× Ωχh2 > 0.095

Sensitivity lines for a NaI detector with a low energy threshold and a large exposure for various WIMP distribution functionsIn the galactic halo

AB, Donato, Fornengo and Scopel, hep-ph/0304080

N eutralinoN eutralinoN eutralinoN eutralino----nucleusnucleusnucleusnucleus m ass m ass m ass m ass m atchingm atchingm atchingm atching

NaI

Neutralino – nucleon cross sectionColor code:

● Ωχh2 < 0.095

×××× Ωχh2 > 0.095

Extending the scatter plot tohigher neutralino masses

DAMA modulation region, likelyhood function values distant

more than 4 σ from the null result (absence on modulation)

hypothesis, Riv. N. Cim. 26 n. 1 (2003) 1-73, astro-ph/0307403

Exposure: about 108.000 kg day

Neutralino – nucleon cross sectionColor code:

● Ωχh2 < 0.095

×××× Ωχh2 > 0.095

Extending the scatter plot tohigher neutralino masses

Neutralino – nucleon cross section

CDMS

D. S. Akerib et al., astro-ph/0405033

(in astro-ph/0509259 the upper limit is

improved by a factor of 2.5 )

EDELWEISS

A. Benoit et al.,

Phys. Lett. B 545, 43 (2002)

Upper limits from direct searches

assumptions:

isothermal sphere,

v0=220 km/sec,

ρ0=0.3 GeV/cm3

Dependence of the upper bounds on the WIMP galacticdistribution function

B1 = non-isotropic velocity dispersionA0 = isothermal sphereC3 = axisymmetric spatial distribution

E xperim entalE xperim entalE xperim entalE xperim ental data data data data fromfromfromfrom

A keribA keribA keribA kerib etetetet al., al., al., al., astroastroastroastro----phphphph/0509259/0509259/0509259/0509259

annihilationrate R

2222 1

relic abundance

SignalsSignalsSignalsSignals due due due due totototo WIMP WIMP WIMP WIMP selfselfselfself----annihilationannihilationannihilationannihilation in the in the in the in the halohalohalohalo

subdominant here

at constant χm

χΩχCDMΩ

122

int

020

2 11)(χχ

χ

σσσ

ρρ

mv

v

mvR

ann

annann

loc ><>∝< 2

int

1><

∝Ωvannσ

χ

Thus the quantity0

2)( >< vannloc

σρρχ

is maximal at 1.0)( min ≅Ω=Ω CDMχ

236max0

2 10])[( cmvannloc

−≅>< σρρχ

202 1)(

χ

χ σρρ

mvR ann

loc

>

Antiprotons

Among the signals due to WIMP self-annihilation in the halo, those of antiprotons are the most constraining ones for relicneutralinos with masses in the range GeVmGeV 200 10 ≤≤ χ

maximal annihilationrate R

experimentalupper bound

χmGeV 200

above antiprotons from neutralino self annihilationare irrelevant (e.g. are dominated by secondary production) unless the halo is substantially clumpy

GeVm 200≈χ

a qualitative plot

M aurin, Taillet, D onato, Salati, B arrau, B oudoul, astro-ph/0212111

P ropagation and diffusion of cosm ic rays in the haloP ropagation and diffusion of cosm ic rays in the haloP ropagation and diffusion of cosm ic rays in the haloP ropagation and diffusion of cosm ic rays in the halo

A .BA .BA .BA .B ., D onato, ., D onato, ., D onato, ., D onato, F ornengoF ornengoF ornengoF ornengo and Salati: and Salati: and Salati: and Salati: hephephephep----phphphph/0507086/0507086/0507086/0507086

effectseffectseffectseffects due due due due totototo light light light light neutralinosneutralinosneutralinosneutralinos can can can can bebebebe sizeablesizeablesizeablesizeable, , , , butbutbutbut hardlyhardlyhardlyhardly distinguishabledistinguishabledistinguishabledistinguishable

fromfromfromfrom background background background background

constraints constraints constraints constraints relaxedrelaxedrelaxedrelaxed bybybyby astrophysicalastrophysicalastrophysicalastrophysical uncertaintiesuncertaintiesuncertaintiesuncertainties of of of of prim aryprim aryprim aryprim ary fluxesfluxesfluxesfluxes

10 GeV 20 GeV30 GeV

Diffusion in a two-zones halo: - energy-dependent coefficient- L = halo thickness parameter

)(0 rigidityRRKK ==δβ

Com patibility am ong the W IM P and the astrophysical param etersCom patibility am ong the W IM P and the astrophysical param etersCom patibility am ong the W IM P and the astrophysical param etersCom patibility am ong the W IM P and the astrophysical param eters

A .B ., D onato, F ornengo, Salati, hepA .B ., D onato, F ornengo, Salati, hepA .B ., D onato, F ornengo, Salati, hepA .B ., D onato, F ornengo, Salati, hep ----ph/0507086 ph/0507086 ph/0507086 ph/0507086

The Gamma-rays Saga

Cesarin iCesarin iCesarin iCesarin i, , , , F ucitoF ucitoF ucitoF ucito , L ionetto, , L ionetto, , L ionetto, , L ionetto, M orselliM orselliM orselliM orselli, , , , U llioU llioU llioU llio , , , ,

astroastroastroastro----phphphph/0305075/0305075/0305075/0305075

EGRET excess from the Galactic Center

A .BA .BA .BA .B ., D onato, ., D onato, ., D onato, ., D onato, F ornengoF ornengoF ornengoF ornengo , , , , ScopelScopelScopelScopel, , , , hephephephep----phphphph/0401186/0401186/0401186/0401186

Explanation in terms of neutralino self-annihilation possible, but not compelling (boost factor required)

Elsasser and Mannheim: astro-ph/0405235

Extragalactic gamma-ray background

best fit: GeVm 11075515+−=χ

Important caveats:- the background is affected by large uncertainties- such a sizeable primary flux would imply violation of observationalbounds on gamma-ray flux from the Galactic Center (S. Ando, astro-ph/0503006)

EGRET excess of diffuse galactic gamma-rays fluxes

Analysis by de Boer, Sander, Zhukov, Gladyshev and Kazakov of the EGRET data in 180 independent sky directionsClaims: - the common spectral shape of the excess singles out a WIMP mass ~ 60 GeV- the flux of the excess determines a halo dark matter distribution in good

agreement with rotation curve

But ...

Conclusions by de Boer at al. contradicted by Bergstrom, Edsjo, Gustafsson and Salati, astro-ph/0602632:

the peculiar features of the dark matter distribution used by de Boer et al. difficult to achieve with non-dissipative dark matter and may have problemswith the disc surface mass density

the ensuing antiproton fluxes would overshoot the observational data

J. Albert et al (MAGIC Collaboration, astro-ph/0512469

High energy gamma-flux from the Galactic Center

Aharonian et al (HESS Collaboration) astro-ph/0408145

Power-law spectrum with an index

15.009.02.2 ±±−=α

The TeV radiation is well explained by astrophysical processes (Aharonian and Neronov, astro-ph/0503354)

Zaharijas, Hooper, astro-ph/0603540

Hard to disentangle a signal due to WIMP self-annihilation

Signals from dwarf galaxies satellites of the Milky Way: the case of Draco - good prospects for GLAST and MAGIC in case of favorable neutralino schemes :

Bergstrom and Hooper, hep-ph/0512317

See also: Profumo and Kamionkowski, astro-ph/0601249

The sensitivities of present direct and indirect WIMP searches already allow investigation of some interestingregions of the neutralino parameter space

Main challenge - to reduce some large uncertaintiesaffecting the astrophysical aspects: WIMP distributionfunction, propagation and diffusion properties of CRs, ...

In view of these uncertainties the interpretation of experimental data requires a conservative approach

Among the signals due to WIMP self-annihilation in the halo,the antiprotons are the most powerful signal for

Gamma-rays very intriguing – but great caution is needed before drawing strong conclusions

Independent information from accelerators is desperately needed

Conclusions

GeVm 200≤χ