10 - Particle Physics and Particle Astrophysics

hep.shef.ac.uk

10 - Particle Physics and Particle Astrophysics

Indirect Detection of

neutralinos

Joakim Edsjö

Stockholm University

Sweden

edsjo@physto.se

idm2004

Edinburgh, September 10, 2004


Outline

• Will focus on the neutralino in the MSSM

(and partly in the mSUGRA)

• Ways to search indirectly for neutralinos

• Direct detection versus neutrino telescopes

• Recent developments in Earth rates

(gravitational diffusion revisited)

• Comparison of future searches


The neutralino as a WIMP

Will focus on the neutralino in the MSSM as a

dark matter WIMP candidate.

The neutralino:

˜χ 0 1 = N 11 ˜B + N12 ˜W 3 + N 13 ˜H0 1 + N 14 ˜H0 2

The neutralino can be the lightest supersymmetric

particle (LSP). If R-partity is conserved, it is stable.

The gaugino fraction

Z g = |N 11 | 2 + |N 12 | 2


Calculational flowchart

1. Select model parameters

2. Calculate masses etc

3. Check accelerator constraints

4. Calculate the relic density Ω χ h 2

5. Check if the relic density is cosmologically OK

6. Calculate fluxes, rates, etc

Calculation done with

The relic density

Ω χ h 2 = 0.103 +0.020

−0.022

from WMAP+SDSS

M.Tegmark et al., astro-ph/0310723

DarkSUSY 4.1 available on

www.physto.se/~edsjo/darksusy

JCAP 06 (2004) 004 [astro-ph/0406204]


P. Gondolo, J. Edsjö, P. Ullio,

L. Bergström, M. Schelke

and E.A. Baltz

• MSSM or mSUGRA

• Masses and couplings

• Relic density

• Lab constraints

• Rates: neutrino

telescopes

• Rates: gamma rays

• Rates: antiprotons, positrons, antideuterons

• Rates: direct detection

Version 4.1 available now

ournal of Cosmology and Astroparticle Physics

JAn IOP and SISSA journal

JCAP 06 (2004) 004 [astro-ph/0406204]

DarkSUSY: computing supersymmetric

dark-matter properties numerically

P Gondolo 1 , J Edsjö 2 , P Ullio 3 , L Bergström 2 , M Schelke 2

and E A Baltz 4

1 Department of Physics, University of Utah, 115 South 1400 East, Suite 201,

Salt Lake City, UT 84112-0830, USA

www.physto.se/~edsjo/darksusy

2 Department of Physics, Stockholm University, AlbaNova University Center,

SE-106 91 Stockholm, Sweden

3 SISSA, via Beirut 4, 34014 Trieste, Italy

4 KIPAC, Stanford University, PO Box 90450, MS 29 Stanford, CA 94309, USA

E-mail: paolo@physics.utah.edu, edsjo@physto.se, ullio@sissa.it, lbe@physto.se,

schelke@physto.se and eabaltz@slac.stanford.edu

Received 9 June 2004

Accepted 22 June 2004

Published

Online at stacks.iop.org/JCAP/2004

DOI: 10.1088/1475-7516/2004/06/004

JCAP 06(2004)00


The

m χ − Z g

parameter space

10 5 10 10 2 10 3 10 4

J. Edsjö, 2004

Gaugino

Z g

/ (1-Z g

)

10 4

10 3

10 2

Ω χ h 2 > 0.2

10

LEP

Mixed

Higgsino

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6

10 -7

10 -8

0.05 ! !h 2 ! 0.08

0.08 ! !h 2 ! 0.12

0.12 ! !h 2 ! 0.2

Ωχh 2 < 0.05

Low sampling

Neutralino Mass (GeV)

(No sfermion

coannihilations in

this plot yet)


WIMP search strategies

• Direct detection

• Indirect detection:

– gamma rays from the galactic halo

– gamma rays from external galaxies/halos

– neutrinos from the Earth

– neutrinos from the Sun

– antiprotons from the galactic halo

– antideuterons from the galactic halo

– positrons from the galactic halo

– synchrotron radiation or neutrinos from

the galactic center

– ...

CDMS @ Soudan constrains

our models already now

Bergström and

Snellman, ’84

Freese, ’86; Krauss, Srednicki & Wilczek, ’86

Gaisser, Steigman & Tilav, ’86

Silk, Olive and Srednicki, ’85

Gaisser, Steigman & Tilav, ’86

Silk & Srednicki, ’84

Stecker, Rudaz & Walsh, ’85

Donato, Fornengo, Salati, ’99

Silk & Srednicki, ’84

Gondolo & Silk, ’00

Bertone, Sigl & Silk ’01


Annihilation in the halo

Neutral annihilation products

χχ → γγ, Zγ, ν

χχ → γ, ν

• Gamma rays can be searched for with e.g. Air

Cherenkov Telescopes (ACTs) or GLAST.

• Signal depends strongly on the halo profile,

Φ ∝


line of sight

ρ 2 dl


Annihilation to gamma rays

• Monochromatic.

At loop-level, annihilation can occur to

γγ ⇒ E γ = m χ

Zγ ⇒ E γ = m χ − m2 Z

4m χ

Features

• directionality – no propagation

uncertainties

• low fluxes, but clear signature

• strong halo profile dependence

• Continuous.

Neutralino annihilation can also produce a

continuum of gamma rays

χχ → · · · → π 0 → γγ

For fits of continuous gamma to

EGRET data, see de Boer @ idm2004.

Features (compared to lines)

• lower energy

• more gammas / annihilation

• rather high fluxes

• not a very clear signature


he flux of 3 × 10 −7 (cm −2 s −1 sr −1 ) in a field

Example of line signal

f 44 ◦ ×1 ◦ at b ≃ −10

• 78 GeV neutralino

annihilating to γγ

gamma-ray line at

simulation of Moore

• Clumpy halo as

tion realized for 3 years, in N-body inalactic

diffuse emis-

et al

Photons/bin

100

90

80

70

60

50

40

30

Neutralino annihilation gamma-ray

20

• Simulated signal in

CALET for 3 years

10

0

20 40 60 80 100 120 140

Gamma-ray Energy(GeV)

Figure from Yoshida @ idm2004


Gamma lines – rates in GLAST

Number of photons in 2 years

10

2! line

10 2 50 100 150 200 250 300

Z g

" 0.01

0.01 # Z g

# 0.99

Z g

# 0.99

Number of photons in 2 years

10

Z! line

10 2 50 100 150 200 250 300

Z g

" 0.01

0.01 # Z g

# 0.99

Z g

# 0.99

1

1

E

! ! GeV "

E

! ! GeV "

NFW halo profile, ∆Ω ≈ 1 sr

Bergström, Ullio & Buckley, ’97


Gamma lines – rates in ACTs

γγ


Gamma Flux !ph cm -2 sec -1 "

10 -9 10 10 2 10 3 E !

! GeV "

10 -10

10 -11

10 -12

Gamma Flux !ph cm -2 sec -1 "

10 -9 10 10 2 10 3 E !

! GeV "

10 -10

10 -11

10 -12

10 -13

10 -13

10 -14

10 -14

10 -15

10 -15

NFW halo profile, ∆Ω ≈ 10-5 sr

Bergström, Ullio & Buckley, ’97


Diffuse extragalactic gammas

23

E 2 d! "

/dE [ GeV cm -2 s -1 sr -1 ]

10 -6

10 -7

10 -8

10 -5 10 -1 1 10 10 2 E [ GeV ]

EGRET

diff. back.

Expected background

for GLAST

M #

= 171 GeV

Moore profile

c subh vir

/ c h vir

= 4

f = 5 %

Flux of diffuse gammas

from neutralino

annihilation in external

dark matter halos.

• Moore halo profile.

• High-rate MSSM

models chosen

M #

= 76 GeV

10 -9

Bergström, Edsjö and Ullio, PRD 66 (2002) 123502


High energy gammas from

the galactic center

• Cangaroo-II

and HESS

sources

detected at

galactic center

• Could be fit by

neutralinos, but

very heavy

ones in case of

HESS

log 10 [f ! !/ (erg cm -2 s -1 )]

-8

-9

-10

-11

-12

-13

Meyer-Hasselwander (1998)

3EG J1746-2851

CANGAROO II

Whipple

H.E.S.S. soft stereo

H.E.S.S. hard stereo

m " =18 TeV

m " =1.1 TeV

0.0001 0.001 0.01 0.1 1 10 100

E/TeV

Fig. 2. A summary of data and best-fit models for WIMP annihilation from the

Galactic center: H.E.S.S. (open triangles), CANGAROO (open boxes), EGRET

Figure from Horns, astro-ph/0408192

(solid and open circles), 10m Whipple telescope of the VERITAS collaboration

(solid diamond).


Annihilation in the halo

Charged annihilation products

Diffusion zone

χχ → ¯p, ¯D, e +

• Diffusion of charged particles. Diffusion model with

parameters fixed from studies of conventional cosmic

rays (especially unstable isotopes).

• Current detectors are e.g. HEAT, Caprice and BESS.

Future detectors are e.g. AMS, Pamela and GAPS.

+ CALET (see Yoshida @ idm2004)


Diffusion model

• Cylindrical diffusion model with free escape

at the boundaries

• Energy losses on the interstellar medium (for

antiprotons and antideuterons) or starlight

and CMB (for positrons)

• Reacceleration can change the energy of the

particles (can partly be mimicked by a break

in the diffusion coefficient)


Antiprotons – signal

!-

p (m-2 s -1 sr -1 GeV -1 )

10 -2

10 -3

4

7

2

6

1

5

3

L. Bergström, J. Edsjö and P. Ullio, 1999

Interstellar fluxes

background

10 -1 10 -1 1 10 10 2

#-

p (m-2 s -1 sr -1 GeV -1 )

10 -2

10 -3

10 -4

10 -5

10 -1 10 10 2 10 3 10 4

L. Bergström, J. Edsjö and P. Ullio, 1999

T-

p

= 0.35 GeV

Solar modulated, " F

= 500 MV

BESS 97

0.025 ! !h 2 ! 0.1

0.1 ! !h 2 ! 0.2

0.2 ! !h 2 ! 1.0

10 -4

10 -5

10 -6

10 -7

10 -8

Kinetic Energy, T-

p (GeV)

Neutralino Mass (GeV)

Easy to get high fluxes, but...


Antiprotons – fits to BESS data

Background only

Background + signal

10 -1 10 -1 1 10

L. Bergström, J. Edsjö and P. Ullio, 1999

L. Bergström, J. Edsjö and P. Ullio, 1999

!-

p (m-2 s -1 sr -1 GeV -1 )

BESS 95+97

Solar Modulated, " F

= 500 MV

!-

p (m-2 s -1 sr -1 GeV -1 )

BESS 95+97

10 -1 10 -1 1 10

Solar Modulated, " F

= 500 MV

total

background

signal

10 -2

10 -2

10 -3

10 -3

Kinetic Energy, T-

p (GeV)

Kinetic Energy, T-

p (GeV)

Room for, but no need for a signal!


Antideuterons

• Compared to antiprotons, the background of

antideuterons is essentially zero at low

energies.

• Search for a signal at e.g. 0.1-0.4 GeV,

either in the solar system, but preferably in

interstellar space.

F. Donato, N. Fornengo and P. Salati,

Phys. Rev. D62 (2000) 043003.

• No current experiments, but possibly future:

AMS, GAPS (Gaseous AntiParticle Spectrometer

Mori et al., ApJ 566 (2002) 604).


Future cosmic rays

Focus point region in mSUGRA

I !

visibility ratio

10

10 -6

10 -7

10 -8

10 -9

10 -1

-5

0 200 400 600 800 1000 1200

e + tan " = 50, µ > 0

p

-

~ Pamela:

1 yr

3 yr

N03 profile

Burkert profile

10 2 direct detection

-

D

10

1

$ flux from

the Sun

0 200 400 600 800 1000 1200

m #

[ GeV ]

• Expected future

sensitivities in two

extreme halo models

• Antideuteron

sensitivity with GAPS

in the solar system

• Direct detection

sensitivity of 1 ton

Xenon detector

Edsjö, Schelke and Ullio,

JCAP 2004, to appear.


Positron fluxes from neutralinos

Compared to antiprotons,

• energy losses are much more important

• higher energies due to more prompt

annihilation channels (ZZ, W+W-, etc)

• propagation uncertainties are higher

• solar modulation uncertainties are higher


Positrons - signal

E.A. Baltz and J. Edsjö, 1998

! e

+ (cm -2 s -1 sr -1 GeV -1 )

10 -7

10 -8

10 -9

10 -10

HEAT 94

MS, 1998

Gaugino-like

Mixed

Higgsino-like

• Compared to

antiprotons,

the fluxes are

typically lower

(except

possibly at

10 -6 10 10 2 10 3 10 4

10 -11

high energies),

but...

10 -12

E e

+ = 8.9-14.8 GeV

Neutralino Mass (GeV)


Positrons – example spectra

• the positron spectra can have features that could be detected!

• The signal strength needs to be boosted, e.g. by clumps, though...

• ...and the fit is not perfect


(Kamionkowski & Turner, Phys.Rev.D (199

Positrons - future searches

• Positrons will be measured more carefully by

– Pamela (see Morselli @ idm2004) flying 2005

– AMS (see de Boer @ idm2004) to be launched

CALET 3σ Detection Limit

2007/2008 () on ISS

– CALET (see Yoshida @

idm2004) on the ISS

to be launched 2010 ()

(cannot separate

e + and e - )

CALET simulation for 300

GeV KK DM (figure from

Yoshida @ idm2004)

E 3.2 J (electrons m −2 s −1 sr −1 GeV 2 )

390

380

370

360

350

340

330

320

310

100 1000

Electron Energy (GeV)

CALET


WMAP excess as neutralino annihilation

• In the WMAP data

there seems to be an

excess towards the

galactic center (see

Finkbeiner @ idm2004,

astro-ph/0409027)

• Simple model with a

100 GeV neutralino,

annihilating, giving e +

e - that emit

synchrotron radiation

WMAP

– 17 –

excess

Model

+45

Haze Difference

b

-45

+45

b

-45

+45

b

-45

+45

b

K (23GHz) Ka (33GHz) Q (41GHz) V (61 GHz)

-45

45 l -45 45 l -45 45 l -45


Direct detection

current limits

Cross section, ! SI

(pb)

10 -4

10 -5

10 -6

10 -7

10 -8

10 -9

10 -3 10 10 2 10 3 10 4

Excluded, CDMS Soudan, May 2004

J. Edsjö, 2004

• CDMS @ Soudan,

astro-ph/0405033

• Direct detection

experiments have

really started to

explore the MSSM

parameter space!

10 -10

10 -11

10 -12

Gaugino-like

Mixed

Higgsino-like

Neutralino Mass (GeV)

• Use this to

constrain our

models


Neutralino Capture

χ

velocity distribution

Sun

ρ χ

ν interactions

ν µ

Earth

σ ann

σ scatt

Γ ann

Γ capture

Detector

µ

Silk, Olive and Srednicki ‘85

Gaisser, Steigman & Tilav ‘86

Freese ‘86

Krauss, Srednicki & Wilczek ‘86

Gaisser, Steigman & Tilav ‘86


Review of capture rate calculations

• 1985: Press & Spergel, ApJ 296 (1985) 679:

Capture in the Sun

• 1987: Gould, ApJ 321 (1987) 571:

Refined Press & Spergel’s calculation for the Earth.

• 1988: Gould, ApJ 328 (1988) 919:

Pointed out that the Earth cannot capture efficiently from the halo since

the Earth is deep within the potential well of the Sun (v esc

≈42 km/s)

• 1991: Gould, ApJ 368 (1991) 610:

WIMPs will diffuse around in the solar system due to gravitational

scattering off the planets. Net result is that the velocity distribution at

Earth is approximately as if the Earth was in free space, i.e. the 1987

expressions are still valid.


Earth Capture

Why are low velocities needed

• Capture can only occur when a WIMP scatters off a nucleus

to a velocity less than the escape velocity

Cutoff velocity u cut (km/s)

10 3

10 2

10 1

forbidden

allowed

10 0

10 1 10 2 10 3 10 4 10 5

Wimp mass (GeV )

Capture on Fe most

important.

For a given lowest

velocity of the velocity

distribution, we can

only capture WIMPs

up to a maximal mass.


Diffusion effects of the planets

Speed at the Earth (km/s)

• Gravitational scattering off one planet causes diffusion along

spheres of constant velocity with respect to that planet.

• When seen from another planet’s frame, the velocity can have

changed.

25

20

15

10

5

u♀ =16

u♀ =14

u♀ =12

u♀ =10

u♀ =9

u♀ =8

u♀ =7

u♀ =6

u♀ =5

u♀ =4

u♀ =3

0

25 20 15 10 5 0 5 10 15 20

Speed at the Earth (km/s)

The net effect is

that Venus and

Jupiter diffuse to

velocities down to

2.5 km/s

The velocity

distribution at

Earth is ‘as in

free space’

A. Gould, ApJ 368 (1991) 610, J. Lundberg & J. Edsjö, PRD69 (2004) 123505.


Possible problems: solar capture

• 1994: Farinella et al, Nature 371 (1994) 314:

Simulations of asteroids thrown out of the asteroid belt showed

that they were typically forced into the Sun in less than 2·10 6

years.

• 2001: Gould and Alam, ApJ 549 (2001) 72:

If Farinella’s results hold for general WIMP orbits, the bound

WIMPs in the solar system could be depleted.

• 2004: J. Lundberg and J. Edsjö, PRD69

(2004) 123505:

Numerical simulation of WIMP orbits to find out if this is the case.


Velocity distribution at Earth

Phase space density: FMx/ρx [sm −1 ]

#! !'

#! !(

#! !*

#! !)

#! !#!

#! !##

#! !#$

Gaussian

Without solar depl.

Best estimate

Raw numerical

Conservative

Ultra conservative

! " #! #" $! $" %! %" &! &" "! "" '! '" (!

WIMP velocity u at the Earth (km/s)

• Without solar

capture,

Gould’s results

of ‘capture as

in free space’

are confirmed.

• Including solar

capture, we

get a

significant

suppression at

low velocities,

not as bad as

initially

thought, but

still significant


Earth capture rates

!" !'

!" !&

Gaussian

Best estimate

Conservative

Ultra conservative

Capture rate [s −1 ]

!" !(

!" !#

!" !"

!" '

Up to almost

an order of

magnitude

suppression at

higher masses!

!" &

!" !"" #"" $"" %"" !""" %"""

WIMP mass (GeV)

σ scatt = 10 −42 cm 2


Earth annihilation rates

Suppression of annihilation rate

1

10 -1

10 -2

J. Lundberg and J. Edsjö, 2003

0.05 # "h 2 # 0.2

max

#

sup

min

#

sup

! old !

" 10 km -2 yr -1

! old !

# 10 km -2 yr -1

10 10 2 10 3 10 4

Neutralino Mass (GeV)

Γ A = 1 2 C tanh2 t

τ

Annihilation and

capture is not in

equilibrium in the

Earth


The annihilation

rates are

suppressed by up

to almost two

orders of

magnitude!


Neutrino-induced muon fluxes from

the Earth

Usual Gaussian

approximation

New estimate including

solar capture

10 6 10 10 2 10 3 10 4

10 6 10 10 2 10 3 10 4

Muon flux from the Earth (km -2 yr -1 )

10 5

10 4

10 3

10 2

10

! SI

J. Lundberg and J. Edsjö, 2004

AMANDA 2004

lim

! SI

! ! SI

BAKSAN 1997

lim lim

! SI

! ! SI

! 0.1! MACRO 2002

SI

lim SUPER-K 2004

0.1! SI

! ! SI IceCube Best-Case

lim

= CDMS 2004

0.05 # " #

h 2 # 0.2

E th " = 1 GeV

Muon flux from the Earth (km -2 yr -1 )

10 5

10 4

10 3

10 2

10

! SI

J. Lundberg and J. Edsjö, 2004

AMANDA 2004

lim

! SI

! ! SI

BAKSAN 1997

lim lim

! SI

! ! SI

! 0.1! MACRO 2002

SI

lim SUPER-K 2004

0.1! SI

! ! SI IceCube Best-Case

lim

= CDMS 2004

0.05 # " #

h 2 # 0.2

E th " = 1 GeV

New solar system diffusion

1

1

Neutralino Mass (GeV)

Neutralino Mass (GeV)

Maxwell-Boltzmann velocity distribution assumed.


Neutrino-induced muon fluxes from

the Sun

10 6 10 10 2 10 3 10 4

Muon flux from the Sun (km -2 yr -1 )

10 5

10 4

10 3

10 2

10

1

! SI

J. Edsjö, 2004

BAKSAN 1997

lim

! SI

! ! SI

MACRO 2002

lim lim

! SI

! ! SI

! 0.1! SUPER-K 2004

SI

lim IceCube Best-Case

0.1! SI

! ! SI Antares, 3 yrs

lim

= CDMS 2004

0.05 # " #

h 2 # 0.2

E th " = 1 GeV

AMANDA-II, 2001

Neutralino Mass (GeV)

Antares sensitivity

(see Hößl @

idm2004)

• Compared to

the Earth, much

better

complementarity

due to spindependent

capture in the

Sun.


A note about velocity distributions

Remember the different velocity dependencies!

Capture sensitive to the

low-velocity region

Direct detection sensitive

to higher velocities

f(v)

v


Comparison of future searches

• We will now compare future expected

sensitivities in reasonably optimistic

scenarios:

– Cuspy halo profiles (NFW) for cosmic ray

signatures (no spike though)

– Expected sensitivities of various searches

in the coming 5–10 years


Neutrino-induced fluxes and

future direct detection limits

Sun

Earth

10 6 10 10 2 10 3 10 4

J. Edsjö, 2004

J. Lundberg and J. Edsjö, 2004

10 6 10 10 2 10 3 10 4

Muon flux from the Sun (km -2 yr -1 )

10 5

10 4

10 3

10 2

10

1

10 -1

10 -2

10 -3

10 -4

E th ! = 1 GeV

0.05 " "h 2 " 0.2

Sun

bkg

BAKSAN 1997

MACRO 2002

SUPER-K 2004

IceCube Best-Case

Antares, 3 yrs

Visible, ! SI

Some visible

None visible

lim

= 10 -9 pb at best

! SI

Muon flux from the Earth (km -2 yr -1 )

10 5

10 4

10 3

10 2

10

1

10 -1

10 -2

E th ! = 1 GeV

0.05 " " #

h 2 " 0.2

lim

= 10 -9 pb at best

! SI

Visible, ! SI

Some visible

None visible

AMANDA 2004

BAKSAN 1997

MACRO 2002

SUPER-K 2004

IceCube Best-Case

New solar system diffusion

Neutralino Mass (GeV)

Neutralino Mass (GeV)

Future direct detection limit is assumed to be Ge like with a

sensitivity down to 10 -9 pb.


Comparing future searches in the

m χ − Z g

parameter space

10 5 10 10 2 10 3 10 4

Z g

/ (1-Z g

)

10 4

10 3

10 2

10

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6

10 -7

10 -8

LEP

0.05 ! !h 2 ! 0.08

0.08 ! !h 2 ! 0.12

0.12 ! !h 2 ! 0.2

Ωχh 2 < 0.05

Ω χ h 2 > 0.2

J. Edsjö, 2004

Low sampling

Neutralino Mass (GeV)


Comparison of future searches I

Direct detection, SI

10 5 10 10 2 10 3 10 4

J. Edsjö, 2004

Z g

/ (1-Z g

)

10 4

10 3

10 2

10

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6

10 -7

10 -8

Visible, ! SI

Some visible

None visible

Future limit is

assumed to be Ge

like with a

sensitivity down to

10 -9 pb.

Neutralino Mass (GeV)


Comparison of future searches II

Earth

Sun

10 5 10 10 2 10 3 10 4

J. Edsjö, 2004

J. Edsjö, 2004

10 5 10 10 2 10 3 10 4

Z g

/ (1-Z g

)

10 4

10 3

10 2

Z g

/ (1-Z g

)

10 4

10 3

10 2

10

10

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6

10 -7

10 -8

Visible, Earth

Some visible

None visible

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6

10 -7

10 -8

Visible, Sun

Some visible

None visible

Neutralino Mass (GeV)

IceCube-like, 1 km 3 running for

10 years (10 years live time)

Neutralino Mass (GeV)

IceCube-like, 1 km 3 running for

10 years (5 years live time)


Comparison of future searches III

Z g

/ (1-Z g

)

Antideuterons

10 5

10 4

10 3

10 2

10

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6 Visible, dbar

10 -7

Some visible

None visible

10 -8

10 10 2 10 3 10 4

J. Edsjö, 2004

Neutralino Mass (GeV)

• Compare with future

suggested mission GAPS

(Gaseous AntiParticle

Spectrometer, K. Mori

et al, ApJ 566

(2002) 604)

• Require at least one

event (background ≈ 0)

at low energies with

e.g. GAPS

• Antideuteron production

yields from F. Donato, N.

Fornengo and P. Salati,

Phys. Rev. D62

(2000) 043003.


Comparison of future searches IV

γ γ

Z γ

10 5 10 10 2 10 3 10 4

J. Edsjö, 2004

J. Edsjö, 2004

10 5 10 10 2 10 3 10 4

Z g

/ (1-Z g

)

10 4

10 3

10 2

Z g

/ (1-Z g

)

10 4

10 3

10 2

10

10

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6

10 -7

10 -8

Visible, !!

Some visible

None visible

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6

10 -7

10 -8

Visible, Z !

Some visible

None visible

Neutralino Mass (GeV)

Neutralino Mass (GeV)

Significant signal in ACTs or GLAST towards the galactic

center with a NFW profile.


Comparison of future searches V

Z g

/ (1-Z g

)

10 5

10 4

10 3

10 2

10

1

10 -1

10 -2

10 -3

10 -4

10 -5

10 -6 Visible, any exp.

10 -7

Some visible

None visible

10 -8

10 10 2 10 3 10 4

J. Edsjö, 2004

Neutralino Mass (GeV)

• Large parts of

the MSSM

parameter space

can be probed by

future

experiments

• The halo model is

assumed to be

an optimistic

NFW profile.

• LHC e.g., will cut

into this plane

mainly from the

left and top.


Summary of indirect searches

Signal

High rates

Clear

signature

Gamma ray lines No Yes

Continuous gammas Yes No

Antiprotons from halo Yes No

Antideuterons from halo Yes No/Yes

Positrons from halo No Yes

Neutrinos from Sun Yes Yes

Neutrinos from Earth No Yes

Signals from galactic center Yes No

Direct detection Yes Yes


Conclusions

• Detection prospects of neutralinos are reasonably good.

• For ‘standard’ halo models, direct detection seems more

promising than the neutrino-flux from the Earth,

especially after including the depletion of WIMPs due to

solar capture

• The neutrino-flux from the Sun is complementary to

direct detection due to spin-dependent capture in the

Sun

• Searching for various cosmic rays can also prove

fruitful, even if the astrophysical uncertainties can be

large. Searching for antideuterons seems promising.

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