Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 1

DARK2007Sydney, Sept 24th-28th, 2007

The Prospects for the Search for Dark Matter with GLAST Brian L. WinerThe Ohio State UniversityLAT Dark Matter and New Physics Working Group

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 2

GLAST LAT CollaborationUnited States California State University at Sonoma University of California at Santa Cruz - Santa Cruz Institute of Particle Physics Goddard Space Flight Center – Laboratory for High Energy Astrophysics Naval Research Laboratory The Ohio State University Stanford University (SLAC and HEPL/Physics) University of Washington Washington University, St. LouisFrance IN2P3, CEA/SaclayItaly INFN, ASIJapanese GLAST Collaboration Hiroshima University ISAS, RIKENSwedish GLAST Collaboration Royal Institute of Technology (KTH) Stockholm University

PI: Peter MichelsonPI: Peter Michelson (Stanford & SLAC)

~225 Members (including ~80 Affiliated Scientists, plus 23 Postdocs, and 32 Graduate Students)

Cooperation between NASA and DOE, with key international contributions from France, Italy, Japan and Sweden.

Managed at Stanford Linear Accelerator Center (SLAC).

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 3

GLAST Burst Monitor (GBM) 5 keV - 25 MeV

Large Area Telescope (LAT)20 MeV - 300 GeV

GLAST is a NASA/DOE MissionLaunch: Feb-April 2008Lifetime: 5-years (10-years goal)Orbit: 565 km, circularInclination: 28.5o

GLAST is the next generation after EGRET… factor > 30 improvement in sensitivity

• Large effective area, factor > 5 better than EGRET

• Field of View ~20% of sky, factor 4 greater than EGRET

• Point Spread function factor > 3 better than EGRET for E>1 GeV. On axis >10 GeV, 68% containment < 0.12 degrees

• Smaller deadtime. Minimize rejection of E>10GeV gamma

rays due to backscatter into cosmic ray shield

No expendables (EGRET had spark chamber gas) - long mission without degradation (5-10 years)

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 4

e+ e– Calorimeter

Particle tracking detectors

Conversion foils

Anticoincidenceshield

Basics of a pair conversion telescopes

Basic structure of a pair conversion telescope

Tracker/converter (detection planes + high Z foils): photon conversion and reconstruction of the electron/positron tracks.

Calorimeter: energy measurement.

Anti-coincidence shield (ACD): backgound rejection (cosmic rays flux ~104 higher than the gamma flux).

Signature of a gamma event: No ACD signal 2 tracks (1 Vertex)* Calorimeter signal (~Energy)

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 5

GLAST Large Area Telescope (LAT)

e+ e–

Tracking detector16 tungsten foils (12x3%R.L.,4x18%R.L.) 18 pairs of silicon strip arrays884736 strips (228 micron pitch)

Anti-Coincidence Detector4% R.L.89 scintillating tilesefficiency (>0.9997) for MIPs

Calorimeter 8.5 radiation lengths8 layers cesium iodide logs1536 logs total (1200kg)

1.8 m

1.0 m

One of the biggest Silicon Tracking systems ever constructed.

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 6

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 7

GEANT4 detector simulation

High-energy interacts in LAT

Black: Charged particlesWhite: PhotonsRed: Deposited energyBlue: Reconstructed tracksYellow: Inferred γ direction

Geometry Detail Over 45,000 volumes, and growing! Interaction Physics QED: derived from GEANT3 with extensions to higher and lower energies (alternate models available)

Hadronic: based on GEISHA (alternate models available)

Propagation Full treatment of multiple scattering Medium-dependent range cut-off Surface-to-surface ray tracing.

Includes information from actual LAT tests detailed instrument response dead channels noise etc.

Overall Deadtime Effects

F. Longo

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 8

Expected GLAST-LAT Performance

Angular resolution of better than 1 degree at energies > 1 GeV

Angular resolution of better than 0.2 degree at energies > 10 GeV

Better than 10% energy resolution for 100 MeV through 100 GeV

About 5% around 1 GeV

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 9

GLAST Science

0.01 GeV 0.1 GeV 1 GeV 10 GeV 100 GeV 1 TeV0.01 GeV 0.1 GeV 1 GeV 10 GeV 100 GeV 1 TeV

Gamma Ray Bursts

Unidentified sources

Cosmic ray acceleration

Active Galactic Nuclei

Dark matter

Solar flares

Pulsars

Quantum

Gravity ?

thanks: N. Omodei

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 10

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 11

Gammas from lines

For Line, energy = WIMP mass For WIMP masses > MZ /2 can also have Z0 line

Measurement of line branching fractions would constrain particle theory

γ

γ

time

γ

Z0

Branching fractions are in the range 10-2 - 10-4

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 12T. A. Porter et al. 30th ICRC, Merida, Mexico

- Final rejection power:

1/106

- γ efficiency: 0.8

Sreekumar et al. Astrophys.J.494:523-534,1998

Strong et al. Astrophys.J.613:956-961,2004

Black, total; light green, GCR protons; lavender, GCR He; red, GCR electrons; blue, albedo protons; light blue, albedo positrons; green, albedo electrons; and yellow albedo gammas.

Background to all photons: charged particles

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 13

Galactic diffuse: conventional and optimized GALPROP model

’conventional’ GALPROP: calibrated with locally measured electron and

proton,helium spectra, as well as synchroton emission

Optimized GALPROP:

Strong, Moskalenko, Reimer, ApJ 537, 736, 2000

Strong, Moskalenko, Reimer, ApJ 613, 962-976, 2004

Conventional Optimized

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 14

Dark Matter in the gamma ray sky

Galactic center

Milky Way halo

Milky Way satellites

Extragalactic

Milky Way Halo simulated by Taylor & Babul (2005)

All-sky map of DM gamma ray emission (Baltz 2006)

Only dm annihilation radiation shown….

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 15

Several Different Search Modes

Search Technique advantages challenges

Galactic center

Good Statistics

Source confusion/Diffuse background

Satellites, subhalosPoint sources

Low background,Good source id

Low statistics

Milky Way halo

Large statistics

Galactic diffuse background

Extra-galactic

Large Statistics

Astrophysics, galactic diffuse background

Spectral lines No astrophysical uncertainties, good source id

Low statistics

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 16

WIMP annihilation: gamma-ray fluxWIMP annihilation: gamma-ray flux

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 17

WIMP annihilation: gamma-ray yield

200GeV mass WIMPWIMP pair annihilation

gamma spectrum

MWIMP Total# >100MeV >1GeV >10GeV

10 GeV 17.3 12.6 1.0 0

100GeV 24.5 22.5 12.4 1.0

1TeV 31.0 29.3 22.4 12.3

Gamma ray yield per final state bb

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 18

Galactic Center

ROI: 1.0 degree GC, E > 1 GeV 4 years of operation

Simulate Particle-yield (DarkSUSY)

Simulate GLAST response (ObsSim)

Assume background given by conventional/optimized galprop model

Check if WIMP + background can be distinguished from background only (using χ2 for simplicity).

1 GeV 10 Gev

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 19

Dark Matter From the Galactic Center

E. Nuss, A. Lionetto, A. Morselli

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 20

Senstivity to lines: where to look

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 21

Line 5σ sensitivity

Simulated detector response to δ function in energy

)()( 2min

2min

2 bbs

Average χ (bootstrapped) > 25

10-9

10-8

Y. Edmonds, E. Bloom, J. Cohen-Tanugi

5 Years Worth of data

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 22

Example: Dark Matter Satellites

Optimistic case: 70 counts signal,

43 counts background

within 1.5 deg of clump center

55-days GLAST in-orbit counts map (E>1GeV)

GalacticCenter

30-deglatitude

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 23

Semi-analytic models of halo substructure1)

Signal, background flux inside the tidal radius

WIMP mass = 100GeV

Significance [ σ]

No

. o

f sa

tell

ites

Satellites/Subhalos

GLAST 1-yr

GLAST 5-yrs

How many sources at which signficiance ?

WIMP mass [GeV]

100 GeV WIMP, 10 σ detection

<σ

an

nihv >

[2.3

e.-

26

cm

-3s

-1]

P. Wang, L. Wai, E. Bloom

Green: optimized

Red: conventional1) Taylor & Babul, MNRAS, 364, 535 (2004) - MNRAS, 364, 515 (2005) -MNRAS, 348, 811 (2004)

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 24

Galactic Halo Analysis

Use the large statistics of the full sky. Remove the Galactic Center (<10o) from consideration Consider a range of Neutralino Masses Perform a simulaneous fit to both the energy and spatial

distribution. Measure the sensitivity

to observing a signal. Mass vs < v> 1 year of running

A. Sander, R. Hughes, B. Winer

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 25

Sensitivity for Galactic Halo Analysis

<

v>

cm

3-s

-1

A. Sander, R. Hughes, B. Winer

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 26

Acknowledgements

E. Bloom, Y. Edmonds, P. Wang, L. Wai, J. Cohen-Tanugi(SLAC/KIPAC) I. Moskalenko (Stanford) A. Morselli, A. Lionetto (INFN Roma/Tor Vergata) E. Nuss (Montpellier) R. Hughes, A. Sander, B. Winer (Ohio State) L. Bergström, J. Edsjö, A. Sellerholm (Stockholm) A. Moiseev (Goddard)

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 27

Summary

Launch Early 2008! GLAST will shed light on the

multi-GeV EGRET data. The GLAST LAT team is

pursing complementary searches for signatures of particle dark matter. These analyses will continue

to be optimized over the next 4-6 months prior to launch.

We are looking forward to launch and adding a new piece to the puzzle of dark matter.

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 28

1st International GLAST symposium, Stanford, USA (Feb 2007)

L. Bergström, J.C., J. Edsjö, A. Sellerholm: Cosmological WIMPs

G. Bertone, T. Bringmann, R. Rando, A. Morselli : Point sources

A. Lionetto: mSUGRA and ED from the Galactic Centre A. Morselli, A. Lionetto, E. Nuss: Galactic Centre Y. Edmonds, E. Bloom, J. C. , J. Scargle, L. Wai: Line

sensitivity A. Sander, B. Winer, R. Hughes, L. Wai: Halo sensitivity L. Wai : Overview P. Wang, E. Bloom, L. Wai: Galactic Satellites

Summary Paper in preparation

More Information...

http://glast.gsfc.nasa.gov/science/symposium/2007/program.html

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 29

BACKUP SLIDES

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 30

Extra Higgs-Doublet, additional symmetry,Z2(Ho ) (Inert Doublet Model, Barbieri et. al. PRD 74 (2006) )

one could think the model was designed for GLAST ... It wasn’t.

Inert Higgs Dark Matter

Gustaffson et. al. astro-ph/0703512

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 31

Generic WIMP flux

γ yield per annihilation

Flux from given source

line continuum

Dark Matter structure

Annihilation cross setcion. Constraint by cosmology to ~ 10-26 cm2

ISASUGRA

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 32

”Optimized model”: allow average CR spectrum to deviate from local spectrum

Modify antiprotons and electrons

Background to WIMP signal: galactic diffuse

(slide from Igor Moskalenko)

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 33Jan Conrad (KTH, Sthlm) La Thuile March 2007 33

Identification of Dark Matter subhalos

Molecular cloud

Pulsar

30 GeV

WIMP

200 GeV

WIMP

Baltz, Taylor, Wai, astro-ph/0610731

5 yr GLAST, single clump, 1 degree

rejected allowed

rejectedrejected

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 34Jan Conrad (KTH, Sthlm) Scineghe07 June 2007 34

mSUGRA exclusion (Galactic Center)

A.Morselli, E. Nuss, A. Lionetto. First Glast Symposium, 2007

Similar ”analysis” as in generic WIMP case

5yr, 3σ discovery

trunc. NFW

A0 = 0

Acc. Limits:Baer et al. hep-ph/0405210

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 35

tang = 60

A0 = 0

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 36

Sagittarius

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 37

EGRET excess: Disk surface mass density within 0.8 kpc

- Allowed density within 0.8 kpc of the disk 57 – 66 M (Sun) /pcsqr from observations

-Stars ~ 40 M(Sun)/pc^2

- ISM ~ 13 M(Sun)/pc^2

- DM ~ 4- 16 M(Sun)/pc^2

- de Boer: 29 M(Sun)/pc^2

Bergström et. Al. JCAP05(2006)006

Brian L. Winer, Ohio State University GLAST DARK2007, University of Sydney Page 38

EGRET excess: anti-protons

Bergström et. Al. JCAP05(2006)006

Anti protons from a SUSY model yelding good fit to EGRET data

Spread due to uncertainty in propagation