Dark Matter Searches Dark Matter Searches

8/6/2019 Dark Matter Searches Dark Matter Searches

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Dark Matter SearchesDark Matter Searches

Katherine FreeseMichigan Center for Theoretical Physics

University of Michigan


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Vera RubinVera Rubin

Studied rotation curves

of galaxies, and found

that they are FLAT


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95% of the matter in galaxies is95% of the matter in galaxies is

unknown dark matterunknown dark matter Rotation Curves of Galaxies:Rotation Curves of Galaxies:

EXPECTED

FROM STARS

OBSERVED:FLAT ROTATION

CURVE


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Good news: cosmologists

don't need to "invent" newparticle:

Weakly Interacting

Massive Particles

(WIMPS). e.g.,neutralinos

Axions

ma~10-(3-6) eV

arises in Peccei-Quinn

solution to strong-CP

problem


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THE BEGINNINGS OF

DARK MATTERPARTICLE

PHENOMENOLOGY


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Axion detector

(axion to photon conversion)

Pierre Sikivie

PRL 51 (1983) p. 1415


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Axion masses


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Overall status of axion bounds


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The WIMP Miracle

Weakly Interacting Massive Particles are the bestmotivated dark matter candidates, e.g.: LightestSupersymmetric Particles (such as neutralino) are theirown antipartners. Annihilation rate in the early universe

determines the density today. The annihilation rate comes purely from particle physicsand automatically gives the right answer for the relicdensity!

This is the mass fraction of WIMPs today, and givesthe right answer (23%) if the dark matter is weakly

interacting

h2

=

31027

cm3/sec

ann

WIMP mass: GeV 10 TeV


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WIMP Dark Matter

Phenomenology: History Looking for neutrinos (Drukier and Stodolsky)

First paper suggesting direct detection: Goodman and

Witten 1986 Second paper on direct detection: we

(I) took into account WIMP distribution in galaxy and (ii)suggested annual modulation (Drukier, Freese, and

Spergel 1986). A followup paper (Freese, Frieman, Gould 1988)

suggested using annual modulation to pull out signalfrom background. This is how the only current claimfor direct detection was done (DAMA experiment).


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Drukier and Stodolsky

(1984)proposed MeV neutrino detection via elasticscattering off nuclei with 100 eV recoil energy

Andrzej

Drukier

Leo Stodolsky


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GOODMAN AND WITTEN (1986)

turned same approach to DMdetection


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Drukier, Freese, & Spergel (1986)

i) included model for galactic halo,

ii) proposed annual modulation, iii)

SI/SD for various detector elements


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EXCITING TIMES

We made WIMP proposals twenty years

ago:

It is coming to fruition!

My personal prediction: one of the

anomalous results is right and we will

know very soon.


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LHC-Making DM

Coming Soon(We hope)


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Supersymmetric Particles in LHC Signature: missing energy when SUSY particle is

created and some energy leaves the detector

Problem with identification: degeneracy ofinterpretation

SUSY can be found, but, you still dont know howlong the particle lives: fractions of a second to leavedetector or the age of the universe if it is dark matter

Proof that the dark matter has been found requiresastrophysical particles to be found


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Direct Detection of WIMP dark

matterA WIMP in the Galaxy

travels through our

detectors. It hits a

nucleus, and depositsa tiny amount of

energy. The nucleus

recoils, and we detect

this energy deposit.

Expected Rate: less than one count/kg/day!


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Event rate

dR

dE

=

NT

MT

d

dE

nv f(v, t)d3v

(number of events)/(kg of detector)/(keV of recoil energy)

=

0F2 (q)

2m2

f(v, t)

vd

3v

v> ME/ 22

Spin-independent

Spin-dependent

0=A22

p2

p

0=4

2

Sp

Gp + Sn Gn

2


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From DM Tools Website


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Many claims/hints of WIMPdark matter detection: how

can we be sure?

1) The DAMA annual modulation

2) The HEAT, PAMELA, and ATIC positronexcess

3) Gamma-rays from Galactic Center 4) WMAP Haze

HAS DARK MATTER BEENDISCOVERED?


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The DAMA

AnnualModulation


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DAMA annual modulationDrukier, Freese, and Spergel (PRD 1986);Freese, Frieman, and Gould (PRD 1988)

Data do show a 8 modulation

WIMP interpretation???

Bernabei et al 2003


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DAMA/LIBRA

(April 17,2008)

8 sigma


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Can the positive signal in DAMA

be compatible with null resultsfrom other experiments?

Savage, Gelmini, Gondolo, and Freese, arxiv:0808:3607(see also papers by Hooper and Zurek; Fairbairn and Schwetz;

Chang, Pierce and Weiner 2008)


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Small remaining region at 10 GeV WIMP mass

DAMA: spin independent?

DAMA

XENON

CDMS


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DAMA and

Spin-

dependent

cross sections

Savage, Gelmini,

Gondolo, Freese

0808:3607

Remaining window

around 10 GeV.

Removing SuperK:

WIMP mass

up to 20 GeV

allowed

DAMA

SUPER-K

XENON

CDMS

Hooper and Zurek extended Super-K bounds


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New measurements of Suns

velocity relative to Halo:250 km/sec (not 220 km/sec)

All curves movethe left:

Remaining

window moves to

7-8 GeV at 3

sigma (5-15 for

SD)

CRESST

Savage, Freese, Gondolo, Spolyar 2009


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Low mass window: COUPP,KIMS,

COGENT, PICASSO, CRESST

COUPP


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COUPP bounds (2007)COUPP bounds (2007)


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Preview of UC talks:Preview of UC talks:

COUPP (Eric Dahl, Friday) CoGeNT (Juan Collar, Friday)

Demonstration of acoustic discrimination.

Elimination of wall events. Commissioning of COUPP-60 kg.Commissioning of COUPP-60 kg. New spin-dependent limits (4 kg chamber).New spin-dependent limits (4 kg chamber).

Demonstration of surface event rejection.

First results from runs in Soudan. Prospects forProspects for PPCsPPCs in DM detection and beyond.in DM detection and beyond.


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To reconcile DAMA with null

results from other experiements: Popular theory:


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To reconcile DAMA with null

results of other experiments: Popular theory:


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Direct Detection

In past two years, two orders of magnitudeincrease in sensitivity (the following results not

included in our compatibility study):

(i) CDMS

(ii) XENON-10

(iii) ZEPLIN III

New technology: liquid noble gases

XENON, LUX, XMASS

WARP (argon)

DEAPCLEAN (argon and neon)


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ZEPLIN III (in Boulby mine)

Pink: XENON 10

Black: Zeplin IIIBlue: CDMS II

See talk of N. Smith

Future: ZEPLIN and LUX will join forces in DUSEL

(August 2009

First science run)

Second science

Run to begin

soon weeks


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Electron recoils

Nuclear Recoils


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n.b. if include 2008 data, this significance drops


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CDMS bounds

Inelastic Dark Matter


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Direct Detection In past two years, two orders of magnitude

increase in sensitivity:

(i) CDMS(ii) XENON-10

(iii) ZEPLIN II and III

New technology: liquid noble gasesXENON, LUX, XMASS

WARP (argon)

DEAPCLEAN (argon and neon)


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EurekaMAX, GeoDM

DEAP/

Miniclean


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Slide from Pearl Sandick


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CRESST II

See talk by Leo Stodolsky

Scintillation

Plus phonons


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RED OVALS: THOSE EXPTS THAT ARE CURRENTLY UNDERGROUND


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Slide from Elena Aprile


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Slide from Elena Aprile


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LUX experiment, Homestake mine

LUX (DUSEL)


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XENON,LZ,MAX,GEODM

EUREKA,DARWIN

Ultimate Searches?


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The HEAT and

PAMELA PositronExcess


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The Indirect Detection of Dark Matter

1. WIMP Annihilation

Typical final states include heavy

fermions, gauge or Higgs bosons

2.Fragmentation/DecayAnnihilation products decay and/or

fragment into combinations ofelectrons, protons, deuterium,

neutrinos and gamma-rays

3.Synchrotron and Inverse Compton

Relativistic electrons up-scatterstarlight/CMB to MeV-GeV energies,

and emit synchrotron photons via

interactions with magnetic fields

W+

W-

e+ q

q

p

0

e+


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Annihilation Products 1/3 electron/positrons

1/3 gamma rays

1/3 neutrinos

Typical particles have energies roughly

1/10 of the initial WIMP mass

All of these are detectable!


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Indirect Detection History Indirect Detection (Neutrinos)

Sun (Silk,Olive,Srednicki 85)

Earth (Freese 86; Krauss, Srednicki, Wilczek 86)

Indirect Detection (Gamma Rays, positrons) Milky Way Halo (Ellis, KF et al 87)

Galactic Center (Gondolo and Silk 2000)

Anomalous signals seen in HEAT (e+), HESS,

CANGAROO, WMAP, EGRET, PAMELA.


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New Indirect Detection Results!

Dan Hooper - Direct and Indirect

Searches For Particle Dark Matter

(When it rains it pours)PamelaIceCube

FERMI

NEWMEAS

UREM

ENT!

NEWLI

MIT!

FIRSTLIG

HT


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Positron excess HEAT balloon found anomaly in

cosmic ray positron flux

Explanation 1: dark matter

annihilation Explanation 2: we do not

understand cosmic ray

propagation

Baltz, Edsjo, Freese, Gondolo 2001


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PAMELA EXCESS OF POSITRONS


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Inspiration from our speaker

M. Boezio

ICECUBE/DEEPCORE will


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ICECUBE/DEEPCORE will

see neutrinos in five years if

PAMELA anomaly is from DMSpolyar,

Buckley,

Freese,

Hooper,Murayama

2009

String of phototubes in

ice at South Pole


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Gamma-rays from

the GalacticCenter


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HESS Gamma-ray DataAharonian et al 2004


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FERMI satellite

Launched June

2008

TALK OF

ELLIOTT BLOOM

NASA/DOE

gamma-ray

telescope

Dobler Finkbeiner Cholis Slatyer Weiner 2009


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I. FERMI HAZE: controversial

(gamma rays from Galactic Center)

Dobler, Finkbeiner,Cholis, Slatyer, Weiner 2009

II. See also talk of Dan Hooper for yet another hint of DM


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WMAP microwave emission

interpreted as dark matterannihilation in inner galaxy?

Finkbeiner 2005; Hooper,

Dobler 2007

Consistent with 100 GeV WIMPs.

WMAP HAZE


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Possible evidence for WIMP

detection already now:

The DAMA annual modulation

The HEAT/PAMELA positron excess

Gamma-rays from Galactic Center

WMAP haze

Theorists are looking for models in whichthese results are consistent with one another(given an interpretation in terms of WIMPs)


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Upcoming Data: will the Dark

Matter be found in 2010? LHC (find SUSY)

Indirect Detection due to annihilation:

FERMI (gamma rays)

PAMELA (positrons)

ICECUBE (neutrinos)

GAPS (antideuterons)

Direct Detection: many experiments

Directional Detection: see talk of D. Snowden-Ifft


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What will it take for us to

believe DM has been found? I. Direct detection:

compatible signals in a variety of

experiments made of different detectormaterials, and all the parties agree

2. Indirect detection:

annihilation signals in a variety ofchannels (neutrinos, gamma-rays, etc)

all coming from the same source


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Sagittarius streamDirectional detection with DRIFT-II

Freese, Gondolo, Newberg 2003


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THE END

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