Silicon Detectors for the Search of

Cosmic Antimatter and Dark Matter

Piergiorgio Picozza

INFN and University of Rome Tor Vergata

From e+/e- Colliders to High Energy Astrophysics

Trieste, September 7, 2010

Astrophysics and Cosmology

compelling Issues

Apparent absence of cosmological Antimatter

Nature of the Dark Matter that pervades the Universe

AMSPAMELA AMS

in Space

Accelerators

The Big Bang origin of the Universe requires

matter and antimatterto be equally abundant at the very hot beginning

Search for the existence of Antimatter in the Universe

Gamma Evidence for Cosmic Antimatter?

Steigman 1976, De Rujula 1996, Dolgov 2007

Osservation in the 100 MeV gamma range

Leading process:p p 0+ ………

Other processes:p p +……… μ+……… e+……… γ 1-10 MeV

e+e- γ γ 0.511 MeV

Antimatter Direct research

Observation of cosmic radiation hold out the possibility of directly observing a particle of antimatter which has escaped as a cosmic ray from a distant antigalaxy, traversed intergalactic space filled by turbulent magnetic field, entered the Milky Way against the galactic wind and found its way to the Earth.

Streitmatter, R. E., 24th ICRC , Rome, Italy, 1995Nuovo Cimento, 19, 835 (1996)

High energy particle or antinuclei

THE UNIVERSE ENERGY BUDGET

DM annihilations

DM particles are stable. They can annihilate in pairs.

Primary annihilation channels Decay Final states

σa= <σv>

Gamma Evidence for Cosmic Antimatter

and Dark Matter?

OSO-31967 - 1969

SAS-2

1972 - 1973

GRO: Comptel and EGRET

1991 - 2000

COS-B

1975 - 1982

Energy Calorimeter

Spark Chamber

Trigger Telescope

Cerenkov Counter

Anti-Coincidence

Dome

Cos-B

8/1975-4/1982SAS-2

11/1972-7/1973

EGRET

4/1991-1999

The gamma-

ray

missions

Cosmic Diffuse Gamma Spectrum

P. Sreekumar et al, astroph/9709257

Robert L. Golden R.

Balloon data : Positron fraction before 1990

leaky box

dinamic halo

m =20GeV

Tilka 89

MASS Matter Antimatter Spectrometer

MASS 1989

electron proton

The Turning Point

Calorimeter Performance

TS 93 Si-W Calorimeter

Wizard Si-W Calorimeter for Cosmic Antimatter SearchNuclear Physics B 32 (1993) 77-82

TS 93 NIM A 360 (1995) 17-21

electron positron

23

Elements of a pair-conversion

telescope

• photons materialize

into matter-antimatter

pairs:

E --> me+c2 + me-c2

• electron and positron

carry information about

the direction, energy and

polarization of the -ray

(energy measurement)

GILDA

Fermi

GLAST

CAPRICE FLIGHTSCANADA & NEW MEXICO

CAPRICE Calorimeter

• Charge sign and

momentum

• Beta selection

• Z selection

• hadron – electron

discrimination

CapriceSubnuclear physics

techniques

in space experiments

Antiproton Positron

positron to electron ratioCAPRICE 94

antiproton to proton ratioCAPRICE 98

AMS 01

AMS-01 Silicon tracker

AMS - 01

ZENIT rocket Baikonur, Kazakhstan July 10 1998

COSMOS rocket

Plesetsk, Russia July 15 2000

NINA2-MITA

89 440 km

NINA-RESURS

97 810 km

NINA MissionsNuclei P-Fe

10-200 MeV/n

Cosmic Rays: Galactic

Trapped

Solar Flares

NINA 1

NINA 2

Light Flashes on board Mir Space Station

1995 Cosmonaut Sergej Avdeev with the SilEye-1 detector on board of the Mir Station

Cosmonaut S. Avdeev during measurements with SilEye-2 apparatus on “Mir” Space Station

Antimatter Search

BESS (93, 95, 97, 98, 2000)

Heat (94, 95, 2000)

IMAX (96)

BESS LDF (2004, 2007)

AMS-01 (1998)

Wizard Collaboration

MASS – 1,2 (89,91)

TrampSI (93)

CAPRICE (94, 97, 98)

Cosmic Ray Antimatter

AntiprotonsPositrons

CR + ISM ± + x ± + x e± +

x

CR + ISM 0 + x e±

Moskalenko & Strong 1998 Positron excess?

Charge-dependent

solar modulation

Solar polarity reversal

1999/2000

Asaoka Y. Et al. 2002

¯

+

CR + ISM p-bar + …

kinematic threshold:

5.6 GeV for the reaction

pppppp

Pre-PAMELA

What did we need?

Measurements at higher energies

Better knowledge of background

High statistics

Continuous monitoring of solar modulation

Long Duration Flights

Antimatter and Dark Matter

Space MissionsPAMELA

15-06-2006

AMS-02

02-2011

Fermi/GLAST

11-6-2008

AGILE

23-04-2007

PAMELAPayload for Antimatter Matter Exploration

and Light Nuclei Astrophysics

PAMELA Instrument

GF ~21.5 cm2sr

Mass: 470 kg

Size: 130x70x70 cm3

100MDR ~ 1.2 TeV

Mirko Boezio, COSPAR, Bremen, 2010/07/18

The tracking system

Main tasks:• Rigidity measurement

• Sign of electric charge

• dE/dx

Characteristics:• 6 planes double-side (x&y view) microstrip Si sensors

• 36864 channels

• Dynamic range 10 MIP

Performances:• Spatial resolution: 3 4 m

• MDR ~1.2TV (from flight data)SPECTROMETER

PAMELA

PAMELA Si-W Calorimeter

Flight data: 0.632 GeV/cantiproton annihilation

Mirko Boezio, COSPAR, Bremen, 2010/07/18

Flight data: 0.763 GeV/cantiproton annihilation

Flight data: 84 GeV/c

interacting antiproton

Flight data: 92 GeV/c

positron

Mirko Boezio, COSPAR, Bremen, 2010/07/18

Flight data: 14.7 GV

Interacting nucleus

(Z = 8)

Antimatter and Dark Matter Search

ANTIPROTONS

Antiproton Flux(0.06 GeV - 180 GeV)

Donato et al. (ApJ 563 (2001) 172)

Ptuskin et al. (ApJ 642 (2006) 902)

Adriani et al., astro-ph 1007.0821 PRL in press

Systematics

errors included

Antiproton to proton ratio (0.06 GeV - 180 GeV)

Donato et al. (PRL 102 (2009) 071301)

Simon et al. (ApJ 499 (1998) 250) Ptuskin et al. (ApJ 642 (2006) 902)

Adriani et al., astro-ph 1007.0821 PRL in press

Systematics

errors included

Wino Dark Matter in a non-thermal Universe

G. Kane, R. Lu, and S. Watson

arXiv:0906.4765v3 [astro-ph.HE)

Trapped antiprotons in SAA

GCR

Trapped

PAMELA

Trapped antiprotons in SAA

Trapped

GCR

PAMELA

Positrons

Positron to Electron Fraction

Secondary productionMoskalenko & Strong 98

Adriani et al, Astropart. Phys. 34 (2010) 1 arXiv:1001.3522 [astro-ph.HE]

A Challenging Puzzle for CR Physics

P.Blasi, PRL 103 (2009) 051104; arXiv:0903.2794Y. Fujita arxiv .0904.5298Positrons (and electrons) produced as secondaries in the sources (e.g. SNR) where CRs are accelerated.But also other secondaries are produced: significant increase expected in the p/p and B/C ratios.

I. Cholis et al., Phys. Rev. D 80 (2009) 123518; arXiv:0811.3641v1

Contribution from DM annihilation.

D. Hooper, P. Blasi, and P. Serpico, JCAP 0901:025,2009; arXiv:0810.1527Contribution from diffuse mature &nearby young pulsars.

Antiprotons in CRs are in agreement with secondary production

A Challenging Puzzle for Dark Matter

Cosmic Ray Spectra

Cosmic Rays Propagation in the

Galaxy

Electrons

Electron (e-) Spectrum

All electrons

e+ + e-

All electron spectrum

96 CsI(Tl)8 layers

ATIC GLAST

HESS

All three ATIC flights are consistent

ATIC-4 with 10 BGO layers has improved

e , p separation. (~4x lower background)

“Bump” is seen in all three flights.

ATIC 1+2

“Source on/source off” significance of bump for ATIC1+2 is

about 3.8 sigmaJ Chang et al. Nature 456, 362 (2008)

Significance for ATIC1+2+4 is 5.1 sigma

ATIC 1+2+4

Preliminary

ATIC 1

ATIC 2

ATIC 4

Preliminary

Fermi (e++ e-)

M. Ackermann et al. astro-ph 1008.3999

Fermi (e++ e-)

M. Ackermann et al. astro-ph 1008.3999

The Completed AMS Detector on ISSTransition Radiation

Detector (TRD)

Silicon Tracker

Electromagnetic Calorimeter (ECAL)

Magnet

Ring Image Cerenkov Counter (RICH)

Time of Flight Detector (TOF)

Size: 3m x 3m x 3mWeight: 7 tons

AMS-02 new configuration

Combining searches in different channels could

give (much) higher sensitiviy to SUSY DM signals

antiprotons

positrons

gamma rays

anti deuterons

Unique

Feature

of

AMS

The Future

Gamma Space

Experiments

W. B. Atwood Talk

AGILE

23-04-2007Fermi/GLAST

11-6-2008

AGILE

the most compact

instrument for high-

energy astrophysics

It combines for the first

time a gamma-ray

imager (30 MeV- 30 GeV)

with a hard X-ray

imager (18-60 keV) with

large FOVs (1-2.5 sr) and

optimal angular

resolution

AGILE in orbit

April 23, 2007

ISRO Sriharikota base, PSLV-C8

Dark Matter Fermi

astro-ph 0912.0973

Third EGRET Catalog 1991-2000, 270 sources , 1.5

M ’s

AGILE 2.5 yr gamma ray map

FERMI Catalog (11 months, 1451 sources)

arXiv:1002.2280

http://fermi.gsfc.nasa.gov/ssc/data/access/lat/1yr_catalog/

Many Thanks

Guido!