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
Search for the existence of Antimatter in the Universe PAMELA AMS in Space AMS Accelerators The Big Bang origin of the Universe requires matter and antimatter to be equally abundant at the very hot beginning
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., 24 th ICRC, Rome, Italy, 1995 Nuovo 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 σ a = <σv>
Gamma Evidence for Cosmic Antimatter and Dark Matter? OSO-3 1967-1969 SAS-2 1972-1973 COS-B 1975-1982 GRO: Comptel and EGRET 1991-2000
SAS-2 11/1972-7/1973 Anti-Coincidence Dome Spark Chamber Trigger Telescope Cerenkov Counter Energy Calorimeter Cos-B 8/1975-4/1982 The gammaray missions EGRET 4/1991-1999
Cosmic Diffuse Gamma Spectrum P. Sreekumar et al, astroph/9709257
Robert L. Golden R.
Balloon data : Positron fraction before 1990 m =20GeV Tilka 89 dinamic halo leaky box
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 Search Nuclear Physics B 32 (1993) 77-82 TS 93 NIM A 360 (1995) 17-21 electron positron
Elements of a pair-conversion telescope photons materialize into matter-antimatter pairs: E --> m e +c 2 + m e -c 2 electron and positron carry information about the direction, energy and polarization of the -ray (energy measurement) 23
GILDA Fermi GLAST
CAPRICE FLIGHTS CANADA & NEW MEXICO
CAPRICE Calorimeter
Caprice Subnuclear physics techniques in space experiments Charge sign and momentum Beta selection Z selection hadron electron discrimination
Antiproton Positron
positron to electron ratio CAPRICE 94
antiproton to proton ratio CAPRICE 98
AMS 01
AMS-01 Silicon tracker
AMS - 01
NINA-RESURS 97 810 km NINA2-MITA 89 440 km ZENIT rocket Baikonur, Kazakhstan July 10 1998 COSMOS rocket Plesetsk, Russia July 15 2000
Nuclei P-Fe NINA Missions 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 Wizard Collaboration MASS 1,2 (89,91) TrampSI (93) CAPRICE (94, 97, 98) BESS (93, 95, 97, 98, 2000) Heat (94, 95, 2000) IMAX (96) BESS LDF (2004, 2007) AMS-01 (1998)
Charge-dependent solar modulation Asaoka Y. Et al. 2002 Cosmic Ray Antimatter Pre-PAMELA Solar polarity reversal 1999/2000 Antiprotons Positrons Moskalenko & Strong 1998 Positron excess? + CR + ISM p-bar + kinematic threshold: 5.6 GeV for the reaction pp pppp CR + ISM ± + x ± + x e ± + x CR + ISM 0 + x e ±
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 Missions PAMELA 15-06-2006 AGILE 23-04-2007 Fermi/GLAST 11-6-2008 AMS-02 02-2011
PAMELA Payload for Antimatter Matter Exploration and Light Nuclei Astrophysics
PAMELA Instrument GF ~21.5 cm 2 sr Mass: 470 kg Size: 130x70x70 cm 3
100 MDR ~ 1.2 TeV
PAMELA The tracking system SPECTROMETER 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) Mirko Boezio, COSPAR, Bremen, 2010/07/18
PAMELA Si-W Calorimeter
Flight data: 0.632 GeV/c antiproton annihilation
Flight data: 0.763 GeV/c antiproton annihilation Mirko Boezio, COSPAR, Bremen, 2010/07/18
Flight data: 84 GeV/c interacting antiproton
Flight data: 92 GeV/c positron
Flight data: 14.7 GV Interacting nucleus (Z = 8) Mirko Boezio, COSPAR, Bremen, 2010/07/18
Antimatter and Dark Matter Search
ANTIPROTONS
Antiproton Flux (0.06 GeV - 180 GeV) Donato et al. (ApJ 563 (2001) 172) Systematics errors included Ptuskin et al. (ApJ 642 (2006) 902) Adriani et al., astro-ph 1007.0821 PRL in press
Antiproton to proton ratio (0.06 GeV - 180 GeV) Simon et al. (ApJ 499 (1998) 250) Ptuskin et al. (ApJ 642 (2006) 902) Donato et al. (PRL 102 (2009) 071301) Systematics errors included Adriani et al., astro-ph 1007.0821 PRL in press
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 PAMELA Trapped GCR
Trapped antiprotons in SAA Trapped PAMELA GCR
Positrons
Positron to Electron Fraction Secondary production Moskalenko & 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:0903.2794 Y. Fujita arxiv.0904.5298 Positrons (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:0810.1527 Contribution from diffuse mature &nearby young pulsars.
A Challenging Puzzle for Dark Matter Antiprotons in CRs are in agreement with secondary production
Cosmic Ray Spectra
Cosmic Rays Propagation in the Galaxy
Electrons
Electron (e - ) Spectrum
All electrons e + + e -
All electron spectrum ATIC GLAST 96 CsI(Tl) 8 layers HESS
All three ATIC flights are consistent Preliminary Preliminary ATIC 1+2+4 ATIC 1 ATIC 2 ATIC 4 Source on/source off significance of bump for ATIC1+2 is about 3.8 sigma J Chang et al. Nature 456, 362 (2008) ATIC-4 with 10 BGO layers has improved e, p separation. (~4x lower background) Bump is seen in all three flights. Significance for ATIC1+2+4 is 5.1 sigma
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 ISS Transition Radiation Detector (TRD) Time of Flight Detector (TOF) Silicon Tracker Magnet Electromagnetic Calorimeter (ECAL) Ring Image Cerenkov Counter (RICH) Size: 3m x 3m x 3m Weight: 7 tons
AMS-02 new configuration
antiprotons Unique Feature of AMS positrons Combining searches in different channels could give (much) higher sensitiviy to SUSY DM signals gamma rays anti deuterons
The Future
Gamma Space Experiments AGILE 23-04-2007 Fermi/GLAST 11-6-2008 W. B. Atwood Talk
AGILE the most compact instrument for highenergy 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
http://fermi.gsfc.nasa.gov/ssc/data/access/lat/1yr_catalog/ arxiv:1002.2280 FERMI Catalog (11 months, 1451 sources)
Many Thanks Guido!