1. Antiproton and Electron Measurements and Dark Matter Searches
Piergiorgio Picozza
INFN and University of Rome Tor Vergata
8th International Workshop on Identification of Dark Matter
26-30 July 2010, Montpellier, France

2. THE UNIVERSE ENERGY BUDGET

3. Primary annihilation channels
DM annihilations
DM particles are stable. They can annihilate in pairs.
Primary annihilation channels
Decay
Final states
σa= <σv>

4. e-

5. Robert L. Golden

6. 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)

7. Charge-dependent solar modulation
Cosmic Ray Antimatter
Charge-dependent solar modulation
Solar polarity reversal 1999/2000
Asaoka Y. Et al. 2002 +
Pre-PAMELA status
Antiprotons
Positrons ?
Moskalenko & Strong 1998
Positron excess? ?
CR + ISM  p-bar + …
kinematic threshold:
5.6 GeV for the reaction
CR + ISM  p± + x  m± + x  e± + x
CR + ISM  p0 + x  gg  e±

8. Antimatter and Dark Matter Space Missions
PAMELA
BESS
ATIC
AMS-02
Fermi/GLAST

9. PAMELA
Payload for Antimatter Matter Exploration and Light Nuclei Astrophysics

10. PAMELA Instrument

11. PAMELA Launch 15/06/06 16 Gigabytes trasmitted daily to Ground NTsOMZ Moscow

12. Antiprotons

13. 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 PRL in press

14. 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) )
Systematics
errors included
Adriani et al., astro-ph PRL in press

15. Time Dependence of PAMELA Proton Flux
Preliminary

16. Antiproton to proton ratio Dark Matter constraints
I. Cholis
astro-ph : v1.

17. Antiproton to proton ratio Di Bernardo et al. astro-ph 0909.4548v3

18. Wino Dark Matter in a non-thermal Universe G. Kane, R. Lu, and S
Wino Dark Matter in a non-thermal Universe G. Kane, R. Lu, and S. Watson arXiv: v3 [astro-ph.HE)

19. SAA
Trapped pbar
• PAMELA
GCR
• PAMELA

20. BESS-Polar II Launch - December 22, 2007

21. BESS Detector √ Min. material (4.7g/cm2) Rigidity measurement JET/IDC
SC Solenoid (L=1m, B=1T)
Min. material (4.7g/cm2)
Uniform field
Large acceptance
Central tracker
(Drift chamber
d ~200mm
Z, m measurement
R,b --> m = ZeR 1/b2-1
dE/dx --> Z
JET/IDC
Rigidity
TOF
b, dE/dx √

22. BESS Polar II Observations/Expectations
Event rate ~2.5 kHz; Total events ~4.7 x 109
Total data volume 13.5 TB (3.07 kB/event)
Expected antiprotons ~10, times previous Solar minimum dataset
ECRS?
Antiproton Antideuteron Antihelium
(Search for PBH) (Search for PBH) (Search for Antimatter)

23. Positrons

24. Positron to Electron Fraction
Secondary production Moskalenko & Strong 98
Adriani et al, Astropart. Phys. 34 (2010) 1 arXiv: [astro-ph.HE]

25. Time Dependence of PAMELA Electron (e-) Flux
Preliminary

26. Charge dependent solar modulation
Preliminary!!
Pamela
2006
A > 0
Positive particles
A < 0

27. A Challenging Puzzle for CR Physics
Uncertainties on:
Secondary production (primary fluxes, cross section)
Propagation models
Electron spectrum
But antiprotons in CRs are in agreement with secondary production

28. A Challenging Puzzle for CR Physics
P.Blasi, PRL 103 (2009) ; arXiv:
Y. Fujita arxiv
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.
D. Hooper, P. Blasi, and P. Serpico, JCAP 0901:025,2009; arXiv:
Contribution from diffuse mature &nearby young pulsars.
I. Cholis et al., Phys. Rev. D 80 (2009) ; arXiv: v1
Contribution from DM annihilation.

29. Electrons

30. Electron (e-) Spectrum
Preliminary
Preliminary

31. Talk
William
Gillard

33. All electrons e+ + e-

34. Courtesy of Luca Baldini

35. All electron spectrum
GLAST
ATIC
HESS

36. All three ATIC flights are consistent
Preliminary
ATIC 1
ATIC 2
ATIC 4
Preliminary
“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

37. Example: DM I. Cholis et al. arXiv:0811.3641v1
See Neal Weiner’s talk

38. Fermi (e++ e-)

39. Electrons measured with H.E.S.S.

40. Fermi (e++ e-) and PAMELA ratio Bergstrom et al. astro-ph 0905.0333v1

41. Pulsars: Most significant contribution to high-energy CRE: Nearby (d < 1 kpc) and Mature (104 < T/yr < 106) Pulsars D. Grasso et al.
Example of fit to both Fermi and Pamela data with known
(ATNF catalogue) nearby, mature pulsars and with a single,
nominal choice for the e+/e- injection parameters

42. Fermi (e++ e-) D. Grasso astro-ph 0912.3887

43. All electrons PAMELA very preliminary

44. AMS-02 on ISS In Orbit Nov. 2010 – Feb. 2011
TRD
RICH
Vacuum
Case
Tracker
MAGNET
He Vessel

45. The Completed AMS Detector on ISS
Transition Radiation Detector (TRD)
Time of Flight Detector (TOF)
Magnet
Silicon Tracker
Electromagnetic Calorimeter (ECAL)
Ring Image Cerenkov Counter (RICH)
Size: 3m x 3m x 3m
Weight: 7 tons

46. AMS-02 new configuration

47. Unique Feature of AMS positrons antiprotons
Combining searches in different channels could
give (much) higher sensitiviy to SUSY DM signals
anti deuterons
gamma rays

48. The Next Future

49. Future

50. Perspectives

51. Thanks!
pamela.roma2.infn.it