Transcript Results from PAMELA Mirko Boezio INFN Trieste, Italy On behalf of the PAMELA collaboration Indirect and Direct Detection of Dark Matter February 7th 2011

Results from PAMELA
Mirko Boezio
INFN Trieste, Italy
On behalf of the PAMELA collaboration
Indirect and Direct Detection of Dark Matter
February 7th 2011
Isotopic
composition
[ACE]
Solar Modulation
[PAMELA,ULYSSES]
Antimatter
Dark Matter
[BESS, PAMELA, AMS]
Elemental
Composition
[CREAM, ATIC, TRACER, NUCLEON,
CALET, GAMMA-400?]
Extreme Energy CR
[AUGER, EUSO, TUS/KLYPVE, OWL??]
PAMELA
Payload for Antimatter Matter Exploration
and Light Nuclei Astrophysics
PAMELA Collaboration
Italy:
Bari
Florence Frascati
Naples
Rome
Trieste CNR, Florence
Russia:
Moscow
St. Petersburg
Sweden:
Germany:
Siegen
KTH, Stockholm
PAMELA Instrument
GF ~21.5 cm2sr
Mass: 470 kg
Size: 130x70x70 cm3
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Design Performance
• Antiprotons
Energy range
80 MeV - 190 GeV
• Positrons
50 MeV – 300 GeV
• Electrons
• Protons
up to 800 GeV
up to 1 TeV
• Helium
up to 400 GeV/n
• Electrons+positrons
up to 2 TeV ( by calorimeter)
• Light Nuclei (Li/Be/B/C)
• AntiNuclei search
up to 200 GeV/n
sensitivity of 3x10-8 in He/He
Mirko Boezio, IDDDM, Aspen, 2011/02/07
PAMELA
Launch
15/06/06
16 Gigabytes trasmitted daily
to Ground
NTsOMZ Moscow
Orbit Characteristics
350 km
SAA
70o
610 km
•
Low-earth elliptical orbit
• 350 – 610 km
• Quasi-polar (70o inclination)
• SAA crossed
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Outer
radiation belt
Download @orbit 3754 – 15/02/2007 07:35:00 MWT
NP
SP
S1
Inner
radiation belt
(SSA)
orbit 3751
orbit 3752
EQ
95 min
orbit 3753
EQ
S2
S3
Subcutoff particles
Mirko Boezio, IDDDM, Aspen, 2011/02/07
PAMELA milestones
Launch from Baikonur  June 15th 2006, 0800 UTC.
‘First light’  June 21st 2006, 0300 UTC.
• Detectors operated as expected after launch
• Different trigger and hardware configurations evaluated
 PAMELA in continuous
data-taking mode since
commissioning phase
ended on July 11th 2006
Trigger rate* ~25Hz
Fraction of live time* ~ 75%
Event size (compressed mode) ~5kB
25 Hz x 5 kB/ev  ~ 10 GB/day
(*outside radiation belts)
Main antenna in NTsOMZ
Till ~now:
~1400 days of data taking
~20 TByte of raw data downlinked
>2x109 triggers recorded and analyzed
Scientific goals
• Search for dark matter annihilation
• Search for antihelium (primordial antimatter)
• Search for new Matter in the Universe
(Strangelets?)
• Study of cosmic-ray propagation (light nuclei
and isotopes)
• Study of electron spectrum (local sources?)
• Study solar physics and solar modulation
• Study terrestrial magnetosphere
Dark Matter
Indirect Detection
Mirko Boezio, IDDDM, Aspen, 2011/02/07
DM annihilations
DM particles are stable. They can annihilate in
pairs.
Primary annihilation
channels
Decay
Final states
σa= <σv>
Particle ID with PAMELA
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Flight data:
0.171 GV positron
Flight data:
0.169 GV electron
Flight data: 0.763 GeV/c
antiproton annihilation
Antiproton / Positron Identification
Time-of-flight:
trigger, albedo
rejection, mass
determination
(up to 1 GeV)
Bending in
spectrometer:
sign of charge
Ionisation energy
loss (dE/dx):
magnitude of
charge
Interaction
pattern in
calorimeter:
electron-like or
proton-like,
electron energy
Antiproton
(NB: e-/p ~ 102)
Positron
(NB: p/e+ ~103-4)
Flight data: 14.7 GV
Interacting nucleus
(Z = 8)
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)
PRL 102, 051101 (2009) and PRL. 105, 121101 (2010)
Antiproton Flux
(0.06 GeV - 180 GeV)
Donato et al. (ApJ 563 (2001) 172)
Systematics
errors included
Ptuskin et al.
(ApJ 642
(2006) 902)
PRL. 105, 121101 (2010)
PAMELA trapped antiprotons
Antiprotons inside SAA
Galactic Antiprotons
Antiprotons below cutoff at equator
Galactic antiprotons
Mirko Boezio, IDDDM, Aspen, 2011/02/07
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
Uncertainties on:
• Secondary
production (primary
fluxes, cross section)
• Propagation models
• Electron spectrum
But antiprotons
in CRs are in
agreement with
secondary
production
A Challenging Puzzle for CR Physics
P.Blasi, PRL 103 (2009)
051104; arXiv:0903.2794
Positrons (and electrons)
produced as secondaries
in the sources (e.g. SNR)
where CRs are
accelerated.
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 CR Physics
G. Kane, R. Lu,
and S. Watson,
Phys.Lett.B681,
151 (2009);
arXiv:0906.4765
v3
T. Delahaye et al., A&A 501, 821(2009); arXiv: 0809.5268v3
Cosmic Ray Spectra
Cosmic-Ray Acceleration and
Propagation in the Galaxy
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Diffusion Halo Model
Mirko Boezio, IDDDM, Aspen, 2011/02/07
PAMELA
Proton and Helium Nuclei Spectra
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Proton and Helium Nuclei Spectra
GALPROP
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Proton and Helium Nuclei Spectra
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Boron and Carbon nuclei Spectra
Carbon
Boron
Mirko Boezio, IDDDM, Aspen, 2011/02/07
H isotopes separation
0.9 GV < R < 1 GV
p
d
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Positrons detection
Where do positrons come from?
Mostly locally within 1 Kpc, due to the energy losses by
Synchrotron Radiation and Inverse Compton
Typical lifetime
PAMELA electron (e-) spectrum
e-
e+ + e-
Mirko Boezio, IDDDM, Aspen, 2011/02/07
PAMELA electron (e-) spectrum
Tracker based
Calorimeter based
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Theoretical uncertainties on “standard”
positron fraction
γ = 3.54
γ = 3.34
Flux=A • E-
T. Delahaye et al., arXiv: 0809.5268v3
PAMELA electron (e-) spectrum
Flux=A • E-
 = 3.18 ±0.05
prediction
from
e- flux
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Fit of electron spectrum
Independently to the fit of the electron spectra, we also perform a χ2
comparison between the expected positron fraction from
GALPROP simulation and PAMELA measurement of the positron
fraction.
Preliminary
electron spectrum
Confidence level, in parameter
space (2;ϕ0) obtained from a fit
of the electron spectra (red) and
of the positron fraction (green).
Cruces
show
the
best-fit
combination.
positron
fraction
Interestingly, the best fit value
for the two independent fit are
very similar.
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Solar Modulation
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Positron to Electron Fraction
Solar Modulation?
Secondary production
Moskalenko & Strong 98
Adriani et al, Astropart. Phys. 34 (2010) 1
arXiv:1001.3522 [astro-ph.HE]
Solar Modulation of Galactic Cosmic Rays
Hermanus NM (4.6 GV) South Africa
A<0
A<0
A>0
A>0
A<0
Percentage (100% in May 1965)
100
95
90
85
22-year cycle
77.5
80
1960
1965
1970
1975
1980
1985
1990
Time (Years)
Courtesy of M. Potgieter
1995
2000
2005
2010
PAMELA
Time Dependence of PAMELA Proton Flux
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Time Dependence of PAMELA Proton Flux
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Time Dependence of PAMELA Electron (e-)
Flux
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Time Dependence of PAMELA Electron (e-)
Flux
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Time Dependence
Flux variation as a function of time for rigidities
between 0.72 and 1.04 GV
Time Dependence
Increase of the flux measured by PAMELA from
July 2006 to December 2008
PAMELA Electron to Positron Ratio and Theoretical Models
Preliminary
U.W. Langner, M.S.
Potgieter, Advances in
Space Research 34
(2004).
Summary PAMELA Results
PAMELA Data
Mirko Boezio, IDDDM, Aspen, 2011/02/07
Summary
• PAMELA has been in orbit and studying cosmic rays for ~4.5 years.
>109 triggers registered and >19 TB of data has been down-linked.
• Antiproton-to-proton flux ratio and antiproton energy spectrum (~100
MeV - ~200 GeV) show no significant deviations from secondary
production expectations.
• High energy positron fraction (>10 GeV) increases significantly (and
unexpectedly!) with energy. Primary source?
•The proton and helium nuclei spectra have been measured up to 1.2
TV. The observations challenge the current paradigm of cosmic ray
acceleration and propagation.
• The e- spectrum up to 600 GeV shows spectral features that may point
to additional components.
• Analysis ongoing to finalize the antiparticle measurements (positron
flux, positron fraction), continuous study of solar modulation effects at
low energy.
• Waiting for AMS to compare contemporary measurements.
Mirko Boezio, IDDDM, Aspen, 2011/02/07
AMS-02 on ISS
In Orbit April 2011
TRD
Mexico
Florida
A&M
MIT
Yale
Johns Hopkins
Mary land
Ciemat-Madrid
LIP-Lisbon
ETH-Zurich
Genev a Univ.
Helsinki
Turku
Kurchatov I nst.
Inst. of Theor. & Experim ental Phy sic
s
Moscow State Univ ercity
Achen I & II I
Karlsruhe
Munich
Bucharest
Bologna
Milano
Perugia
Pisa
Roma
Siena
IEE, IHEP
Jiao Tong Univ ersity
Sout heast Univ ersity
Korea
IHEP
Taiwan
CSIST
NCU
Academ ia Sinica
NSPO
Vacuum
Case
Tracker
RICH
He Vessel
Annecy
Grenoble
Mont pellier
Aarhus
MAGNET
ESA
NIKHEF
NLR, Amsterdam
The Completed AMS Detector on ISS
Transition Radiation
Detector (TRD)
Time of Flight
Detector (TOF)
Magnet
Silicon Tracker
Ring Image Cerenkov
Counter (RICH)
Electromagnetic
Calorimeter (ECAL)
Size: 3m x 3m x 3m
Weight: 7 tons
AMS-02 new configuration
AMS S.C. Magnet:
MDR 2.18 TV
AMS Perm. Magnet:
MDR 2.14 TV
AMS Capability Space Part 2006
Mirko Boezio, IDDDM, Aspen, 2011/02/07