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Antimatter and Dark Matter Searches in Space: Antimatter and Dark Matter Searches in Space:
the PAMELA Space Missionthe PAMELA Space Mission
Piergiorgio Picozza INFN and University of Rome Tor Vergata
XIII Workshop on “Neutrino Telescopes”
VeniceMarch 10-13, 2009
PAMELAPAMELAPPayload for ayload for AAntimatter ntimatter MMatter atter EExploration xploration
and and LLight Nucleiight Nuclei AAstrophysicsstrophysics
PAMELA CollaborationPAMELA Collaboration
Moscow St. Petersburg
Russia:
Sweden:KTH, Stockholm
Germany:Siegen
Italy:Bari Florence Frascati TriesteNaples Rome CNR, Florence
PAMELA InstrumentPAMELA Instrument
GF ~21.5 cmGF ~21.5 cm2srsr Mass: 470 kg Mass: 470 kg
Size: 130x70x70 cmSize: 130x70x70 cm3
Design PerformanceDesign PerformanceEnergy range
Antiprotons 80 MeV - 150 GeV
Positrons 50 MeV – 300 GeV
Electrons up to 500 GeV
Protons up to 700 GeV
Electrons+positrons up to 2 TeV (from calorimeter)
Light Nuclei (He/Be/C) up to 200 GeV/n AntiNuclei search sensitivity of 3x10-8 in
He/He
Simultaneous measurement of many cosmic-ray species New energy range Unprecedented statistics
Resurs-DK1 satelliteResurs-DK1 satellite
Mass: 6.7 tonnesHeight: 7.4 mSolar array area: 36 m2
Main task: multi-spectral remote sensing of earth’s surface Built by TsSKB Progress in Samara, Russia
Lifetime >3 years (assisted) Data transmitted to ground via high-speed radio downlink
PAMELA mounted inside a pressurized container
PAMELAPAMELA
LaunchLaunch15/06/0615/06/06
16 Gigabytes trasmitted 16 Gigabytes trasmitted daily to Grounddaily to Ground
NTsOMZ MoscowNTsOMZ Moscow
OrbitOrbit Characteristics Characteristics
km
km
SAA
• Low-earth elliptical orbit
• 350 – 610 km
• Quasi-polar (70o inclination)
• SAA crossed
Download @orbit 3754 – 15/02/2007 07:35:00 MWT
S1 S2 S3
Inner radiation belt
(SSA)
orbit 3752 orbit 3753orbit 3751
NP SP
EQ EQ
Outer radiation belt
95 min
PAMELA OrbitPAMELA Orbit
The Physics of PAMELAThe Physics of PAMELA
Study of solar physics and solar modulation
Study of terrestrial magnetosphere
Study of high energy electron spectrum (local sources?)
Search for dark matter annihilation
Search for antihelium (primordial antimatter)
Search for new Matter in the Universe (Strangelets?)
Study of cosmic-ray propagation
(GLAST-FERMIAMS-02)
Signal (supersymmetry)…
… and background
Another possible scenario: Another possible scenario: KK Dark MatterKK Dark Matter
Lightest Kaluza-Klein Particle (LKP): B(1)
Bosonic Dark Matter:fermionic final states no longer helicity suppressed.e+e- final states directly produced.
As in the neutralino case there are 1-loopprocesses that produces monoenergeticγ γ in the final state.
PAMELA StatusPAMELA Status
• Today 1003 days in flight Today 1003 days in flight • data taking ~73% live-timedata taking ~73% live-time
• ~13 TBytes of raw data downlinked~13 TBytes of raw data downlinked
• >10>1099 triggers recorded and under triggers recorded and under analysisanalysis
AntiprotonsAntiprotons
Flight data: 84 GeV/c interacting antiproton
PAMELA antiproton PAMELA antiproton discriminationdiscrimination
Proton Spillover
PositronsPositrons
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
Time-of-flight: trigger, albedo rejection, mass determination (up to 1 GeV)
PositronProton
Proton / positron discrimination Proton / positron discrimination
p (non-int)
ee--
ee++
p (non-int)
Fraction of energy released along the calorimeter track (left, hit, right)
p (int)
p (int)
Rigidity: 20-30 GV
Positron selection with Positron selection with calorimetercalorimeter
LEFT HIT RIGHT
strips
plan
es
0.6 RM
Positron selection with calorimeterPositron selection with calorimeter
ee--
Fraction of charge released along the calorimeter track (left, hit, right)
ppee++
+ •Energy-momentum match•Starting point of shower
Rigidity: 20-30 GV
Positron selection with Positron selection with calorimetercalorimeter
pp
ee--
ee++
pp
Flight data:rigidity: 20-30 GV
Fraction of charge released along the calorimeter track (left, hit, right)
Test beam dataMomentum: 50GeV/c
ee--ee--
ee++
•Energy-momentum match•Starting point of shower
(~R
M)
+-
Selections on total detected energy, starting point of shower
e- e+
(p)- p
Flight data: 51 GeV/cpositron
Positron selection with calorimeterPositron selection with calorimeter
ee--
Fraction of charge released along the calorimeter track (left, hit, right)
pp
ee++
+ • Energy-momentum match• Starting point of shower • Longitudinal profile
Rigidity: 20-30 GV
Positron selectionPositron selection
ee--
pp
ee--
ee++
pp
Neutrons detected by ND
Rigidity: 20-30 GVFraction of charge released along the calorimeter track (left, hit, right)
ee++
•Energy-momentum match•Starting point of shower
The “pre-sampler” The “pre-sampler” methodmethod
2 W planes: ≈1.5 X0
20 W planes: ≈15 X0
CALORIMETER: 22 W planes: 16.3 X0
The “pre-sampler” The “pre-sampler” methodmethod
POSITRON SELECTION
PROTON SELECTION
2 W planes: ≈1.5 X0
20 W planes: ≈15 X0
20 W planes: ≈15 X0
2 W planes: ≈1.5 X0
ee++ background estimation background estimation from datafrom data
+ • Energy-momentum match• Starting point of shower
e-
‘presampler’ p
Rigidity: 20-28 GV
e+
p
ee++ background estimation background estimation from datafrom data
+ • Energy-momentum match• Starting point of shower
e-
‘presampler’ p
Rigidity: 28-42 GV
e+
p
ee++ background estimation background estimation from datafrom data
+ • Energy-momentum match• Starting point of shower
e-
‘presampler’ p
Rigidity: 6.1-7.4 GV
e+
p
RESULTSRESULTS
Antiproton to proton ratioAntiproton to proton ratio PRL 102, 051101 (2009)PRL 102, 051101 (2009)
Seconday Production Models
Antiproton to proton ratioAntiproton to proton ratioPRL 102, 051101 (2009)PRL 102, 051101 (2009)
Antiproton FluxAntiproton FluxPrelim
inary
statistical errors onlyenergy in the spectrometer
Mirko Boezio, SLAC Seminar, 2009/01/12
Antiproton FluxAntiproton Flux
Preliminary
statistical errors onlyenergy in the spectrometer
Secondary production:F. Donato et al., 536 (2001) 172
Secondary production: V. S. Ptuskin et al, ApJ 642 (2006) 902
Prelim
inar
y
Positrons to all electrons ratioPositrons to all electrons ratio
Secondary production Moskalenko & Strong 98
Positron to Electron RatioPositron to Electron Ratioastro-ph 0810.4995astro-ph 0810.4995
InterpretationInterpretation
• 0808.3725 DM
• 0808.3867 DM• 0809.2409 DM• 0810.2784
Pulsar• 0810.4846 DM /
pulsar• 0810.5292 DM• 0810.5344 DM• 0810.5167 DM• 0810.5304 DM• 0810.5397 DM• 0810.5557 DM• 0810.4147 DM• 0811.0250 DM• 0811.0477 DM
During first week after PAMELA During first week after PAMELA results posted on arXivresults posted on arXiv
)
Secondary production Moskalenko & Strong 98
Pulsar ComponentAtoyan et al. 95
Pulsar ComponentZhang & Cheng 01
Pulsar ComponentYüksel et al. 08
KKDM (mass 300 GeV)Hooper & Profumo 07
PAMELA Positron FractionPAMELA Positron Fraction
Example: eExample: e++ & p DM & p DM
P. Grajek et al., arXiv: 0812.4555v1
See Gordon Kane’s talk
Astrophysical Explanation: Pulsars Astrophysical Explanation: Pulsars
S. Profumo Astro-ph 0812-4457S. Profumo Astro-ph 0812-4457
Positrons production and acceleration mechanismPositrons production and acceleration mechanism
Young Pulsars (T ~ 10Young Pulsars (T ~ 105 5 years) and nearby (< 1kpc) years) and nearby (< 1kpc) Too young: contribution does not escape from the nebula Too young: contribution does not escape from the nebula
cloud of the pulsar.cloud of the pulsar. Too old: much diffusion, low energy, too low flux.Too old: much diffusion, low energy, too low flux.
Geminga: 157 parsecs from Earth and 370,000 years oldGeminga: 157 parsecs from Earth and 370,000 years old B0656+14: 290 parsecs from Earth and 110,000 years old.B0656+14: 290 parsecs from Earth and 110,000 years old.
Diffuse mature pulsars?Diffuse mature pulsars?
Mirko Boezio, LHC & DM Workshop, 2009/01/06
Example: pulsarsExample: pulsars
H. Yüksak et al., arXiv:0810.2784v2Contributions of e- & e+ from Geminga assuming different distance, age and energetic of the pulsar Hooper, Blasi, and Serpico
arXiv:0810.1527
Standard Positron FractionStandard Positron FractionTheoretical UncertaintiesTheoretical Uncertainties
T. Delahaye et al., arXiv: 0809.5268v3
γ = 3.54 γ = 3.34
Explanation with supernovae Explanation with supernovae remnantsremnants Shaviz and al. astro-ph.HE Shaviz and al. astro-ph.HE
0902.03760902.0376
Only secondaries?Only secondaries?P. Serpico hep-ph 0810.4846P. Serpico hep-ph 0810.4846
Anomalous primary electron source spectrumAnomalous primary electron source spectrum Spectral feature in the proton flux responsible for Spectral feature in the proton flux responsible for
secondariessecondaries Role of Helium nuclei in secondary productionRole of Helium nuclei in secondary production Difference between local and ISM spectrum of Difference between local and ISM spectrum of
protonsprotons Anomalous energy-dependent behaviour of the Anomalous energy-dependent behaviour of the
diffusion coefficientdiffusion coefficient Rising cross section at high energiesRising cross section at high energies High energy beaviour of the eHigh energy beaviour of the e++/e/e--
PAMELA Proton SpectrumPAMELA Proton Spectrum
Galactic H and He spectraGalactic H and He spectraPrelim
inar
y !!!
Secondary nucleiSecondary nuclei
• B nuclei of secondary origin: CNO + ISM B + …
• Local secondary/primary ratio sensitive to average amount of traversed matter (lesc) from the source to the solar system
Local secondary abundance: study of galactic CR propagation
(B/C used for tuning of propagation models)
SPescP
S σλNN
LBM
Preliminary
Antiproton to proton ratioAntiproton to proton ratioPRL 102, 051101 (2009)PRL 102, 051101 (2009)
Positron FractionPositron Fraction
Solar Modulation of galactic cosmic rays
BESS
Caprice / Mass /TS93AMS-01
Pamela• Study of charge sign dependent effects
Asaoka Y. et al. 2002, Phys. Rev. Lett. 88, 051101),
Bieber, J.W., et al. Physi-cal Review Letters, 84, 674, 1999.
J. Clem et al. 30th ICRC 2007 U.W. Langner, M.S. Potgieter,
Advances in Space Research 34 (2004)
Solar modulationInterstellar spectrum
July 2006August 2007 February 2008
Decre
asin
g
sola
r activ
ity
Incre
asin
g
GC
R fl
ux
sun-spot number
Ground neutron monitor PAMELA
(statistical errors only)
A > 0
Positive particles
A < 0
¯
+
¯
+
Pamela
2006
(Preliminary!)
Charge dependent solar modulation
Thanks!Thanks!
PAMELA Physics WorkshopPAMELA Physics WorkshopMay 11-12, 2009May 11-12, 2009
ROMAROMA
http:// pamela.roma2.infn.ithttp:// pamela.roma2.infn.it /workshop09/workshop09
A > 0 Positive particles A < 0
p, e+
p, e--
Secondary production Bergström et al. ApJ 526 (1999) 215
Secondary production (upper and lower limits)Simon et al. ApJ 499 (1998) 250.
from χχ annihilation
P
Proton fluxes at TOAProton fluxes at TOAAnnual Variation of P spectrum
Kinetic Energy (GeV)
Comparison of p/p ratio with model
Time variation of p/p ratio at solar maximum
Observed data by BESS
Charge dependent model
prediction(Bieber et al.)
Charge dependent solar modulation model well follows
the suddenly increase of p/p ratio observed by BESS
at the solar polarity reversal between 1999 and 2000
Solar Physics with PAMELASolar Physics with PAMELA
December 2006 Solar particle December 2006 Solar particle eventsevents
Dec 13th largest CME since 2003, anomalous at sol min
December 13th 2006 eventDecember 13th 2006 event
Preliminary!
Preliminary!
December 13th 2006 He December 13th 2006 He differential spectrumdifferential spectrum
December 14th 2006 event
Preliminary!
Solar Quiet spectrum
Low energy tail of Dec 13th event
Below galactic spectrum: Start of Forbush decrease
Magnetic Field
Neutron Monitor
X-ray
P,e-
Decrease of primary spectrum
Arrival of magnetic cloud from CME of Dec 13th
Shock 1774km/s (gopalswamy, 2007)
Decrease of Neutron Monitor Flux
Magnetic Field
Neutron Monitor
X-ray
P,e-
Arrival of event of Dec 14th
End of event of Dec 14th
Radiation BeltsRadiation Belts
South Atlantic AnomalySouth Atlantic Anomaly
Secondary production from CR Secondary production from CR interaction with atmosphereinteraction with atmosphere
SAA
SAA morphology
Lati
tud
eA
ltit
ude Altitude
Longitude
Neutron rate(background)
South-Atlantic Anomaly (SAA)South-Atlantic Anomaly (SAA)
•Grigorov, Sov. Phys. Dokl. 22, 305 1977•NINA ApJ Supp.132 365, 2001•AMS Phys. Lett. B 472 2000.215,
Phys. Lett. B 484 2000.10–22•Lipari, Astrop. Ph. 14, 171, 2000•Huang et al, Pys Rev. D 68, 053008 2003•Sanuki et al, Phys Rev D75 043005 2007•Honda et al, Phys Rev D75 043006 2007
Atmospheric neutrino contributionAstronaut dose on board International Space StationIndirect measurement of cross section in the atmosphere nell’atmosfera Agile e Glast background estimation
--- M. Honda, 2008
Proton flux at various cutoffs
Proton spectrum in SAA, polar and equatorial regionsProton spectrum in SAA, polar and equatorial regions
Other ObjectivesOther Objectives
High Energy electronsHigh Energy electrons The study of primary electrons is especially The study of primary electrons is especially
important because they give information on the important because they give information on the nearest sources of cosmic rays nearest sources of cosmic rays
Electrons with energy above 100 MeV rapidly Electrons with energy above 100 MeV rapidly loss their energy due to synchrotron radiation loss their energy due to synchrotron radiation and inverse Compton processes and inverse Compton processes
The discovery of primary electrons with energy The discovery of primary electrons with energy above 10above 1012 12 eV will evidence the existence of eV will evidence the existence of cosmic ray sources in the nearby interstellar cosmic ray sources in the nearby interstellar space (rspace (r300 pc) 300 pc)
CALO SELF TRIGGER EVENT: 167*103 MIP RELEASED279 MIP in S4 26 Neutrons in ND
An example is the search for “strangelets”.
There are six types of Quarks found in accelerators.All matter on Earth is made out of only two types of quarks. “Strangelets” are new types of matter composed of three types of quarks which should exist in the cosmos.
i. A stable, single “super nucleon” with three types of quarks
ii. “Neutron” stars may be one big strangelet
Carbon Nucleus Strangelet
uuddss
ssdd
ddss
ssuudd
uudduuuudddd
ssuussuuuudd
dd dd dddd dd
uuuu
uuuu
ssuu ss
ssss
dddd uu
uuuudd
uuuudd
dddd uu
uuuudd
dddd uu dddd uu dddd uudddd uu
uuuudd uuuudd
uuuudd
p n
AMS courtesy
Search for New Matter in the Universe:Search for New Matter in the Universe:
Positron selection with calorimeter
Test Beam Data