Results of the

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Results of the PAMELA Space Mission
Piero Spillantini University and INFN, Florence,
Italy (on behalf of Pamela collaboration)
Benasque, 12 February 2009
XXXVII International Meeting on Fundamental
Physics,
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Summary
COSMIC RAYS from far away, .... at high speed...
ANTIMATTER measuring antiparticles and hunting
for antinuclei
WIZARD on Astromag ? ballooning ? ? Russian
Italian Mission program ? PAMELA
PAMELA the choices the detectors the
results the future and ... the competition
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• 19-th century
• discovery of electricity
• acceleration of the electrons
• production of X-rays

• End of 19-th century
• discovery of natural radioactivity

• Beginning of 20-th century
• - access to high atmosphere
• discovery of Cosmic Rays

Second half of 20-th centuries - accelerators
reach CR energies
Years 60s of 20-th century - access to space
Years 70s of 20-th century - permanent presence
in space
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Permanent presence in Space
Hubble Space Telescope
International Space Station FREEDOM
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Space Station FREEDOM (1983)
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Great Observ. (scritte)
1990
2002
1999
1991
AXAF (CXOXMM)
CGRO
HST
SIRTF
Heavy Nuclei Collector (HNC) and
Particle-Antiparticle Superconducting Magnet
(ASTROMAG) facilities on board of the Freedom SS
Advanced Composition Explorer (ACE)
1999
Very Long Base Interferometer (VLBI)
CANCELLED
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Cosmic Rays from Space
Direct detection Balloons Satellites
Indirect detection (EAS) arrays florescence
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NASA Part. Astroph. Program - 3
Cut-off momentum
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• 1964 CP violation in nature
• 1967 Sakharovs conditions to
• achieve baryon asymmetry
• in the Early Universe
• Baryon decay allowed
• CP violation allowed
• A period out of equilibrium

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(indirect observation)
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(direct observation)
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--- Experimental summary (lt2008)

• ? The MeV bump disappeared (in 1995)
• The p- and e measured fluxes can be justified
• by production on ISM
• ? The search for N- gave only upper limits

--- AT PRESENT (lt2008)
NO EXPERIMENTAL INDICATIONS FOR COSMOLOGICAL
ANTIMATTER
--- NEEDED
HIGHER ENERGIES (for p-, e, N-) CLEANER
ENVIRONMENT (p-, e in space)
--- WHAT FOR THE NEXT FUTURE??
BESS by LDB flights (p- exotic, N-) going on
PAMELA on satellite (p-, e, N-) flown middle
2006 AMS-02 on ISS (N-, p-, e) to be flown in
2010
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AntiM. ideal scheme
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Open balloons
Air
Air
Class A balloons 2.8 Mm3 _at_ 5 g/cm2 Lifting power
11t Balloon 5 t services 3 t payload 3 t _at_
38?40km (5g/cm2 residual atm.)
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Atmosph. T vs Altitude
Atmospheric temperature versus Altitude
4-5 g/cm2 residual atmosphere
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open balloons Volume _at_ 5g/cm2 gt 1 Mm3 Very
thin material (20mm), does not support
pressure differences Maximum load ? 3 t Line of
sight (LOS) ? 800 km Tipical duration of the
flight 20 hours Maximum altitude ? 40 km
(45g/cm2)
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New Generation of AntiM
It is necessary a
New Generation of Antimatter Researches in
Cosmic Rays
BESS PAMELA AMS-2
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PAMELA
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Experiments for ASTROMAG
Experiments approved for the first phase of the
ASTROMAG facility
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from WIZARD to PAMELA
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WiZard ? Russian Italian Missions (RIM)
?Antimatter search ?
ALTEA SILEYE-4
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PAMELA Background
PAMELA Background
Balloon exps MASS (89) MASS1(91) TS93
(93) CAPRICE (94) CAPRICE (97) CAPRICE (98)
Life Science on MIR and ISS SIL-EYE-1
(95)MIR SIL-EYE-2 (97) MIR SIL-EYE-3 (02)
ISS ALTEA (05) ISS
Low En. C.R. in orbit NINA (98) NINA2 (00)
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O. Adriani1, M. Ambriola2, G.Barbarino16, L.M.
Barbier4, G. Bazilevskaja6, R. Bellotti2, D.
Bergstrom7, M. Boezio3, E. Bogomolov10, V.
Bonvicini3, M. Boscherini1, F. Cafagna2, P.
Carlson7, M. Casolino8, G. Castellini15, E.R.
Christian4, M. Circella2, R. DAlessandro1, C.N.
De Marzo2, M.P. De Pascale9, G. Furano9, A.M.
Galper11, A. Grigorjeva6, P. Hansen7, S.V.
Koldashov11, M.G. Korotkov11, J.F. Krizmanic4, S.
Krutkov10, A. Iannucci9,B. Marangelli2, A.
Menicucci9, W. Menn12, V.V. Mikhailov11, M.
Minori9, N. Mirizzi2, J.W. Mitchell4, E.
Mocchiutti7, A.A. Moiseev11, A. Morselli9, R.
Mukhametshin6, J.F. Ormes4, G.Osteria16, P.
Papini1, G. Percossi9, P. Picozza9, M. Ricci5, P.
Schiavon3, M. Simon12, R. Sparvoli9, P.
Spillantini1, P. Spinelli2, S.A. Stephens13, S.J.
Stochaj14, Y. Stozhkov6, R.E. Streitmatter4, F.
Taccetti15, A. Vacchi3, E. Vannuccini1, G.
Vasiljev10, S.A. Voronov11, N. Weber7, R.
Wischenwksi9,Y. Yurkin11, N. Zampa3, GL. Zampa3
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Max antip E (40) (60) (80) (150)
(?RR)
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PAMELA apparato nudo
MASS 480 kg POWER 345 W GF 20.5 cm2sr MDR
740 GV/c
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PAMELA (RIM 02)
PAMELA
GF 20.5 cm2 sr Mass
480 Kg Dimensions 120 x 40x45
cm3 Power Budget 345W
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PAMELA milestones

• Launch from Baikonur June 15th 2006, 0800 UTC.
• Power On June 21st 2006, 0300 UTC.
  
• Detectors operated as expected after launch
• PAMELA in continuous data-taking mode since
  commissioning phase ended on July 11th 2006
• As of now
• 600 days of data taking (73 live-time)
• 10 TByte of raw data downlinked
• gt109 triggers recorded and under analysis

Mirko Boezio, INFN Trieste - ICHEP08, 2008/08/01
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32.3 GV positron
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36 GeV/c interacting proton
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Antiprotons
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Search of structures in antiproton spectrum
Primary production from ?? annihilation (m(?)
1 TeV) ( astro-ph 9904086)
Secondary production (upper and lower
limits) Simon et al.
Secondary production (CAPRICE94-based) Bergström
et al.
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Antiproton identification
Preliminary!!
-1 ? Z ? 1
p ( e)
p
e- ( p-bar)
proton-consistency cuts (dE/dx vs R and b vs R)
spillover p
electron-rejection cuts based on
calorimeter-pattern topology
p-bar
( For Z1, deflection1/p )
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Proton-spillover background
MDR 1/sh (evaluated event-by-event by the
fitting routine)
p
p-bar
spillover p

• MDR depends on
• number and distribution of fitted points along
  the trajectory
• spatial resolution of the single position
  measurements
• magnetic field intensity along the trajectory

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Antiproton-to-proton ratio
preliminary
astro-ph 0810.4994 ? PRL 102 (2009)
(Petter Hofverbergs PhD Thesis)
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Antiproton-to-proton ratioSecondary Production
Models
CR ISM ? p-bar

• (Moskalenko et al. 2006) GALPROP code
• Plain diffusion model
• Solar modulation drift model ( Alt0, a15o )

• (Donato et al. 2001)
• Diffusion model with convection and
  reacceleration
• Solar modulation spherical model (f500MV )
• ? Uncertainty band related to propagation
  parameters (10 _at_10GeV)
• ? Additional uncertainty of 25 due to
  production cs should be considered !!

• (Ptuskin et al. 2006) GALPROP code
• Plain diffusion model
• Solar modulation spherical model ( f550MV )

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Antiproton-to-proton ratioSecondary Production
Models
CR ISM ? p-bar
No evidence for any antiproton excess
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Positrons
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Pamela e results

• (Moskalenko Strong 1998)
• GALPROP code
• Plain diffusion model
• Interstellar spectra

• Till August 30th about 20000 positrons from 200
  MeV up to 200 GeV have been analyzed
• More than 15000 positrons over 1 GeV
• Other eight months data to be analyzed

arXiv0810.4995v1 astro-ph 28 Oct 2008
Accepted on Nature
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Pamela e results
arXiv0810.4995v1 astro-ph 28 Oct 2008
Accepted on Nature
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Positrons to Electrons ratio
Preliminary
___ Moskalenko Strong 1998
statistical errors only
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Positron fractionSecondary Production Models
CR ISM ? p ? m ? e CR ISM ?
p0 ? gg ? e

• (Moskalenko Strong 1998)
• GALPROP code
• Plain diffusion model
• Interstellar spectra

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Positron fractionSecondary Production Models
CR ISM ? p ? m ? e CR ISM ?
p0 ? gg ? e

• (Moskalenko Strong 1998)
• GALPROP code
• Plain diffusion model
• Interstellar spectra

soft hard

• (Delahaye et al. 2008)
• Plain diffusion model
• Solar modulation spherical model (f600MV)
• Uncertainty band related to e- spectral index
• (ge 3.440.1 (3s) ? MINMAX)
• Additional uncertainty due to propagation
  parameters should be considered

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Positron fractionSecondary Production Models
soft hard
Quite robust evidence for a positron excess
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Primary positron sources

• Dark Matter
• e yield depend on the dominant decay channel
• LSPs seem disfavored due to suppression of ee-
  final states
• low yield (relative to p-bar)
• soft spectrum from cascade decays
• LKPs seem favored because can annihilate directly
  in ee-
• high yield (relative to p-bar)
• hard spectrum with pronounced cutoff _at_ MLKP
  (gt300 GeV)

LKP -- M 300 GeV (Hooper Profumo 2007)
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Primary positron sources

• Astrophysical processes
• Local pulsars are well-known sites of ee- pair
  production
• ? they can individually and/or coherently
  contribute to the ee- galactic flux and explain
  the PAMELA e excess (both spectral feature and
  intensity)
• No fine tuning required
• if one or few nearby pulsars dominate,
  anisotropy could be detected in the angular
  distribution
• possibility to discriminate between pulsar and
  DM origin of e excess

All pulsars (rate 3.3 / 100 years) (Hooper,
Blasi, Serpico 2008)
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(Chang et al 2008)
PAMELA positron excess might be connected with
ATIC electronpositron structures
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Primary positron sources

• PAMELA positron fraction alone insufficient to
  understand the origin of positron excess
• Additional experimental data will be provided by
  PAMELA
• e fraction _at_ higher energy (up to 300 GeV)
• individual e- e spectra
• anisotropy (maybe)
• high energy ee- spectrum (up to 2 TV)
• Complementary information from
• gamma rays
• neutrinos

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Cosmic-ray antimatter search
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Galactic cosmic-ray origin propagation
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PAMELA Galactic H and He spectra
Preliminary !!!
Very high statistics on a very wide energy range
- Precise measurement of spectral shape
- Possibility to study time variations and
transient phenomena
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Proton flux
Preliminary!!

• Local spectrum
• injection spectrum ? galactic propagation
• Local primary spectral shape
• study of particle acceleration mechanism

(statistical errors only)
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Secondary nuclei
Preliminary!!

• 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)

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PAMELA Proton Spectra
Preliminary
RED JULY 2006 BLUE AUGUST 2007
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Solar modulation
Preliminary!!
(statistical errors only)
July 2006 August 2007 February 2008
Decreasing solar activity
Increasing GCR flux
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Proton spectrum in SAA, polar and equatorial
regions
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Primary and secondary spectra Magnetic equator
Penumbra
P/(cm2 sr GeV s)
Secondary particles (reentrant albedo)
RED JULY 2006 BLUE AUGUST 2007
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Primary and secondary spectra Intermediate
latitudes
Penumbra
P/(cm2 sr GeV s)
Secondary particles (reentrant albedo)
RED JULY 2006 BLUE AUGUST 2007
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A look at Earththe geomagnetic field
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Spectrum of proton radiation belt inside the SAA
Preliminary!!
(statistical errors only)
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Solar Physics

• Solar CR prpagation
• Solar Energetic Particle events (SEPs)

• Solar modulation effects
• High energy component of Solar
• Proton Events (from 80 Mev to 10 GeV)

80 MeV
Proton detection threshold
-High energy component of e- and e in Solar
Events (from 50 MeV)
50 MeV
Electron detection threshold
Nuclear composition of Gradual and
Impulsive Events
He isotopic composition
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December 13th 2006 event
Preliminary!
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• PAMELA is measuring the Antiprotons and Positrons
  to the high energies (gt 150GeV) with an
  unprecedented statistical precision
• PAMELA is setting a new lower limit for finding
  Antihelium
• PAMELA is looking for Dark Matter candidates
• PAMELA is providing measurements on elemental
  spectra and low mass isotopes with an
  unprecedented statistical precision and is
  helping to improve the understanding of particle
  propagation in the interstellar medium
• PAMELA is able to measure the high energy tail of
  solar particles.

• For the future (other gt2 years data)
• Fluxes of e (300GeV), e- (500 GeV, 2TeV), p
  (700GeV)
• Fluxes of light nuclei (up to O) and light
  isotopes
• Monitoring of solar activity by SEP measurement
• Anomalous CR (??), Jovian e- (?)

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BESS
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BESS

• Balloon-borne
• Experiment with a
• Superconducting
• Spectrometer
• Search for
• Primordial Antiparticle
• antiproton Novel primary origins (PBH,DM)
• antihelium Asymmetry of matter/antimatter
• Precise Measurement of Cosmic-ray flux
• highly precise measurement at lt 1 TeV

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BESS Polar LDB
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Ballooning in Antarctica
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ULDB - Balloon Material
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PAMELA
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AMS-2
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Cosmic-ray antimatter search
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AMS
Altezza 320-390 KmInclinazione 51.7
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AMS-02 on ISS In Orbit 2009
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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
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Pamela and AMS-02 Space Observatories at 1AU
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(further acceleration?)
SIRFT CGRO AXAF(CXO) HST
VLBI
Definition of Astrop.expts (con animazione)
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Thank you for your attention
Gracias por su atencion!