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PAMELA Space Mission First Results in Cosmic Rays. Piergiorgio Picozza INFN & University of Rome “ Tor Vergata” , Italy Pamela Collaboration Rencontres de Blois 2008 Challenges in Particle Astrophysics Blois, May 22, 2008. PAMELA.
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PAMELA Space Mission First Results in Cosmic Rays Piergiorgio Picozza INFN & University of Rome “ Tor Vergata” , Italy Pamela Collaboration Rencontres de Blois 2008 Challenges in Particle Astrophysics Blois, May 22, 2008
PAMELA Payload for Antimatter Matter Exploration and Light NucleiAstrophysics
Italy: CNR, Florence Bari Florence Frascati Naples Rome Trieste Russia: Moscow St. Petersburg Germany: Sweden: Siegen KTH, Stockholm PAMELA Collaboration
Pamela as a Space Observatory at 1AU Search for dark matter annihilation Search for antihelium (primordial antimatter) Search for new Matter in the Universe (Strangelets?) Study of cosmic-ray propagation Study of solar physics and solar modulation Study of terrestrial magnetosphere Study of high energy electron spectrum (local sources?)
- p e+ p (He,...) e- Trigger, ToF, dE/dx + - Sign of charge, rigidity, dE/dx Electron energy, dE/dx, lepton-hadron separation GF ~21.5 cm2sr Mass: 470 kg Size: 130x70x70 cm3
Design performance • Energy range • Antiproton flux 80 MeV - 190 GeV • Positron flux 50 MeV – 270 GeV • Electron/positron flux up to 2 TeV (from calorimeter) • Electron flux up to 400 GeV • Proton flux up to 700 GeV • Light nuclei (up to Z=6) up to 200 GeV/n He/Be/C: • Antinuclei search Sensitivity of O(10-8) in He-bar/He • Unprecedented statistics and new energy rangefor cosmicray physics • Simultaneous measurements of many species
Resurs-DK1 satellite • 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 Mass: 6.7 tonnes Height: 7.4 m Solar array area: 36 m2
PAMELALaunch15/06/0616 Gigabytes trasmitted daily to GroundNTsOMZ Moscow
350 km SAA 70o 610 km Orbit Characteristics • Low-earth elliptical orbit • 350 – 610 km • Quasi-polar (70o inclination) • Lifetime >3 years (assisted)
Download @orbit 3754 – 15/02/2007 07:35:00 MWT 95 min orbit 3753 orbit 3751 orbit 3752 PAMELA Orbit Outer radiation belt NP SP EQ EQ S1 S2 S3 Inner radiation belt (SSA)
Flight data: 0.171 GV positron Flight data: 0.169 GV electron
Flight data: 0.632 GeV/c antiproton annihilation
Flight data: 84 GeV/c interacting antiproton
Flight data: 92 GeV/c positron
Flight data: 14.7 GV Interacting nucleus (Z = 8)
PAMELA Status • Till 2nd of March 2008 PAMELA has collected ~ 8.8TB of data, corresponding to ~ 109 triggers
4% 23% 73%
Signal (supersymmetry)… (GLAST AMS-02) … and background
Lightest Kaluza-Klein Particle (LKP): B(1) Another possible scenario: KK Dark Matter Bosonic Dark Matter: fermionic final states no longer helicity suppressed. e+e- final states directly produced. As in the neutralino case there are 1-loop processes that produces monoenergetic γ γ in the final state.
P Secondary production (upper and lower limits) Simon et al. ApJ 499 (1998) 250. Secondary production Bergström et al. ApJ 526 (1999) 215 from χχ annihilation (Primary production m(c) = 964 GeV) Ullio : astro-ph/9904086
Antiproton-Proton Ratio preliminary
Antiproton-Proton Ratio preliminary
Cirelli, Franceschini, Strumia arXiv:0802.3378v2 [hep-ph]
Potgieter at al. arXiv:0804.0220v1 [astro-ph]
Pamela Positrons • 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
Positron - Electron ratio Preliminary PAMELA
Positron - Electron ratio Preliminary
Positrons with HEAT & PAMELA Preliminary
Problems • Background calculation • Solar Modulation at low energies • Charge-sign dependence of solar modulation
Antiproton flux B/C Ratio AstrophysicB/C constraints Nuclear cross sections!! Secondaries / primaries i.e. Boron/ Carbon to constrain propagation parameters D. Maurin, F. Donato R. Taillet and P.Salati ApJ, 555, 585, 2001 [astro-ph/0101231] F. Donato et.al, ApJ, 563, 172, 2001 [astro-ph/0103150]
Preliminary Results B/C Preliminary
Flux (p/cm^2 sr s) Kinetic Energy (GeV) Proton flux July 2006
Galactic H and He spectra Preliminary !!!
Pamela AMS-01 Caprice / Mass /TS93 BESS Solar Modulation of galactic cosmic rays • Continuous monitoring of solar activity • 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
Antiproton-Proton Ratio preliminary
P/(cm^2 sr GeV s) Proton Spectra Preliminary !!! RED: JULY 2006 BLUE: AUGUST 2007
July 2006 497±2 January 2007 481±2 August 2007 441±2 F = Primary spectrum
BESS Coll. 30th ICRC 2007
Positron Fraction Preliminary Mirko Boezio, INFN Trieste - Fermilab, 2008/05/02
Pamela Pamela Clem at al. 30th ICRC 2007
Charge sign dependence of cosmic ray modulation. • Two systematic deviations from reflection symmetry of the interplanetary magnetic field: • 1) The Parker field has opposite magnetic polarity above and below the equator, but the spiral field lines themselves are mirror images of each other. This antisymmetry produces drift velocity fields that for positive particles converge on the heliospheric equator in the A+ state or diverge from it in A- state. Negatively charged particles behave in the opposite manner and the drift patterns interchange when the solar polarity diverge. • 2) Systematic ordering of turbulent helicity can cause diffusion coefficients to depend directly on charge sign and polarity state. Bieber, J.W., et al. Phys. Rev. Letters, 84, 674, 1999.