Direct measurements of cosmic rays in space ROBERTA SPARVOLI ROME “TOR VERGATA” UNIVERSITY AND INFN, ITALY Vulcano Workshop 2014 Vulcano Island (Italy), 23° May 2014

Galactic cosmic rays: open questions

Main physics research lines

Balloon experiments (CREAM, ATIC, BESS- Polar, TRACER, TIGER, …) Satellite experiments (PAMELA, FERMI, Gamma-400, …) ISS experiments (AMS, Calet, ISS-Cream, …) Existing platforms

Balloon experiments

Long Duration Balloons (LDB)

Science goals

Advanced Thin Ionization Calorimeter (ATIC)

ATIC instrument

TRACER detector

CREAM flights

CREAM instrument

GCR energy spectra

Proton and helium spectra

Boron to Carbon ratio

TIGER instrument

GCR source abundances

Cosmic ray electrons

Antiproton flux: BESS-Polar

Antiproton spectrum

Search for antihelium

Satellite experiments

PAMELA Payload for Matter/antimatter Exploration and Light- nuclei Astrophysics Direct detection of CRs in space Main focus on antiparticles (antiprotons and positrons) Launch from Baykonur PAMELA on board of Russian satellite Resurs DK1 Orbital parameters: - inclination ~70 o (  low energy) - altitude ~ km (elliptical) - active life >3 years (  high statistics)  Launched on 15th June 2006  PAMELA in continuous data-taking mode since then!

PAMELA published results Antiproton flux + antiproton/proton ratio (100 MeV-200 GeV) Positron flux + positron/electron ratio (100 MeV-200 GeV) Electron flux (1 – 500 GeV) Proton and helium flux (1 GeV – 1.2 TeV) B/C ratio (500 MeV – 100 GeV) H and He isotope flux AntiHe/He Proton flux vs. time – solar modulation Trapped antiproton flux SEP data

Antiproton flux Antiproton/proton ratio Positron Fraction Positron flux No evidence for antiproton increase Strong evidence for positron increase

Electron flux P and He flux B/C ratio Strong evidence for spectral break

All particles PAMELA results Results span 4 decades in energy and 13 in fluxes

FERMI OBSERVATORY

FERMI all Electron Spectrum A. Abdo et al., Phys.Rev.Lett. 102 (2009) M. Ackermann et al., Phys. Rev. D 82, (2010) Found an excess in the all-electron spectrum, but no ATIC feature

Fermi Positron Fraction Confirmation of PAMELA positron excess

PAMELA & Fermi electron (e - ) spectra Adriani et al., Phys. Rev. Lett. 106, (2011) Ackermann et al., Phys. Rev. Lett. 108, (2012)

ISS experiments

AMS ALPHA MAGNETIC SPECTROMETER  Search for primordial anti-matter  Indirect search of dark matter  High precision measurement of the energetic spectra and composition of CR from GeV to TeV AMS-01: 1998 (10 days) - PRECURSOR FLIGHT ON THE SHUTTLE AMS-02: Since May 19 th, 2011, safely on the ISS. Four days after the Endeavour launch, that took place on Monday May 16th, the experiment has been installed on the ISS and then activated. and then activated. COMPLETE CONFIGURATION FOR >10 YEARS LIFETIME ON THE ISS

The AMS-02 detector

Positron fraction M. Aguilar et al, PRL 110, 2013 Further confirmation of positron excess

AMS preliminary data (ICRC 2013) Good agreement with PAMELA data beyond solar modulation

Direct measurements: electron spectrum e + + e - e-e-

Direct measurements: Positron flux increasing !

AMS preliminary data (ICRC 2013)

Apparent conflict with PAMELA (and CREAM, ATIC) data. No hint for break in spectral shape.

Direct measurements: P and He: Some “tension”

Excellent agreement PAMELA-BESS Proton flux Proton flux x E^2.7

Direct  indirect measurements

Direct and indirect measurements are starting to meet at 10^14 eV. Direct measurements aim at reaching the “knee”. This would be very important to test and calibrate hadronic interaction models.

Future experiments

CALET CREST DAMPE GAMMA-400 GAPS The future

CALET: launch in

ISS-CREAM: launch in

DAMPE: launch in 2015 DAMPE: Dark Matter Particle Explorer. Project of Chinese Academy of Sciences, in collaboration with ItalY (INFN) and the University of Geneva for the construction of the tracker Si. Precursor of HERD.

Gamma-400: launch in 2018 Approved Russian Space Mission With international cooperation

CREST: Cosmic Ray Electron Synchrotron Telescope (E> 2 TeV) One flight completed (2011/2012  10 days): analysis in progress

The GAPS experiment A balloon-borne detector ready to flight in 2017/2018

Conclusions High energy line Some conflict in the current data: H and He spectra harden with energy (>230 GV) ? H and He spectra are different ? Hi-Z spectra do not show similar hardening Energy dependance of propagation still undecided Composition line Source matter must be a composition of old ISM with newly synthetized matherial, in percentage 80%-20% (sites of acceleration rich in massive stars?)

Antimatter line Positrons show enhancement in the E>10 GeV region (new e+ e- source. Correlated to previous?) All electron spectrum shows enhancement at high energy (hundreds GeV). Correlated to previous? No antiproton excess observed both at low and high energy (several DM models and exotics ruled out) No heavier anti-nucleus observed (very stringent limits) Conclusions The new instruments poised to come on line such as CALET, ISS-CREAM, DAMPE, Gamma-400 and GAPS, as well as space instruments continuing to operate and new balloon flights of existing instruments, promise a robust future for cosmic ray research.