High energy cosmic rays

High energy cosmic rays

R O B E R TA S PA RV O L IR O M E “ T O R V E R G ATA ” U N I V E R S I T Y

A N D I N F N , I TA LY

Nijmegen 2012

SATELLITE AND ISS EXPERIMENTS

FUTURE ACTIVITIES

Lecture # 2 : outline

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Satellite flights

PAMELAPayload 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 ~70o ( low energy)- altitude ~ 360-600 km (elliptical) - active life >6 years ( high statistics)

Launched on 15th June 2006 PAMELA in continuous data-taking mode since then!

PAMELA detectorsMain requirements:

- high-sensitivity antiparticle identification

- precise momentum measurement

GF: 21.5 cm2 sr Mass: 470 kgSize: 130x70x70 cm3

Power Budget: 360W

Spectrometer microstrip silicon tracking system + permanent magnetIt provides:

- Magnetic rigidity R = pc/Ze- Charge sign- Charge value from dE/dx

Time-Of-Flightplastic scintillators + PMT:- Trigger- Albedo rejection;- Mass identification up to 1 GeV;- Charge identification from dE/dX.

Electromagnetic calorimeterW/Si sampling (16.3 X0, 0.6 λI) - Discrimination e+ / p, anti-p / e- (shower topology)- Direct E measurement for e-

Neutron detector36 He3 counters :- High-energy e/h discrimination

+ -


Flight data: 0.169 GV electron

Flight data: 0.171 GV positron

SECONDARY ORIGIN, COMING FROM INTERACTION OF PRIMARY CR WITH THE

INTERSTELLAR MEDIUM

Antiparticles

AntiprotonsAntiproton/proton identification:Negative/positive curvature in the spectrometer

p-bar/p separationRejection of EM-like interaction patterns in the calorimeter

p-bar/e- (and p/e+ ) separation

Main issue:Proton “spillover” background:

wrong assignment of charge-sign @ high energy due to finite spectrometer resolution

Strong tracking requirements•Spatial resolution < 4mm •R < MDR/10

Residual background subtraction •Evaluated with simulation (tuned with in-flight data)•~30% above 100GeV

Antiproton flux

• Largest energy range covered hiterto

• Overall agreement with pure secondary calculation

• Experimental uncertainty (statsys) smaller than spread in theoretical curves constraints on propagation parameters

(Ptuskin et al. 2006) GALPROP code • Plain diffusion model • Solar modulation: spherical model ( f=550MV )

(Donato et al. 2001)• Diffusion model with convection and reacceleration

• Uncertainties on propagation param . and c.s.

• Solar modulation: spherical model ( f=500MV )

Adriani et al. - PR

L 105 (2010) 121101

Antiproton-to-proton ratio

Adriani et al. - PRL 105 (2010) 121101

Overall agreement with pure secondary calculation

Very stringent constraintsto exotic production mechanisms!

New antiproton/proton ratio

Using all data till 2010 and multivariate classification algorithms 20-50% increase in respect to published analysis

Preliminary

New positron fraction data

Using all data till 2010 and multivariate classification algorithms about factor 2-3 increase in respect to published analysis

Preliminary

PositronsPositron/electron identification:Positive/negative curvature in the spectrometer

e-/e+ separationEM-like interaction pattern in the calorimeter

e+/p (and e-/p-bar) separation

Main issue:Interacting proton background:

fluctuations in hadronic shower development: p0 gg mimic pure e.m. showers

p/e+: ~103 @1GV ~104 @100GV

Robust e+ identification Shower topology + energy-rigidity match

Residual background evaluation Done with flight data No dependency on simulation

S1

S2

CALO

S4

CARD

CAS

CAT

TOFSPE

S3

ND


32.3 GV positron

Positron fraction

Low energy charge-dependent solar modulation

High energy (quite robust) evidence of positron excess above 10 GeV

Adriani et al. , Nature 458 (2009) 607 Adriani et al., AP 34 (2010) 1 (new results)

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

Positron fraction

Low energy charge-dependent solar modulation (see tomorrow)

High energy (quite robust) evidence of positron excess above 10 GeV

Adriani et al. , Nature 458 (2009) 607 Adriani et al., AP 34 (2010) 1 (new results)

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

New positron fraction data

Using all data till 2010 and multivariate classification algorithms about factor 2-3 increase in respect to published analysis

Preliminary


Positron Flux

Antiprotons Consistent with pure secondary production

Positrons Evidence for an excess

A challenging puzzle for CR physicists

Positron-excess interpretations

Dark matterboost factor required

lepton vs hadron yield must be consistent with p-bar observation

Astrophysical processes• known processes

• large uncertainties on environmental parameters

(Blasi 2009) e+ (and e-) produced as secondaries in the CR acceleration sites (e.g. SNR)

(Hooper, Blasi and Serpico, 2009) contribution from diffuse mature & nearby young pulsars.

(Cholis et al. 2009) Contribution from DM annihilation.


M. Cirelli et al., Nucl. Phys. B 813 (2009) 1; arXiv: 0809.2409v3Interpretation: DM

Which DM spectra can fit the data?DM with and dominant annihilation channel (possible candidate: Wino)

positrons antiprotons

Yes!

No!


Interpretation: DMWhich DM spectra can fit the data?

DM with and dominant annihilation channel (no “natural” SUSY candidate)

Yes!

Yes!

But B≈104

M. Cirelli et al., Nucl. Phys. B 813 (2009) 1; arXiv: 0809.2409v3

positrons antiprotons


Interpretation: DMDM with and dominant annihilation channel

positrons

Yes!

Yes!

Yes!

M. Cirelli et al., Nucl. Phys. B 813 (2009) 1; arXiv: 0809.2409v3

antiprotons


Interpretation: DM

I. Cholis et al. Phys. Rev. D 80 (2009) 123518; arXiv:0811.3641v1


Astrophysical Explanation: SNR

P.Blasi et al., PRL 103 (2009) 051104 arXiv:0903.2794

Positrons (and electrons) produced as secondaries in the sources (e.g. SNR) where CRs are accelerated.But also other secondaries are produced: significant increase expected in the p/p and B/C ratios.


Astrophysical Explanation: PulsarsAre there “standard” astrophysical explanations of the high energy positron data?

Young, nearby pulsars

Not a new idea: Boulares, ApJ 342 (1989), Atoyan et al (1995)

Geminga pulsar


Astrophysical Explanation:Pulsars

Mechanism: the spinning B of the pulsar strips e- that accelerated at the polar cap or at the outer gap emit γ that make production of e± that are trapped in the cloud, further accelerated and later released at τ ~ 105 years.

Young (T < 105 years) and nearby (< 1kpc) If not: too much diffusion, low energy, too low flux.

Geminga: 157 parsecs from Earth and 370,000 years oldB0656+14: 290 parsecs from Earth and 110,000 years

old.

Diffuse mature pulsars


Astrophysical Explanation: Pulsars

H. Yüksak et al., arXiv:0810.2784v2Contributions of e- & e+ from Geminga assuming different distance, age and energetic of the pulsar diffuse mature &nearby young pulsars

Hooper, Blasi, and Serpico arXiv:0810.1527

Mirko Boezio, Innsbruck, 2012/05/29


How to clarify the matter?C

ourtesy of J. Edsjo

Positronsvs antiprotons

• Large uncertainties on propagation parameters allows to accommodate an additional component

• A p-bar rise above 200GeV is not excluded

(Donato et al. 2009)• Diffusion model with convection and reacceleration

(Blasi & Serpico 2009) • p-bar produced as secondaries in the CR acceleration sites (e.g. SNR)

consistent with PAMELA positron data

+(Kane et al. 2009)• Annihilation of 180 GeV wino-like neutralino

consistent with PAMELA positron data

(Strong & Moskalenko 1998) GALPROP code

Adriani et al. - PR

L 105 (2010) 121101


Theoretical uncertainties on “standard” positron fraction

T. Delahaye et al., Astron.Astrophys. 501 (2009) 821; arXiv: 0809.5268v3

γ = 3.54 γ = 3.34

Flux=A • E-

Absolute fluxes of primary GCRs

NEEDED FOR:

(a) IDENTIFY SOURCES AND ACCELERATION PROPAGATION MECHANISMS OF COSMIC RAYS;

(b) ESTIMATE THE PRODUCTION OF SECONDARY PARTICLES, SUCH AS POSITRONS AND ANTIPROTONS, IN ORDER TO DISENTANGLE THE SECONDARY PARTICLE COMPONENT FROM POSSIBLE EXOTIC SOURCES;

(c) ESTIMATE THE PARTICLE FLUX IN THE GEOMAGNETIC FIELD AND IN EARTH'S ATMOSPHERE TO DERIVE THE ATMOSPHERIC MUON AND NEUTRINO FLUX.

H & He absolute fluxes

• First high-statistics and high-precision measurement over three decades in energy

• Dominated by systematics (~4% below 300 GV)

• Low energy minimum solar activity (f = 450÷550 GV)

• High-energy a complex structure of the spectra emerges…

Adriani et al. , Science 332 (2011) 6025

P & He absolute fluxes@ high energy

Deviations from single power law (SPL): Spectra gradually soften in the range 30÷230GV

Abrupt spectral hardening @ ~235 GV

Eg: statistical analysis for protons SPL hp in the range 30÷230 GV rejected @ >95% CL

SPL hp above 80 GV rejected @ >95% CL

Sola

r m

odul

atio

n

Sola

r m

odul

atio

n

2.852.67

232 GV

Spectral index

2.77 2.48

243 GV

Standard scenario of SN blast waves expanding in the ISM needs additional features

H/He ratio vs R

Instrumental p.o.v. Systematic uncertainties partly cancel out (livetime, spectrometer reconstruction, …)

Theoretical p.o.v. Solar modulation negligible information about IS spectra down to GV region

Propagation effects (diffusion and fragmentation) negligible above ~100GV information about source spectra

(Putze et al. 2010)

P/He ratio vs R

First clear evidence of different H and He slopes above ~10GV

Ratio described by a single power law (in spite of the evident structures in the individual spectra)

aHe-ap = 0.078 ±0.008c2~1.3


2H and 1H flux 2H/1HPreliminary


3He and 4He flux 3He/4HePreliminary


2H/4He


Boron and Carbon nuclei spectraCarbon Boron


Anisotropy studies (p up to 1 TeV)

Electrons

NEEDED FOR:

(a) RECALCULATHE THE EXPECTED POSITRON FRACTION WITH BET TER ACCURACY

(b) CLOSEBY SOURCES?


Results from ATIC


Theoretical uncertainties on “standard” positron fraction

FERMI e+ + e- flux (2009)

FERMI All-Electron Spectrum

A. Abdo et al., Phys.Rev.Lett. 102 (2009) 181101M. Ackermann et al., Phys. Rev. D 82, 092004 (2010)


Electrons measured with H.E.S.S.

Electron energy measurements

Two independent ways to determine electron energy:

1.Spectrometer • Most precise• Non-negligible energy losses (bremsstrahlung) above the spectrometer unfolding

2.Calorimeter• Gaussian resolution• No energy-loss correction required

• Strong containment requirements smaller statistical sample

spectrometer

calorimeter

Adriani et al. , PRL 106, 201101 (2011)

Electron identification:• Negative curvature in the spectrometer• EM-like interaction pattern in the

calorimeter

Spectrometric measurement

Adriani et al. , PRL 106, 201101 (2011) e+ +e-

Calorimetric measurements

e-Electron absolute flux

Largest energy range covered in any experiment hitherto with no atmospheric overburden

Low energy• minimum solar activity (f = 450÷550 GV)

High energy No significant disagreement with recent ATIC and Fermi data

Softer spectrum consistent with both systematics and growing positron component


New data: PAMELA Electron & Positron Spectra

Flux=A • E-

= 3.18 ±0.04

Flux=A • E-

= 2.70 ±0.15

Preliminary

(e+ + e- )absolute flux

Compatibility with FERMI (and ATIC) data

Beware: positron flux not measured but extrapolated from PAMELA positron flux!

Low energy discrepancies due to solar modulation

ONLY AN EXERCISE ……..

(e+ + e- )absolute flux

Compatibility with FERMI (and ATIC) data

Beware: positron flux not measured but extrapolated from PAMELA positron flux!

Low energy discrepancies due to solar modulation

ONLY AN EXERCISE ……..

Solar and terrestrial physics

Discovery of geomagnetically Trapped antiprotons

First measurement of p-bar trapped in the inner belt

29 p-bars discovered in SAA and traced back to mirror pointsp-bar flux exceeds GRC flux by 3 orders of magnitude, as expected by models

Adriani et al. –APJ Letters 737 L29, 2011

The geomagnetically trapped antiproton-to-proton ratio measured by PAMELA in the SAA region (red) compared with the interplanetary (black) antiproton-to-proton ratio measured by PAMELA, together with the predictions of a trapped model.

Discovery of geomagnetically Trapped antiprotons


Solar modulation: p and He spectra

H

He


Solar modulation: e+ and e-

All particlesPAMELA resultsResults span 4 decades in energy and 13 in fluxes


FERMI OBSERVATORY


Orbiting Space Station

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 SHUTTLEAMS-02: Since May 19th, 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.COMPLETE CONFIGURATION FOR >10 YEARS LIFETIME ON THE ISS

http://www.youtube.com/watch?v=RqksBepilVs



AMS-02 : the collaboration

USAA&M FLORIDA UNIV.JOHNS HOPKINS UNIV.MIT - CAMBRIDGENASA GODDARD SPACE FLIGHT CENTERNASA JOHNSON SPACE CENTERUNIV. OF MARYLAND-DEPRT OF PHYSICSUNIV. OF MARYLAND-E.W.S. S.CENTERYALE UNIV. - NEW HAVEN

MEXICOUNAM

DENMARKUNIV. OF AARHUS

FINLANDHELSINKI UNIV.UNIV. OF TURKU

FRANCEGAM MONTPELLIERLAPP ANNECYLPSC GRENOBLE

GERMANYRWTH-IRWTH-IIIMAX-PLANK INST.UNIV. OF KARLSRUHE

ITALYASICARSO TRIESTEIROE FLORENCEINFN & UNIV. OF BOLOGNAINFN & UNIV. OF MILANOINFN & UNIV. OF PERUGIAINFN & UNIV. OF PISAINFN & UNIV. OF ROMAINFN & UNIV. OF SIENA

NETHERLANDSESA-ESTECNIKHEFNLR

ROMANIAISSUNIV. OF BUCHAREST

RUSSIAI.K.I.ITEPKURCHATOV INST.MOSCOW STATE UNIV.

SPAINCIEMAT - MADRIDI.A.C. CANARIAS.

SWITZERLANDETH-ZURICHUNIV. OF GENEVA

CHINA BISEE (Beijing)IEE (Beijing)IHEP (Beijing)SJTU (Shanghai)SEU (Nanjing)SYSU (Guangzhou)SDU (Jinan)

KOREAEWHA

KYUNGPOOK NAT.UNIV.

PORTUGAL

LAB. OF INSTRUM. LISBON

ACAD. SINICA (Taiwan)CSIST (Taiwan)NCU (Chung Li)NCKU (Tainan)

NCTU (Hsinchu)NSPO (Hsinchu)

TAIWAN

» 500 physicists, 16 countries, 56 Institutes


The AMS-02 detector


AMS first events

42 GeV Carbon nucleus


FIRST AMS RESULT?

So far no physics results given by the collaboration to the science community;

First results expected for the the 4th International Conference on Particle and Fundamental Physics in Space (SpacePart), which will take place at CERN from November 5th to November 7th 2012.


Future experiments

78

CALET: Calorimetric Electron TelescopeMain Telescope: Calorimeter (CAL)

• Electrons: 1 GeV – 20 TeV• Gamma-rays: 10 GeV – 10* TeV (Gamma-ray Bursts: > 1 GeV)• Protons and Heavy Ions: 　　 several tens of GeV – 1,000* TeV• Ultra Heavy Ions ： over the rigidity cut-off Gamma-ray Burst Monitor (CGBM)• X-rays/Soft Gamma-rays: 7keV – 20MeV

(* as statistics permits)

CALCGBM

Nearby cosmic-ray sources through electron spectrum in the trans-TeV region Signatures of dark matter in electron and gamma-ray energy spectra in the 10

GeV – 10 TeV region Cosmic ray propagation in the Galaxy through p – Fe energy spectra, B/C ratio,

and UH ions measurements Solar physics through electron flux below 10 GeV Gamma-ray transient observations

Science objectives:


CALET Payload Overview

ASC 　 (Advanced Stellar Compass)

GPSR 　(GPS 　Receiver)

CAL/CHD

CAL/IMCCAL/TASC

CGBM/SGM

MDC 　(Mission Data Controller)

FRGF( Flight Releasable Grapple Fixture)

Mass: 650kg (Max) Standard Payload Size Power: 500W (Max)

Launch carrier: HTV-5 Launch target date: CY 2014 Mission period: More than 2 years

(5 years target)

Data rate: Medium data rate: 300 kbps Low data rate: 20 kbps

CGBM/HXM


Main Telescope: CAL (Calorimeter) 450 mm

Shower particles

CHD (Charge Detector): Double layer segmented

plastic scintillator array (14 x 2 layer with a unit of 32mm x 10mm x 450mm)

Charge measurement (Z=1 – 40)

IMC (Imaging Calorimeter): 7 layers of tungsten plates with 3 r.l.

separated by 2 layers of scintillating fiber belts which are readout by MA-PMT.

Arrival directions, Particle ID

TASC (Total Absorption Calorimeter): 12 layers of PWO logs (19mm x

20mm x 326mm) with total thickness of 27 r.l. The top layer is used for triggering and readout by PMT. Other layers are readout by PD/APD.

Energy measurement, Particle ID


It will combine for the first time photon and particle (electrons and nuclei)detection in a unique wayExcellent Silicon Tracker (30 MeV – 300 GeV),

breakthrough angular resolution 4-5 times better than Fermi-LAT at 1 GeV

improved sensitivity compared with Fermi-LAT by a factor of 5-10 in the energy range 30 MeV – 10 GeV

Heavy Calorimeter (25 X0) with optimal energy resolution and particle discrimination Electron/positron detection up to TeV energies Nuclei detection up to 1015 eV energies

Gamma-400 on Russian satellite


Counts estimation, electrons

G400 configuration: CsI(Tl), 20x20x20 crystals Size: 78.0x78.0x78.0 cm3 – gap 0.3 cmTaking into account: geometrical factor and exp. duration + selection efficiency 80%

Experiment Duration

Planar GF (m2 sr)

Calo s(E)/E

Calo depth

e/p rejection

factorE > 0.5 TeV E > 1 TeV E > 2 TeV E > 4 TeV

CALET 5 y 0,12 ~2% 30 X0 105 3193 611 95 10

AMS02 10 y 0,5** ~2% 16 X0 103 ** 26606 5091 794 84

ATIC 30 d 0,25 ~2% 18 X0 104 109 21 3 0

FERMI 10 y

1,6@300 GeV *

0,6@800 GeV *

~15% 8,6 X0 104 59864 2545 0 0

G400 10 y 8,5 ~0,9% 39 X0 106 452303 86540 13502 1436

* efficiencies included ** calorimeter standalone

Experiment

Duration

Planar GF

(m2 sr)

e selCalo s(E)/E

Calo depth

E > 0.1 PeV E > 0.5 PeV E > 1 PeV E > 2 PeV E > 4 PeV

e conv p He p He p He p He p He

CALET 5 y 0,120,8

~40%30 X0 1,3 l0

146 138 9 10 2 3 1 1 0 00,5

CREAM 180 d 0,430,8

~45%20 X0 1,2 l0

41 39 3 3 1 1 0 0 0 00,4 CT*

ATIC 30 d 0,250,8

~37%18 X0 1,6 l0

5 5 0 0 0 0 0 0 0 00,5 CT*

TRACER 30 d 50,8

- TRD 200 189 12 13 3 4 1 1 0 0-

G400 10 y 8,50,8

~20%39 X0 1,8 l0

16521 15624 979 1083 261 326 60 92 10 210,4

~ knee

Counts estimation, protons and helium nuclei

* carbon target

Polygonato modelG400 configuration: CsI(Tl), 20x20x20 crystals Size: 78.0x78.0x78.0 cm3 – gap 0.3 cmTaking into account: geometrical factor and exp. duration + selection efficiency 80%

~ knee

Counts estimation, heavier nuclei (3 ≤ Z ≤ 24)

*carbon target** better than 20% using TRD

Experiment

Duration

Planar GF

(m2 sr)

e selCalo s(E)/E

Calo depth

E > 0.1 PeV E > 0.5 PeV E > 1 PeV E > 2 PeV E > 4 PeV

e conv3Li to

9F10Ne to

24Cr3Li to

9F10Ne to

24Cr3Li to

9F10Ne to

24Cr3Li to

9F10Ne to

24Cr3Li to

9F10Ne to

24Cr

CALET 5 y 0,120,8

~30%30 X0 1,3 l0

68 70 5 5 1 2 0 1 0 00,5

CREAM 180 d 0,460,8

~45% **20 X0 1,2 l0

21 21 1 1 0 0 0 0 0 00,4 CT*

ATIC 30 d 0,250,8

~37%18 X0 1,6 l0

2 2 0 0 0 0 0 0 0 00,5 CT*

TRACER 30 d 50,8

TRD TRD 93 96 6 7 2 2 1 1 0 0-

G400 10 y 8,50,8

~17%39 X0 1,8 l0

7698 7910 533 555 169 180 51 60 15 170,4

Polygonato modelG400 configuration: CsI(Tl), 20x20x20 crystals Size: 78.0x78.0x78.0 cm3 – gap 0.3 cmTaking into account: geometrical factor and exp. duration + selection efficiency 80%


ISS-CREAMThe idea is to put the CREAM detector,

developed as a Long Duration balloon experiment, onboard the ISS, at the Japanese Experiment Modules Exposed Facility (JEM-EF) KIBO.

The 1,200 kg estimated mass of the payload is over twice the mass of any previously launched payload using the JAXA’s HTV. The development team will modify the existing instruments to meet the new requirements of the launch vehicle and ISS.

Very good chance to reach 1015 eV.


ConclusionsWith respect to the standard GCR scenario, what have we learned by the recent direct measurements?

High energy lineH and He spectra are differentH and He spectra harden with energy (230 GV)Hi-Z spectra might show similar hardeningEnergy dependance of propagation still

undecided

Composition lineSource matter must be a composition of old ISM

with newly sinthetized matherial, in percentage 80%-20% (sites of acceleration rich in massive stars?)


Antimatter line

All electron spectrum shows enhancement at high energy (hundreds GeV). Nearby source?

Positrons show enhancement in the E>10 GeV region (new e+ e- source. 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

New fresh data from AMS-02 could improve the understanding of some of the still open issues in the direct

measurements sectorTHANK YOU!

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High energy cosmic rays