Extensive Air Shower and cosmic ray physics above 1017 eV

M. Bertaina Univ. Torino & INFN

ISMD 2015, Wildbad Kreuth 5-9 October 2015

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Outline:» Part I: A general overview of cosmic

ray science. » Part II: The interconnection between

cosmic ray and particle physics.

» I will mention aspects that will be discussed in detail in the talks that follow in this session (S. Ostapchenko, R. Ulrich, D. Veberic, R. Abbasi).

» A few key slides taken by J. Pinfold and R. Engel review talks at ICRCs 2013 and 2015.

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Part I: A general overview of cosmic ray science

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~102/m2/second

~1/m2/year

~1/km2/yearKnee

Ankle~E-2.7

~E-2.7

~E-3.1

Direct measurements balloons, satellites

Indirect measurements (from EAS)

~1/km2/millen.

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6E < 10 14 eV

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Extensive Air Showers (EAS)

E > 10 14 eV

8R. Engel (KIT)

Astroparticle Physics 9

Development in atmosphere of EAS produced by protons or Fe nuclei at E=1015 eV

Hadronic Interaction Models needed to simulate the particle interactions in atmosphere: EPOS, QGSjet, SIBYLL,…

They are embedded in a software that simulates the EAS cascade in atmosphere such as CORSIKA.

EAS detection techniques

measurement of radio signal

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E > 1017 eV

12R. Engel (KIT)

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direct measurements

1 part/m2/year

1 part/km2/year

EAS

knee(s)

ankleend of spectrum?

COSMIC RAY SPECTRUM

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direct measurements

1 part/m2/year

1 part/km2/year

EAS

knee(s)

ankleend of spectrum?

Technical: direct to ground based experiments

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direct measurements

1 part/m2/year

1 part/km2/year

EAS

knee(s)

ankleend of spectrum?

Origin of the knee?

Astroparticle Physics 16

Acceleration in Supernova Remnant

B~3µG

The energetic limit of the acceleration mechanism of galactic c.r.? Emax ~ Z •1015 eV

1a

What is the origin of the knee?

1bIt is due to the limit due to the increase of probability to escape probability of galactic confinement?

Pescape ~ rigidity’ ~ 1/Z

Z=1

Z=26Z=7

Cut-off in the spectrun of single elements Ek(Z)

~Z

knee

M. Bertaina

1

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E(eV)1510 1610 1710 1810

)1.

5 e

V-1

s-1

sr

-2 (m

2.5

dI/d

E x

E

1410

1510

1610

1710EAS-TOP (1999)Akeno (1992)Yakutsk (2008)GAMMA (2008)TUNKA-133 (2013)TUNKA-25 (2013)IceTop (2013)TIBET-III (2008)

KASCADE all (2013)KASCADE H (2013)KASCADE medium (2013)KASCADE Fe (2013)KASCADE-Grande all (2012,2013)KASCADE-Grande H (2013) )KASCADE-Grande He+CNO+Si (2013)KASCADE-Grande Fe (2013)

Results in the knee region

M.B., Comptes Rendus (2014)

18R. Engel (KIT)

direct measurements

1 part/m2/year

1 part/km2/year

EAS

knee(s)

ankleend of spectrum?

Origin of the ankle? (transition between galactic/extra-galactic CRs)

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γ=2.7γ=2.7γ=3.0

‘KNEE ‘ANKLE’ ‘GZK Limit’

Limit of galactic C.R.? Extra-galactic component?

…the ankle marks the transition between galactic and extra galactic cosmic rays ?

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E/eV1610 1710 1810 1910 2010

)1.

5 e

V-1

s-1

sr

-2 (m

2.5

dI/d

E x

E

1310

1410

1510

1610

1710

KASCADE-Grande heavy QGSJet-II (2011)KASCADE-Grande light QGSJet-II (2013)

AUGER (2013)HiResII (2008)KASCADE-Grande all QGSJet-II (2012)TUNKA-133 (2013)

IceTop (2013)TA (2013)TIBET-III (2008)KASCADE all QGSJet-II (2013)KASCADE H-Si QGSJet-II (2013)KASCADE Fe QGSJet_II (2013)

KASCADE-Grande results:

M.B., Comptes Rendus (2014)

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Composition vs Energy

M.B., Comptes Rendus (2014)

22R. Engel (KIT)

direct measurements

1 part/m2/year

1 part/km2/year

EAS

knee(s)

ankleend of spectrum?

Anisotropies

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Random path of Cosmic Rays

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A. Castellina (COMPOSITION 2015)

amplitude of dipole

Tsunesada, ICRC 2013

IceCube & IceTop

Where does this anisotropy comes from? Why it changes above hundred TeV?

26R. Engel (KIT)

direct measurements

1 part/m2/year

1 part/km2/year

EAS

knee(s)

ankleend of spectrum?

End of spectrum?

Astroparticle Physics 27

The cosmic microwave background at 3 0K makes the Universe opaque to the cosmic rays of extreme energy K. Greisen - G.T.Zatsepin & V.A.Kuz’min (1966)

p

p+γ ! p+π0

p+γ ! n+π+

Ethr=6.8 1019 eV

l=1/σρ=6Mpc

ρ~410 γ/cm3

σ=135mbarn

GZK Cutoff

Cosmic rays with energy E> 7•1019 eV must have their sources within 50Mpc

M. Bertaina

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ORIGIN and PROPAGATION of UHECRs

−+

+

++→Δ→+

+→Δ→+

+→Δ→+

eepp

pp

np

K

K

K

7,2

07,2

7,2

γ

πγ

πγ

GZK cut-off for protons

Laboratory System: E proton = 1020 eV; E photon: 0.5 meV

Proton reference system: E proton = 0 eV ; E photon: 300 MeV

( )( )

−+ ++→+

+−→+

+−→+

eeAA

NAANAA

K

K

K

7,2

7,2

7,2

221

γ

γ

γ

Photo-dissociation for heavier nuclei

Ene

rgie

(eV

)

Propagation distance (Mpc)

Cosmic rays with energy E> 7•1019 eV must have their sources within 50Mpc

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Other possibility: end of spectrum due to the fact that sources are running out of steam

Globus et al. (ICRC 2015)

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Cosmic Ray Propagation in our Galaxy

Deflection angle < 1 degree at 1020eV for protons

Anisotropy Hints >60 EeV

P5 Presentation 12/3/13

E > 5.7x 1019 eV 20o smoothing ≈ 5 σ pretrial

# of events correlating with AGN, ordered in energy (integral plot)

Auger preliminary

isotropy expect.

Auger

Statistically limited evidence for Comic Ray Anisotropy above 5.7x 1019 eV in the North and South

TA

Auger≈ 3 σ pretrial

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The connection with the ‘knee’ and the highest energies

Extra-Galactic

Galactic

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Part II: The interconnection between cosmic rays

and particle physics

Slide 2 Pierog. Lo spettro dei raggi cosmici

Inserire tutte le animazioni del passato (vedi S.Vito)

Models tuned here LHC data

×105 extrapolation

×103 extrapolation

√sGZK ~300 TeV

35R. Engel (ICRC 2015)

CR exp.

Rapidity regions of CR experiments and LHC detectors

Pinfold, ICRC 2013

37R. Engel (ICRC 2015)

38R. Engel (ICRC 2015)

Pinfold, ICRC 2013

40R. Engel (ICRC 2015)

41R. Engel (ICRC 2015)

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Shortcomings of the hadronic interaction models

R. Engel (ICRC 2015)

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Pierre Auger Collaboration (ICRC 2015)

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Shortcomings of the hadronic interaction modelsXmax distributions

Pierre Auger Collaboration (ICRC 2015)

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CONCLUSIONSA review of the current understanding of cosmic ray data at different energies has been presented.

The interpretation of CR data requires the knowledge of the physics of hadronic interactions in atmosphere, but at the same time provides a means to cross-check the validity of the physics principles embedded in the models.

Hadronic interaction models do a fairly well job not only in the interpretation of EAS cascades in atmosphere but also of LHC data.

However, shortcomings exist! LHC data are extremely helpful in fine tuning the models and give solid bases for the extrapolation at high energies.

CR remain the sole mean to test hadronic interactions at energies well beyond those reachable with colliders.

CRs and accelerator data provide an excellent mix of information to understand the physics of interactions!

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THANK YOU