What are Cosmic Rays?A short historyWhat do we know now about CRsCR – their energy spectrum

Why all these is interesting?How CRs can be accelerated?Ultra High Energy and GZK Cut-OffVarious speculations

EAS detection from the SpaceEUSO, OWL, TUSUHECR simulation and reconstructionExpected Performance

Conclusions

UHECR detection from the Space

MunichMarch 2004

…by Dmitry Naumov(JINR)

What are Cosmic Rays?Cosmic Rays (CR) are high-energyparticles of extraterrestrial origin

The astrophysical filed of activityfor particle and nuclear physics

Secondary CR (produced by the primaries in the Earth’s atmosphere) consist of essentially allelementary particles and nulei (both stable and unstable). The most important are

• nucleons, nuclei & nucleides,• (hard) gammas,

• mesons (±,0,K±, …, D±,…),• charged leptons (e±, ±, ±),• neutrinos & antineutrinos (e, , ).

However the above definition is much wider and includes in fact all stable and quasistableparticles:

• neutrons,• antiprotons & (maybe) antinuclei,• hard gamma rays ( cm),• electrons & positrons,• neutrinos & antineutrinos,• esotheric particles (WIMPs,

magnetic monopoles, mini blackholes,...).

“Classical” CR are nuclei or ionized atomsranging from a single proton up to an ironnucleus and beyond, but being mostlyprotons (~90%) and particles (~9%).

Courtesy by V.Naumov

A gold-leaf Bennet-type electroscope(ca. 1880s) manufactured by Ducretet.

Even very well isolated gold-leaf electroscopes

are discharged at a slow rate.

… observed by scientists before 1900

J.Elster, H. F.Geitel, C.Wilson investigated this phenomenon and concluded that some unknown source of ionizing radiation existed. Wilson even surmised that the ionization might be

“…due to radiation from sources outside our atmosphere, possibly radiation like Röntgen rays or like cathode rays, but of enormously greater penetrating power.”

1900-1901

Soon after, two Canadian groups, Ernst Rutherford and H. Lester Cooke(1903) at McGill University, and J. C. McLennan and E. F. Burton (1902) at theUniversity of Toronto showed that 5 cm of lead reduced this mysterious radiationby 30%. An additional 5 t of pig lead failed to reduce the radiation further.

Courtesy by V.Naumov

1911–1913

Von Victor Franz Hess, studying at the Radium Inst.,Vienna, decided to take the experiment a step furtherand a few thousand meters higher. In 10 balloonascents (with open gondola) reaching altitudes of17,500 ft (about 5.3 km), he found that radiationslowly decreased with height (up to about 700 m) butthen at about 1.5 km it began to rise, until at 5 km itwas over twice the surface rate. Hess concluded :

"The results of the present observations seem to be most readily explained by the assumption that a radiation of very high penetrating power enters our atmosphere from above, and still produces in the lowest layers a part of the ionization observed in closed vessel."

Hess also found that the ionization was similar for day and nigh t time and did not decrease on his flight during a solar eclipse on April 12, 1912; he concluded the sun could not be the main source of the radiation.

Courtesy by V.Naumov

Victor Hess won The Nobel Prize in Physics 1936"for his discovery of cosmic radiation" .

Classic references:

• V.F. Hess, Physik. Zeitschr. 12 (1911) 998.• V.F. Hess, Physik. Zeitschr. 13 (1912) 1084.• V.F. Hess, Physik. Zeitschr. 14 (1913) 610.

Background of the slide:

H.E.S.S. (High Energy Stereoscopic System) a next-generation system of Imaging Atmospheric Cherenkov Telescopes for the investigation of cosmic gamma rays in the 100 GeV energy range.

Courtesy by V.Naumov

EAS

1938: Pierre Victor Auger, Raymond Maze, Roland Maze and Thérèse Grivet-Meyer positioned their particle detectors high in the Alps. They obtained that two detectors distanced many meters one from another detected the arrival of particles at exactly the same time.

Thus Pierre Auger and collaborators discovered the extensive air showers(EAS), the cascades of secondary particles and nuclei produced by the collision of primary high-energy particles with air molecules. In this way, changing the distance between detectors, Auger could observe particles with energies of about 1 PeV(1015 eV) - ten million times higher than reached so far. *)

________________________________________

*)Of course, this is the today’s estimaton. Auger was not able to estimate the primary energy. Courtesy by V.Naumov

Up to now EAS are detected on the Earth ground

Today the largest ground detector Pierre Auger in Argentina camps will cover ~3000 km2 surface and detect both:

Charged particlesFluorescent light

Courtesy by V.Naumov

1st knee

Foot (?)

Modulated by solar activity

1 particle per m2×second

1 particle per m2×year

2nd knee

Ankle

Fingers (?)

1 particle per km2×year

A Bird view of the CR spectrum

1st knee~ 3×106 GeV

GZK~ 5×1010 GeV

ankle~ 5×109 GeV

2nd knee~ 4×108 GeV

Courtesy by V.Naumov

A lower energy data suggests a dominance of the protons… •The AGASA data seems to conflict to both Hires and GZK prediction.•There is also a 2 times difference in the flux measurement between Hires and AGASA at low energies!

Hires is a fluorescent detectorAGASA is a charge track detector

A brief history of AGASA-HIRES conflict

NO

W

One if the HiRes cameras which has an exposure slightly greater then that of AGASA recorded only 2 events above 1020 eV compared to 20 expected if AGASA is right.

PAST

Also HiRes reported data from their stereo system (20% of their monocular exposure). They observed only 1 event with 1020.5 eV

Recently AGASA reported 17 events above 1020eV consistent with their previous work.

HiRes showed 7 events above 1020 eV in agreement with AGASA

Before 2001 event rate at 1019 eV reported by different experiments was in agreement at 10-15% level.

Haverah Park experiment (England) reassessed their energy spectrum

4 events above 1020 eV shifted by 30% below 1020 eV.

On top of that…

The arrival direction of UHECRs

There is a systematic enhancement of events with energy until 1019 eV correlated to the galactic plane

There is a deficit of events correlated to the galactic plane above 1019 eV

Haverah Park indicates a correlation with super-galactic plane (plane with Virgo radio galaxies cluster) above 4.1019 eV

However AGASA, SUGAR and Fly’s Eye do not confirm this result

Isotropic distribution of CR events with energy > 1019 eV observed (Takeda et al., 1999).

AGASA Super GZK event distribution.

Do UHECRs come from the same Source?

Probability of clusters at AGASA

Impressive chance probability howeverSignificantly depends on the binning.This is NOT a blind analysis

AGASA resolution

How UHECRs are accerelated?

1. Top down (TD, Big-Bang Remnants, WIMPs etc)

2. Bottom Up (shock waves, RadioGalaxies, etc)

3. Diffusion acceleration at Newtonian Shocks

4. Unipolar induction (rotating magnetic fields strong electric field)

5. Non-linear particle-wave interaction 6. Active Galactic Nuclei and Dead Quasars 7. Neutron Stars 8. Gamma Ray Bursts 9. etc… A lot of speculation but nobody knows (and

if knows does not tell us) the truth…

How UHECRs Propagate?

• 2.73°K cosmic microwave background (CMB)

• (GZK) Cutoff

eV

cmphotonsn

4

3

1035.6

413

eVENp

eVENp

NCMB

NCMB

20

20

105.2,

101.1,

Eth > 5.1019eV

Proton Propagation

• 2.73°K cosmic microwave background (CMB)

• (GZK) Cutoff

eV

cmphotonsn

4

3

1035.6

413

eVENp

eVENp

NCMB

NCMB

20

20

105.2,

101.1,

Greisen-Zatsepin-Kuzmin (GZK) CutOff

Eth > 5.1019eV

The mainmechanism

Heavy Nuclei Propagation

1. Compton interactions2. Pair production3. Photodisintegration4. Hadron

photoproduction

t[s]1014 1016

Photon Propagation

Energy loss is well understood as a pair creationTrough collisions with various radiation fields

How to avoid GZK?

Z0 burst from the annihilation with CNB relic neutrinos in Virgo Cluster. The decay products of Z0 are gamma rays, nucleons and neutrinos, as firmly established by the CERN LEP experiments.

Strong neutrino flux @ E>1021eV can propagate unattenuated and give us photons, nucleons and pions interacting with CNB!

Neutrino can propagate trougth CNB = (n)-

1~4 x 1028 cmAbove the size of the horizon (H0

-

1~1028cm)

Galactic Halo

Extra Galactic

SUSY U (uhecron)Good candidate is g~-hadron (gluino containing hadron): QCD sum rules suggests gluballino (gg~).

There are two narow allowed windows for g~-hadron mass:(1.5-3) GeV/c2 and (25-35) GeV/c2

1.5 GeV1 GeV2 GeV

Lorenz symmetry violationNo reason to believe for a universal scale below which

theLorenz symmetry is violated.However Local Lorenz Invariance could be violated

With anomalous kinematics

Without anomalous kinematics

Lorenz symmetry violationNo reason to believe for a universal scale below which

theLorenz symmetry is violated.However Local Lorenz Invariance could be violated

Could exist a maximum attainable velocity for each particle

ik = ci-ck difference in speeds4wpE + (m

2-mp2)/E energy

conservationIf p >4w2/ (m

2-mp2) = 3.5

10-25(w/w0)2

Has no solution no GZK limit

Lorenz symmetry violation

There are no direct constrains on the parameter p

However we can compare the speed of light to that oh highenergy CR which should emit the Cherenkov light if c < cCR Today constrains:p<3.0 10-23

e<1.3 10-13From CRs of highest energy

e<1.3 10-

15

<1.0 10-8

From Multi-TeV ray observationsFrom SN1987a

• Spectrum of energy

• Nature (p, Fe, , … )

• Sources

unknown!

• Unknown in addition :Is GZK limit is violated or no ?

unknown!

unknown !

What do we know about UHECRs today?

Who and How is going to address the problem(s)?

Courtesy by C.Lauchaud

Concept ofTUS/TUS2 space free flyer

16x16

PMTs

Fresnel mirror10 rings

Focal distance is 1.5 mField of View is 7.3o

mold production in JINR/DubnaSpace qualified carbon-plastic Fresnel mirror to be produced@ “Luch” (Syzran)

Mirror moldsection

Ring number

Measured vs theory

Measured - theory

[mm]

Orbiting Wide Angle Light-collector (OWL)

Original concept AirWatch (1996)

Improved every year

Two satellites flying in formation

Angular Resolution: 0.2

Energy Resolution: 14%

Aperture: 2X106 km2 ster

Duty Cycle ~12%

Eff. Aperture: 2.3X105 km2 ster

http://owl.gsfc.nasa.gov

EUSO: ISS stationed

optics 2 m diameter

Fresnel lenses 30o FoV 3 years data

taking Now end of Phase A

UHECR

Atmoshpere shower

Air fluoresence

Cerenkov light

Reflection from the Earth

Attenuation in air

Description of telescope

Optique d’EUSO (NASA) : Lentilles de Fresnel

Surface focale: • Structure porteuse FS (France)• électronique ( Italie et France)• PM Multi-anodes ( Japon )

Hamamatsu R5900-M-16/64

Interfaces / Lanceur + Module ISS

Structure porteuse intermédiaire « Alenia » (Italie)

EUSO Frequently Used Software

UNISIM PARIS SLASTS.Bottai E.Plagnol D.NaumovS.Bottai

HYBRID METHODS : FULL MC SIMULATION FOR E>Eth , PARAMETRIZATION FOR E<Eth. Good reproduction of fluctuations with Eth=1017eV.

LPM EFFECT INCLUDED

NEUTRINO SIMULATION OF EHE NEUTRINO INTERACTIONS CC+NC

Single cherenkov scatteringClouds simulation

Common features:3D Geometry and Earth Curvature hadron-air initial interactionProduction of fluorescent and cherenkov lightAtmosphere response

Energy distribution of electrons in shower (impact on both fluorescent and cherenkov light)

Easy configurable atmosphere profiles, attenuation, detector parameters

Neurino CC +NC interactions

ESAF light production engine

D.Naumov, EUSO-SDA-015

h=0 km

h=100 km

An example from LOWTRAN7.1: a vertical transmission from h to

Shower development

Atmosphere response

Fluorescence in air

The Background. The night view of the EARTH

@moonless night we expect 500 photons m-2 ns-1 sr-1, corresponding to 0.3 p.e./s

Clouds

Reflection of the Earth 22 june 2002

EUSO Reconstruction. 1. Incoming directionHired X,Y pixels allows to recover the shower track direction

EUSO Reconstruction. 1. Incoming directionHired X,Y pixels allows to recover the shower track direction

P.Colin, D.Naumov, P.Nedelec, EUSO-SDA-REP-016

EUSO Reconstruction. 1. Incoming directionHired X,Y pixels allows to recover the shower track direction

P.Colin, D.Naumov, P.Nedelec, EUSO-SDA-REP-016 Assuming infinite pixel resoltion

EUSO Reconstruction. 1. Incoming directionHired X,Y pixels allows to recover the shower track direction

EUSO Reconstruction. 2. Altitude of Shower Maximum

Use of Cherenkov echo

Hmax

Xmax

P.Colin, D.Naumov, P.Nedelec, EUSO-SDA-REP-016

Need for an extra device (LIDAR) to detect the reflective surface (cloud) while the Earth relief must be recovered by other meansCherenkov light is drastically suppresed at zenith angle > 70 deg. (important for neutrino showers)

EUSO Reconstruction. 2. Altitude of Shower Maximum

Use only fluorescenceUse of Cherenkov echo

Hmax

Xmax

5km

20 km

Time development of two horizonthal showers. Nmax/Ntot ~ (h)

EUSO Reconstruction. 2. Altitude of Shower Maximum

P.Colin, D.Naumov, P.Nedelec, EUSO-SDA-REP-016

EUSO Reconstruction. 3. Energy

Statistical limit

EUSO Reconstruction. 3. Energy

• Events were generated by Eric Plagnol with the Model Clouds.

- Cloud distribution, types, and population;

• Overall EUSO instrument efficiency 0.07056 is used with SLAST.

• Energy, Height of the shower maximum and/or clouds are blind-fold for EUSO. All of them are autonomously analyzed by the shape methods.

• Two sets of events are provided without identity:

GZK and Super-GZK types.

• Blind-fold testing to reproduce and identify the energy spectrum of two types.

• Existence or absence of the cloud, (and the type of cloud or its height), if any, is not given but derived by the self-diagnosis.

We got quite promising results...People still are not convinced.

Let us play a blind game!

Shower fit by two Gaussian- Wide Fluorescence and narrow Cherenkov

plus Poissonian background noise

Thick-Cloud-hittinghigh Cherenkov peakand close to Nmax

Ground-hittingor low-altitude,thin-cloud hitting

PARIS event (Cloud)E/E (Shape - Cherenkov)= 1.08 x 1020 eV - 1.19 x 1020 eV= 3 - 5% at 7 x 1020 eV.

Hmax = [H (Fluorescence 5.83 km) - H (Cherenkov 4.22 km)] = 1.61kmgives the altitude of clouds Hcloud = 1.6km.

SLAST (no clouds)Hmax = [H (Fluorescence 5.56 km) - H (Cherenkov 5.23 km)] = 0.3km

E/E = 3 - 5% at 7 x 1020 eV

Xmax= 7% (Shape) and 2% (Ch).

Recovery of energy spectra

Conclusions

Whatever the scientific objectives are EUSO is a very interesting and power tool to enter the game! EUSO will collect in 3 years ~few

1000 of events EUSO will be able to separate (to

some extent) p, Fe and neutrino 20-30% error for the energy

measurement is expected