neutrinos and ultra-high energy cosmic rays dmitry semikoz mpi, munich & inr, moscow in...

Neutrinos and Neutrinos and Ultra-High Energy Cosmic RaysUltra-High Energy Cosmic Rays

Dmitry SemikozDmitry SemikozMPI, Munich & INR, MoscowMPI, Munich & INR, Moscow

in collaboration with in collaboration with

F.Aharonian, O.Kalashev, V.Kuzmin, F.Aharonian, O.Kalashev, V.Kuzmin, A.Neronov and G.SiglA.Neronov and G.Sigl

Ultra High Energy \\ Cosmic Rays

IFIC Valencia October 22, 2002

Overview: Introduction Experimental detection of high energy neutrinos:

Under/ground/water/iceHorizontal air showersRadio detection Acoustic signals from neutrinos

Neutrinos from UHECR protons Neutrinos from AGN Most probable neutrino sources Neutrinos in exotic UHECR models Conclusion


INTRODUCTION


Extragalactic neutrino flux?

Only ~ 20 neutrinos with energy

E~ 10-40 MeV from SN 1987A


Why UHE neutrinos can exist?

Protons are attractive candidates to be accelerated in astrophysical objects up to highest energies.

Neutrinos can be produced by protons in P+P pions or P+pions reactions inside of astrophysical objects or in intergalactic space.

Neutrinos can be produced directly in decays of heavy particles. Same particles can be responsible for UHECR events above GZK cutoff.


Pion production

ee

...

'

i

b

i

b

PP

NN

p

n

20

eepn

Conclusion: proton, photon and neutrino fluxes are connected in well-defined way. If we know one of them we can predict other ones: tottot EE ~


High energy neutrino

experiments


Neutrino – nucleon cross section

Proton density

np~ 1024/cm3

Distance R~104km Cross section

N=1/(Rnp)~10-33cm2

This happens at energy E~1015 eV.

~E0.4


Experimental detection of E<1017eV neutrinos

Neutrinos coming from above are secondary from cosmic rays

Neutrino coming from below are mixture of atmospheric neutrinos and HE neutrinos from space

Earth is not transparent for neutrinos E>1015eV

Experiments: MACRO, Baikal, AMANDA


MACRO


4-string stage (1996)

First underwater telescopeFirst neutrinos underwater


AMANDA-II

depth AMANDA

Super-K

DUMANDAmanda-II:677 PMTsat 19 strings

(1996-2000)


Experimental detection of UHE (E>1017eV) neutrinos

Neutrinos are not primary UHECR

Horizontal or up-going air showers – easy way to detect neutrinos

Experiments: Fly’s Eye, AGASA


Neutrino penetration depth


Radio detection


e + n p + e-

e- ... cascade

relativist. pancake ~ 1cm thick, ~10cm

each particle emits Cherenkov radiation

C signal is resultant of overlapping Cherenkov cones

for >> 10 cm (radio) coherence

C-signal ~ E2

nsec

negative charge is sweeped into developing shower, which acquiresa negative net chargeQnet ~ 0.25 Ecascade (GeV).

Threshold > 1016 eV


GLUE Goldstone Lunar Ultra-high Energy Neutrino Experiment

E2·dN/dE < 105 eV·cm-2·s-1·sr-1

Lunar Radio Emissions from Inter-actions of and CR with > 1019 eV

1 nsec

moon

Earth

Gorham et al. (1999), 30 hr NASA Goldstone70 m antenna + DSS 34 m antenna

at 1020 eV

Effective target volume~ antenna beam (0.3°) 10 m layer

105 km3


RICE Radio Ice Cherenkov Experiment

firn layer (to 120 m depth)

UHE NEUTRINO DIRECTION

300 METER DEPTH

E 2 · dN/dE < 10-4 GeV · cm-2 · s-1 · sr-1

20 receivers + transmitters

at 1017 eV


Acoustic detection


d

R

Particle cascade ionization heat pressure wave

P

t

s

Attenuation length of sea water at 15-30 kHz: a few km(light: a few tens of meters)

→ given a large initial signal, huge detection volumes can be achieved.

Threshold > 1016 eV

Maximum of emission at ~ 20 kHz


Present limits on neutrino flux

p


Future limits on neutrino flux

p


Mediterranean Projects

4100m

2400m

3400mANTARESNEMO NESTOR


NEMO 1999 - 2001 Site selection and R&D

2002 - 2004 Prototyping at Catania Test Site 2005 - ? Construction of km3 Detector

ANTARES 1996 - 2000 R&D, Site Evaluation 2000 Demonstrator line 2001 Start Construction

September 2002 Deploy prototype line December 2004 10 (14?) line detector complete 2005 - ? Construction of km3 Detector

NESTOR 1991 - 2000 R & D, Site Evaluation Summer 2002 Deployment 2 floors Winter 2003 Recovery & re-deployment with 4 floors Autumn 2003 Full Tower deployment 2004 Add 3 DUMAND strings around tower 2005 - ? Deployment of 7 NESTOR towers


Baikal km3 project: Gigaton Volume Detector GVD


IceCube

1400 m

2400 m

AMANDA

South Pole

IceTop

- 80 Strings- 4800 PMT - Instrumented

volume: 1 km3

- Installation: 2004-2010

~ 80.000 atm. per year


Pierre Auger observatory


Telescope Array


MOUNT


OWL/EUSO


ANITA Antarctic

Impulsive

Transient

Array

Flight in 2006


Natural Salt Domes

Potential PeV-EeV Neutrino Detectors

SalSA Salt Dome Shower Array


Renewed efforts along acoustic method for GZK neutrino detection

Greece: SADCO Mediterannean, NESTOR site, 3 strings with hydrophones

Russia: AGAM antennas near Kamchatka:existing sonar array for submarine detection

Russia: MG-10M antennas: withdrawn sonar array for submarine detection

AUTEC: US Navy array in Atlantic:existing sonar array for submarine detection

Antares: R&D for acoustic detection

IceCube: R&D for acoustic detection


RICE AGASA

Amanda, Baikal2002

2004

2007

AUGER

Anita

AABN

2012

km3

EUSO,OWLAuger

Salsa

GLUE


Neutrinos from UHECR protons


Why neutrinos from UHE protons?

All experiments agree (up to factor 2) on UHECR flux below cutoff. All experiments see events above cutoff!

Majority of the air-showers are hadronic-like

Simplest solution for energies 5x1018 eV < E < 5x1019 eV: protons from uniformly distributed sources like AGNs.


Active galactic nuclei can accelerate heavy nuclei/protons


Photo-pion production

ee

iNN '

p

n

20

eepn


Parameters which define diffuse neutrino flux

Proton spectrum from one source:

Distribution of sources:

Cosmological parameters:

E

AEF )(

maxmin EEE

3)1( mzD maxmin zzz

0H vac


Theoretical predictions of neutrino fluxes

WB bound: 1/E2 protons; distribution of sources – AGN; analytical calculation of one point near 1018 eV.

MPR bound: 1/E protons; distribution of sources – AGN; numerical calculation for dependence on Emax

The ray bound: EGRET


The high energy gamma ray detector on the Compton Gamma Ray Observatory (20 MeV - ~20 GeV)

EGRET: diffuse gamma-ray flux


Detection of neutrino fluxes: today

i

p


Future detection of neutrinos from UHECR protons

AGN,1/E

Old sources1/E^2


Neutrinos from Active galactic

nuclei


Active Galactic Nuclei (AGN)

Active galaxies produce vast amounts of energy from a very compact central volume.

Prevailing idea: powered by accretion onto super-massive black holes (106 - 1010 solar masses). Different phenomenology primarily due to the orientation with respect to us.

Models include energetic (multi-TeV), highly-collimated, relativistic particle jets. High energy -rays emitted within a few degrees of jet axis. Mechanisms are speculative; -rays offer a direct probe.


Neutrinos from AGN core


Photon background in core Energy scale

E= 0.1 – 10 eV Time variability

few days or

R = 1016cm Model: hot thermal

radiation.

T=1 eVT=10 eV


Photo-pion production

ee

iNN '

p

n

20

eepn


Neutrino spectrum for various proton spectra and backgrounds

1/E

1/E2

T=10 eV

1/E2

T=1 eV

E~1018eV

Atm.flux


Most probable neutrino sources


Neutrino production in AGN


Which sources ?

Blazars (angle – energy correlation)


Optics: SDSS. Most powerful objects are AGNs

500 sq deg of the sky, 14 million objects, spectra for 50,000 galaxies and 5,000 quasars.

Distance record-holder

>13,000 quasars (26 of the 30 most distant known)


Low energy radiation from AGN is collimated

Typical gamma-factor is

Radiation is collimated in 1/ angle ~ 5o in forward direction.


EGRET 3rd Catalog: 271 sources

Most of identified MeV-GeV sources are blazars


All TeV sources are blazars


Which sources ?

Blazars (angle – energy correlation) Blazars should be GeV loud


High energy photons from pion decay cascade down in GeV region


EGRET 3rd Catalog: 271 sources

Only 22 sources from 66 are GeV - loud


Which sources ?

Blazars (angle – energy correlation) Blazars should be GeV loud ‘Optical depth’ for protons should be large:

pnR


Bound on blazars which can be a neutrino sources


TeV blazars does not obey last condition

Indeed, in order TeV blazars be a neutrino sources:

pnR nR

p= 10-28cm2 while = 6.65 x 10-25cm2

CONTRADICTION!!!


Which sources ?

Blazars (angle – energy correlation) Blazars should be GeV loud Optical depth for protons should be large:

pnR No 100 - kpc scale jet detected (model-dependent)


Neutrino production in AGN


Collimation of neutrino flux in compare to GeV flux


Acceleration of protons to higher energies


Neutrinos from exotic UHECR

models


Top-down models


Z-burst mechanism

Resonance energy E = 4 1021 (1 eV/m) eV

Works only if

meV

Mean free path of neutrino is

L = 150 000 Mpc >> Luniv


Cross sections for neutrino interactions with

relict background and


Problem: too high -ray flux

m1 eV (Yoshida,Sigl,Lee,1998)


Possible solution: local relic overdensitybut factor 20 over 5 Mpc is needed


Numerical simulations of the possible local neutrino over-density give factor 2-3


Non-uniform distribution of sources O.Kalashev, V.Kuzmin, D.S. and G.Sigl, hep-ph/0112351


Sources of both and


X -> only (Gelmini-Kusenko model)


Conclusions Sensitivity of the neutrino telescopes will be increased

in 103-5 times during next 10 years. Now they just on the border of theoretically interesting region.

Secondary neutrino flux from UHECR protons can be detected by future UHECR experiments.

Neutrino flux from AGN’s can be detected by under-water/ice neutrino telescopes. GeV-loud blazars with high optical depth for protons are best candidates for neutrino sources.

Some of exotic UHECR models will be ruled out or confirmed in near future by neutrino data.


References:

Diffuse neutrino flux. O.Kalashev, V.Kuzmin, D.S. and G.Sigl, hep-ph/0205050

Extragalactic neutrino sources. A.Neronov & D.S., hep-ph/0208248

AGN jet model. A.Neronov, D.S., F.Aharonian and O.Kalashev, astro-ph/0201410

Z-burst model. O.Kalashev, V.Kuzmin, D.S. and G.Sigl, hep-ph/0112351

neutrinos and ultra-high energy cosmic rays dmitry semikoz mpi, munich & inr, moscow in...

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