Controversy and Mystery in Highest-Energy Cosmic rays

Cosmo2004, September 19Tom Weiler, Vanderbilt University

Controversy and Mystery in Highest-Energy Cosmic rays

Tom Weiler

Vanderbilt University


Cosmic Photo- Proto-Spectra

Rad

io

CM

B

Vis

ible

-ra

ys

CERN/Fermilab

x-ra

ysUV

IRCosmic-rays

TeV

-w

all

(after Ressell & Turner ‘90)

hadron wall?

no wall a’tall

sunSN87a NeutrinoIncognito


The Cosmic Ray Timeline1912 Hess (Austrian) balloons to 5km, his sparks increase;

also sees no change during solar eclipse1929 Cloud chambers,

and the birth of particle physics:

1933 Anderson’s positron; Kunze’s muon (Rostock) 1937 Anderson’s muon 1938 Auger’s remarkable PeV air-shower 1949-54 Fermi’s “Doppler” acceleration via magnetized shocks 1966 3K CMB discovered; GZK predict cutoff at 5x1019 eV

(But Linsley already reported (PRL) event at 1020 eV)

1987 IMB/Kamiokande neutrinos from SN87a

04/19/23 Cospar2004 4

AUGER’s key discovery Auger, in 1938, separated two particle counters by a kmhigh in the Swiss Alps (Jungfrau, near Bern), he discovered coincident signals. He calculated ETOT to be about 1015 eV.

His inference was correct. His energy was 107 times the prior record event,And now thought to be typical of emission from a SN remnant.


1991 Fly’s Eye reports 3x1020 eV, with proton-like profile;

Akeno/AGASA Xpt begins

mid-90sDUMAND taken off life-support

90s SuperK neutrinos from the sun (directional astro)

1996 AGASA reports event clustering within 2.50 ang. res’n

and: F(E 1020 eV) ~ 1/km2/century,

with shower diameter ~ 5km, N(e) ~ 1011

2000 20 events at and above 1020 eV

2001 HiRes withdraws 7 events; AGASA adds 6 (from z > 45o);

And the controversy has begun!

Importantly, Auger gets first “light”

2002 AMANDA pushes to 1014 eV thru-Earth neutrinos

2005 Auger Observatory data expected

2008 Extreme Universe Space Observatory (EUSO) ?


CR Spectrum above a TeV

from Tom Gaisser

VLHC(100 TeV)2


Highest Energy Event

The CR record energy is 3x1020 eV (0.3 ZeV). Found by Fly’s Eye a decade ago (they got lucky!). This is truly a macroscopic energy: 3x1020 eV = 50 Joules equivalent to a Roger Clemens fastball,

a Tiger Woods tee shot,a Pete Sampras tennis serve,Or a speeding bullet.

(Also to 12 Calories, which heats a gram of water by 12oC)


3 x1020 eV = macroscopic 50 Joules

Clemens does this with 1027 nucleons;Nature does this with one nucleon, 1027 times more efficient !


Fly’s Eye 3x1020 eV event (1992)

100 billion e+e- pairs at xmax ~ 800 g/cm2

This longitudinal profile is consistent with a primary proton, but not with a primary photon; Disfavors “local” top-down sources such as massive Particle DK, topo-defects,Z-bursts, etc.


Size mattersEUSO ~ 300 x AGASA ~ 10 x AugerEUSO (Instantaneous) ~3000 x AGASA ~ 100 x Auger

Exposure

1

10

100

1000

10000

Year

Expo

sure AGASA

HiResAugerEUSO


Extreme Universe Space Observatory

2009 EUSO onboard the ISS (Or Not!)

2012 Hundredth anniversary of Hess

– EUSO finishes three-year data-taking

http://www.esa.int/export/esaHS/ESA6NE0VMOC_iss_3.html


“clear moonless nights”

Blackout_14aug03.jpeg

Or New York State power blackout


Orbiting Wide-angle Lens (OWL)3000 events/year above 1020eV

and UHE Neutrinos!


AGASA Spectrum: EeV to ZeV

AGASA, July 2002


Greisen-Zatsepin-Kuzmin and the Cosmic-Ray Wall

-resonance

multi-pions

Photo-pion production off CMB

p+cmb p/n+


HiRes vs. AGASA UHE spectrum

discovery

opportunity

GZK recovery ?Z-burst uncovery ?

FlysEye event goes here

EUSO reach x 103 better


AGASA hot-spots -- Data

red: E > 4 1019 eVgreen: E > 1020 eV

Cluster Component~ E -1.8±0.5


AGASA hot-spots -- numbersWithin 2.5 degree circles,AGASA identifies six doublet, one triplet,Out of 57 events;

Opening the angle to just 2.6 degrees,AGASA identifies seven doublets, two triplets;

Haverah Park contributes two more paired events in AGASA directions.

NOT corroborated by HiRes.

Source number ~ N12/2N2 ~ 270 to 50%,

weighting with GZK suppression, ~ 10-5 /Mpc3for source density


Berezinsky et al Xgal proton fluxMass-composition data (HiRes 2002)

Xgal proton dominance begins at 1018 eV, not 1019 eV !F ~ 50 x Waxman-Bahcall AMANDA/RICE/EAS-sensitive !!

(AGHW, to appear)

Theory threshold for p2.7Kpe+e- and data (knee) are at 1017.6 eV.


Xgal proton fit huge flux

is pion energy/CR energy at source (1 for WB “limit”);z is cosmic evolution factor, 0.6 (no) to 3.0 (SFR)

WB fluxes

low Xgal dominance flux,with no evolution

AGHW


Neutrinos versus Cosmic-Rays and Photons

s come from central engines

- near Rs of massive BHs

- even from dense “hidden” sources

cf. s vs. s from the sun

s not affected by cosmic radiation(except for annihilation resonance)

s not bent by magnetic fields- enables neutrino astronomy

Also, besides Energy and Direction, ’s carry flavor


diagnostic of astro-engines:pp vs. p

The process e+e-- W-- is resonant at 6.4 PeV;

IceCube will have flavor ID, and E/E of 25%,and so can measure On-Res/Off-Res ratio.

pp make nearly equal

::e:e = 2:2:1:1 flavor democracy, e = 1/6 total

p via + make + e = 1:1:1 (no e) e = 1/15 total

IceCube can resolve this (AGHW in prep.)


AMANDA to 100 TeV


“Essentially Guaranteed” Xgal FluxHiRes 2004 fit:Green: galactic componentRed: Xgal componentEvolution parameter 2.8 +/- 0.3

Cosmogenic ’s:

F(Ep/5/4) = Fp(E>5 1019) x 20


“Essentially Guaranteed”Xgal Cosmogenic Flux

Cosmogenic ’s:

F(Ep/5/4) = Fp(E>5 1019) x 20

graphs from Semikoz and Sigl


“Essentially Guaranteed” High-Energy Galactic Neutrino Flux

cn = 10 kpc (En / EeV)and

E/ En ~ Q / mn ~ 0.8 x 10-3

E ~ PeV, for En ~ EeV


“More Guaranteed”Icecube atmos background in 1o circle is just 1.5events/yr, 3.5 events offers 95% CL detection in 1 yr;

Calculated signal is 4 /yr and 16 e+ showers/yr.

Conclude that in a few years, IceCube attains 5discovery sensitivity for Fe n e Providing “smoking ice” for GP neutron hypothesis.

Comparing to “guaranteed” cosmogenic flux, Galactic beam (here) is higher !


Relic Neutrino density – meV astrophysicsNeutrino density from CMB density


Resonant Neutrino Annihilation Mean-Free-Path

From Fargion, Mele, Salis

nDH/h70

(neglecting higher densities at earlier times)


Escher’s Angels and Devils”

Looking back, n~(1+z)3,

And so the absorption is greatly

Enhanced for ’s from high-z sources


Neutrino mass-spectroscopy: absorption and emissionThe only possibility to directly infer the relic density


-mass spectroscopy zmax=2, 5, 20 (top to bottom), n-=2(bottom-up acceleration)Eberle, Ringwald, Song, TJW, 2004


Z-bursts

Mpc

TJW, 1982;

Revival – 1997


HiRes vs. AGASA UHE spectrum

discovery

opportunity

GZK recovery ?Z-burst uncovery ?

FlysEye event goes here

EUSO reach x 103 better

Documents

Controversy and Mystery in Highest-Energy Cosmic rays