Ultra High Energy Cosmic Rays Theoretical Perspective(s) Angela V. Olinto CfCP, DAA, EFI University of Chicago
Jan 15, 2016
Ultra High Energy Cosmic RaysTheoretical Perspective(s)
Angela V. OlintoCfCP, DAA, EFI
University of Chicago
Outline
The Basics The Recent Past The Present The Future (Perspectives)
The Basics
©S. Swordy
Cosmic Rays exist! Still not clear where they come from
Because of ...
Galactic Magnetic Fields
But at Ultra High Energies...
should be able to point back
and see the SOURCES!
Ultra High Energy CRs trajectories
O’Neil, A.O., Blasi ‘01
From Diffusive to Straight Line
Isola, Lemoine, Sigl ‘02
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Isotropic Distribution of Arrival Directions
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HiRes >1018 eV
AGASA >1019 eV
Still at ~1020 eV (if protons) extragalactic sources interact with CMB GZK feature!
The Basics
High Energy Proton sees CMB as High Energy Proton sees CMB as High Energy Gamma Rays! High Energy Gamma Rays!
GZK CutoffGZK Cutoff
Greisen ‘66, Zatsepin & Kuzmin ‘66
p+cmb + p + 0
n + +
The Basics
-resonance
multi-pions
Extragalactic UHE ParticlesProtons, nuclei and gamma rays lose energy in intergalactic space
Proton energy vs. distance (J. Cronin)Energy loss on Cosmic Microwave Background
Protons:
Photo Pion production off CMB
p+cmb p/n+
Fe:
photo-dissociationInfrared Background
Photons: e+e -
Radio Background
The Basics
GZK Feature
Blasi, A.O. ‘01
The Basics
E3 Flux
E
The Recent Past
3 x 1020 eV“Super-GZK” event
Hadronic Primary! Proton? Fe? Not ?But only 1 event!
Fly’s Eye
1992
AGASAThe Recent Past
A Theorist’s Field Day
~ 10 events above 1020 eV
Isotropic + small scale clustering?
galactic plane
supergalactic plane
AGASA>4 x 1019 eV
Red squares : events above 1020 eV, green circles : events of (4 – 10)x1019 eV
The Recent Past
Bottom-Up
ZeVatrons Astrophysical Accelerators reach ZeV’s
Energy: ≥ 1020 eV is the 1st challenge(If 1 TeV is hard imagine 109 TeV!!)
Propagation: the 2nd challenge Bigm (determines the spectrum and arrival direction)
Acceleration = Macroscopic motions transferred to particles a la Fermi
Hillas plot: require particles to be contained, ie, Gyroradius < size of Accelerator
Not many objects left:Neutron Stars
AGNsRadio Lobes
ClustersColliding Galaxies/Clusters
Gamma Ray Bursts
The Recent Past
Hillas Plot
Gyroradius < size of Accelerator
The Recent Past
Neutron Stars:
Young Neutron
Star Winds?
Crab Nebula with Chandra
A Galactic Fe option!
(A.O., Epstein, Blasi ’99, Blasi, Epstein, A.O. ’00)
The Recent Past
Local Source Solution
New ComponentFrom Local Source!
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E-2
E-1
The Recent Past
YNSWsCOMPOSITION: Heavy, Fe
SPECTRUM: Hard & No GZK feature
GALACTIC correlations at highest energies
But if Extra Galactic…protons
Very Energetic (High B and ) YNSWs
cause extragalactic UHECRs,
Rare events with E-1 spectrum
A Milky Way event ~ 106 flux higher E > 1014 eV
Association with GRBs ...
(Arons ‘02, Konigl et al ‘02)
The Recent Past
AGNs:
Central Regions High energy Photons observed -
Emax≈1019-20 eV but too many losses
(Norman,Melrose, Achterberg ‘95)GZK plus Cosmography hurt.
Dead Quasars maybe but GZK cut!
(Bolt & Ghosh ‘99)
Radio Lobes
Emax≤ 1021 eV (Rachen & Bierman ‘93) Emax≤ 1022 eV (Bierman ‘00)
But, in general they are Too far!! Except for M87,
Need very specific BGal & Bigm
Other Extragalactic Sources:
But GZK plus local Hot Spot!!!!!!
The Recent Past
TheHot Spot
The Recent Past
Cluster Accretion Shocks
Emax≈1019-20 eV (Kang, Ryu, & Jones ‘96)
Even if energy is close, they don’t get out (Blasi ‘99)
Galactic Winds
Emax≈1019 eV (Jokopii & Morfill ‘85)
Gamma Ray Bursts (Vietri ‘95, Waxman ‘95)
Transient Relativistic Shocks
Similar p & emissivity
But need 102-103 more
for UHECRs
E/E ~1 or
needs Bigm ≥ 10-10 G E20/d30 /l10.5
NO Clusters
The Recent Past
BOTTOM -UP
Galactic Neutron Stars
Extragalactic Radio Lobes
Gamma Ray Bursts
Protons, Iron, nuclei?
Hard Spectrum
Strong Designer Magnetic Fields
to Isotropize
Clustering to be understood
The Recent Past
Half & Half Aproach:
New Particles from Astrophysical Zevatrons
For Ex: Uhecrons - Heavy-quark composites
(Chung, Farrar, & Kolb ‘98)
FE shower development says: Not above 50 GeV(Albuquerque, Farrar, & Kolb ‘98)
Monopoles (Weiler & Kephart‘96)No also: (FE shower development)Unless… (Wick, Kephart, Weiler & Bierman‘00)
UHE Neutrinos scatter off background: Z-pole (Fargion ‘99, Weiler ‘99)
Needs Very High Energy (High Flux) Neutrino Source (Sigl et al ‘02)
Tests: No Clustering!!! Photon primaries
The Recent Past
Top-Down Energy >> 1020 eV is Easy! (Usually start at 1023 eV or higher!!)
Flux is the challenge!! (determined by typical separation scales ~ H0-1)
& Composition!!
Topological Defectsgenerated in the early Universe through the Kibble Mechanism – as
symmetries are broken. (Hill 83, Hill, Schramm 82, Hill, Schramm, & Walker 87, Bhattacharjee, Hill, Schramm 92, Sigl, Bhattacharjee, Schramm 94)
Super Conducting Strings (Hill, Schramm &Walker ‘85)Cosmic Strings (Bhattacharjee & Rana ‘90)Monopolia (Hill 83, Bhattacharjee & Sigl 95)String Cusps (Brandenberger ‘87)Monop-String Network (Berezinsky Martin &Vilenkin97)Necklaces (Berezinsky & Vilenkin 97)Vortons (Masperi & Silva 98)
Super Heavy Relic particles long lived – weakly interacting = CDM Mx > 1012 GeV
Metastable (Kuzmin &Rubakov 97; Berezinsky, Kachelriess, &Vilenkin 97)Dark Matter – Halo Distribution - small percentage decays today - Cryptons, …
(Chung, Kolb, & Riotto 98, Kuzmin & Tkachev 98)
The Recent Past
Super Heavy Relics
Berezinsly, Blasi, Vilenkin `99
The Recent Past
Cosmic Necklaces
Berezinsly, Blasi, Vilenkin `99
The Recent Past
Top-Down Signatures
Composition: Photons >> Protons
Spectrum: Hard QCD fragmentation NOT Power law like the Zevatrons!
Cosmography: Halo Distribution!! (SHRs & Local TDs)or ~ Homogeneous
No Clustering! Unless CDM clumps
Violation of Lorentz Invariance
The Recent Past
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HiRes
Spectrum
HiRes Collab ‘02
The Present
HiRes vs.
AGASA
Spectrum
HiRes Collab ‘02
The Present
Exposures - systematics?
Teshima ‘02
The Present
Systematic Errors below 1019eV?
Teshima ‘02
The Present
AGASA vs. HiRes I mono, HiRes II mono
Teshima ‘02
The Present
UHECR: Discovery vs. Measurement
Fly’s Eye & AGASA - may have Discovered a
New Source of UHECRs
HiRes - may have Measured the GZK cutoff
"There are two possible outcomes: If the result confirms the hypothesis, then you've made a MEASUREMENT. If the result is contrary to the hypothesis, then you've made a DISCOVERY." Enrico Fermi
The Present
Auger - will Discover or Measure The Spectrum at EHEs
Theorists’ Attitudes
Theorist A Theorist B Theorist C Theorist D
Theorist B
HiRes Collab ‘02
Theorist B
Energy rescalings from 10 to 33%
HiRes Collab ‘02
Theorist B
Theorist B example
2 (one power law)=
2 (GRB) / 2
No AGASA data + re-scaling to Yakutsk data
Bahcall & Waxman ‘02
DeMarco et al ‘02
Theorist C
Blanton, Blasi, A.O. ‘01
Photo-Pion Production has large uncertainty with low statistics!!!!!!
Theorist C
Blanton, Blasi, A.O. ‘01
+ Evolution matters
DeMarco, Blasi, & A.O. ‘02
AGASA is better at probing the GZK feature than HiRes ‘02
Theorist C
Even with larger aperture Statistics are too low
Auger x
AGASA
DeMarco, Blasi, A.O. ‘02
Theorist C
HORIZONTAL SHOWERS will probe
Neutrino Cross Sections Above the Standard Model
Tau showers from the Earth or the Andes
Theorist D
Neutrino Fluxes
Tyler, A.O., Sigl, ‘01
Theorist D
HE Cross Section
Tyler, A.O., Sigl, ‘01
Limits on Large ExtraDimensions w/Production of Mini Black Holesp-Branes…
Feng, Shapere ‘01Anh, Cavaglia, A.O.’02and …
Theorist D
Neutrinos at Auger
Letessier-Selvon ‘00
Theorist D
EUSO Extreme Universe Space Observatory
UHE Neutrinos!
Theorist D
OWL
Ni Fluorescence from ABOVE!= 30 x Auger
3000 events/year E > 1020eV !!!
UHE Neutrinos!
Theorist D
JC pointing the way for ~10 yrs
Theorist A
Theorist A
Just 1570 to go!
Drives the Truck!
Theorist A’s other options
Hybrid Events & Horizontal Events
Sun 9 Dec. 02:56:45 2001 - Auger sees first hybrid event
Los Leones Bay 4 Tank Huron
The night before Jim Cronin’s event ... !
11 Fold Event 2.6 1019 eV
Fly’s Eye saw 0 !! But there are GZK ’s!!
(1019eV) ≤ 5 10-29cm2
Auger can reach ~ SM probe interactions beyond Standard
Model
(1019eV) ≥ SM ~10-30-31cm2
Auger can also detect decays!
(1017-18eV) produce ’s
Andes (50 km) or Ground (upward ’s)
Full mixing GZK ‘s !!!
(Tyler, A.O., Sigl, ‘01)
The Telescope Array