UHE Neutrinos: II
25 June, 2006
D. Seckel, Univ. of Delaware
Topics
• Models w/focus on GZK
• Radio concept
• Coherent Radiation from Showers
• Radio/Acoustic
• Model independent limits
UHE Models, Erice, 25 June 2006 (Seckel)
Overview of UHE models
• Proton acceleration models & UHE neutrinos
• Top-down scenarios
• Focus on GZK
– Techniques
– Cosmic evolution & model parameters
– Reasonable, Guaranteed?
UHE Models, Erice, 25 June 2006 (Seckel)
Neutrinos from accelerated protons
• Lots of evidence for shock acceleration
– SN remnants & TeV g‟s
– AGN, GRB, m-quasars, etc.
• Power law spectrum
– E-2, maybe a bit softer
• En ~ 1/20 Ep
UHE Models, Erice, 25 June 2006 (Seckel)
UHE Production: Acceleration
1. Acceleration predictions depend on scenario – could be “no n‟s”.
2. “GZK” neutrinos are guaranteed – a guide for experiment design.
3. Still some model dependence.
4. Constraints from EGRET & UHECR
5. En ~ .05 Ep
UHE Models, Erice, 25 June 2006 (Seckel)
Waxman & Bahcall “limit”
• Assume
– Relativistic shock limit
– Flat, i.e. equal energy per decade
• Normalize to UHE CR @ 1019 GeV
– Above Galaxy
– Below GZK
• Yield 1 neutrino per proton
– t=1 source ?
– Neutron escape v. acceleration
• Not a “limit” – think of as scale due to energy budget
UHE Models, Erice, 25 June 2006 (Seckel)
Top down models
UHE Models, Erice, 25 June 2006 (Seckel)
Jet Fragmentation
color
1. Mesons & Baryons created with same E distribution
2. Mesons more numerous by 20
3. n and g fluxes much higher than for “bottom up”
UHE Models, Erice, 25 June 2006 (Seckel)
UHE production: top down
1. For “direct” production, En > Ep
2. #direct > #p
3. Constraints from EGRET
4. “GZK” there, but unimportant
UHE Models, Erice, 25 June 2006 (Seckel)
Typical summary of models
UHE Models, Erice, 25 June 2006 (Seckel)
GZK neutrinos
These exist (AGASA, HiRes, Auger..)
CMBR is observed
Cross-sections are known
Lorentz invariance
Robust prediction for
n and g
UHE Models, Erice, 25 June 2006 (Seckel)
GZK cosmic cascade codes
• propagation & dE/dx
– adiabatic (cosmic expansion)
– photonuclear: g+p B+X (ESS use SOPHIA)
– pair production: g+p pe+e-
• source characteristics
– injection spectrum dN/dE ~ E-(1+g)
– source cutoff Ec
– luminosity (ESS – normalize to UHECR, KKSS limit from EGRET)
– homogenous
• cosmology
– integrate over red-shift
– source evolution: (1+z)m, zmax
– H0, L…
UHE Models, Erice, 25 June 2006 (Seckel)
dE/dx (g+p B+X (SOPHIA))
More to life than the D-resonance
En / Eem
En / E p
UHE Models, Erice, 25 June 2006 (Seckel)
Neutrino yield
m
p
e
UHE Models, Erice, 25 June 2006 (Seckel)
Spectrum and source evolution
• Simple scaling with m, g for matter dominated
Factors of q for p and g
q=1+z
Shift energy of yield
Change magnitude of yield
with epoch
with epoch
UHE Models, Erice, 25 June 2006 (Seckel)
Simple scaling of GZK
g =1.5, m = 0 • Spectrum: (Ep)-(1+g)
• Evolution (1+z)m
g =1.0, m = 0.5
• Matter dominated cosmology (1+z)-5/2
• Spacing D(ln q) = 1 dB
g =1.0, m = 0
• Shape of Y changes with g
g =1.5, m = 3
UHE Models, Erice, 25 June 2006 (Seckel)
ESS result for a “reasonable” model
• Model
– m=3, zmax = 1.9, flat to 2.7,
rolloff for z > 2.7.
– Log Ec = 21.5
– Norm. (19 1 EeV hadronic-showers – y = .2
– 3 flavors * (CC + NC) = 4.5 channels
– No LPM - no p0 decay above a few PeV (coincidence).
UHE Models, Erice, 25 June 2006 (Seckel)
Hadronic showers II. (HM)
Excess charge
Wider in q suggests
E-field @ 1 GHz shorter shower.
Contained charge @1/GHz
• Size similar to AZ
• Same RM ? (Affects Gy) – also see S. Klein
• Difference between proton and jet (Gz)?
• What about charm (~10%)?
UHE Models, Erice, 25 June 2006 (Seckel)
Scaling with medium
AVZ scaled
G4: From S. Hussain
Yield of projected track length
UHE Models, Erice, 25 June 2006 (Seckel)
Phases & Pulse shapes
Time domain pulse for 10 TeV shower at 2°
0.4
0.3
0.2
Hussain: G4 10 TeV shower, reconstructed complex
E(w) at q = (-4,-2,0,2,4), FFT => E(t) 0.1
E
0
-0.1
-0.2
-0.3
Comparison to AVZ scaled at q=4. AVZ pulse shape
symmetric bipolar. Comparison shown with and -6 -4 -2 0 2 4 6
t ns
Without filter
f0avz ,gyavz ,gzavz ,phisavz
If r(t) symmetric, Gz is real, f=0. inGz will transform to 150
dnu : 0.02 eev : 0.01
time derivative of r will be bipolar symmetric. If not, 100 nu0 : 20.48 d : 4.
then f0, asymmetric shape. Changes sign with q. mat : ice r: 0.00001
50
V cm
type : em
0
-50
E -100
-150
-4 -2 0 2 4
t ns
UHE Models, Erice, 25 June 2006 (Seckel)
Gamma is a better pulse shape
• Without phases AVZ effectively gaussian shower
profile.
• Gamma function is approximation to shower
profile.
• Causal, analytic phase, easy to scale.
f0avz ,gyavz ,gzgam ,phisgam
150 dnu : 0.02 eev : 0.01
nu0 : 20.48 d : 4.
100 mat : ice r: 0.00001
V cm
type : em
50
E 0
• Comparison to G4 -50
-100
-4 -2 0 2 4
t ns
UHE Models, Erice, 25 June 2006 (Seckel)
Determine Gy, Gz from G4 shower & test
f0sh ,gysh ,gzsh ,phisavz f0sh ,gysh ,gzsh ,phisavz f0sh ,gysh ,gzsh ,phisavz
750
dnu : 0.02 eev : 1 300 dnu : 0.02 eev : 1 dnu : 0.02 eev : 1
100 nu0 : 5.12 d : 4. nu0 : 5.12 d : 2. 500 nu0 : 5.12 d : 0.
mat : ice r: 1 200 mat : ice r: 1 mat : ice r: 1
250
V cm
V cm
V cm
50 type : em 100 type : em type : em
0 0
0 -250
-100
E
E
E
-50 -200 Gz -500 Gy
-300 -750
-4 -2 0 2 4 -4 -2 0 2 4 -4 -2 0 2 4
t ns t ns t ns
f0sh ,gysh ,gzsh ,phisavz f0sh ,gysh ,gzsh ,phisavz
300 dnu : 0.02 eev : 1 dnu : 0.02 eev : 1
200 nu0 : 5.12 d : 2. 50 nu0 : 5.12 d : 4.
100 mat : ice r: 1 mat : ice r: 1
V cm
V cm
type : em 0 type : em
0
-100 -50
-200
E
E
-300 -100
-400
-4 -2 0 2 4 -4 -2 0 2 4
t ns t ns
Spectrum at q = (-4,-2,0,2,4) from Hussein.
Use q = 0 to get f0, Gy
Use q = -2 to get Gz
q = (-4,2,4) from scaling, with phase part of Gz
UHE Models, Erice, 25 June 2006 (Seckel)
Multiple showers & fluctuations
Comparison of RF signal from split shower black to original red
ne CC events
Separation of 4. m, distance 1km , d 4°, e 1
• 0.000075
0.00005
0.000025
m V cm
0
• Multiple interactions
E
-0.000025
-0.00005
-0.000075
• Model fluctuations by
-4 -2 0 2 4
t ns
adding subshowers
from beginning of
shower ?
• Fluctuations from
distribution a,b ?
UHE Models, Erice, 25 June 2006 (Seckel)
Acoustic
• Same as radio…. except
– scalar vs vector
– total track length
– v/c is (a bit) smaller
– Attenuation is different
– experiment bandwidth
• See more information in talk by C. Spiering
UHE Models, Erice, 25 June 2006 (Seckel)
Acoustic detection contours in ice (Vanderbroucke)
Contours for Pthr =
9 mPa:
raw discriminator,
no filter
UHE Models, Erice, 25 June 2006 (Seckel)
Radio & Acoustic
• Radio
– Ice: in-situ (RICE, AURA, …)
– Ice: remote (ANITA, FORTE, Europa)
– Salt: in-situ (SALSA)
– Rock: remote (GLUE, NuMoon, LORD, …)
• Acoustic
– Water (SAUND, ACORnE, KM3)
– Ice ( SPATS, Hybrid IceCube Extension: (ORA))
UHE Models, Erice, 25 June 2006 (Seckel)
Antarctic Impulsive Transient Antenna (ANITA)
Peter Gorham
UHE Models, Erice, 25 June 2006 (Seckel)
ANITA-Lite: Dec ‟03-Jan „04
TIGER/ANITA-lite
flight path, 18d 5hr
duration
UHE Models, Erice, 25 June 2006 (Seckel)
ANITA-lite
UHE Models, Erice, 25 June 2006 (Seckel)
ANITA @ SLAC
UHE Models, Erice, 25 June 2006 (Seckel)
In-ice AURA
• Askaryan Underice Radio Array
• Long term goal
• Design issues
UHE Models, Erice, 25 June 2006 (Seckel)
10 year goals
• Completed Detector
– 1000 km3 sr
– Ethr 200 m
0 1000 2000 3000 4000 5000
r m
UHE Models, Erice, 25 June 2006 (Seckel)
Timing & vertex reconstruction
• 10 ns relative timing across array, for event
reconstruction and pointing.
• Achievable with current IceCube DOM
technology
UHE Models, Erice, 25 June 2006 (Seckel)
AURA design (Ratlaff)
UHE Models, Erice, 25 June 2006 (Seckel)
More on AURA
UHE Models, Erice, 25 June 2006 (Seckel)
Acoustic at Pole (Boser)
• Status
– Technique theoretically understood, but…
– Attenuation ?
– Background Noise ?
• South Pole Acoustic Test System (SPATS)
– Instruments in three holes (2006/7)
UHE Models, Erice, 25 June 2006 (Seckel)
Radio/Acoustic/Optical at SP (Besson etal)
UHE Models, Erice, 25 June 2006 (Seckel)
SALSA: RF in salt domes
• Pro:
– Salt domes are common
– Cf ice: r=2.22, n=2.43
– Shielded by overburden
• Questions:
– ? attenuation
– ? drilling costs
UHE Models, Erice, 25 June 2006 (Seckel)
Lunar observations: GLUE
UHE Models, Erice, 25 June 2006 (Seckel)
NuMoon (Scholten et al)
Vacuum
3 GHz
θc
Cosmic particle
interaction
Vacuum
100 MHz
θc
Cosmic particle
interaction
UHE Models, Erice, 25 June 2006 (Seckel)
NuMoon II
UHE Models, Erice, 25 June 2006 (Seckel)
Model Independent Limits
• Goals
– Reasonable, easy to apply, limits for theorists – must be fair to both
experiments and models!
– Fair comparison of experiments
• I. Collection of Models
– Good: Always correct.
– Bad: Hard to make graphical without misleading, not comprehensive,
selection of models is subjective. May favor one exp. over another.
• II. Model Independent Bins
– Good: Easy to describe, and compare. Model independent.
– Bad: ad-hoc bin sizes. Not justified. Not really model independent. Common
use tends to underestimate experimental reach. Convention not established
• Proposal: MI bins with underlying flux model ~1/EA
– Good: Independent of physics model, characterized by experiment. Easy to
compare experiments. Improves on scheme in common use. Graphical
representation has reasonable meaning, and fairly represents experiments.
– Bad: Community acceptance of yet another scheme?
UHE Models, Erice, 25 June 2006 (Seckel)
Collection of model limits, e.g. RICE
UHE Models, Erice, 25 June 2006 (Seckel)
This is just like the figure above. Not so Ad-Hoc anymore,
but why does it work?
UHE Models, Erice, 25 June 2006 (Seckel)
Power Law Models
UHE Models, Erice, 25 June 2006 (Seckel)
Bin size: D, limits
• D
• Curvature:
• D=3
• D=h-6
• Limits
UHE Models, Erice, 25 June 2006 (Seckel)
Summary
• UHE Models
– p-acceleration, top down
– GZK: robust, test of source models
• Radio detection
– Large volume due to long attenuation
– RF pulse calculations
• Radio & Acoustic Exps
– RICE, ANITA, AURA, GLUE, NuMoon (others)
– South Pole acoustic tests
• Model independent limits
UHE Models, Erice, 25 June 2006 (Seckel)