1. Shigeru Yoshida and Aya Ishihara
Constraints on the origins of the ultra-high energy cosmic-rays using the IceCube diffuse neutrino limits
Shigeru Yoshida and Aya Ishihara
Department of Physics
Chiba University

2. IceCube is reaching to the GZK regime
A.Ishihara for the IceCube collaboration ICRC (2011)
¼ IceCube
½ IceCube 2009
Full IceCube sensitivity
(MC)

3. IceCube is reaching to the GZK regime
IceCube collaboration (Corres. A. Ishihara) PRD (2011)
Models
The half IceCube
# of events
The full IceCube
(3 years)
　GZK1 (Yoshida et al) *
0.57
3.1
　GZK2 Strong Evol. (Sigl) **
0.91 (C.L 53.4%)
4.9
　GZK3 (ESS with WL=0.0) ***
0.29
1.5
　GZK4 (ESS with WL=0.7) ***
0.47
2.5
　GZK5 (Ahlers max) ****
0.89 (C.L 52.8%)
4.8
　GZK6 (Ahlers best fit) ****
0.43
2.3
　Z-Burst #
1.03 (C.L 55.7%)
5.1
　Top Down(SUSY) ##
5.68 (C.L 99.6%)
31.6
　Top Down(QCD) ###
1.19 (C.L 66.4%)
6.3
　W&B(evol) ^
3.7
24.5
　W&B(no evol) ^
1.1
5.5

4. “GZK” n = history of UHECR radiation
Yoshida and Teshima, Prog.Theo.Phys (1993)
m=4
In < 1 EeV
 source evolution
m=2
~ (1+z)m
In > 10 EeV
 Emax
Emax =1022 eV
Emax =1021 eV

5. In @ 1EeV is robust against
Kotera, Allard, Olinto JCAP (2010)
Emax dependence
IceCube
Energy
Range
IceCube collaboration (Corres. A. Ishihara)
PRD (2011)
Transition model dependence
1EeV is robust against
Emax and UHECR transition model

6. Identify UHECR sources by measurement of cosmological evolution
Kotera, Allard, Olinto JCAP (2010)
Evolution Curve
IceCube
Energy
Range
GZK n
early history of cosmic radiation!

7. GZK cosmogenic n flux estimates: model-independent analytical approach
Adding up contribution from sources at z
Emission rate per comoving volume
~(1+z)m
n yield with EGEN=En(1+zn) from UHECR proton
emitted from sources at z>zn. zn; redshift when generates n
Semi-analytically computable when
neglect IR/O background – n is generated only by pgCMB
photo-pion production only via D-resonance
simplify the pg collision kinematics as a single pion production
approximate UHECR energy attenuation length as a constant above 1020 eV
Usable as GZK n version of Waxman-Bahcall Formula

8. Comparison with the “full-blown” MC
IceCube
Energy
Range
Remarkable agreement
around En~ 1EeV
departure at En<100PeV
due to the far-IR contribution
and D-resonance approximation
departure at En>5EeV
Analytical formula
due to Emax, E-a dependence
Numerical/MC
Provides reasonable estimates
In the IceCube energy range
within uncertainty of ~factor of two
uncertain far-IR roles
uncertain UHECR flux
accuracy of the approx.
consistent with

9. Constraints on UHECR source evolution
At present --- a half IceCube run
IceCube collaboration PRD (2011)
r ~ (1+z)m
0<z<zmax
Already disfavors
AGN radio-loud jet
as UHECR emitter
AGN
FR II

10. Constraints on UHECR source evolution
In 3 years --- full IceCube 5 year run
r ~ (1+z)m
0<z<zmax
IF null detection…
Completely rule out
AGN radio-loud jet
as UHECR emitter
AGN
FR II

11. Constraints on UHECR source evolution
In 3 years --- full IceCube 5 year run
GRB
r ~ (1+z)m
0<z<1
IF null detection…
r ~ const.
1<z<zmax
SFR
Disfavors
GRB/normal galaxies
as UHECR emitter
UHECR composition hypothesis
(proton dominated)
now in question!

12. Summary and Conclusion
GZK n search by IceCube puts solid constraints on UHECR source evolution
insensitive to uncertain radio, IR/O BSL and B in contrast to the bound by the Fermi diffuse g limit (ex. Ahlers et al Astropart.Phys. 2010)
UHE n detection rate at O(EeV) is a practical indicator of the source evolution realizable by IceCube, ARA, ARIANNA etc.
A null detection by IceCube would suggest UHECR sources are very weakly evolved with m<3 or heavy nuclei composition

13. Backup

14. GZK cosmogenic n estimates: derivation from the energetics
Similar method used in
Wang, Liu, Aharonian, ApJ (2011)
Total energy channeling into n relative to injected p energy
(Engel Seckel, Stanev PRD )
Pros:
No D-resonance approximation 
better description for low En
This method
Cons:
Significant overestimation of flux for
higher En, and consequently, high-Z epochs
because it neglects attenuation of UHECR flux
by the GZK mechanism