What the IceCube UHE ν results
tell about
the origin of UHE Cosmic Rays
Shigeru Yoshida
Chiba University

Shigeru Yoshida

1The Neutrino Flux: overview
Solar ν (8B)
SN relic νAtmospheric ν
The main background for astro-ν“On-source” astro-ν
produced at the UHECR sources
Not established yet“GZK” cosmogenic ν
MeV
Shigeru Yoshida

GeV

TeV

PeVEeV

produced in the CMB fieldNot detected yet
6The Cosmic Neutrinos
Production Mechanisms“On-source” νp

TeV - PeVmatterpraiontadi“GZK” cosmogenic ν100EeV ppp Æ π Æ νγp Æ π Æ νphotopion production

νEeVCMBγp Æ π Æ νShigeru Yoshida

7

The executive summary
The model-independent
upper limit on flux in UHE

null observationin this regime
nearly exclude• radio-loud AGN jets
• m>4 for (1+z)m• emission maximallyallowed by the Fermi γTeV
all flavor sumShigeru Yoshida

PeV

EeV

Bert & Ernie + O(10) sub-PeV events
4.1 σ excess over atmospheric

8The executive summary
atmosphericbackground

The model-independent
on-source ν GZK cosmogenic upper limit on flux in UHE
ex. AGN, GRB

null observationin this regime
nearly exclude• radio-loud AGN jets
• m>4 for (1+z)m• emission maximallyallowed by the Fermi γ
TeV
all flavor sum

Shigeru Yoshida

PeVEeV

Bert & Ernie + O(10) sub-PeV events
4.1 σ excess over atmospheric9Effective Areas
expanding down to 100 TeV’s
Area x ν flux x 4π x livetime = event rate
IC79+IC86 livetime 670.1 days

Shigeru Yoshida

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The Cosmic Neutrinos
Production Mechanisms“On-source” νp

TeV - PeVmatterp
raonitdia“GZK” cosmogenic ν100EeV ppp Æ π Æ νγp Æ π Æ νphotopion production

νEeVCMBγp Æ π Æ νShigeru Yoshida

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UHE cosmic ray and GZK ν fluxes
Cosmic Ray flux
(IceTop)

UHE CR flux
(Auger/TA)

GZK cosmogenic ν’sallowed range of the ν flux
Ahlers et al, Astropart.Phys. 34 106 (2010)the ν fluxes from strongly
evolved and no evolved sources
SY et al, Prog.Theo.Phys. 89 833(1993)

Ranges more than an orderof magnitude
100PeVEeV

10EeVwhy?
Shigeru Yoshida12Tracing history ofthe particle emissions with ν flux
color : emission rate of ultra-high energy particles
rare

Intensity gets higher
if the emission is more
active in the pastνbecause ν beams are
penetrating overcosmological distances

frequent

Present

Past

Redshift (z)Hopkins and Beacom, Astrophys. J. 651 142 (2006)

The cosmological evolution
Many indications that the past wasmore active.

Star formation rateÆThe spectral emission rate

ρ(z) ~ (1+z)mm= 0 : No evolution
Shigeru Yoshida13I ν @ 1EeV is an excellent indicator
GZK

for the UHECR emission history

Emax dependence

IceCubeEnergy
Range
PeV

EeV

IceCube collaboration
PRD 83 092003 (2011)

EeVTransition model dependence
Ahlers et al, Astropart.Phys. 34 106 (2010)

Kotera, Allard, Olinto
JCAP 10 013 (2010)

PeV

EeV

Shigeru Yoshida“Dip” model“Ankle” model 14

I ν @ 1EeV is an excellent indicator
GZK

present

IceCubeEnergyRange

PeV
Kotera, Allard, Olinto
JCAP 10 013 (2010)

pastemission rate

evolution dependence

for the UHECR emission history

EeVredshiftν = early history of cosmic radiation!

Shigeru Yoshida

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GZK cosmogenic ν flux estimates:model-independent analytical approach
Yoshida and Ishihara, PRD 85, 063002 (2012)

Adding up contribution from sources at zEmission rate per comoving volume~(1+z)mν yield in the CMB field with EGEN=Eν(1+zν) from UHECR proton
emitted from sources at z>zν. zν; redshift when generates ν

Semi-analytically computable when
1. neglect IR/O background – ν is generated only by pγCMB
2. photo-pion production only via Δ-resonance3. simplify the pγ collision kinematics as a single pion production
4. approximate UHECR energy attenuation length as a constant above 1020 eVUsable as GZK ν version of Waxman-Bahcal Formula
Shigeru Yoshida16Ultra-high energy ν intensity

depends on the emission rate in far-universe

intensity above 1 EeV(=1018 eV)

Yoshida and Ishihara, PRD 85, 063002 (2012)

more than an order ofmagnitude difference

ρ(z) ~ (1+z)m“quiet”“dynamic”

particle emissions in far-universe

Shigeru Yoshida

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GZK cosmogenic ν intensity @ 1EeVin the phase space of the emission history
Yoshida and Ishihara, PRD 85, 063002 (2012)

GZK ν flux φ = (m, zmax)

ρ ~ (1+z)m0<z<zmax

x IceCube Exposure
Number of events
we should have detected

We have seen null events

Shigeru Yoshida

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The Constraints on evolution(=emission history)of UHE cosmic ray sources
ρ(z) ~ (1+z)mz<Zmax

Ahlers et al, Astropart.Phys. 34 106 (2010)

Shigeru Yoshida

edudStar Formation
RateclexGRBs

The best guessfrom the cosmic ray spectrum

AGNs withradio-loud jets

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The Cosmic Neutrinos
Production Mechanisms“On-source” νp

TeV - PeVmatterpra

onit
dia

“GZK” cosmogenic ν100EeV ppp Æ π Æ νγp Æ π Æ νphotopion production

νEeVCMBγp Æ π Æ νShigeru Yoshida

20

The executive summary
atmosphericbackground

The model-independent
on-source ν GZK cosmogenic upper limit on flux in UHE
ex. AGN, GRB

null observationin this regime
nearly exclude• radio-loud AGN jets
• m>4 for (1+z)m• emission maximallyallowed by the Fermi γ
TeV
all flavor sumShigeru Yoshida

PeVEeV

Bert & Ernie + O(10) sub-PeV events
4.1 σ excess over atmospheric

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The on-source PeV ν : many scenarios.
involving lots of uncertain parameters

extra-galactic

galacticexotic• AGN cores, Stecker, arXiv:1305.7404• Distant AGNs + EBLs, Kalashev et al PRL 111, 041103 (2013)• Low-Power GRB jets, Murase and Ioka, arXiv:1306.2274• Extragalactic pp collisions, Murase, Ahlers, Lacki, arXiv:1306.3417• Galactic diffuse with the interstellar matter, Gupta, arXiv:1305.4123• Galactic TeV UnID sources, Fox et al arXiv:1305.6606• Dark matter with PeV mass, Esmaili and Serpico, arXiv:1308.1105

and many more!!

Shigeru Yoshida

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(My) Assumptions on
the “on-source” TeV-PeV ν• They are extra-galactic• γp Æ π’s (not ppÆπ’s)
for pp, see Murase, Ahlers, Lacki (2013)

The generic consequence – you need γ targetγpγ(Eπ/Ep)(1-mμ2/mπ2) (mΔ2-mp2)/4Eν ~< Γ2Eγ

max -1
E> 1 Γ2 ( ν[eV]Eγ ~10PeV(γconsistent with AGN(Γ~1) or GRBs (Γ~1000)
Shigeru Yoshida

What else can we say in general ?

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On-source ν flux estimates:model-independent analytical approach
Adding up contribution from sources at zEmission rate per comoving volume~(1+z)mν yield with EGEN=Eν(1+zν) from UHECR proton
emitted from sources at z>zν. zν; redshift when generates νdJν ~ F
Rcosmic -α τ(E) ζ(z, m, z , E)
EGZK CR
maxdE
RGZK

Shigeru Yoshida24On-source ν flux estimates:model-independent analytical approachpraiontadiγp Æ π Æ ννphotopion production

optical depth(<1)

dJν ~ FRcosmic -α τ(E) ζ(z, m, z , E)E
GZK CRmaxdE
RGZK
Primary Extragalactic
CR proton flux ~E-α

The cosmological termto account the source evolution

We do NOT know how large: strongly depends on α
Shigeru Yoshida

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The Cosmic Ray Spectrum
The relevant • extra-galactic fraction?
• proton or heavy?
range
The ν observation
bounds extra-galactic
p flux!
Kascade-G “Light”

TeVPeV

EeV

Recompiled from the ICRC 2013 Rapporteur talk (Y.Tsunesada)
Shigeru Yoshida26

Constraints on the optical depth
and extra-galactic CR flux

pra

iontadiγp Æ π Æ ννphotopion production

optical depth(<1)

dJν ~ F
Rcosmic -α τ(E) ζ(z, m, z , E)
EGZK CRmaxdE
RGZK
Fixed to the Star Formation Rate
Constrain them by
the IceCube 100TeV-PeV observation
Shigeru Yoshida

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The “on-source” ν fluxes=Integral flux

α dependences(unknown) extra-galactic
proton flux dependences

On-Source
PeV
Shigeru Yoshida

GZKEeV28

Constraints on the optical depth
and extra-galactic CR fluxall particle cosmic ray flux
(data by IceTop)the highest bounddue to the observed flux
KASCADE-Grande“light” component

the lowest bounddue to τ<1PeV

Shigeru Yoshida

10PeV100PeV

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Constraints on the optical depth
and extra-galactic CR flux

extra-galactic proton flux
must be > 10-2 ofthe all-particle CR flux
@ 10 PeV
optical depth mustbe > 10-2~

Shigeru Yoshida

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The Constraints on evolution(=emission history)of UHE cosmic ray sourcespraiontadiγp Æ π Æ ννphotopion production

optical depth(<1)

dJν ~ F
Rcosmic -α τ(E) ζ(z, m, z , E)E
GZK CRmaxdE
RGZK
Fixed to E-2.3
Shigeru Yoshida

Constrain them by
the IceCube 100TeV-PeV observation
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The “on-source” ν fluxes

Shigeru Yoshida32

The Constraints on evolution(=emission history)of UHE cosmic ray sourcesedludShigeru Yoshidaexcρ(z) ~ (1+z)mz<Zmax

The solid bound by
the GZK ν

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The Constraints on evolution(=emission history)of UHE cosmic ray sources
exc
edlud

ρ(z) ~ (1+z)mz<Zmax

The solid bound bythe GZK ν+
by the on-source νShigeru Yoshida

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The Constraints on evolution(=emission history)of UHE cosmic ray sources
ρ(z) ~ (1+z)mz<Zmax

The solid bound by
the GZK νexc+
by the on-source νed
lud+by the on-source ν
if optical depth ~1
no high-redshift emission
consistent withthe star formation rate

Shigeru Yoshida

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Conclusion: The ν has indicated that…
IF the extra-galactic UHE cosmic rays are protons
The cosmic ray sources (whatever they are) are not strongly
evolving with cosmic time.
• disfavors far sources like quasars and radio-loud AGNs
• may still OK GRBs – we need to know their rate better.
If they are also effective PeV neutrino emitters (i.e., τ~1), must be
no sizable evolution – the emission is mostly at z<<2
• just like a (boring) standard star following the star formation rate
The PeV ν emitters, if via pγ, are responsible for only ~O(1 %) of
the observed cosmic ray bulk at O(10 PeV)or must be optically very thin (τ<<1), otherwise• extra-galactic proton spectrum is likely harder thanthe observed all particle cosmic ray spectrum beyond knee
Shigeru Yoshida36

A Personal View:
Diffuse Search Vs. Point Sources• Looks boooooooooring• But the intensity and even its limit
would provide rich implications• ν is sensitive to (unresloved) dim emission
Shigeru Yoshida• Looks coooooooooool!
• But doesn’t mean anything• ν ‘s are NOT local messengers –no good at resolving sources
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A Personal View:
Diffuse Search Vs. Point Sources

But we want to ID a source(s) in the end!
This isTHE UHECR SOURCE!

PKS0XYZ+0xy(ICECUBE J1XYZ-3xy)

Shigeru Yoshida

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The Multi Messengers:
UHE ν Æ γ

look up this direction!

νShigeru Yoshida“GFU”γ39

The Multi Messengers:
UHE ν Æ γ
The IceCube UHE ν search
signalbackground• sensitive to ν > O(10PeV)• the robust algorithm~ 2 events/year for νe+μ+τ ofE2φ = 3x10-8GeVm-2sec-1sr-1
BG: ~ 0.1 event/year
newcascade

track

event topology separationΔθ~1degShigeru Yoshida

40The Multi Messengers:
UHE ν Æ γ This is the next movethe detection sensitivity
flavor dependence
preliminary

Shigeru Yoshidaof the Japan’s IceCube groupdeclination dependence
preliminarydec. -30~0 = southern sky!
Æ H.E.S.S.
Æ VERITAS with Large ZenithÆ MAGIC?
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Shigeru Yoshida42