Probing the origin of UHECRs
with neutrinos
The recent results from IceCube and its outlook
Shigeru Yoshida
Department of Physics
ICEHAP, Chiba Universityν
UHECRs1

Neutrino Astronomy
Scan star core
Solar neutrinos comeExplore the energetic phenomenain the deep universe

from the Sun’s core

VLA image of Cygnus A
Visible lights are
emitted from its
surface

The High Energy Neutrino
Astronomy
2Why ν is so powerful
to explore high energy universe?
GZK
cutoffpγ 2.7 K → π ±+ X
→ μ ±+ν
→ e±+ν ' sγ + γ 2.7K

超銀河団SuperCluster

e+ + e-SDSS

Distant Young Universe
Our Galaxy

Super Cluster

3

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

TeV

PeVEeV

produced in the CMB fieldNot detected yet4

The Cosmic Neutrinos
Production Mechanisms“On-source” νp

TeV - PeVmatterp
raiontadi“GZK” cosmogenic ν
100EeV ppp Æ π Æ νγp Æ π Æ νphotopion productionνEeVCMBγp Æ π Æ ν5

The IceCube Neutrino Observatory
Cetlpom

2004: Project Start
1 string
2011: Project completion 86 strings

Full operation with all strings since May 2011

1002ecD:edConfiguration
chronology
2006: IC9
2007: IC22
2008: IC40
2009: IC59
2010: IC79
2011: IC86

PMT

6Digital Optical Module (DOM)

Detectors shipped from Japan

Constructions
2005-2011
Drill House

The IceCube Lab 「Beer Can」

Researchers working on deployment

7

Topological signatures ofIceCube events
Down-going track• atmospheric μ• secondary producedμ from νμτ from ντ @ >> PeV

Up-going track• atmospheric νμCascade (Shower)
directly induced by νinside the detector volume• via CC from νe• via NC from νe, νμ ,ντ8all 3 flavor sensitiveNeutrino Signatures
UHE (>100 PeV) VHE(>100 TeV)CRUHE νBackground:Atmospheric muonμ,τν e,τ,μμμμμ,τ

μVHE νμPost Bert & Ernie

The Discovery Analyses

10TeV

PeVEeVLE (<10 TeV)
CIceryanimilPreeub

IceCube 2 years data (2010-2012)

11TeVPeVEeVMid Energy (10 TeV-)
veto + “cascade”

CIceryanimilPreeub

12

TeV

PeV

EeV

Mid Energy (60 TeV-)
IceCube 3 years data (2010-2013)

2PeV“Big Bird”

IceCube collaboration
Phys. Rev. Lett. 113, 101101

13

TeV

PeV

EeV

Mid Energy (60 TeV-)
IceCube 3 years data (2010-2013)

BertBig Bird

Gal.CenterErnie

14

TeV

PeV

EeV

VHE (100 TeV-PeV)The “traditional” νμ searchlooking into upgoing tracks
IceCube 2 years data (2010-2012)νμ Æ μdetected as upgoing track

CIceryanimilrePube

3.9 σ excess
over the atmospheric BG
E2 φ (E)~9.6 x 10-9νμ[GeV/cm2 sec sr]
15Eν = O(100TeV)TeV

PeVEeVUHE (PeV-EeV)

The model-independent upper limit on flux
IceCube 2 years data (2010-2012)
systematics included

νe+μ+τ

IceCube collaboration
Phys. Rev. D 88, 112008

any model adjacent to the limit
is disfavored by the observation

19

TeV

PeV

EeV

UHE (PeV-EeV)

IceCube 6 years data (2008-2014) all combined
νe+μ+τ

ModelEvent Rate[/(2008-20014)]

Yoshida(FR-II compat.)

6.5Ahlers

5.0(Best fit to HiRes)

Ahlers(Minimum)

CIceryanimil
rePube1.1

Kotera(GRB)

3.9

Kotera(STF)

2.9
21

TeVPeVEeV

UHE (PeV-EeV)

IceCube 6 years data (2008-2014) all combined

CIceCebuolait
endifnSearch Results coming soon

22

The Cosmic Neutrinos
Production Mechanisms“On-source” νp

TeV - PeVmatterp
ra

onit
dia

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

νEeVCMBγp Æ π Æ ν23ν emission always accompanies γpγ
pp(p,n) π2γ

Fermi
observations !!

μνeνν

24

γ-ray sky bounds high energy ν emission
Fermi GeV γ-ray skyγν25

EBL cools energetic γ
Extra-galactic Background Light

26

Bounds on ppÆν by Fermi
Murase, Ahlers, Lacki, PRD 201327

if ppÆνa tension
with Fermi

if pγÆνno rich target
photons (~ X-rays)
to yield TeV ν’s

E ν ~ 10TeV(@ obs. framepγÆνEγ -1E γ -1)

1keV

threshold effectof the pγ reaction

E ν ~ 1 PeV ()10eVtarget γ visible light/IR
Ly α

Any other genericconstraints?
28

Constraints on the optical depth
and extra-galactic CR flux

praiontadiγp 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
29

Constraints on the optical depth
and extra-galactic CR flux
Yoshida, Takami
PRD (2014)

extra-galactic proton flux
must be > 10-2 ofthe all-particle CR flux
@ 10 PeV
optical depth mustbe > 10-2~30

Constraints on the optical depth
and extra-galactic CR flux
if they are also
100EeV CR sources

strongevolution

Quasars/FR-II
GRBs (internal shock)energetics

BL Lac/FR-I
GRBs (external shock)31

Suppose the PeV ν emitters
are also UHECR (E~100EeV)

Flux

t heo bssourceserve

d cosmic

ra yflux

extragalactic

extending to EeVsPν

TeVPeV

EeV
32

Constraints on the optical depth
and extra-galactic CR flux
• extra-galactic proton flux
must dominate
in the all-particle CR flux
@ 1 EeV(=1000PeV)• optical depth mustbe ~133

The numbers to challenge
Requirements@ 10PeVγp optical depth ~ 0.1
Proton emission energy budget
310PeV
45O(10%)x L CR ~ 10 erg/Mpc yr34

The numbers to challenge
Requirements@ 10PeVγp optical depth ~ 0.1
Proton emission energy budget
310PeV
45O(10%)x L CR ~ 10 erg/Mpc yr@EeV=1000PeV
if emitted proton spectrum extends further to this energy(this is probably easy to achieve)

γp optical depth ~ 1

Proton emission energy budget
1EeV~ LCR ~ 10 44erg/Mpc3 yr
45
L > 10 erg/sγ35

The numbers to challenge
GRBs@ 10PeV○γp optical depth ~ 0.1

×Proton emission energy budget
310PeV45
O(10%)x L CR ~ 10 erg/Mpc yr@EeV=1000PeV
if emitted proton spectrum extends further to this energy

×○◎(this is probably easy to achieve)

γp optical depth ~ 1

Proton emission energy budget
1EeV~ LCR ~ 10 44erg/Mpc3 yr
45
L > 10 erg/s
γ36

The numbers to challengeBlazars (BL Lac)
@ 10PeV×γp optical depth ~ 0.1△

Proton emission energy budget
310PeV45O(10%)x L CR ~ 10 erg/Mpc yr@EeV=1000PeV
if emitted proton spectrum extends further to this energy

×○○(this is probably easy to achieve)

γp optical depth ~ 1

Proton emission energy budget
1EeV~ LCR ~ 10 44erg/Mpc3 yr
45
L > 10 erg/s
γ37

The numbers to challenge
Blazars (FSRQs)@ 10PeV○γp optical depth ~ 0.1△

Proton emission energy budget
310PeV45O(10%)x L CR ~ 10 erg/Mpc yr@EeV=1000PeV
if emitted proton spectrum extends further to this energy

×○◎(this is probably easy to achieve)

γp optical depth ~ 1

Proton emission energy budget
1EeV~ LCR ~ 10 44erg/Mpc3 yr
45
L > 10 erg/s
γ38

An example of γp Æ ν models
ν emission from Blazars (FSRQs)
Murase, Inoue, Dermer, PRD 201439

An example of γpÆν models

ν emission from Blazars (FSRQs)

Murase, Inoue, Dermer, PRD 2014

Lp>>Lγruled out by IceCube EeV limit

imply most of EeV cosmic rays are from Blazars

no galactic cosmic rays at EeVs
No TeV emissionpp?

Not naturally explain the IceCube observations
40

The Cosmic Neutrinos
Production Mechanisms“On-source” νp

TeV - PeV
matter

p
ra

on
it
dia

“GZK” cosmogenic ν
100EeV ppp Æ π Æ νγp Æ π Æ νphotopion production

νEeV

CMBγp Æ π Æ ν41

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
100PeV

EeV

10EeV

why?
42

Tracing history of
the 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 arepenetrating overcosmological distances

frequent

Present

PastRedshift (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
43I ν @ 1EeV is an excellent indicator
GZK

presentIceCube
EnergyRange

PeVKotera, Allard, Olinto
JCAP 10 013 (2010)

pastemission rate

evolution dependence

for the UHECR emission history

EeV

redshiftν = early history of cosmic radiation!

44

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

45

GZK cosmogenic ν intensity @ 1EeVin the phase space of the emission history
Yoshida and Ishihara, PRD 85, 063002 (2012)ρ ~ (1+z)m0<z<zmax

GZK ν flux φ = (m, zmax)
x IceCube Exposure
Number of events
we should have detected

We have seen null events46

The Constraints on evolution(=emission history)of UHE cosmic ray sources
IceCube collaboration
Phys. Rev. D 88, 112008

ρ(z) ~ (1+z)mz<Zmax

The solid bound by
the GZK νAhlers et al, Astropart.Phys. 34 106 (2010)

edudStar Formation
Rateclex

GRBs

The best guessfrom the cosmic ray spectrum

AGNs withradio-loud jets

47

The Constraints on evolution(=emission history)of UHE cosmic ray sources
IceCube collaboration
Phys. Rev. D 88, 112008
exc

ρ(z) ~ (1+z)mz<Zmaxedlud

The solid bound by
the GZK ν
The region scanned by
IceCube 2008-2014

GRBsStar Formation
Ratecoming soon!
AGNs withradio-loud jets

48The Multi Messengers:UHE ν Æ γ (or any other messengers)

look up this direction!

ν“GFU”γ49

TeVPeV

EeV

UHE (PeV-EeV)
newOnline Analysis for γ-ray/optical follow-up

event topology separationtrack

χ2 for track hypothesis

tracknon track-like
like

cascade (non track-like)

50

TeV

PeV

EeV

UHE (PeV-EeV)
Online Analysis for γ-ray/optical follow-up
track

backgroundenergy proxysignalcos(zenith)cos(zenith)

3.8 event/year for νe+μ+τ ofE2φ = 3x10-8GeVm-2sec-1sr-1
GZK: ~ 0.3-0.9 event/yearWe will send you:

BG: ~ 2-3 event/year• direction• Energy (proxy)• rating of signal-likelihood

Δθ~0.3 deg51

Next Generation: IceCube HEX52

Next Generation: IceCube HEX
Photo-detector development
Two 8’ Hamamatsu R5912 High-QE PMTs
•up/down symmetry: good for veto, reco etc•two PMTs insead of one: Better saturation response
Maximal DiameterΦ284mm620mm

customized glass shape/curvature• designed best match curvature toour PMT• less thickness top/bottom part(9mm-10mm where PMT cceptance)
for better light transmittanceSlightly enhanced diameterand glass thickness in themiddle for a mechanicalstrength53

Two-PMT Optical Module
A baseline design
8” SBA PMT R5912-100

534 mm

φ 300

54

Two-PMT Optical Module
background: down-going muons
to be vetoed

up-down symmetry isbeneficial.

good signal:
up/horizontally-going track55

Next Generation: IceCube HEX
Photo-detector development
Glass + PMT assembly
8’ high-QE PMT

Lovely ballSilicon gel

56

Next Generation: IceCube HEX
Photo-detector development
QE@340nm

7% (present icecube) Æ 24%57

Next Generation: ARA58

Next Generation: ARA“end-to-end” calibration

Expected signals from ice

59

Executive Summary

ν = THE smoking gun

60