Latest	
  results	
  of	
  the	
  IceCube	
  experiment	
  -­‐	
  Especially	
  the	
  extremely	
  high	  energy	  cosmogenic	
  neutrino	
  search	
  K.	
  Mase,	  Chiba	
  Univ.	
  1	
 n Cosmic	
  rays	  Ø Firstly	
  detected	
  by	
  V.	
  F.	
  Hess	
  in	
  
1912	
  
Ø Wide	
  energy	
  spectrum	  (109-­‐21	
  eV).	
  (1eV:	
  ~visible	
  light)	
  Ø Believed	
  to	
  be	
  accelerated	
  in	
  a	
  
shock	  of	
  a	
  source	  Ø The	  origin	  not	
  fully	
  understood	
  
yet!	
  
Knee	
 
EHECRs	
 

LHC	
 
LHC	
 can	
 reach	 Ankle	 V.	
  F.	
  Hess	
  

2	
 

■	
  But,	
  where?	
  Tycho	
 Where	  are	
  cosmic	
  rays	  generated?	
  
→	
  we	
  don't	
  know	
  yet	  
	  (We	
  know	
  where	  electrons	
  are	
  accelerated)	
  →	
  Neutrinos	
  can	
  tag	
  it.	  	  in	
  case	  of	
  a	
  photo-­‐pion	  Note:	
  producMon,	
  roughly	
  same	  energy	
  amount	  goes	
  to	
  neutrinos	
  and	
  gammas	  	  	
   p + ! ! n + " + ! n + µ + # µ	  ! n + e + # e + 2# µ	   p + ! ! p + " 0	  ! p + 2!

Even	
  more	  if	
  we	
  consider	
  gamma-­‐ray	
  absorpMon.	
  

ApJ.	
  LeR.,	
  744	  L2	  (2012)	
 3	
 ■ Neutrinos should be thereThe	
  source	
  of	
  cosmic	
  rays	  are	  the	
  neutrino	
  source	  	
  p! ! n" + ! µ# µ

Waxman-­‐Bahcall	
  limit	  E.	
  Waxman	  and	  J.	
  Bahcall,	
  PRD,	
  59,	
  023002	
  (1998)	
 Limit	
  from	  observed	
  CR	
  (opMcally	
  thin	
  assumed)	
 "c 2 dN! CR
E !! µ = # Z t H
ECR
8
4$
dECR
2
!

Baikalε:	
  fracMon	
  of	
  energy	
  going	
  to	
  neutrinos	
  ξz:	
  cosmological	
  evoluMon	
  (order	
  unity)	
  If	
  ε=1,	
  WB	
  limit	  2"

AMANDA II

WB	  limit	  Full IceCube 1 yr (expect)

&8

&2 &1

E #" µ $ 2 %10 GeV cm s sr

&1

The	
  sensiMvity	
  of	
  1	
  km3	
  size	  ! detector	
  is	
  lower	
  than	
  WB	
  limit.	
  4	
 ■ The physics of IceCube
Want	
  to	
  open	
  the	
  neutrino	
  astronomy	   AGNs GRBs Cosmic ray origin

 GZK neutrinos
 Supernova

 Dark Matter particle physics

 Exiotic(monopole, Q-ball, etc…)
5	
 

■	
  The	
  IceCube	
  experiment	  ² Deployed	
  in	
  the	  AntarcMca	
  glacier	
  IceTop	

IceCube	² In-­‐ice	
  +	
  IceTop	
  +	
  deep	  core	  ² 86	
  strings	
  (completed	
  2010!)	
  ² ~	
  5,000	
  photo-­‐mulMplier	
  tubes	
  (PMTs)	
  ² Detector	
  volume:	
  ~	
  1	
  km3	  ² ATWD	  300MSPS	
  
	
  	
  	
  	
  	
  	
  	
  3	
  diﬀerent	
  gains	
  (x16,	
  x2,	
  x0.25)	
  ² FADC	  for	
  long	  duraMon	
  pulse	  In-­‐‑ice  detector	
1km3	

deep  core	² Targets	
  for	
  cosmic	
  high	  energy	
  neutrinos	
  	
  
	
  	
  	
  	
  	
  	
  	
  (>~	
  100	
  GeV)	
  Digital	
  OpMcal	  Module	  (DOM)	
  

PMT
6	
 

The IceCube Collaboration	

36	
  insMtutes	
  and	
  ~250	
  physists	  Univ.	  of	
  Alberata,	
  Canada	  Bartol	  Research	
  Inst,	
  Univ.	
  of	
  Delaware,	
  USA	
  Pennsylvania	
  State	  University,	
  USA	
  Univ.	  of	
  Wisconsin-­‐Madison,	
  USA	
  Univ.	  of	
  Wisconsin-­‐River	
  Falls,	
  USA	
  
LBNL,	
  Berkeley,	
  USA	  UC	  Berkeley,	
  USA	  UC	
  Irvine,	
  USA	
  Univ.	  of	
  Alabama,	
  USA	
  Clark-­‐Atlanta	
  University,	
  USA	
  Univ.	  of	
  Maryland,	
  USA	
  University	
  of	
  Kansas,	
  USA	
  Southern	
  Univ.	
  and	
  A&M	  College,	
  USA	
  Univ.	  of	
  Alaska	
  Anchorage,	
  USA	
  Georgia	  Tech,	  USA	  Ohio	
  State	  Univ.,	
  USA	
  Chiba	
  Univ.,	
  Japan	  Univ.	  Of	  West	  Indies,	
  Barbados	
  Univ.	  of	
  Canterbury,	  New	
  Zealand	
  Univ.	
  Libre	  de	
  Bruxelles,	
  Belgium	
  Vrije	
  Univ.	
  Brussel,	  Belgium	
  Univ.	  de	
  Mons-­‐Hainaut,	
  Belgium	
  Univ.	  of	
  Gent,	
  Belgium	
  Univ.,	
  Mainz,	  Germany	
  DESY-­‐Zeuthen,	  Germany	
  Univ.	
  Wuppertal,	  Germany	  RWTH	  Aachen	
  Univ.,	
  Germany	
  Humboldt	
  Univ.	
  zu	
  Berlin,	
  Germany	
  Univ.	
  Bonn,	
  Germany	
  Ruhr-­‐Univ.	
  Bochum,	
  Germany	  	
  Univ.	
  Dortmund,	
  Germany	
  MPI	
  Heidelberg,	
  Germany	
  Uppsala	  Universitet,	
  Sweden	
  Stockholm	
  universitet,	
  Sweden	
  University	
  of	
  Oxford,	
  UK	
  Ècole	  Polytechnique	
  Fèdèrale,	
  Switzerland	
  
7	
 

■	
  The	
  detecPon	
  principle	  Cherenkov	
  light	
  
ν"

muon	
  

, ν"W, Z
hadronic	  shower	  interacPon	
  
Ø	
  A	
  large	  volume	  Ø	  transparent	
  medium	  →	
  AntarcMca	
  glacier	
  neutrino	  8	 ■ Particle types
νμ	
 

Muon	
 
μ	
 

νe	
 

ντ	
 
e	
 

τ	
 

ντ	
 
NC	
  interacMons	
  also	  make	  cascades	
  	
 

9	
 

■ The extremely high energy (EHE)
cosmogenic neutrinos (> 108 GeV)p" 2.7K # $ ± + X # µ ± + % # e ± + % 's

π	

!

µ	

 νµ	

νµ	

 νe	
  
e

Shed light on the EHECR origin² Source position² Composition (proton/iron)?
² Source evolution / when the EHECR
generation stars
Predicted, but never detected→ detectable with IceCube	
 

10	
 

q Effect of source evolution and maximum
energy on neutrino flux
eﬀect	  of	
  the	
  maximum	
  energy	
 eﬀect	  of	
  the	
  source	
  evoluMon	 neutrino	
  ﬂux	
  depend	
  on	
  the	
  source	  evoluMon	
  and	
  maximum	
  energy	  -­‐>	
  constraint	
  on	
  the	  parameters	 Kotera	  et	
  al.,	
  JCAP	
  10	
  (2010)	
  013	 11	 

■ The detection principleCRs	
   Atmospheric	
  muons	  µ	

Down-­‐going	
 

µ	

µ,τ	

µ	

τ	

τ	

Up-­‐going	 ντ	EHE ν	

²	  EHE	
  neutrino	
  signal	
  (all	  ﬂavor)	
  ²	
  horizontal	
  (opaque	
  to	
  the	
  earth)	
  ²	
  high	  energy	
  (>	  108	
  GeV)	
  ²	
  Atmospheric	
  muon	  background	
  

ντ	

µ	

²	
  down-­‐going	  ²	
  low	
  energy	
  (the	  energy	
  spectrum	  is	
  steep	
  (~E-­‐3.7))	
  νµ >1PeV

Yoshida	
  et	
  al	
  PRD	  69	  103004	
  (2004)	
  Energy	  Dist.	
  @	
  IceCube	  Depth	  Zenith	  Dist.	
  @	
  IceCube	  Depth	
  

12	
 

■	
  The	
  spectrum	
  of	
  backgrounds	
  atmospheric	  μ	
 dN dN CRA!
dE
dE 1+ B cos! E"θ:	
  zenith	
  angle,	
  ε:	
  criMcal	
  energy	 ² atmospheric	
  μ	
  
dN µ
! E "3.7 (> !" = 115 GeV )
dE
dN µ
dN
! 10 6 !
	
   dE
dE

² atmospheric	
  ν	
  
dN!
! E "3.7 (> " # = 115 GeV )dEHarder Spectrum ν (E-2)² prompt	
  ν	
  ² decay	
  from	  charmed	
  parMcles	
 dN! E "2.7 (< !charm = 10PeV )
dE
13	
 

q Datasets

IC79	
  (2010-­‐2011)	
  Five datasets are used in this analysis:
1. Observational datataken in 2010-2011 (319.2 days)
taken in 2011-2012 (350.9 days)
EHE level2a data (NPE > 1000)~3.0 M events, ~ 0.9-1.3 Hz (2010-2011)

2. Signal MC data (JULIeT)
105-1011 GeV, E-1
20k events for µ, τ, νe, νµ, ντ

3. Atmospheric muon background MC data (CORSIKA data)105-1011 GeV, E-1, takes long time…
15k events for proton and iron
SIBYLL HE interaction model

IC86	
  =	
  full	
  IceCube	
  (2011~)	
  

4. Coincidence muon MC data (CORSIKA data)
600-1011 GeV, E-1.7, polygonate model (J. R. Hoerandel, 2003)
10G events (10000 files)
SIBYLL HE interaction model

5. Atmospheric neutrino background MC data103-109 GeV, E-1, νµ, νe
10M events (2000 files)
Honda flux (2007) + knee correction (Gaisser)14	 ■ How to determine the energy

dE
∝E
dx
µ	

e+e-

π	

γ	

e+e- photo-nuclear

pair-creation
bremsstrahlung

IC79	
 
muon	
 
Detected total number of photoelectrons (NPE) ∝ Energy
NPE is a good energy estimator!	
 

15	
 

q Analysis schemev Oﬄine	
  ﬁlter:	
  select	
  high	  energy	  events	  and	
  fundamental	
  cleaning	
  
NPE	
  >	
  103.5	
  Before cleaning	 After cleaning	
 

NDOM	
  >	
  300	
  coincidence	
  cleaning	
  
	
  
	
  
	
  
	
  
v Final	
  ﬁlter:	  precise	  geometry	  reconstrucMon	
  remove	  remained	
  coincidence	
  events	  SPE12	
  (likelihood	
  base)	
 lineﬁt	 16	 q Offline filter level
NPE	
  >	
  103.5	
  &&	
  NDOM	
  >	
  300	  &&	  Coincidence	
  cleaning	 33.4	
  days	Obs.	
  data	GZK	  signal	

all	(5.23±0.02)x104	

0.174±0.001	

proton	iron	

Coin.	

Atm.	
  nu	

(2.53±0.51)x104	
 (9.10±0.52)x104	
 (8.74±0.08)x103	
 0.769±0.032	

Test data

NPE:	
  4.3x104	
  

CORSIKA (iron)zenith	  angle:	
  19	
  deg.	
  	
 CORSIKA (proton)
CORSIKA (coin.)
GZK signal (Yoshida)Atm. Nu (Honda+ knee correction)	
 atmospheric	
  muon	  (data)	
 108 GeV (at surface, GZK spectrum)	
 1010 GeV (CR primary)	
 reasonable	
  MC/data	
  agreement	  Dominated	
  by	
  atmospheric	
  muons	
 17	
 q Final filter levelwith	
  precise	  reconstrucMon	
  algorithms	
  &&	
  further	
  coincidence	
  cleaning	 33.4	
  days	Obs.	
  data	GZK	  signal	

all	(5.22±0.02)x104	

0.170±0.001	

Below	
  horizon	

0±0	

proton	iron	

Coin.	

Atm.	
  nu	

(2.53±0.51)x104	
 (9.10±0.52)x104	
 (8.72±0.08)x103	
 0.769±0.032	

0.0459±0.0004	
 (2.25±0.94)x10-­‐4	
 (1.61±0.80)x10-­‐3	
 (2.35±1.63)x10-­‐3	
 0.383±0.017	

Zenith angle distribution 	
 NPE:	
  4.6x103	
  Test data
CORSIKA (iron)zenith	  angle:	  140	
  deg.	
 CORSIKA (proton)
CORSIKA (coin.)

atmospheric	
  neutrino	
  (MC)	
 GZK signal (Yoshida)Atm. Nu (Honda+ knee correction)	
 v mis-­‐reconstructd	
  events	
  are	  cleaned	
  cos(zenith angle)	
 v atmospheric	
  neutrinos	
  also	  come	  from	
  horizon,	
  but	
  low	
  energy	
 
	
 

18	
 

q Final selection criteria
Model discovery potential method used (4 sigma)
Iron + coin. + atm. nu is used for the background to be conservative	 Background
GZK signal	 (iron + coin. + AtmNu)	
 108 GeV (at surface, GZK)	
 1010 GeV (CR primary)	
 319.2	  days	Obs.	
  data	GZK	  signal	

all	

0±0	

0.978±0.005	

Below	
  horizon	

0±0	

0.0363±0.003	

proton	Coin.	

Atm.	
  nu	

(6.77±1.29)x10-­‐3	
 (3.31±0.25)x10-­‐2	

0±0	(1.59±0.10)x10-­‐2	

(7.88±6.08)x10-­‐4	
 (1.92±1.09)x10-­‐3	

0±0	(1.29±0.09)x10-­‐2	

* 0.57 per 333 days for IC40	
 

iron	

test data	
 
Data	
 

19	
 

q The total exposure (IC79 + IC86)
2010-2011 (319.2 days)
2011-2012 (350.9 days)
both effective areas are similar20	 ;8<=;$$

34'552;D;9:&%'(87<7788?$
1,$?=5?$J>+'$7- backgroundbackground (atm.
atm.
Q) expectation
0.140.14
events(atm.PP++conventional
conventional
atm.
Q)
expectation
events(J4K4)($6$?=5?$
D$@@A:$6B8?2C5=
preliminary
p-value:0.0094(2.36V
preliminary p-value: 0.0094 (2.36V 
D$@A:$8B66?2C5=q
Twocascadelike
eventsfound in 2011-2012 data@
34'552;D;9:&%'(87<7788?$@4EF%1$#G$H*(0/+.$I%')#1)$75?$&%'(78;;8<=;$34'552;D;9:&%'(87<7788?$%'(78;;8<=;$
Run118545-Event63733662(-$?=5?$(-$?=5?$
J4K4)($6@4EF%1$#G$H*(0/+.$I%')#1)$7;D$
J4K4)($6th 2011$')#1)$75?$
August
9
May,	
  
2
011	
  
-­‐
	
  
M
ay,	
  
2
012	
  
(D$350.9	  days),	
  IC86	
  conﬁguraMon	
 
D$
CC/NC
interactions
in
the
det
@A:$8B66?2C5==D$D$@A:$8B66?2C5=
4$
NPE
6.9928x10$@4EF%1$#G$H*(0/+.$I%')#1)$7;D$*(0/+.$I%')#1)$75?$$@4EF%1$#G$H*(0/+.$I%')#1)$7;D$(0/+.$I%')#1)$75?$
Either	
  in
CC	
  the
interacMon	
  
of	
  νe	
  oSensorsr	
  NC	
  interacMon	
  of	
  any	
  ﬂavor	  ν	  	 Numberof Optical354
Cinteractions
detector
$ $
MC
CC/NC
interactions
inthedetector
CC/NC interactions in the detector$
$
$
$
th

!"!#$%&'#"(#)"#*#+,-"&+"./#012#"34"

MC$
Aug.,	  MC
9 ,	  2011	  event	
  rate	  MCin	
  670.1	
  days	$ $Run118545	
   561+7"&+"-#89/:";69"/6-<6=#+&/"+#1,9&+6-">&,:".0?@"A".034"BC8D"!EFE"G"C8D"!EF!H$-­‐Event63733662	
  Atmospheric	
  muons	
0.036	  ±	  0.0062	
2
events/672.7
days
background
(atm.
P
+
conventional
atm.
Q)
expectation
0.140.14
events2
events/672.7
days
background
(atm.
P
+
conventionalatm.
Q) expectation
even
4
NPE:	
  7.0	  x	  10 	  preliminary p-value:(2.36V  0.021	
  ±	
  0.001	
preliminary
p-value:0.0094
0.0094(2.36V
convenMonal	  NDOM:	
  354	
 atmospheric	
  neutrinos	
34'552;D;9:&%'(87<7788?$
34'5567589:&%'(78;;8<=;$34'552;D;9:&%'(87<7788?$
34'5567589:&%'(78;;8<=;$
Run118545-Event63733662(-$?=5?$
1,$?=5?$(-$?=5?$1,
J4K4)($6>+'$7
total	  background	
0.0573	
  ±	
  0.0063	
J4K4)($6th 2011>+'$7 $?=5?$
August9
D$
D$
D$@A:$8B66?2C5=@A:$6B8?2C5=D$@A:$8B66?2C5=@A:$6B8?2C5=
NPE
6.9928x104@4EF%1$#G$H*(0/+.$I%')#1)$7;D$@4EF%1$#G$H*(0/+.$I%')#1)$75?$
total	
  background	
  
wof
ith	
  Optical
0.190	  ±	
  0.0063	
@4EF%1$#G$H*(0/+.$I%')#1)$7;D$@4EF%1$#G$H*(0/+.$I%')#1)$75?$
NumberSensors354
prompt	  $neutrinos	
  
[1]	
$
CC/NC interactions+6"!EF!O"P##",8%'"2D"Q&'#"C&77#%%"8,",:&-"<##R+=M".P)SQ0T.!EF!"
CC/NC
interactionsininthe
thedetector
detector
$
$
rd
Jan,	
  3 ,	  2012	
  $ $J6<"K8&--#9"F3"MC
MC signiﬁcance:	
  Run119316	
  
$$
$ $
2$
-­‐Event36556705	
  2.95	
  sigma	
  without	
  prompt	
  [1]	
  NPE:	
  9.6	  x	  104	
  $$2$ 2.18	
  sigma	
  with	  prompt	
  [1]	
  
NDOM:	
  312	
 2$!"#$%&%'()$*+))%,$(-%$)%.%/(0#'$/10(%10+$!"#$%&%'()$*+))%,$(-%$)%.%/(0#'$/10(%10+$
$

by	
  A.	
  Ishihara	 [1] R. Enberg, M.H. Reno, and I. Sarcevic.
PRD78, 043005 (2008).	
 21	
 LD8".-&:898M"N#1,9&+6"!EF!O"P##",8%'"2D"Q&'#"C&77#%%"8,",:&-"<##R+=M".P)SQ0T.!EF!"q The August event
Aug.,	
  9th,	
  2011	
  Run118545	
  -­‐Event63733662	
  NPE:	
  7.0	  x	  104	
  
NDOM:	
  354	 22	
 q The January eventJan,	
  3rd,	
  2012	
  Run119316	
  -­‐Event36556705	
  NPE:	
  9.6	  x	  104	
  
NDOM:	
  312	 23	
 /10(%10+$%'()$*+))%,$(-%$)%.%/(0#'$/10(%10+$

2 events/ 672.7/ 672.7days
days-- backgroundbackground (atm.
atm.
Q) expectation
0.140.14
events2 events(atm.PP++conventional
conventionalatm.
Q) expectation
events7) days- backgroundP + conventional
atm.
expectation
0.14 (atm.
eventspreliminary
p-value:(2.36VQ) expectation 0.14 events
preliminary
p-value:0.0094
0.0094(2.36V
preliminary p-value: 0.0094 34'552;D;9:&%'(87<7788?$(2.36V
34'5567589:&%'(78;;8<=;$34'552;D;9:&%'(87<7788?$
34'5567589:&%'(78;;8<=;$
Run118545-Event63733662
J4K4)($6$?=5?$q The brightest
stringpositions
August9 201134'552;D;9:&%'(87<7788?$@A:$8B66?2C5=(J4K4)($6(th$?=5?$@A:$8B66?2C5=D$4 D$
NPE 6.9928x10(-$?=5?$@4EF%1$#G$H*(0/+.$I%')#1)$7;D$
J4K4)($6@4EF%1$#G$H*(0/+.$I%')#1)$7;D$
Numberof Optical Sensors 354$ $D$@A:$8B66?2C5=
CC/NC interactions
CC/NC
interactionsininthe
thedetector
detector$ $@4EF%1$#G$H*(0/+.$I%')#1)$7;D$

1,1,
>+'$7
$?=5?$>+'$7$?=5?$
67589:&%'(78;;8<=;$@A:$6B8?2C5=D$D$@A:$6B8?2C5=%'(87<7788?$,$?=5?$@4EF%1$#G$H*(0/+.$I%')#1)$75?$@4EF%1$#G$H*(0/+.$I%')#1)$75?$?$B8?2C5=D$ Jan.	
 $$D$=%1$#G$H*(0/+.$I%')#1)$75?$
MC
MC
$
$
$ $
0/+.$I%')#1)$7;D$$
CC/NC interactions in the detector
$$

$

MC

#*#+,-"&+"./#012#"34" $$(-%$)%.%/(0#'$/10(%10+$$(-%$)%.%/(0#'$/10(%10+$+#1,9&+6-">&,:".0?@"A".034"BC8D"!EFE"G"C8D"!EF!H"m. PP++conventionalatm.
Q) expectation
0.140.14
eventsatm.
conventionalatm.
Q) expectation
eventsyyp-value:(2.36V 
p-value:0.0094
0.0094(2.36V

LD8".-&:898M"N#1,9&+6"!EF!O"P##",8%'"2D"Q&'#"C&77#%%"8,",:&-"<##R+=M".P)SQ0T.!EF!"34'552;D;9:&%'(87<7788?$
34'552;D;9:&%'(87<7788?$
J4K4)($6$?=5?$
J4K4)($6$?=5?$
August9th 2011
D$ D$@A:$8B66?2C5=@A:$8B66?2C5=
NPE
6.9928x104@4EF%1$#G$H*(0/+.$I%')#1)$7;D$@4EF%1$#G$H*(0/+.$I%')#1)$7;D$$
Numberof Optical Sensors 354
$ $
tions
in
the
detector
ctions in the detector$ $Run118545-Event63733662
FI$E3$!EF!"(- (-J6<"K8&--#9"

2$

Aug.	
 

MC
MC

F3"

2$

2$

$ $

2$

'"2D"Q&'#"C&77#%%"8,",:&-"<##R+=M".P)SQ0T.!EF!"J6<"K8&--#9"

by	
  A.	
  Ishihara	
 

F3"

2$

Well	
  contained	
 24

q IceTop (surface array) veto information² IceTop	
  veto	  informaMon	
  was	
  checked	
  ² hits	
  search	
  in	
  allowed	
  8μs	  Mme	
  window	
  ² 0	
  and	  1	  hit	
  observed	
  again	  2.1	
  hits	
  expected	
  
-­‐>	
  No	
  CR	
  shower	
  

by	
  J.	
  Auﬀenberg	 25

q The NPE distribution
model	

event	
  rate	  in	
  670.1	
  
days	

GZK	
  Yoshida	
  and	  Teshima	

2.1	

GZK	
  Kotera	
  et	
  al.	  (FRII)	

4.1	

GZK	
  Ahlers	
  et	
  al.	  (maximal)	

3.2	

GZK	
  Ahlers	
  et	
  al.	  (best	
  ﬁt	
  
with	
  Fermi)	

1.6	

E2φ	

11.7	

prompt	0.13	

total	
  BG	0.057	

observed	2	

108 GeV (at surface, GZK)	
 

by	
  A.	
  Ishihara	
 

26	
 

$

events/ 672.7daysdays -- backgroundbackground (atm.
atm.
Q) expectation
0.140.14
eventsents / 672.7(atm.PP++conventional
conventionalatm.
Q) expectation
eventspreliminary p-value:(2.36V 
preliminary
p-value:0.0094
0.0094(2.36V
34'552;D;9:&%'(87<7788?$
34'552;D;9:&%'(87<7788?$
Run118545-Event63733662(-$?=5?$(-$?=5?$
J4K4)($6J4K4)($6
August9th 2011
D$ D$@A:$8B66?2C5=@A:$8B66?2C5=
NPE 6.9928x104@4EF%1$#G$H*(0/+.$I%')#1)$7;D$@4EF%1$#G$H*(0/+.$I%')#1)$7;D$
Numberof Optical Sensors 354$ $CC/NC interactions
CC/NC
interactionsininthe
thedetector
detector$ $34'5567589:&%'(78;;8<=;$34'5567589:&%'(78;;8<=;$
1,1,
>+'$7
$?=5?$>+'$7$?=5?$@A:$6B8?2C5=@A:$6B8?2C5=D$D$@4EF%1$#G$H*(0/+.$I%')#1)$75?$@4EF%1$#G$H*(0/+.$I%')#1)$75?$$$$$

34'552;D;9:34'552;D
Run118545-E(-$?=(J4K4)($6
J4K4)($6
August9th 20@A:$8B66?2C@A:$8B66?
NPE
6.9928x@4EF%1$#G$H@4EF%1$#
Numberof O$ $CC/NC interactions
CC/NC
interactionsininthe
thedetector
detector$ $34'5567589:&%'(78;;8<=;$34'5567589:&%'(78;;8<=;$
1,1,
>+'$7
$?=5?$>+'$7$?=5?$@A:$6B8?2C5=D$D$@A:$6B8?2C5=@4EF%1$#G$H*(0/+.$I%')#1)$75?$@4EF%1$#G$H*(0/+.$I%')#1)$75?$

q The energy deposit reconstruction
$$
MC
MC

$ $

$$

red	
  shaded	  region	  not	  used	
  for	  the	  ﬁt	
  due	  to	
  saturaMon	
  

Aug.	
 
1.1±0.4	
  PeV	
 

$$

MC
MC

$ $

$$

2$

LD8".-&:898M"N#1,9&+6"!EF!O"P##",8%'"2D"Q&'#"C&77#%%"8,",:&-"<##R+=M".P)SQ0T.!EF!"FI$E3$!EF!"preliminary p-value:(2.36V
preliminary
p-value:0.0094
0.0094(2.36

J6<"K8&--#9"LD8".-&:898M"N#1,9&+6"!EF!O"P##",8%'"2D"Q&'#"C&77#%%"8,",:&-"<F3"

FI$E3$!EF!"

2$

Jan.	
 

J6<"K8&--#9"

1.3±0.5	
  PeV	
 2$

2$

including	
  systemaMcs(reconstrucMon	
  +	
  ice	  +	
  DOM	
  eﬀ.)	
 

by	
  J.	
  Santen	 27	 q Reconstructed energy at surface!"#$%&%'()$*+))%,$(-%$)%.%/(0#'$/10(%10+$!"#$%&%'()$*+))%,$(-%$)%.

2 eventsatm.
/ 672.7- backgroundP + conve$/10(%10+$%'()$*+))%,$(-%$)%.%/(0#'$/10(%10+$
2 events / 672.7 days - background (atm. P + conventionalQ) days
expectation
0.14 (atm.
eventspreliminary p-value: 0.0
7 days- backgroundP + conventional
atm. Q)
expectation
0.14 events
preliminary
p-value:0.0094(2.36V 
Q)
expectation
0.14 (atm.
eventssystemaMc	
  error	
 preliminary p-value:without	
  0.0094 (2.36V34'5567589:&%'(78;;8<=;$34'552;D;9:&%'(87<7788?$
34'5567589:&%'(78;;8<=;$
1,$?=5?$34'552;D;9:&%'(87<7788?$ J4K4)($6(->+'$7
567589:&%'(78;;8<=;$1,$?=5?$%'(87<7788?$>+'$7 $?=5?$
D$
1,$?=5?$@A:$6B8?2C5=
J4K4)($6(-$?=5?$
D$
D$@A:$8B66?2C5=?$@A:$6B8?2C5=
D$@4EF%1$#G$H*(0/+.$I%')#1)$75?$@A:$8B66?2C5=D$
6B8?2C5=D$with	  systemaMc	
  error	
 
=@4EF%1$#G$H*(0/+.$I%')#1)$7;D$@4EF%1$#G$H*(0/+.$I%')#1)$75?$@4EF%1$#G$H*(0/+.$I%')#1)$7;D$
F%1$#G$H*(0/+.$I%')#1)$75?$
CC/NC interactions in the d$(0/+.$I%')#1)$7;D$$$
CC/NC interactions in the detector$

CC/NC interactions in the detector$

MC"#*#+,-"&+"./#012#"34"$$MC+#1,9&+6-">&,:".0?@"A".034"BC8D"!EFE"G"C8D"!EF!H",$(-%$)%.%/(0#'$/10(%10+$,$(-%$)%.%/(0#'$/10(%10+$

$

MC

$
!"! $%&'#"(#)"#*#+,-"&+"./#012#"34"#$

561+7"&+"-#89/:";69"/6-<6=#+&/"+#1,9&+6-">&,:".0?@"A".034"BC8D"!EFE"G"C8D"!EF!"#$%&%'()$*+))%,$(-%$)%.%/(0#'$/10(%10+$$!"#$%&%'()$*+))%,$(-%$)%.%/(0#'$/10(%10+$$

2 events/ 672.7/ 672.7days
days-- backgroundbackground (atm.
Q) expectation
0.140.14
events2 events(atm.PP++conventional
conventionalatm.
Q) expectation
eve
GZK	
  
ﬂux	
  atm.
assumed	 preliminary p-value:(2.36V 
preliminary
p-value:0.0094
0.0094(2.36V
Top-­‐down	
  approach	
  (in-­‐ice)	
  +	
  propagaMon	
  to	
  surface	
 

atm.
atm.
Q) expectation
0.140.14
eventsatm.PP++conventional
conventionalatm.
Q) expectation
eventsry p-value:(2.36V 
aryp-value:0.0094
0.0094(2.36VIn	
  case	  of	  ν 	  CC,	
  full	  energy	
  deposit	  34'552;D;9:&%'(87<7788?$
34'552;D;9:&%'(87<7788?$
Run118545-Event63733662
e(-$?=5?$(-$?=5?$
J4K4)($6J4K4)($6
August9th 2011
D$
D$@A:$8B66?2C5=@A:$8B66?2C5=
NPE
6.9928x104@4EF%1$#G$H*(0/+.$I%')#1)$7;D$?$?$@4EF%1$#G$H*(0/+.$I%')#1)$7;D$
Number of Optical Sensors 354$ $ctionsinthedetector
actions in the detector$ $34'552;D;9:&%'(87<7788?$
34'552;D;9:&%'(87<7788?$
Run118545-Event63733662(-$?=5?$(-$?=5?$
J4K4)($6J4K4)($6
August9th 2011
D$ D$@A:$8B66?2C5=@A:$8B66?2C5=
NPE
6.9928x104@4EF%1$#G$H*(0/+.$I%')#1)$7;D$@4EF%1$#G$H*(0/+.$I%')#1)$7;D$
Numberof Optical Sensors 354
$ $
CC/NC
interactions
inthedetector
CC/NC interactions in the detector$ $34'5567589:&%'(78;;8<=;$34'5567589:&%'(78;;8<=;$
1,1,
>+'$7
$?=5?$>+'$7$?=5?$@A:$6B8?2C5=@A:$6B8?2C5=D$D$@4EF%1$#G$H*(0/+.$I%')#1)$75?$@4EF%1$#G$H*(0/+.$I%')#1)$75?$

Other	
  case	  of	  NC,	  parMal	
  energy	
  deposit	
  by	
  Bjorken	
  y	
  	
 

MC
MC

$$
$$

$ $

Aug.	
 

MC
MC

$$

8%'"2D"Q&'#"C&77#%%"8,",:&-"<##R+=M".P)SQ0T.!EF!"J6<"K8&--#9"

F3"

$ $

Jan.	
 

6.01	
  <	
  log(E/GeV)	
  <	
  8.03	  (90%)	
  	
 

by	
  S.	
  Yoshida	
 

6.09	
  <	
  log(E/GeV)	
  <	
  8.65	  2$(90%)	
 28	
 LD8".-&:898M"N#1,9&+6"!EF!O"P##",8%'"2D"Q&'#"C&77#%%"8,",:&-"<##R+=M".P)SQ0T.!EF!"q Model test for two eventsHow	
  models	
  are	
  compaMble	
  with	  the	
  two	
  events	  Fisher’s	
  method	 ! 2 = !2 ln(PE ) ! 2 ln(Ppois (2; µ ))follows	
  4	
  degrees	
  of	
  freedom	
 Energy	  distribuMon	 rate	
  (Poisson)	
  Kotera	  et	
  al.,	
  JCAP	
  10	
  (2010)	
  013	 Preliminary	
 K-­‐S	
  test	 IC40+IC79+IC86	
 neutrino	
  model	PE	

expected	
  
rate	

Ppos	

x2	

p-­‐value	

GZK	  Yoshida	
  and	  Teshima	

6.0x10-­‐1	

2.8	

5.5x10-­‐1	
 6.82	
 1.5x10-­‐1	

GZK	  Kotera	
  FR-­‐II	

1.8x10-­‐1	

5.9	

3.8x10-­‐2	
 9.91	
 4.2x10-­‐2	

GZK	  Kotera	
  GRB-­‐1	

2.5x10-­‐1	

1.12	

4.2x10-­‐1	
 4.56	
 3.4x10-­‐1	

GZK	
  Ahlers	
  Fermi	  best	
 6.0x10-­‐2	

2.1	

7.3x10-­‐1	
 6.25	
 1.8x10-­‐1	

GZK	  Kotera	
  FR-­‐II	
  is	
  rejected	
  with	  2	
  sigma	  -­‐>	
  high	
  ﬂux	  model	  is	
  not	  preferable	
  

by	
  S.	
  Yoshida	
 power-­‐law	
  spectrum	  is	
  more	  preferable	
  

29	
 

q The model test with null hypothesis
assumes	  two	
  events	
  are	
  from	  other	  sources	
  esMmated	  the	
  eﬀect	
  of	
  the	
  two	
  events	
  by	
  the	
  energy	
  PDF	
 IC40+IC79+IC86	 model	

expected	
  rate	  (>100	
  PeV)	

p-­‐value	

GZK	  Yoshida	
  Teshima,	
  m=4,	
  Zmax=4	

2.6	

9.6x10-­‐2	

GZK	
  Sigl,	
  m=5,	
  Zmax	
  =3	

4.0	

2.4x10-­‐2	

GZK	  Yoshida	
  Ishihara,	
  m=5,	
  Zmax=2	

2.8	

7.4x10-­‐2	

GZK	
  Ahrlers,	
  Fermi	  best	2.0	

16.2x10-­‐2	

GZK	
  Ahrlers,	
  Fermi	  max	

4.1	

2.3x10-­‐2	

GZK	  Kotera,	
  SFR	

0.60	67x10-­‐2	

GZK,	
  Kotera,	
  GRB	

0.63	66x10-­‐2	

GZK,	
  Kotera,	
  FRII	

3.8	

3.1x10-­‐2	

Top-­‐down	
  SUSY	

21	

<0.1x10-­‐2	

Top-­‐down	
  GUT	

5.0	

<0.1x10-­‐2	

Preliminary	
 high	
  evoluMon	  models	
  (m>4)	
  are	
  ruled	
  out	 by	
  S.	
  Yoshida	  30	 q The model independent upper limit
similar	
  as	
  previous,	
  but	  model	  independent	
 diﬀerenMal	
  limit	
  per	
  one	
  energy	
  decade	
 

by	
  A.	
  Ishihara	
 

31	
 

q Energy calibration by the standard candles (SCs)
Absolutely calibrated source
337 nm (nitrogen laser)

SC1Standard Candle Ⅰ• string 40, depth = 1810m• pointing upward

Standard Candle II• string 55, depth = 2153m• pointing downward

SC2

40

55

32	
 

q Agreement between data and MC
SC2 3 % intensity	 dataspicemiestring54	 string54 OM43	
 data
MC (spice-mie)
10 waveforms	
 spice1aha	
 string54 OM46	
 SC2 position	
 string54 OM49	
 data and MC agree well	
 33	
 q MC vs Data comparison
100%	
 spicemiespice1NPE distribution	
 

51%	
 
30%	
 

aha	
 
10%	
 

SC2 10% intensity 	 3% intensity	 preliminary	 (data-MC)/MC = -17.8%
108 GeV (at surface, GZK spectrum)	
 *spice1	
 

34	
 

q	
 Error budget
BG	

signal	Stat.	
  error	±	
  9.3%	±	
  0.6%	

NPE	
  shi•	

-­‐	

+2.9	
  -­‐6.8	
  %	

Yearly	  variaMon	

±	
  17	
  %	

-­‐	

Neutrino	
  cross	
  secMon	

-­‐	

±	
  9%	

Photo-­‐nuclear	
  int.	

-­‐	+	
  10%	LPM	
  eﬀect	

-­‐	

±	
  1%	

Hadronic	
  int.	
  model	+36.9%	-­‐	

total	

±	  9.3(stat.)	
  ±	
  0.6	  (stat.)	
  ±	
  40.7(sys.)	
  %	
 +13.8	  -­‐11.3	
  (sys.)	
  %	

35	
 

■	
  Next	  plan	  -­‐	  Askaryan	
  Radio	
  Array	
  (ARA)	
  
12	
  x	
  12km	
  

2	
  km	
 
37	
  string	
  clusters	  	
  ² Each	
  cluster	  has	  4	  strings	
  of	
  200m	  depth	  	
  ² Each	
  string	
  has	  2	  Vpol	  +	
  2Hpol	
  broadband	
  antennas	
  (200	
  MHz	  -­‐	  1	  GHz)	
  	
  ² Total	
  surface	  area	  ~180	
  km2	
 36

■	
  The	  ARA	
  sensiPvity	
  Preliminary	
 Model	  #/year	  GZK	  (*)	
  

7.0	
  

Iron	
  CR	
  BG	
  

~1	
  

More	
  events,	
  more	  physics!	
  Sheds	
  light	
  on	
  EHECR	
  origin	 (*)	  Yoshida	
  et	
  al.,	
  ApJ,	
  1997,	
  m=4,	
  Zmax=4	
 

37

q	
  Summary	  Ø IceCube is aim for detecting neutrinos from astronomical origins toshed light on the cosmic ray origin
Ø The IceCube detector completed in 2010Ø The sensitivity is below Waxman-Bahcall limitØ Two cascade like events foundØ Significance of cosmogenic neutrino hypothesis is 2.95 sigma
without taking prompt contribution into accountØ High evolution GZK models are ruled outØ Larger detector (ARA) is coming38	 backups

39	
 

■	
  The	
  history	  2004:	
  project	
  started	
  2006-­‐2007:	
  	
  IC9	  2007-­‐2008:	  	
  IC22	  2008-­‐2009:	  	
  IC40	
  2009-­‐2010:	
  	
  IC59	  2010-­‐2011:	
  	
  IC79	  2011:	
  IceCube	
  completed!	
  2011~:	
  	
  IC86	
  IC59	
  (2009-­‐2010)

	
  

IC22	
  (2007-­‐2008)

IC79	
  (2010-­‐2011)	
  

	
  

IC40	
  (2008-­‐2009)

	
  

IC86	
  =	
  full	
  IceCube	
  (2011~)	
  

40	
 

■	
  The	
  South	  Pole	  The	  South	  Pole	  IceCube	
  

1	
  km	
  

41	
 

■	
  The	  Digital	
  OpPcal	  Module	
  (DOM)	
  HV	
  Base	  “Flasher	  Board”	
  Main	
  Board	  	
  (DOM-­‐MB)	
  10”	
  PMT	  13”	  Glass	  (hemi)sphere	
  Calibrated	
  at	
  Chiba	
  University	
 42	
 q Coincident event cleaning
Before cleaning	 After cleaning	 R: 150m
t: 1000 ns	
 ü Geometrical and time constraint is used to separate coincident eventsü Useful to clean coincident events	 43	
 q Better reconstruction for corner clippers

SPE12	
  SPE12: uses only the arrival time of
the first photon in optical modules
to construct likelihood 	 (likelihood	
  base)	
 lineﬁt	 J. Ahrens et al., NIM A 524 (2004)	
 red: Pandel function (model),black: simulation data	 ü Linefit mis-reconstructs corner clippers
ü Likelihood-base reconstruction reconstructs corner clippers better
44	
 

q	
  The	
  ice	
  property	
  Average optical parameters:	

λabs ~ 110 m @ 400 nm

Clear	
  depth	  dependence	  	

λscat ~ 20 m @ 400 nm→	
  taken	
  into	  account	
  in	
  simulaMon	
 
45	
 

46	
 

47	
 

48	
 

GZK1 and 2: S. Yoshida et al. (1997) [1], m=4,
Zmax=4, γ=2, Emax=10 ZeV and m=4, Zmax=5, γ=1.5,
Emax=10 ZeV,GZK3 and GZK4: Kotera et al. (2010), SFRI and FRII
with γ=2.5, Emax=316 EeV,GZK 5 and 6: M. Ahlers et al. (2010), Emin=10 EeV,
Emax=1 ZeV best fit with Fermi, m=4.6, Zmax=2, γ=2.5
and m=4.4, Zmax=2, γ=2.1 (max)49