Transcript C. Mariani (INFN Rome) for K2K collaboration XLth Rencontres de Moriond March 6

March 6th, 2005
@XLth
Rencontres de Moriond
C. Mariani (INFN Rome)
for K2K collaboration
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
K2K Collaboration
250km
JAPAN: High Energy Accelerator Research Organization (KEK) / Institute for Cosmic Ray Research
(ICRR), Univ. of Tokyo / Kobe University / Kyoto University / Niigata University / Okayama
University / Tokyo University of Science / Tohoku University
KOREA: Chonnam National University / Dongshin University / Korea University / Seoul National
University
U.S.A.: Boston University / University of California, Irvine / University of Hawaii, Manoa /
Massachusetts Institute of Technology / State University of New York at Stony Brook / University
of Washington at Seattle
POLAND: Warsaw University / Solton Institute
Since 2002
JAPAN: Hiroshima University / Osaka University U.S.A.: Duke University
CANADA: TRIUMF / University of British Columbia
ITALY: Rome FRANCE: Saclay SPAIN: Barcelona / Valencia SWITZERLAND: Geneva
RUSSIA: INR-Moscow
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
1. Introduction and history of K2K





1995
 Proposed to study neutrino oscillation for atmospheric neutrinos
anomaly.
1999
 Started taking data.
2000
 Detected smaller number of neutrinos than the expectation at a
distance of 250 km. Disfavored null oscillation at the 2s level.
2002
 Observed indications of neutrino oscillation. The probability of
null oscillation is less than 1%.
2004

Confirm neutrino oscillation with both a deficit of nm
and the distortion of the En spectrum.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
2. K2K experiment
~1 event/2days
~1011 nm/2.2sec
(/10m10m)
12GeV protons
p+
~106 nm/2.2sec
nm (/40m40m)
SK nt
m+
Target+Horn
p monitor
200m
decay pipe
m monitor
100m
~250km
Near n detectors
(ND)
(monitor the beam center)
Signal of n oscillation at K2K
Reduction of nm events
 Distortion of nm energy spectrum

C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Neutrino beam and the
directional control
~1GeV neutrino beam by a dual horn
system with 250kA.
<1mrad
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
~5 years
Y center
≤1 mrad
X center
The beam direction
monitored by muons
Accumulated POT (Protons On Target)
protons/pulse Accumulated POT
(×1018)
(×1012)
10.5x1019 POT, 8.9×1019 POT for Analysis
K2K-I
K2K-I
K2K-II
K2K-II
Jan 03
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Oct-Nov 04
Neutrino spectrum and the far/near ratio
n beam
250km
Far/Near Ratio
nm energy spectrum
@ K2K near detector
R  f ( En )  (
Lnear 2
250m 2
) (
)  106
L far
250Km
beam MC w/
PION Monitor
10-6
En (GeV)
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
1.0
2.0
En (GeV)
SK Events
GPS
Tspill
SK
TOF=0.83msec
TSK
Decay electron cut.
500msec
20MeV Deposited Energy
No Activity in Outer Detector
Event Vertex in Fiducial Volume
More than 30MeV Deposited Energy
5msec Analysis Time Window
107 events
-0.2<TSK-Tspill-TOF<1.3msec
(BG: 1.6 events within 500ms
2.4×10-3 events in 1.5ms)
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
TDIFF. (ms)
3. Analysis Overview
KEK
Observation
#n, pm and qm
Measurement
F(En), n int.
n interaction MC
Far/Near Ratio
(beam MC with p mon.)
SK
Observation
#n and En rec.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
(sin22q, Dm2)
Expectation
#n and En rec.
NEUT: K2K Neutrino interaction MC

CC quasi elastic (CCQE)

CC (resonant) single
p(CC-1p)


DIS
NC
s/E (10-38cm2/GeV)
Total (NC+CC)
CC Total
CC quasi-elastic
DIS
CC single p
NC single p0
En (GeV)
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
4. Near detector measurements





1KT Water Cherenkov Detector (1KT)
Scintillating-fiber/Water sandwich Detector (SciFi)
Lead Glass calorimeter (LG) before 2002
Scintillators Bar Detector (SciBar) after 2003
Muon Range Detector (MRD)
LG calorimeter
Muon range detector
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
4.1 1KT Flux measurement


N
The same detector technology as Super-K.
Sensitive to low energy neutrinos.
exp
SK
N
obs
KT
F


F
( En )s ( En )dEn
M SK  SK


M KT  KT
KT ( En )s ( En ) dEn
SK
Far/Near Ratio (by MC)~1×10-6
M: Fiducial mass
: efficiency
N
exp
SK
MSK=22,500Kton,
SK-I(II)=77.0(78.2)%,
=150.9
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
+12
-10
N
obs
SK
MKT=25ton
KT=74.5%
=107
4.2 SciBar neutrino interaction study

Full Active Fine-Grained detector (target: CH).


Sensitive to a low momentum track.
Identify CCQE events and other interactions (non-QE)
separately.
CCQE Candidate
n
CCQE
p
m
non-QE
DATA
CC QE
CC 1p
CC coherent-p
CC multi-p
Dqp =qobs -qCCQE
p
m
25
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
2 track events
Dqp (degree)
Neutrino energy reconstruction
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
A hint of K2K forward m deficit.
K2K observed forward m deficit.


A source is non-QE events.
For CC-1p,
 Suppression of ~q2/0.1[GeV2]
at q2<0.1[GeV2] may exist.
(0.1GeV2 value comes from fitting 2 track
nonQE sample in SciBar)

For CC-coherent p,
 The coherent p may not exist.
We do not identify which process
causes the effect. The MC CC-1p
(coherent p) model is corrected
phenomenologically.
Oscillation analysis is insensitive to
the choice.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
q2rec
Preliminary
DATA
CC 1p
CC coherent-p
q2rec (GeV/c)2
(Data-MC)/MC
SciBar
non-QE Events
q2rec (GeV/c)2
4.3 Near Detector Spectrum Measurements

1KT


SciBar


Fully Contained 1 ring m (FC1Rm) sample.
1 track, 2 track QE (Dqp≤25), 2 track nQE
(Dqp>25) where one track is m.
SciFi

1 track, 2 track QE (Dqp≤25), 2 track nQE
(Dqp>30) where one track is m.
After applying the low q2 suppression of nQE
observed in SciBar, the angular distributions of all
other samples are reasonably reproduced.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
1KT: m momentum and angular distributions.
with measured spectrum
flux measurement
low q2 corr.
0
800
1600
pm (MeV/c)
1Kt m-like sample
Quasi elastic
Single pion
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
0
20
qm (deg.)
90
4.4 Near Detectors combined measurements
(pm,qm) for 1track, 2trackQE and 2track nQE samples
 F(En), nQE/QE


Fitting parameters
 F(En), nQE/QE ratio
 Detector uncertainties on the energy scale and the track
counting efficiency.
 The change of track counting efficiency by nuclear effect
uncertainties; proton re-scattering and p interactions in
a nucleus …
Strategy
① Measure F(En) in the more relevant region of qm20 for
1KT and qm10 for SciFi and SciBar.
② Apply a low q2 correction factor to the CC-1p model (or
coherent p).
③ Measure nQE/QE ratio for the entire qm range.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
qm (MeV/c)
En
KT data
0-0.5 GeV
0.5-0.75GeV
0.75-1.0GeV
Pm (MeV/c)
• n flux FKEK(En) (8 bins)
• n interaction (nQE/QE)
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
1.0-1.5GeV
QE (MC)
nQE(MC)
MC templates
Flux measurements
c2=638.1 for 609 d.o.f









F1 (
En < 500) = 0.78  0.36
F2 ( 500 En < 750) = 1.01  0.09
F3 ( 750 En <1000) = 1.12  0.07
F4 (1000 En <1500) = 1.00
F5 (1500 En <2000) = 0.90  0.04
F6 (2000 En <2500) = 1.07  0.06
F7 (2500 En <3000) = 1.33  0.17
F8 (3000 En
) = 1.04  0.18
nQE/QE
= 1.02  0.10
The nQE/QE error of 10% is assigned based
on the sensitivity of the
fitted nonQE/QE value by varying the fit
criteria.
 q>10(20 ) cut:
nQE/QE=0.95 0.04
 standard(CC-1p low q2 corr.):
nQE/QE=1.02 0.03
 No coherent: p=nQE/QE=1.06 0.03
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
F(En) at KEK
preliminary
En
SciFi (K2K-IIa with measured
spectrum)
qm 1trk
Pm 1trk
flux measurement
0
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Pm 2trk
QE
qm 2trk
QE
Pm 2trk
non-QE
qm 2trk
non-QE
2
(GeV/c)
0 10
40
(degree)
SciBar (with measured flux)
qm 1trk
Pm 1trk
flux measurement
Pm 2trk QE
qm 2trk QE
qm 2trk nQE
Pm 2trk nQE
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
10
5. Super-K oscillation analysis



Total Number of events
Enrec spectrum shape of FC-1ring-m events
Systematic error term
L(Dm 2 , sin 2q , f x )
 Lnorm (Dm 2 , sin 2q , f x )  Lshape (Dm 2 , sin 2q , f x )  Lsyst ( f x )
f x : Systematic error parameters
Normalization, Flux, and nQE/QE ratio are in fx
Near Detector measurements, Pion Monitor
constraint, beam MC estimation, and SuperK systematic uncertainties.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
K2K-SK events
K2K-all
(K2K-I, K2K-II)
FC 22.5kT
1ring
m-like
for Enrec
e-like
Multi Ring
DATA
(K2K-I, K2K-II)
107
(55, 52)
67
(33, 34)
57 (56)
(30, 27)
10
(3, 7)
40
(22, 18)
*Updated
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
MC
(K2K-I, K2K-II)
150.9
(79.1*, 71.8)
93.7
(48.6, 45.1 )
84.8
(44.3, 40.5)
8.8
(4.3, 4.5)
57.2
(30.5, 26.7)
from the previous analysis
x
x
Lshape( f )
Lnorm ( f )
KS probability=0.08%
#SK Events
Toy MC
Expected shape
(No Oscillation)
CC-QE assumption
107
150.9
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
En
rec

Enrec[GeV]
(mN  V ) Em  mm2 2 + mNV  V 2 2
(mN  V )  Em + pm cos q m
V: Nuclear potential
6. Results

Dm2

Best fit values.
 sin22q  1.51
 Dm2 [eV2] = 2.1910-3
Best fit values in the physical region.
 sin22q  1.00
A toy MC
 Dm2 [eV2] = 2.7910-3
DlogL=0.75
2.79
sin22q=1.51 can occur due to a
a statistical fluctuation with 12.6%.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
12.6%
1.00 1.51
sin22q
Data are consistent with the oscillation.
Dm2[eV2]

preliminary

NSKobs=107
NSKexp (best fit)=150.9
Best Fit
KS prob.=36%
sin22q
Based on DlnL
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Enrec[GeV]
Log Likelihood difference from the minimum.
DlnL
DlnL
- 68%
- 90%
- 99%
Dm2[eV2]

C.Mariani@XLth Rencontres de Moriond (6th March 2005)
- 68%
- 90%
- 99%
sin22q
Dm2<(1.87~3.58)×10-3 eV2 at sin22q=1.0 (90%
C.L.)
nm disappearance versus En shape distortion
En shape
Dm2[eV2]
Dm2[eV2]
NSK (#nm)
sin22q
sin22q
Both disappearance of nm and the distortion of
En spectrum have the consistent result.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
K2K-I vs K2K-II
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Null oscillation probability
The null oscillation probabilities are calculated based on DlnL.
K2K-I
nm disappearance
K2K-II
K2K-all
2.0%
3.7%
0.26%(3.0s)
En spectrum
distortion
19.5%
5.4%
0.74% (2.6s)
Combined
1.3%*
0.56%
0.0050%
(2.5s)
(2.8s)
(4.0s)
*: The value is changed from the previous one.
Disappearance of nm and distortion of the energy
spectrum as expected in neutrino oscillation.
K2K confirms neutrino oscillation
discovered in Super-K atmospheric neutrinos.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
8. Summary

With 8.91019 POT, K2K has confirmed neutrino
oscillations at 4.0s (hep-ex/0411038).
 Disappearance of nm
3.0s
 Distortion of En spectrum
2.6s
Dm2[eV2]
0.006
K2K new results
0.004
- 68%
- 90%
- 99%
preliminary
0.002
0.0 0.2 0.4 0.6 0.8 1.0
sin22q
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Backup slide
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Additional Error on nonQE

nonQE value depends on fitting condition.





Small angle cut:
0.979
8%
CC1p re-weighting: 1.056
Official value
No coherent p:
1.093
3.5%
CC1p re-weighting factor +/– 0.03 (1s)
(SciBar only fit): +/– 4%
In total, ~10% uncertainty exists.

Fitting error is ~5%
 add 10% to nonQE error.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
7. Other Physics in K2K (K2K-I data only)
nm +H2ONC1p0
1KT
Mgg(MeV)
s n m  NC1p 0 
=0.0650.0010.007


s n m  CCall
=0.064 (our MC)
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
90%CL limit
Dm2[eV2]
not NC1p0
nmne search
90%CL sensitivity
sin22qme
PRL 93 (2004) 051801
NEUT: K2K Neutrino interaction MC





CC quasi elastic (CCQE)
 Smith and Moniz with
MA=1.1GeV
CC (resonance) single p(CC-1p)
 Rein and Sehgal’s with
MA=1.1GeV
DIS
 GRV94 + JETSET with Bodek
and Yang correction.
CC coherent p
 Rein&Sehgal with the cross
section rescale by J. Marteau
NC
+ Nuclear Effects
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
s/E (10-38cm2/GeV)
Total (NC+CC)
CC Total
CC quasi-elastic
DIS
CC single p
NC single p0
En (GeV)
Overall normalization error on Nsk for
Nov99~
Errors
(Event)
Central Value
76.05evts
KT: dominated
by FV error
SK: also.
Stat
0.28 0.37%
KT
3.32 4.37%
SK
2.28 3.00%
Flux
+2.81
-2.59
F/N
+4.26
-5.55
NC/CC
+0.15
-0.23
nQE/QE
+0.38
-0.61
CT
Total
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
0.46 0.60%
+6.53
-7.37
Take errors not
considered in matrix
5.34%
Null oscillation DlnL
preliminary
The null oscillation probabilities are calculated based on DlnL.
K2K-I
K2K-II
K2K-all
nm disappearance
2.72
2.18
4.55
En spectrum
distortion
1.63
2.91
4.90
Combined
4.33
5.19
9.90
*: The value is changed from the previous one.
Disappearance of nm and distortion of the energy
spectrum as expected in neutrino oscillation.
K2K confirmed neutrino oscillation
discovered in Super-K atmospheric neutrinos.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
The change of NSKexp in K2K-I (Bugs)

The detector position

295m  294m
-1%
294m 295m

MC difference between KT and SK


KT; MA(QE)=1.1
SK; MA(QE)=1.0
s (NCel)KT=1.1×s(NCel)SK
 Efficiency change! -1%
NSKexp Change ~2%
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
CC-1p suppression versus coherent p
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Systematic Bias without the MC correction.
ND (SciBar) measurement
DATA; MC w/ CC-1p suppression
MC template; Default MC
Oscillation Results
MC w/o low q2 correction
sin22q=1.00
Dm2=2.65 ×10-3 eV2
Prob.(null oscillation)=0.0049%
Toy MC
Corrected MC for low q2
sin22q=1.00
Dm2=2.73×10-3eV2
Prob.(null oscillation)=0.011%
systematic bias
There is a small bias in nQE/QE
and the low energy flux.
flux
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
nQE/QE
Oscillation result with a default MC
Without low q2 MC correction
The result w/o low q2 MC correction gives the better (biased)
measurement due to the more low energy flux and the smaller nQE/QE.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
K2K-I vs K2K-II

Best fit values.
 sin22q  1.08, 1.51
 Dm2 [eV2] = 2.7310-3, 2.1910-3

Best fit values in the physical region.
 sin22q  1.00, 1.00
 Dm2 [eV2] = 2.8610-3 , 2.7910-3
 DlogL=0.02, 0.75
 KSK2K-I & K2K-II =77%
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Enrec for K2K-I and K2K-II
K2K-I
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
K2K-II
K2K-I vs K2K-II
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
1KT sys error summary and the change.
 SciBar sys. error
…

C.Mariani@XLth Rencontres de Moriond (6th March 2005)
1KT sys. error
Systematic error

Fiducial: updated

Escale : updated

FADC (scale) updated

FADC(cut position)

Background

Multi-event

Event rate(New)

Profile
(New)
KT origin

SK efficiency

CT norm.

Far/Near
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
+-4.0% (<- 4.0%) : Smy’s analysis
+-0.3%
+-0.8%
+-1.5% (New) : Shaomin’s analysis
+-0.5%
+-0.7%
+-2.0%
+-0.3%
+-4.9% (Prev. 4.4%)
+-3.0%
+-0.3 % for K2K-II ±0.6% for K2K-I
+5.6 -7.3%
SciBar Systematic Error (2track/1track)
 Detector oriented
 Vertex Matching Efficiency
 Threshold Effect (+-15%)
 Xtalk Effect
(2%/4%/6%)
 Finding Efficiency
 Total (Detector)
 Nuclear Effect
 Proton Re-scattering
 Pion Absorption
 Pion inelastic scattering
 Total (Nuclear)
+2.9% -2.6%
+1.7% -1.7%
+2.3% -2.9%
+4.1% -4.2%
 Total
+5.1%
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
+2.7%
+0.7%
+1.1%
+0.9%
+3.1%
-1.0%
-1.1%
-4.3%
-4.5%
-6.2%
SciBar Systematic Error
(2track QE/2track nQE)
 Detector oriented
 Angle resolution
 X-talk Effect
 Momentum scale (+-2.7%)
 Total (Detector)
 Nuclear Effect
 Proton Re-scattering
 Pion Absorption
 Pion inelastic scattering
 Total (Nuclear Effect)
 Total
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
+1.0%
+2.2% -2.9%
+1.5% -4.3%
+2.8% -5.2%
+2.9%
-2.8%
-5.4%
+0.3% -4.7%
+2.9% -7.7%
+4.0%
-9.3%
Track finding Efficiency
2nd Track Efficiency (MC)
MC true 2nd Track
(NHITX/Y≧3Hit)
Finding Efficiency
Detected! (= 1. Could Find 2nd Track
2. Rec.track overlap
with more than 1 true Hit)
1.0
0.8
0.6
0.4
0.2
Overall Eff. 59.0%
>20Hit 85.3%
>40Hit 91.1%
(This can be improved!)
0
20 40 60 80 100 120 140
(NHIT)
Evaluated DATA/MC w/ Eye scan.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Eye scan Result
● Data (Eye)
□ MC (Eye)
Eye scanners
(M.Hasegawa ,K.Hiraide
Y.Takubo,S.Yamamoto)
Integrated bin (>40Hits)
1.35 0.93 0.97 1.01 1.00 0.96 0.98 0.98
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Systematic error (Finding Eff.)
Compared
DATA
2Track/1Track (default MC) vs 2Track/1Track (MC*
)
MC
Entry
(each bin MC)
DATA/ MC
Total
<5
0
0
0
0
0
5-9
265
1.35
0.54
358
143
10 -14
2257
0.93
0.10
2108
226
15 -19
3824
0.97
0.06
3719
229
20 - 24
3976
1.01
0.05
4034
199
25 - 29 30 - 34
3654 3027
1.00 0.96
0.04 0.03
3659 3017
146
91
35 - 39
2406
0.98
0.03
2364
72
40 –
8009 27418
0.98
0.02 (stat.err)
7849 27034
160
475
2track/1track :
0.5032 (27418/54106)  0.496 +/- 0.013 (27034/54490)
Systematic Error (Track finding Eff.) : + 0.9% , -4.3%
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Same as previous one except binning size is
125/2 nsec that is a half of intervals of two
bunches.
C.Mariani@XLth Rencontres de Moriond (6 March
2005)
th
Residual of K2K-SK event timing relative to neutrino beam
bunches. Timing correlation is clearly seen and a sigma is
obtained
as about 30nsec.
C.Mariani@XLth Rencontres
de Moriond (6 March 2005)
th
Number of observed events (F.C. in fid. vol.) as a
function
of integrated CT
C.Mariani@XLth Rencontres de Moriond
(6 March 2005)
th
Number of observed events (F.C. in all inner volume) as
a (6function
of integrated CT
C.Mariani@XLth Rencontres de Moriond
March 2005)
th
Results (without small angle)


1kt q > 20deg., SciFi and SciBar q > 10deg.
In each En bin, fitted flux is consistent each other.
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
CC1p suppression factor tuning



By using SciBar 2tracknonQE and fitted flux, I
looked for the best value of
CC1p suppression.
Suppression factor
q2/A (q2>A)
Scan A value and calculate c2
of q distribution.
qm
SciBar 2track nonQE
CC1p
q2/0.10
(Data–MC)/MC
Agree quite well
A=0.10 +/– 0.03
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
A
Results (CC1p re-weighted)



CC1p re-weighting factor : q2/0.10 (q2<0.10)
Flux is fixed
nonQE value : 0.979(q cut)  1.056(this result)
(+8%)
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Results (no coherent p) for comparison



Coherent p production removed.
Flux is fixed.
nonQE value: 1.093(this results)

(CC1p re-weighting : 1.056
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
3.5% difference)
Results (no cut, no re-weighting)
for comparison



Flux is consistent with q cut results.
nonQE is significantly small, and c2 is bad.
nonQE : 0.856, c2 / dof = 773.8 / 595 = 1.30
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Flux v.s. fitting condition

Fitted flux from q cut, CC1p re-weighting
and no coherent are consistent each other.
For comparison
Official flux
For comparison
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
NonQE v.s. CC1p re-weighting factor
(SciBar only fit)

CC1p re-weighting factor +/– 0.03 (1s)
 nonQE +/– 4%
SciBar Only Fit
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Likelihood for Oscillation analysis
L(Dm2 ,sin 2 2q ; f x )  Lnorm (Dm2 ,sin 2 2q ; f x )  Lshape (Dm2 ,sin 2 2q ; f )  Lsyst ( f x )
f x : Systematic error parameters
exp N obs
Lnorm
(N )

N obs !
 exp( N
exp
)
Poisson prob. for FC events
N obs  N Iaobs + N Ibobs + N IIobs : # of observed events
N exp  N Iaexp + N Ibexp + N IIexp : # of expected events
Period
n flux
K2K-Ia
Ihorn = 200 kA
K2K-Ib
K2K-II
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
SK parameters
SK-I
Ihorn = 250 kA
SK-II
Likelihood for Normalization
N
exp
Ia
 f
Ia
 f
KT
 N obs

j
(N

KT 200kA
int ij
)
Pj (Dm2 ,sin 2 2q , En )
Ia
KT
ij
 M
KT
 CT
KT
Ia

2
2
2
 1  sin 2q sin (1.27Dm L / En ) ( j  CC )
1
( j  NC )
i, j
j
SK 200kA SK-I
  f ( N int
)ij
 ij  Pj (Dm 2 , sin 2 2q , Ei ) CTIaSK
N 
KT Ib
obs
i, j
N
exp
Ib
 f
Ib
 f  f
i
j
KT 250kA
( N int
)ij
  ijKT   M KT  CTIbKT
i, j
SK 250kA SK-I
  fi fi R f j ( N int
)ij  ij  Pj (Dm 2 ,sin 2 2q , Ei ) CTIbSK
i, j
N IIexp  f II
 f  f
i
N 
KT
obs
j
  f i f i f ( N
R
II
KT 250kA
( N int
)ij
  ijKT   M KT  CTIIKT
i, j

i: energy bin
j: Interaction mode
j
SK 250kA
int ij
)

SK-II
ij
# of interaction in MC
 Pj ( Dm ,sin 2q , Ei ) CT
2
2
Data/MC for
# of events in KT
SK
II
SK efficiency
i, j
flux
Far/Near
nQE/QE
fj
f
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
1
nQE
( j  QE )
( j  nQE )
 1
( j  CC QE )
CCnQE
f
 NC ( j  CC nQE )
( j  NC )
 f
Likelihood for Spectrum Shape
I
N1SK
Rm

P( Ei ; Dm ,sin 2q ; f , f , f
nQE
  P( Ei ; Dm ,sin 2q ; f , f , f
nQE
Lshape 
2

2
R
,f
 SK  I
, f ESK I )
i
 II
N1SK
Rm
2
i

2
flux
R
Far/Near nQE/QE
,f
 SK  II
, f ESK II )
SK
SK
efficiency Energy Scale
Nj (Erec,Etrue): Event fraction in MC
i
P( Erec
; Dm2 ,sin 2 2q , f  , f R , f nQE , f 

SK ?
, f ESK ? )
1
ESK ? i
 R  SK I
2
2
SK ?
d
E
f
f
f
P
(
E
;
D
m
,sin
2
q
)

N
(
f
Erec , Etrue )

true
j
true
j

N
j

f
N: Normalization factor
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
1
nQE
( j  QE )
( j  nQE )
 1
( j  CC QE )
CCnQE
f
 NC ( j  CC nQE )
( j  NC )
 f
Likelihood for Systematic parameters
flux, nQE/QE,NC
Lsyst  exp   t Df  ,nQE , NC  M ,1nQE , NC  Df  ,nQE , NC neutrino

 exp   Df  M
t

R
 exp  t Df 
SK  I
1
R
 Df
R

Far/Near Ratio
 M SK1 I  Df 
SK  I


 exp  t Df 
SK  II
 M SK1 II  Df 
SK  II

SK efficiency

  (Df Ia ) 2 (Df Ib ) 2 (Df II ) 2  

 exp  
+
+
2
2
2 
2
s
2
s
2
s

Ia
Ib
II  
 

E
E

  (Df SK-I ) 2 (Df SK-II ) 2  

 exp  
+


2
2
2
s
2
s
 
ESK-I
ESK-II
 


Overall Normalization
SK Energy Scale
Systematic parameters for n flux are common for SK-Ib and SK-II
# of free parameter in fit: 25  33
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
34 (fnQE  fCC-nQE, fNC)
Reconstructed vertex distribution for r2 vs Z
K2K-1
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
K2K-2
Visible energy distribution for F.C. events in the fiducial volume in data
(closed circle), M.C. expectation with no oscillation (solid histogram),
oscillated with sin22q=1.0,Dm2=2.0×10-3eV2 (dashed histogram), and
oscillated with sin 2 2q=1.0,Dm2 =3.0×10 -3 eV 2 (dotted histogram).
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Visible energy distribution for F.C. events in the fiducial volume in data
(closed circle), M.C. expectation with no oscillation (solid histogram),
oscillated with sin22q=1.0,Dm2=2.0×10-3eV2 (dashed histogram), and
oscillated with sin 2 2q=1.0,Dm2 =3.0×10 -3 eV 2 (dotted histogram).
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Visible energy distribution for F.C. events in the fiducial volume in data
(closed circle), M.C. expectation with no oscillation (solid histogram),
oscillated with sin22q=1.0,Dm2=2.0×10-3eV2 (dashed histogram), and
oscillated with sin 2 2q=1.0,Dm2 =3.0×10 -3 eV 2 (dotted histogram).
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Reconstructed muon momentum distribution for F.C. 1ring mu-like events
in the fiducial volume in data (closed circle), M.C. expectation with no
oscillation (solid histogram), oscillated with sin22q=1.0,Dm2=2.0×103eV2 (dashed histogram), and oscillated with sin22q=1.0,Dm2=3.0×103 e de Moriond
V (6 2March 2005) ( d o t t e d
h i s t o g r a m ) .
C.Mariani@XLth Rencontres
th
Reconstructed muon momentum distribution for F.C. 1ring mu-like events
in the fiducial volume in data (closed circle), M.C. expectation with no
oscillation (solid histogram), oscillated with sin22q=1.0,Dm2=2.0×103eV2 (dashed histogram), and oscillated with sin22q=1.0,Dm2=3.0×103 e de Moriond
V (6 2March 2005) ( d o t t e d
h i s t o g r a m ) .
C.Mariani@XLth Rencontres
th
Reconstructed muon momentum distribution for F.C. 1ring mu-like events
in the fiducial volume in data (closed circle), M.C. expectation with no
oscillation (solid histogram), oscillated with sin22q=1.0,Dm2=2.0×103eV2 (dashed histogram), and oscillated with sin22q=1.0,Dm2=3.0×103 e de Moriond
V (6 2March 2005) ( d o t t e d
h i s t o g r a m ) .
C.Mariani@XLth Rencontres
th
The distribution of the reconstructed direction of muons relative to the
direction from KEK to SK for F.C. 1ring mu-like events in the fiducial volume
in data (closed circle), M.C. expectation with no oscillation (solid histogram),
oscillated with sin 2 2q=1.0,Dm2 =2.0×10 -3 eV 2 (dashed histogram), and
with
sin 2 2q=1.0,Dm 2 =3.0×10 - 3 eV 2 (dotted histogram).
C.Mariani@XLthoscillated
Rencontres de Moriond (6 March
2005)
th
The distribution of the reconstructed direction of muons relative to the
direction from KEK to SK for F.C. 1ring mu-like events in the fiducial volume
in data (closed circle), M.C. expectation with no oscillation (solid histogram),
oscillated with sin 2 2q=1.0,Dm2 =2.0×10 -3 eV 2 (dashed histogram), and
with
sin 2 2q=1.0,Dm 2 =3.0×10 - 3 eV 2 (dotted histogram).
C.Mariani@XLthoscillated
Rencontres de Moriond (6 March
2005)
th
The distribution of the reconstructed direction of muons relative to the
direction from KEK to SK for F.C. 1ring mu-like events in the fiducial volume
in data (closed circle), M.C. expectation with no oscillation (solid histogram),
oscillated with sin 2 2q=1.0,Dm2 =2.0×10 -3 eV 2 (dashed histogram), and
with
sin 2 2q=1.0,Dm 2 =3.0×10 - 3 eV 2 (dotted histogram).
C.Mariani@XLthoscillated
Rencontres de Moriond (6 March
2005)
th
Reconstructed neutrino energy distribution for F.C. 1ring mu-like events in the
fiducial volume in data (closed circle), M.C. expectation with no oscillation
(solid histogram), oscillated with sin 2 2q=1.0,Dm 2 =2.0×10 -3 eV 2 (dashed
histogram), and oscillated with sin22q=1.0,Dm2=3.0×10-3eV2 (dotted histogram).
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Reconstructed neutrino energy distribution for F.C. 1ring mu-like events in the
fiducial volume in data (closed circle), M.C. expectation with no oscillation
(solid histogram), oscillated with sin 2 2q=1.0,Dm 2 =2.0×10 -3 eV 2 (dashed
histogram), and oscillated with sin22q=1.0,Dm2=3.0×10-3eV2 (dotted histogram)
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Reconstructed neutrino energy distribution for F.C. 1ring mu-like events in the
fiducial volume in data (closed circle), M.C. expectation with no oscillation
(solid histogram), oscillated with sin 2 2q=1.0,Dm 2 =2.0×10 -3 eV 2 (dashed
histogram), and oscillated with sin22q=1.0,Dm2=3.0×10-3eV2 (dotted histogram).
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
Summary of SK-2 absolute energy calibration
• Data agree with MC within +/-1.9%
• Time variation : +/-0.9%
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
total uncertainty : +/- 2.1%
Ring-counting likelihood for SK-2
m-like events
sub-GeV P<400MeV/c
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
sub-GeV P>400MeV/c
multi-GeV
PID distributions for SK-2
C.Mariani@XLth Rencontres de Moriond (6th March 2005)
sub-GeV
multi-GeV
(Evis<1330MeV)
(Evis>1330MeV)
Systematic error on spectrum
K2K-1
ring counting
0.-0.5
1.9%
0.5-1.0
2.1%
1.-1.5
2.5%
1.5-2.0
5.9%
2.0-2.5
5.9%
2.55.9%
PID
1.1%
0.5%
0.7%
0.6%
0.7%
0.7%
vertex
2.0%
2.0%
2.0%
2.0%
2.0%
2.0%
ring counting
0.-0.5
2.6%
0.5-1.0
2.2%
1.-1.5
7.9%
1.5-2.0
7.5%
2.0-2.5
7.1%
2.57.1%
PID
2.5%
0.9%
0.6%
0.5%
0.5%
0.5%
vertex
2.0%
2.0%
2.0%
2.0%
2.0%
2.0%
E scale
2.7%
K2K-2
E scale
2.1%
C.Mariani@XLth Rencontres de Moriond (6th March 2005)