Measurements of Measurements of neutrino charged current scattering neutrino charged current scattering
in K2K Fine-Grained Detector in K2K Fine-Grained Detector
IntroductionIntroduction K2K Near DetectorK2K Near Detector CC interactions (CC interactions (ppQQ22)) Summary Summary
M.Hasegawa Kyoto UniversityM.Hasegawa Kyoto University for the K2K collaborationfor the K2K collaboration
Charged Current ScatteringCharged Current Scattering
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Charged Current Quasi-Elastic (CCQE) Scattering
- Dominant process around 1GeV (~40% of CC)- E can be reconstructed from (pp )
Charged Current non Quasi-Elastic (nonQE) Scattering
- single production (CC1) (~38% of CC) - multi production (CCm(~18% of CC)- Coherent production (~2% of CC)
Coherent production
K2K Charged Current AnalysisK2K Charged Current Analysis
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
… …
1kt data (for example)
(
deg
.)
p (MeV/c)0
20
40
60
500 1000
Data(P, ) = F(i) * [ CCQE + RnQE/QE * nQE ] F(i) : Neutrino flux (i =1~7)
RnQE/QE : NonQE to QE ratio
Main motivation is to determine E spectrum @near siteLatest result in Maesaka’s(Kyoto)talk (WG1 in this morning)
CC Analysis - cont’dCC Analysis - cont’d
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Another Motivation is to study the int. in a few GeV region.
CCQE , CC1 Form factors CC1) / CCQE), CC multi ) / CCQE) LowQ2 (CC1 , Coherent
(Important to understand Background for CCQE)
K2K measures (On-Going Work)
B.G. from non-QE
E (near vs Far)
K2K Near Detectors K2K Near Detectors
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
1kt Water Cherencov detector (1kt) Scintillating Fiber Detector (Scifi) Scintillator Bar Detector (SciBar) (2003-) Muon Range Detector (MRD)
K2K Near Detectors
Neutrino beam properties at production.
Neutrino interactions <E> ~ 1.3GeV
K2K-II Detectors (2003-)
Study int.
Scifi DetectorScifi Detector
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
SciScintillating FiFiber sheet / Water Sandwich detector
Track Finding Efficiency ~93% (single track)Tracking threshold 3layer(>12cm) (=Proton 0.60GeV/c)
260cm 173cm
260cm
Possible to identify CCQE events by using Proton track
SciBar DetectorSciBar Detector
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Extrudedscintillator(15t)
Multi-anodePMT (64 ch)
Wave-lengthshifting fiber
EM calorim
eter
1.7m
3m
3m
Neutrino target is scintillator itself
2.5 x 1.3 x 300 cm3 cell (15000ch)
(Fairly) large volume (10000 int. / month)
Just constructed in last summer!
Fine segmented , Full Active SciScintillator-Bar Bar Tracker
Tracking Threshold : 8cm (=0.4GeV/c Proton)
Track-finding efficiency >99% (Single Track) Excellent p/using dE/dx misID( P) = 1.7% @ PEff=90%
High 2-track CC-QE efficiency
Identify ν interaction mode clearly
Prelim
inar
y
Prelim
inar
y
SciBar Shot !SciBar Shot !
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
p
CCQE candidateCCQE candidate
1
23
CCnQE candidateCCnQE candidate
FGD Charged Current Analysis FGD Charged Current Analysis
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Vertex
MRD(Iron plates and drift tubes)SciBar
Selection
Use events which have more than 1 track connected with MRD ( CC fraction ~100%(Scifi) , ~ 98% (SciBar) )
Scifi SciBar MRD
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
QE/nQE
QE nonQE
DATACC QECC 1CC coherent-CC multi-
p
(deg)
(1) 1 Track 60% QE (2) 2 Track QE enriched 60%(SF) / 70%(SB) QE (3) 2 Track nonQE enriched 85% nQE
Expected proton direction assuming CCQE
p
Observed second track
SciBar p
Use proton track direction to enhance CCQE / non QE
SciBar 1Track Sample
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
p
DATACC QECC 1CC coherent-CC multi-
q2(rec)
Agreement is good exceptfor lowQ2(forward) region.
MC (NEUT4.5) Nucl.Phys.Proc.112,171
- MA(QE) = MA(1) = 1.1GeV/c2
- Marteau model (coherent ) - Bodek/Yang (DIS)
SciBar 2Track QE sample
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
DATACC QECC 1CC coherent-CC multi-
p
Good Agreement(No deficit can be found)
q2(rec)
SciBar 2Track nQE sample
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
DATACC QECC 1CC coherent-CC multi-
p
Agreement is good exceptfor lowQ2(forward) region.
Clear deficit can be seen.
q2(rec)
1Kt , Scifi Q2 distribution
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
1 Kt 1ring muon-like event
(GeV2)
From SciBar (&Scifi) result , source is nonQE. (CC1 or coherent cross section is suspicious )
Scifi 2track nonQE enriched event
DATACC QECC 1CC coherent-CC multi-
Three detectors see the same effect. This cannot be explained by detector systematics.
CC1CC1 suppressing vs No coherent suppressing vs No coherent
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
LowQ2 suppression in CC1QQ No coherent
Currently, we don’t judge which is source of low Q2 deficit.
SB Coherent SB Coherent Analysis (On- Analysis (On-going)going)
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
N
CC1Coherent
No activity around Vertex (Full Active) Hadron track is Pion ( PID )
SciBar can separate them effectively. And just working now
Difference between coherent and CC1
In the case of coherent
Summary
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
K2K Charged Current Analysis provide K2K Charged Current Analysis provide Neutrino Flux & Knowledge of Neutrino Flux & Knowledge of int (~1.3GeV).int (~1.3GeV).
New near detector ‘SciBar’ was installed in New near detector ‘SciBar’ was installed in last summer and works stably and showslast summer and works stably and shows good performance as expected. good performance as expected.
Muon distributions (Muon distributions (ppQQ22)) agreed with MCagreed with MC except for lowQexcept for lowQ22 region. (Origin is CC1 region. (Origin is CC1 or coherent or coherent or Both. Currently we doesn’t judge.) or Both. Currently we doesn’t judge.) SciBar Analysis will answer this question soon. SciBar Analysis will answer this question soon. stay tuned!stay tuned!
Supplement
A
A=0.10 +/– 0.03
CC1q2/0.10
(Data–MC)/MCAgree quite well
• By using SciBar 2track-nonQE and fitted flux, I looked for the best value of CC1 suppression.
• Suppression factorq2/A (q2>A)
• Scan A value and calculate 2 of distribution.
Calculate
2
SciBar 2track nonQECC1 suppression factor tuning
Basic Performance (Tracking) Basic Performance (Tracking)
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Track Finding Efficiency (Single Track)Track Finding Efficiency (Single Track)
Efficiency : 99.2% (>4layer ~ 10cm)
in coming 10cm
SciBar
Track Finding Efficiency (2nd Track)Track Finding Efficiency (2nd Track)
True Length
Detected !
Efficiency:76.7% (>8Hits) Main contribution on ineff. Is overlapping will be improved to > 90% soon
Confirmed w/ eye Systematic error : +0.2 / -2.5 %
Basic Performance (PID)Basic Performance (PID)
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Mu-like(purity ~ 99.6%)
Proton-like(purity 90%)
Range in SciBar (cm)
To
tal d
E (
MIP
s)
Range vs Total deposit energy
DATA
(2track QE sample)
Non Muon-Like Muon-Like
sample
protonsample
Proton Efficiency
Muon mis-ID
Preliminary
Preliminary
Preliminary
PreliminaryExcellent p/using dE/dx
When 90% proton eff. is required,Muon Miss ID probability is 1.7%
Muon C.L.
Basic Performance (Energy Response) Basic Performance (Energy Response)
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Top view Side view
High Accuracy gain monitoring SystEmHigh Accuracy gain monitoring SystEm (HASE moni) (HASE moni)
+5%
-5%
We use a penetrating muon (cosmic as a (strip to strip) relative energy calib. source. All PMT channel’s (~15000ch) gain aremonitored by LED based system.
- Relative energy scale is calibrated at 1.5% precision - response for dE/dx is stable within 1.0% for 4months
Basic Performance (Stability) Basic Performance (Stability)
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Event rate
Date
Eve
nt r
ate
(/10
18P
OT
)Efficiency0.748
Overall int. detection efficiency : ~75% (MC) (w/ >30cm Track)
Event rate is stable for 4 months.
On-Going Analysis
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
MA Analysis(QE) (Scifi)
Coherent search (mainly SciBar)
This is the first measurement of MA with water target.
This is the first search in a few GeV region.
Preliminary
Preliminary
7.03.0
Observed.(CC)Observed.(CC)
(Nuint04 Minerva)
One Candidate of Origin of LowQ2(forward)Deficit
(Nuint04 R.Gran)
K2KK2K
SciBar DetectorSciBar Detector
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Extrudedscintillator(15t)
Multi-anodePMT (64 ch)
Wave-lengthshifting fiber
EM calorim
eter
1.7m
3m
3m
Extruded scintillator
with WLS fiber readout
Neutrino target is scintillator itself
2.5 x 1.3 x 300 cm3 cell
~15000 channels• Detect from less than 10cm track • Distinguish proton from
pion by using dE/dx• (fairly) large volume High 2-track CC-QE efficiency Identify ν interaction mode clearly
Just constructed in last summer!
SciBar Charged Current Analysis SciBar Charged Current Analysis
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Vertex
MRD(Iron plates and drift tubes)SciBar
Selection
Vertex
SciBar-MRD 3D Track Matching (pμ>0.5GeV/c)- 35% of All interaction ( CCQE fraction ~
SciBar-MRD 1L Stopping Event (pμ>0.3GeV/c) - 9% of All interaction ( CCQE fraction ~
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
• CC quasi elastic (CCQE)
– Smith and Moniz with MA=1.1GeV
• CC (resonance) single (CC-1)
– Rein and Sehgal’s with MA=1.1GeV
• DIS
– GRV94 + JETSET with Bodek and Yang correction.
• CC coherent – Rein&Sehgal with the cross secti
on rescale by J. Marteau
• NC
+ Nuclear Effects
/E (10-38cm2/GeV)
Total (NC+CC)
CC Total
CC quasi-elastic
DISCC single
NC single 0
E (GeV)
NEUT: K2K Neutrino interaction MC
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
P 1trk
P 2trkQE
P 2trknon-QE
1trk
2trkQE
2trknon-QE
0 2 (GeV/c) 0 40 (degree)
flux measurement
10
SciFi (K2K-IIa with measured spectrum)
P 1trk
P 2trk QE
P 2trk nQE
1trk
2trk QE
2trk nQE
flux measurement
10
SciBar (with measured flux)
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
K2K Charged Current AnalysisK2K Charged Current AnalysisMain motivation is to determine E spectrum @near site
Latest result in Maesaka’s(Kyoto)talk (WG1 in this morning)
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
cos
22
pEm
mEmE
N
N
K2K Charged Current AnalysisK2K Charged Current Analysis
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
… …
1kt data (for example)
(
deg
.)
p (MeV/c)0
20
40
60
500 1000
Data(P, ) = F(i) * [ CCQE + RnQE/QE * nQE ] F(i) : Neutrino flux (i =1~7)
RnQE/QE : NonQE to QE ratio
Main motivation is to determine E spectrum @near siteLatest result in Maesaka’s(Kyoto)talk (WG1 in this morning)
SB Coherent SB Coherent Analysis (On-goin Analysis (On-going)g)
Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.
Neutrino scatters coherently from the entire nucleuswith small energy transfer.
N
CC1Coherent
No activity around Vertex (Full Active) Hadron track is Pion ( PID )
SciBar can separate them effectively.
SciBarnon-QE Events
K2K observed forward deficit.– A source is non-QE events.
– For CC-1,
• Suppression of ~q2/0.1[GeV2] at q2<0.1[GeV2] may exist.
– For CC-coherent ,
• The coherent may not exist.
We do not identify which process causes the effect. The MC CC-1 (coherent ) model is corrected phenomenologically.
Oscillation analysis is insensitive to the choice.
q2rec
(Data-MC)/MC
DATACC 1CC coherent-
Preliminary
q2rec (GeV/c)2
q2rec (GeV/c)2
CC1 suppression