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Measurements of neutrino charged current scattering in K2K Fine-Grained Detector

Measurements of neutrino charged current scattering in K2K Fine-Grained Detector. M.Hasegawa Kyoto University for the K2K collaboration. Introduction K2K Near Detector CC interactions ( p m,qm, Q 2 ) Summary. Charged Current Scattering. Charged Current Quasi-Elastic

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Measurements of neutrino charged current scattering in K2K Fine-Grained Detector

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  1. Measurements of neutrino charged current scattering in K2K Fine-Grained Detector M.Hasegawa Kyoto University for the K2K collaboration Introduction K2K Near Detector CC interactions (pm,qm,Q2) Summary

  2. Charged Current Scattering • Charged Current Quasi-Elastic • (CCQE) Scattering - Dominant process around 1GeV (~40% of CC) - En can be reconstructed from (pm,qm ) • Charged Current non Quasi-Elastic • (nonQE) Scattering • single p production (CC1p) • (~38% of CC) • multi p production (CCmp) • (~18% of CC) • Coherent p production • (~2% of CC) Coherent p production m n p Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  3. … … K2K Charged Current Analysis Main motivation is to determine En spectrum @near site Latest result in Maesaka’s(Kyoto)talk (WG1 in this morning) Data(Pm, qm)=F(i)* [ sCCQE+RnQE/QE* snQE] F(i):Neutrino flux (i =1~7) RnQE/QE: NonQE to QE ratio 1kt data (for example) qm (deg.) 60 40 20 0 500 1000 pm (MeV/c) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  4. CC Analysis - cont’d Another Motivation is to study the n int. in a few GeV region. En (near vs Far) B.G. from non-QE K2K measures (On-Going Work) • CCQE , CC1p Form factors • s(CC1p) / s(CCQE), s(CC multi p) / s(CCQE) • LowQ2 (CC1p , Coherent p) (Important to understand Background for CCQE) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  5. K2K Near Detectors K2K-II Detectors (2003-) • K2K Near Detectors • Neutrino beam properties • at production. • Neutrino interactions • <En> ~ 1.3GeV • 1kt Water Cherencov detector (1kt) • Scintillating Fiber Detector (Scifi) • Scintillator Bar Detector (SciBar) (2003-) • Muon Range Detector (MRD)  Study n int. Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  6. Scifi Detector Scintillating Fiber sheet / Water Sandwich detector 260cm 173cm 260cm Possible to identify CCQE events by using Proton track Track Finding Efficiency ~93% (single track) Tracking threshold 3layer(>12cm) (=Proton 0.60GeV/c) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  7. Extruded scintillator (15t) EM calorimeter 3m n Multi-anode PMT (64 ch) 3m 1.7m Wave-length shifting fiber SciBar Detector Fine segmented , Full Active Scintillator-Bar Tracker • Neutrino target is scintillator itself • 2.5 x 1.3 x 300 cm3 cell (15000ch) • (Fairly) large volume (10000 int. / month) Tracking Threshold : 8cm (=0.4GeV/c Proton) Preliminary Track-finding efficiency >99% (Single Track) Excellent p/m(p) using dE/dx misID(mP) = 1.7% @PEff=90% High 2-track CC-QE efficiency Identify ν interaction mode clearly Just constructed in last summer! Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  8. p n m 3 2 n 1 SciBar Shot ! CCQE candidate CCnQE candidate Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  9. FGD Charged Current Analysis Selection Use events which have more than 1 track connected with MRD ( CC fraction ~100%(Scifi) , ~ 98% (SciBar) ) m Vertex MRD (Iron plates and drift tubes) SciBar Scifi SciBar MRD Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  10. QE nonQE DATA CC QE CC 1p CC coherent-p CC multi-p Dqp (deg) QE/nQE Use proton track direction to enhance CCQE / non QE • (1) 1 Track 60% QE • (2) 2 Track QE enriched 60%(SF) / 70%(SB) QE • 2 Track nonQE enriched 85% nQE SciBar Dqp m Observed second track Dqp Expected proton direction assuming CCQE Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  11. DATA CC QE CC 1p CC coherent-p CC multi-p SciBar 1Track Sample MC (NEUT4.5) Nucl.Phys.Proc.112,171 - MA(QE) = MA(1p) = 1.1GeV/c2 - Marteau model (coherent p) - Bodek/Yang (DIS) pm Agreement is good except for lowQ2(forward) region. qm q2(rec) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  12. DATA CC QE CC 1p CC coherent-p CC multi-p SciBar 2Track QE sample pm Good Agreement (No deficit can be found) qm q2(rec) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  13. DATA CC QE CC 1p CC coherent-p CC multi-p SciBar 2Track nQE sample Agreement is good except for lowQ2(forward) region. pm Clear deficit can be seen. qm q2(rec) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  14. DATA CC QE CC 1p CC coherent-p CC multi-p 1Kt , Scifi Q2 distribution Scifi 2track nonQE enriched event 1 Kt 1ring muon-like event (GeV2) Three detectors see the same effect.  This cannot be explained by detector systematics. From SciBar (&Scifi) result , source is nonQE. (CC1p or coherent p cross section is suspicious ) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  15. CC1p suppressing vs No coherent p LowQ2 suppression in CC1p (0.10/Q2,Q2 <0.10) No coherent p Currently, we don’t judge which is source of low Q2 deficit. Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  16. SB Coherent p Analysis (On-going) Coherent p CC1p n m n m p p N Difference between coherent p and CC1p In the case of coherent p • No activity around Vertex (Full Active) • Hadron track is Pion ( PID ) SciBar can separate them effectively. And just working now Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  17. Summary • K2K Charged Current Analysis provide • Neutrino Flux & Knowledge of n int (~1.3GeV). • New near detector ‘SciBar’ was installed in • last summer and works stably and shows • good performance as expected. • Muon distributions (pm,qm,Q2)agreed with MC • except for lowQ2 region. (Origin is CC1p • or coherent p or Both. Currently we doesn’t judge.) • SciBar Analysis will answer this question soon. • stay tuned! Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  18. Supplement

  19. CC1p suppression factor tuning SciBar 2track nonQE • By using SciBar 2track-nonQE 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 CC1p q2/0.10 (Data–MC)/MC Agree quite well Calculate c2 A=0.10 +/– 0.03 A

  20. Basic Performance (Tracking) Track Finding Efficiency (Single Track) SciBar in coming m 10cm Efficiency : 99.2% (>4layer ~ 10cm) Track Finding Efficiency (2nd Track) Efficiency:76.7% (>8Hits) True Length Main contribution on ineff. Is overlapping  will be improved to > 90% soon Detected ! Confirmed w/ eye Systematic error : +0.2 / -2.5 % Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  21. Basic Performance (PID) Non Muon-Like Muon C.L. Muon-Like Range vs Total deposit energy m sample DATA Proton-like(purity 90%) (2track QE sample) Total dE (MIPs) Preliminary Mu-like(purity ~ 99.6%) protonsample Range in SciBar (cm) Excellent p/m(p) using dE/dx Preliminary Proton Efficiency When 90% proton eff. is required, Muon Miss ID probability is 1.7% Muon mis-ID Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  22. Top view Side view Basic Performance (Energy Response) • We use a penetrating muon (cosmic m) as a (strip to strip) relative energy calib. source. • All PMT channel’s (~15000ch) gain are monitored by LED based system. m m - Relative energy scale is calibrated at 1.5% precision - response for dE/dx is stable within 1.0% for 4months +5% -5% High Accuracy gain monitoring SystEm (HASE moni) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  23. Event rate Event rate (/1018POT) Date Basic Performance (Stability) • Overall n int. detection efficiency : ~75% (MC) (w/ >30cm Track) • Event rate is stable for 4 months. Efficiency 0.748 Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  24. On-Going Analysis (Nuint04 R.Gran) MA Analysis(QE) (Scifi) Preliminary This is the first measurement of MA with water target. Coherent p search (mainly SciBar) (Nuint04 Minerva) One Candidate of Origin of LowQ2(forward)Deficit K2K Observed.(CC) This is the first search in a few GeV region. 3.0 7.0 Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  25. Extruded scintillator (15t) EM calorimeter 3m n Multi-anode PMT (64 ch) 3m 1.7m Wave-length shifting fiber SciBar Detector • 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! Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  26. m m Vertex MRD (Iron plates and drift tubes) Vertex SciBar SciBar Charged Current Analysis Selection • SciBar-MRD 3D Track Matching (pμ>0.5GeV/c) - 35% of All n interaction ( CCQE fraction ~ 55%) • SciBar-MRD 1L Stopping Event (pμ>0.3GeV/c) - 9% of All n interaction ( CCQE fraction ~ 31%) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  27. Total (NC+CC) CC Total CC quasi-elastic DIS CC single p NC single p0 • 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 NEUT: K2K Neutrino interaction MC s/E (10-38cm2/GeV) En (GeV) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  28. SciFi (K2K-IIa with measured spectrum) qm 1trk Pm 1trk flux measurement Pm 2trk QE qm 2trk QE Pm 2trk non-QE qm 2trk non-QE 10 0 2 (GeV/c) 0 40 (degree) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  29. SciBar (with measured flux) qm 1trk Pm 1trk flux measurement Pm 2trk QE qm 2trk QE qm 2trk nQE Pm 2trk nQE 10 Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  30. K2K Charged Current Analysis Main motivation is to determine En 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.

  31. … … K2K Charged Current Analysis Main motivation is to determine En spectrum @near site Latest result in Maesaka’s(Kyoto)talk (WG1 in this morning) Data(Pm, qm)=F(i)* [ sCCQE+RnQE/QE* snQE] F(i):Neutrino flux (i =1~7) RnQE/QE: NonQE to QE ratio 1kt data (for example) qm (deg.) 60 40 20 0 500 1000 pm (MeV/c) Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  32. SB Coherent p Analysis (On-going) Coherent p CC1p n m n m p p N Neutrino scatters coherently from the entire nucleus with small energy transfer. • No activity around Vertex (Full Active) • Hadron track is Pion ( PID ) SciBar can separate them effectively. Kyoto Univ Masaya Hasegawa NuFact 04 July. 26 – Aug. 1 , 2004 Osaka Univ.

  33. DATA CC 1p CC coherent-p CC1p suppression Preliminary • 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. • 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. q2rec q2rec(GeV/c)2 (Data-MC)/MC SciBar non-QE Events q2rec(GeV/c)2

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