current interactions on iron in the NINJA experiment Contents Toho - - PowerPoint PPT Presentation

Study of neutrino charged current interactions on iron in the NINJA experiment

• H. Oshima, H. Shibuya, S. Ogawa,
• T. Matsuo, Y. Morimoto, K. Mizuno,
• H. Takagi, Y. Kosakai,

for NINJA Collaboration

Contents ・Introduction ・NINJA experiment ・Detector construction ・ν event analysis ・Outcomes ・Summary & Prospect

Monday 9th September 2019 The 16st Topics in Astroparticle and Underground Physics (TAUP2019)

Toho Univ., Nagoya Univ., Kobe Univ.,

Nihon Univ., Kyoto Univ., Yokohama national Univ. ICRR and Univ. of Tokyo 7416001o@nc.toho-u.ac.jp

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Introduction : Neutrino Interactions

→ Neutrino energy reconstruction can be mistaken.

Residual of Neutrino Energy(MC) Number of events (a.u.)

Erec – Etrue (GeV)

CCQE CCRES 2p2h NEUT 5.4.0 Iron int.

Hard to separate interaction modes.

• T. Kikawa : Shin-gakujutsu Workshop(2018)

・hard to detect the low energy protons. ・pions can be re- scattered, charge exchanged or absorbed in nucleus.

→ This is a major systematic uncertainty in neutrino oscillation experiments.

Eν reconstruction (CCQE)

Introduction : What we can measure

What we can measure to solve this problem : ・the number of charged hadrons ・their emission angles and momenta with wide angle acceptance and low energy threshold. We use an emulsion-based detector, Emulsion Cloud Chamber(ECC), which has sub-micron position resolution with wide angle acceptance. We can measure charged hadron final states with low energy threshold.

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NINJA experiment (J-PARC T60 / T66 / T68 / E71)

Neutrino to Kamiokande 3

Neutrino no Intera racti tion

• n rese

sear arch ch with th Nuclea ear r emuls lsion

• n and J-PAR

ARC C Accele lera rator tor

The NINJA collaboration aims to study neutrino-nucleus interactions in the energy range of hundreds of MeV to a few GeV by using emulsion-based detector. → We can study ν–nucleus interactions with sub-micron accuracy. → We can use various target (Fe, H2O, C, etc. )

NINJA Run so far

• A. Hiramoto (oral, TAUP2019, 09/09)
• PTEP. 063C02(2017), PTEP. 063H02 (2017)

Linac(330m)

Nuclear Transmutation

3 Gev Rapid-Cycling Synchrotron, RCS (25 Hz, 1MW) 50 Gev Main Ring Synchrotron (0.75MW)

Materials and Life Science Experimental Facility Hadron Beam Facility

J - PARC

This talk

C) Physics run (75kg water, 130kg iron, CH 15kg target) → under preparation A) Detector test run with emulsion shifter → published B-2) 3kg water target run (2017-2018) → analysis on-going B-1) 65kg iron target run (2016) → analysis on-going

NINJA iron target run in 2016 : Detector construction

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Emulsion Film ＋ Iron PL stacked chamber

Add timestamp for event tracks from ν int.

muon ID

Emulsion film Metal plate Metal plate Emulsion film

ECC (Emulsion Cloud Chamber) Detector：Overall view

ECC1 2 3 4

Size of Iron Plate (Film) : 25cm× 25cm× 0.05 (0.03) cm ν event microscope picture

select CC int.

μ range detector (T2K near detector)

Emulsion multi-stage Shifter

(no magnet)

INGRID Shifter ECC

analyze a Neutrino - Fe interaction

Total：12 ECC (264 Iron PLs, 65kg) Emulsion have no dead time, but do not have time resolution.

Side view

An example of ν – iron interaction (NINJA iron target run in 2016)

354.6 um 281.6 um Emulsion layer image by microscope system (FTS @ Toho Univ.)

ν

60um emulsion base IronPL 180um 500um 60um

ν

This layer

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Expected Neutrino Flux @ ECCs

Neutrino no Beam Mode Anti-Ne Neutr utrino no Beam Mode ν𝜈 95.9 % 7.8 % ത ν𝜈 4.1 % 92.2 % POT 0.40 × 1020 3.53 × 1020 𝐹ν average ν : 1.49 GeV / anti-ν : 1.52 GeV ν : 2.12 GeV / anti-ν : 1.30 GeV 𝐹ν peak ν : 0.90 GeV / anti-ν : 0.70GeV ν : 0.90 GeV / anti-ν : 0.90 GeV

Beam Exposure @ SS floor, Feb. – May 2016

ー ν𝜈 ー ത ν𝜈

Neutrino Beam Mode

ー ν𝜈 ー ത ν𝜈

Anti-Neutrino Beam Mode 0.40 × 1020 POT 3.53 × 1020 POT

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Expected CC Events in ECCs

NEUT 5.4.0, Iron CC int. (tuned flux)

𝐹ν[𝐻𝑓𝑊] QE 2p2h COH RES DIS DFR Other ν𝜈 𝐹ν[𝐻𝑓𝑊] QE 2p2h COH RES DIS DFR Other ത ν𝜈 Neutrino Beam Mode Anti-Neutrino Beam Mode

Neutrino no Beam Mode Anti-Ne Neutr utrino no Beam Mode

POT 0.40 × 1020 3.53 × 1020 ν𝜈 CC int. 98.6 % 28.2 % ത ν𝜈 CC int. 1.4 % 71.8 %

Normalize factor : ・POT ・target mass

We can get the high purity ν – iron CC interactions by selecting ν beam mode events. => In this talk, we analyze these ν CC interactions.

Number of events

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Flow of event reconstruction

Event eye check （FTS)@ Toho Univ.

Track & Event reconstruction @ Toho Univ., Nagoya Univ. Track Scanning(HTS) @ Nagoya Univ. Development, Swelling @Nihon Univ. Beam exposure @J-PARC SS floor Detector preparation @Nagoya Univ., Toho Univ.

ν event FTS picture Track scanning

Overall view of detector (NINJA iron target run in 2016)

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ν + ത ν int.(CC+NC) + cosmic-ray ν CC int. μ cand. ν CC int. events ν CC int. selection with shifter + INGRID： Timestamp + Muon ID Event reconstruction ： Attaching track search

ECC tracks

Extract ν CC interaction events by ScanBack method

Muon ID t track # of Tracks FV out

13,621 tracks

Wall (sand-μ, π, p)

3,2962 tracks

ν + ത ν CC Event candidate

1,318 tracks Muon ID track：47,901 tracks ECC

Trace back to vertex in ECC from INGRID via shifter.

Data：12 ECCs（Target mass 65 kg (fiducial mass 43 kg) ）

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Muon ID t track # of Tracks FV out

13,621 tracks

Wall (sand-μ, π, p)

3,2962 tracks

ν + ത ν CC Event candidate

1,318 tracks

ν beam : 221 events.

Iron n int.

• t. : 194 even

ents. s. Emulsion int. : 13 events. Base int. : 14 events. We are analyzing the ν CC interactions.

ECC

The res esul ults s on the he foll llowing

• wing slid

ides s are re based on these 194 ν-iron iron Char arge ged d Current rrent int nteracti eraction

• ns.

s.

Extract ν CC interaction events by ScanBack method

ത ν beam : 1,097 events.

→ Analysis on-going. ν beam event selection efficiency : ~ 27 % (NEUT 5.4.0 ν - iron int., Normalization : POT, Target mass) (preliminary)

Muon ID track：47,901 tracks Data：12 ECCs（Target mass 65 kg (fiducial mass 43 kg)）

dE/dx & momentum measurments in iron ECC

MIP

Momentum measurements in iron ECC VPH is a measure of dE/dx. Volume Pulse Height (VPH)

μ, p, π

Emulsion layer (60um) Base layer (180um)

VPH is the sum of the number of hit pixels in all 16 layers.

track

• T. Toshito Nucl. Instr.

A, 556(2006) 482-489

The number of tracks

VPH distribution (Iron ECC tracks) Heavily ionizing particles

VPH

・Coordinate method

Measure momentum in three ways and use the best method for each track.

・Angular method

(Nucl. Instrum. Meth. A574 (2007) 192-198.)

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(Pμ err. ~ 16%, Pp/π err. ~ 5%) (1/pβ error sys. ~10%, stat. < ~45%) (1/pβ error sys. ~20%, stat. < ~50%)

Range – energy relation for a short track Measurement of Multiple Coulomb Scattering

Proton and π± PID in ECC

Previous study Y. Morimoto (Toho Univ.), O. Sato (Nagoya Univ.), T. Toshito Nucl. Instr. A, 556(2006) 482-489.

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L =

1 2𝜌𝜏𝑞𝛾,𝑏𝑜𝑕𝑚𝑓 exp[ −(𝑊𝑄𝐼−𝜈𝑞𝛾,𝑏𝑜𝑕𝑚𝑓)2 2𝜏𝑞𝛾,𝑏𝑜𝑕𝑚𝑓

2

]

Pβ(GeV/c) VPH vs. Pβ (Real data)

・muon cand.

(INGRID matching)

・pion like ・proton like

←μ± / π± (mip) like

Likelihood function LR =

𝑀𝑛𝑗𝑞 𝑚𝑗𝑙𝑓 𝑀𝑛𝑗𝑞 𝑚𝑗𝑙𝑓+𝑀𝑞𝑠𝑝𝑢𝑝𝑜 𝑚𝑗𝑙𝑓

Likelihood Ratio

VPH μmip μp σp ↓proton like σmip

Pβ < 0.6 GeV/c

Likelihood Ratio (NEUT 5.4.0, ν-Iron CC int.)

LR proton ID pion ID → p / π± separation by using VPH and pβ is good.

VPH

# of tracks The number of tracks Proton : eff. 94%, purity 98% Pion : eff. 94%, purity 82%

preliminary

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Setup of Monte Carlo simulation

Event Generator : NEUT 5.4.0 Normalization : POT & target mass of NINJA 65kg iron target run in 2016. Considered particle : Muon, charged pion, proton Detector response : Angle … no smeared Momentum … MCS 1/Pβ err. = 50% Range Pμ err. = 16% (using ECC and INGRID iron plates(65mm)) Pp/π err. = 5% (using ECC iron plates(0.5mm))

• Y. Hayato, Nucl. Phys. B, Proc. Suppl. 112, 171 (2002), Y. Hayato, Acta Phys. Pol. B 40, 2477 (2009).

Used in Super-Kamiokande, T2K and the various experiments. NEUT covers a wide energy range of neutrino from several tens of MeV to hundreds of TeV.

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Muon angle & momentum distribution

・Angular distribution is limited to the forward direction because muon ID is performed by matching with ECC-Shifter-INGRID.

Detection condition |tanθx|≦1.7, |tanθy|≦1.7, Nplane(Number of INGRID iron layers) ≧ 2 ⇒ Pμ > ~300 MeV/c

・ Real Data and MC agree well.

Muon angle

Number of events

Muon momentum

☩：Real data Pμ(GeV/c) θμ(deg.)

☩ ： Real data Histogram ： MC

Histogram：MC

Preliminary Preliminary

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The number of protons and π±s from ν-iron interactions

Detection condition |tanθx|≦1.7, |tanθy|≦1.7, Nseg(Number of emulsion layers) ≧ 2

0 p : The number of events in data are larger than that in MC. 1 p : The number of events in data are smaller than that in MC. → Similar tendency was observed in a previous measurement, T2K.

• Phys. Rev. D 98, 032003(2018)

The number of protons The number of charged pions

# of protons Number of events # of charged pions (If particle with angle tanθ=0.0 passed 2 iron plates. ⇒ Pproton > ~200 MeV/c, Pπ > ~50 MeV/c)

☩：Real data

Histogram：MC

☩：Real data Histogram ： MC

Preliminary Preliminary

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Proton angle & momentum distribution

・Low momentum protons down to ~200 MeV/c were detected ! ・The shape of Real Data is in good agreement with that of MC simulation.

Proton angle

Number of tracks θp(deg.) MC Normalization : POT, Target mass

Proton momentum

☩ ： Real data

Pp(GeV/c)

200 MeV/c

☩ ： Real data Histogram ： MC

Histogram ： MC

Preliminary Preliminary

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The number of protons & charged pions

This analysis is an advantage by using ECC. We can measure charged hadron final states with low energy threshold. We aim to measure cross section of CCNπN’p interactions.

𝝆± 𝒒 0 𝑞 1 𝑞 2 𝑞 3 𝑞 ≧ 4 𝑞 0 π 64(50.0) 45(66.6) 18(21.7) 7(8.1) 2(2.9) 1 π 20(21.0) 14(16.3) 0(4.5) 4(1.7) 2(1.0) 2 π 3(2.9) 4(3.1) 1(1.0) 1(0.5) 2(0.3) 3 π 2(0.9) 1(0.6) 0(0.2) 2(0.1) 1(0.1) ≧ 4 π 0(0.2) 1(0.2) 0(0.1) 0(0.0) 0(0.1) 𝝆± 𝒒

CC0π CC1π CC2π CC3π

Real Data (NEUT 5.4.0)

The number of CCNπN’p events (N, N’=0, 1, 2, 3, ≧4)

Preliminary

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Summary & Prospect

・Study of ν - nucleus interactions in sub-multi GeV energy region is very important for current & future neutrino oscillation experiments. ・A 65kg iron ECC target was exposed to the neutrino beam with a mean energy of 1.5 GeV at J-PARC in 2016. From this exposure of 0.40×1020 POT, 194 neutrino-iron CC interactions were located in the target. ・Charged hadrons in the final state were detected with low momentum thresholds, 200 MeV/c for protons and 50 MeV/c for charged pions. The number of protons and pions in the final state of each event, their emission angles and momenta were measured and compared with MC. ・We will measure the CCNπN’p (N,N’=0,1,2,…) cross section and differential cross section with the muon, proton and charged pion angle and momentum. ・In Physics Run (E71a), 75kg water target, 130kg iron target and 15kg CH target will be exposed to the neutrino beam of ~0.5×1021 POT. The number of events will be expected ~30 times of iron target run in 2016.

Thank you for your attention

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Backup

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Introduction : Neutrino Oscillation

Oscillation Probability ( 2 flavor neutrino oscillation, for simplification )

Oscillation prob. is large in low Eν region the neutrino energy can be easily reconstructed by the measurement of muon emission angle and momentum for the QES. Charged Current Quasi Elastic Scattering

∆𝑛2 = 𝑛2

2 − 𝑛1 2

𝑄 ν𝛽 → ν𝛾 = sin22θ sin2 ∆𝑛2𝑀 4𝐹𝜉

Eν vs. Osc. Prob. & ν Flux. (T2K FD(SK))

Eν reconstruction

𝐹𝜉 𝑠𝑓𝑑. = 𝑛𝑂𝐹𝜈 − 𝑛𝜈

2/2

𝑛𝑂 −𝐹𝜈 +𝑄

𝜈 cos 𝜄

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Track recognition algorithm

• T. Fukuda, et al., JINST. 8 (2013) P01023

16 tomographic image taking smoothing binarization expansion coincidence PH cut

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Manual Check by microscope

film IronPL

ν

Iron int. emulsion base emulsion int. base int. FTS @ Toho Univ.

25cm 25cm

Film CMOS Camera XY Stage

For checking a event reconstruction and confirming a interacted target ( Iron / Emulsion / Base ).

ν

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INGRID

Emulsion multi-stage shifter

In order to perform hybrid analysis of ECC and INGRID, a time-stamper with micro meter resolution is required. → emulsion multi-stage shifter was installed in run6. ① ② ③

Position and time relationship driving each stage (concept）

• K. kuretsubo, Bachelor Thesis in Kobe Univ. (2016)
• 4000
• 3000
• 3500

② middle-stage Time peak

1.5 hours / peak

150 μm

dy[μm]

each stage is independently driving. ① 74.4 hours pitch ② 1.5 hours pitch ③ 0.55 μm / sec. Add a timestamp for track from displacement ①, ② and ③. (③ is continuously driving.)

Momentum measurments in iron ECC

Measurement of Multiple Coulomb Scattering in iron ECC

∆𝜄 = 13.6 MeV/c 𝑞𝛾 𝑨 𝑦 𝑌0 [1 + 0.038ln( 𝑦𝑨2 𝑌0𝛾2)]

25 25

Range – energy relation(Iron)

(Geant4, 1GeV/c μ+, tanθ=0.0, Nseg=15, depend on pβ and the number of IronPL, T. Matsuo(Toho Univ.))

∆𝑠 = 2 3 13.6 MeV/𝑑 𝑞𝛾 𝑨𝑌0 𝑦 𝑌0

3 2

[1 + 0.038ln( 𝑦𝑨2 𝑌0𝛾2)]

(Nucl. Instrum. Meth. A574 (2007) 192-198.)

Applicable pβ range Coordinate method Pβ < few GeV/c Angular method Pβ < ~1 GeV/c 1/pβ typical meas. error sys. < ~10%, stat. < ~45% For side-escaping tracks and penetrating tracks

Tracks in iron ECC

For stopped tracks in ECC Stopped tracks → Range – energy relation Side-escaping tracks / Penetrating tracks → Measurement of MCS