t. nakaya for the t2k collaboration results from t2k.pdf · t2k/j-parc recovery after the big...

NEW Results from

T. Nakaya for the T2K collaboration

1

NEUTRINO 2012@Kyoto, June 5th

12年6月5日火曜日

T2K Collaboration

2

CanadaU. AlbertaU. B. ColumbiaU. ReginaU. TorontoTRIUMFU. VictoriaU. WinnipegYork U.

FranceCEA SaclayIPN LyonLLR E. Poly.LPNHE Paris

GermanyU. Aachen

ItalyINFN, U. BariINFN, U. NapoliINFN, U. PadovaINFN, U. Roma

UKImperial C. L.Lancaster U.Liverpool U.Queen Mary U. L.Oxford U.Sheffield U.STFC/RALSTFC/DaresburyWarwick U.

USABoston U.Colorado S. U.U. ColoradoDuke U.U. C. IrvineLouisiana S. U.U. PittsburghU. RochesterStony Brook U.U. Washington

K. Abe,49 N. Abgrall,16 Y. Ajima,18,† H. Aihara,48 J. B. Albert,13 C. Andreopoulos,47 B. Andrieu,37 S. Aoki,27

O. Araoka,18,† J. Argyriades,16 A. Ariga,3 T. Ariga,3 S. Assylbekov,11 D. Autiero,32 A. Badertscher,15 M. Barbi,40

G. J. Barker,56 G. Barr,36 M. Bass,11 F. Bay,3 S. Bentham,29 V. Berardi,22 B. E. Berger,11 I. Bertram,29 M. Besnier,14

J. Beucher,8 D. Beznosko,34 S. Bhadra,59 F. d.M.M. Blaszczyk,8 A. Blondel,16 C. Bojechko,53 J. Bouchez,8,* S. B. Boyd,56

A. Bravar,16 C. Bronner,14 D.G. Brook-Roberge,5 N. Buchanan,11 H. Budd,41 D. Calvet,8 S. L. Cartwright,44 A. Carver,56

R. Castillo,19 M.G. Catanesi,22 A. Cazes,32 A. Cervera,20 C. Chavez,30 S. Choi,43 G. Christodoulou,30 J. Coleman,30

W. Coleman,31 G. Collazuol,24 K. Connolly,57 A. Curioni,15 A. Dabrowska,17 I. Danko,38 R. Das,11 G. S. Davies,29

S. Davis,57 M. Day,41 G. De Rosa,23 J. P. A.M. de André,14 P. de Perio,51 A. Delbart,8 C. Densham,47 F. Di Lodovico,39

S. Di Luise,15 P. Dinh Tran,14 J. Dobson,21 U. Dore,25 O. Drapier,14 F. Dufour,16 J. Dumarchez,37 S. Dytman,38

M. Dziewiecki,55 M. Dziomba,57 S. Emery,8 A. Ereditato,3 L. Escudero,20 L. S. Esposito,15 M. Fechner,13,8 A. Ferrero,16

A. J. Finch,29 E. Frank,3 Y. Fujii,18,† Y. Fukuda,33 V. Galymov,59 F. C. Gannaway,39 A. Gaudin,53 A. Gendotti,15

M.A. George,39 S. Giffin,40 C. Giganti,19 K. Gilje,34 T. Golan,58 M. Goldhaber,6,* J. J. Gomez-Cadenas,20 M. Gonin,14

N. Grant,29 A. Grant,46 P. Gumplinger,52 P. Guzowski,21 A. Haesler,16 M.D. Haigh,36 K. Hamano,52 C. Hansen,20,‡

D. Hansen,38 T. Hara,27 P. F. Harrison,56 B. Hartfiel,31 M. Hartz,59,51 T. Haruyama,18,† T. Hasegawa,18,† N. C. Hastings,40

S. Hastings,5 A. Hatzikoutelis,29 K. Hayashi,18,† Y. Hayato,49 C. Hearty,5,x R. L. Helmer,52 R. Henderson,52 N. Higashi,18,†

J. Hignight,34 E. Hirose,18,† J. Holeczek,45 S. Horikawa,15 A. Hyndman,39 A.K. Ichikawa,28 K. Ieki,28 M. Ieva,19

M. Iida,18,† M. Ikeda,28 J. Ilic,47 J. Imber,34 T. Ishida,18,† C. Ishihara,50 T. Ishii,18,† S. J. Ives,21 M. Iwasaki,48 K. Iyogi,49

A. Izmaylov,26 B. Jamieson,5 R.A. Johnson,10 K.K. Joo,9 G.V. Jover-Manas,19 C.K. Jung,34 H. Kaji,50 T. Kajita,50

H. Kakuno,48 J. Kameda,49 K. Kaneyuki,50,* D. Karlen,53,52 K. Kasami,18,† I. Kato,52 E. Kearns,4 M. Khabibullin,26

F. Khanam,11 A. Khotjantsev,26 D. Kielczewska,54 T. Kikawa,28 J. Kim,5 J. Y. Kim,9 S. B. Kim,43 N. Kimura,18,† B. Kirby,5

J. Kisiel,45 P. Kitching,1 T. Kobayashi,18,† G. Kogan,21 S. Koike,18,† A. Konaka,52 L. L. Kormos,29 A. Korzenev,16

K. Koseki,18,† Y. Koshio,49 Y. Kouzuma,49 K. Kowalik,2 V. Kravtsov,11 I. Kreslo,3 W. Kropp,7 H. Kubo,28 Y. Kudenko,26

N. Kulkarni,31 R. Kurjata,55 T. Kutter,31 J. Lagoda,2 K. Laihem,42 M. Laveder,24 K. P. Lee,50 P. T. Le,34 J.M. Levy,37

C. Licciardi,40 I. T. Lim,9 T. Lindner,5 R. P. Litchfield,56,28 M. Litos,4 A. Longhin,8 G.D. Lopez,34 P. F. Loverre,25

L. Ludovici,25 T. Lux,19 M. Macaire,8 K. Mahn,52 Y. Makida,18,† M. Malek,21 S. Manly,41 A. Marchionni,15

A.D. Marino,10 J. Marteau,32 J. F. Martin,51,x T. Maruyama,18,† T. Maryon,29 J. Marzec,55 P. Masliah,21 E. L. Mathie,40

C. Matsumura,35 K. Matsuoka,28 V. Matveev,26 K. Mavrokoridis,30 E. Mazzucato,8 N. McCauley,30 K. S. McFarland,41

C. McGrew,34 T. McLachlan,50 M. Messina,3 W. Metcalf,31 C. Metelko,47 M. Mezzetto,24 P. Mijakowski,2 C.A. Miller,52

A. Minamino,28 O. Mineev,26 S. Mine,7 A.D. Missert,10 G. Mituka,50 M. Miura,49 K. Mizouchi,52 L. Monfregola,20

F. Moreau,14 B. Morgan,56 S. Moriyama,49 A. Muir,46 A. Murakami,28 M. Murdoch,30 S. Murphy,16 J. Myslik,53

T. Nakadaira,18,† M. Nakahata,49 T. Nakai,35 K. Nakajima,35 T. Nakamoto,18,† K. Nakamura,18,† S. Nakayama,49

T. Nakaya,28 D. Naples,38 M. L. Navin,44 B. Nelson,34 T. C. Nicholls,47 K. Nishikawa,18,† H. Nishino,50 J. A. Nowak,31

M. Noy,21 Y. Obayashi,49 T. Ogitsu,18,† H. Ohhata,18,† T. Okamura,18,† K. Okumura,50 T. Okusawa,35 S.M. Oser,5

M. Otani,28 R.A. Owen,39 Y. Oyama,18,† T. Ozaki,35 M.Y. Pac,12 V. Palladino,23 V. Paolone,38 P. Paul,34 D. Payne,30

G. F. Pearce,47 J. D. Perkin,44 V. Pettinacci,15 F. Pierre,8,* E. Poplawska,39 B. Popov,37,k M. Posiadala,54 J.-M. Poutissou,52

R. Poutissou,52 P. Przewlocki,2 W. Qian,47 J. L. Raaf,4 E. Radicioni,22 P. N. Ratoff,29 T.M. Raufer,47 M. Ravonel,16

M. Raymond,21 F. Retiere,52 A. Robert,37 P. A. Rodrigues,41 E. Rondio,2 J.M. Roney,53 B. Rossi,3 S. Roth,42 A. Rubbia,15

D. Ruterbories,11 S. Sabouri,5 R. Sacco,39 K. Sakashita,18,† F. Sánchez,19 A. Sarrat,8 K. Sasaki,18,† K. Scholberg,13

J. Schwehr,11 M. Scott,21 D. I. Scully,56 Y. Seiya,35 T. Sekiguchi,18,† H. Sekiya,49 M. Shibata,18,† Y. Shimizu,50

M. Shiozawa,49 S. Short,21 M. Siyad,47 R. J. Smith,36 M. Smy,7 J. T. Sobczyk,58 H. Sobel,7 M. Sorel,20 A. Stahl,42

P. Stamoulis,20 J. Steinmann,42 B. Still,39 J. Stone,4 C. Strabel,15 L. R. Sulak,4 R. Sulej,2 P. Sutcliffe,30 A. Suzuki,27

K. Suzuki,28 S. Suzuki,18,† S. Y. Suzuki,18,† Y. Suzuki,18,† Y. Suzuki,49 T. Szeglowski,45 M. Szeptycka,2 R. Tacik,40,52

M. Tada,18,† S. Takahashi,28 A. Takeda,49 Y. Takenaga,49 Y. Takeuchi,27 K. Tanaka,18,† H.A. Tanaka,5,x M. Tanaka,18,†

M.M. Tanaka,18,† N. Tanimoto,50 K. Tashiro,35 I. Taylor,34 A. Terashima,18,† D. Terhorst,42 R. Terri,39 L. F. Thompson,44

A. Thorley,30 W. Toki,11 T. Tomaru,18,† Y. Totsuka,18,* C. Touramanis,30 T. Tsukamoto,18,† M. Tzanov,31,10 Y. Uchida,21

K. Ueno,49 A. Vacheret,21 M. Vagins,7 G. Vasseur,8 T. Wachala,17 J. J. Walding,21 A.V. Waldron,36 C.W. Walter,13

P. J. Wanderer,6 J. Wang,48 M.A. Ward,44 G. P. Ward,44 D. Wark,47,21 M.O. Wascko,21 A. Weber,36,47 R. Wendell,13

N. West,36 L. H. Whitehead,56 G. Wikström,16 R. J. Wilkes,57 M. J. Wilking,52 J. R. Wilson,39 R. J. Wilson,11

T. Wongjirad,13 S. Yamada,49 Y. Yamada,18,† A. Yamamoto,18,† K. Yamamoto,35 Y. Yamanoi,18,† H. Yamaoka,18,†

C. Yanagisawa,34,{ T. Yano,27 S. Yen,52 N. Yershov,26 M. Yokoyama,48 A. Zalewska,17 J. Zalipska,5 L. Zambelli,37

K. Zaremba,55 M. Ziembicki,55 E. D. Zimmerman,10 M. Zito,8 and J. Żmuda58

S KoreaN. U. ChonnamU. DongshinN. U. Seoul

SpainIFIC, ValenciaIFAE, Barcelona

SwitzerlandETH ZurichU. BernU. Geneva

~500 physicistsfrom 12 countries

JapanICRR KamiokaICRR RCCNKEKKobe U.Kyoto U.Miyagi U. Edu.Osaka City U.U. Tokyo

PolandNCBJ, WarsawIFJ PAN, CracowT. U. WarsawU. Silesia, KatowiceU. WarsawU. Wroklaw

RussiaINR

+ J. Caravaca, Y. Kanazawa, P. Sinclair, O. Perevozchikov


T2K/J-PARC recovery after the BIG earthquake in March 11, 2011

3

LINAC

RCS (elec yard)

Neutrino (Dump)

On Dec.9, 2011, J-PARC LINAC operation restarted!!!On Dec.24, 2011, Neutrino events were observed at T2K-ND280!!

Heartfelt gratitude to the tremendous supports to J-PARC and T2K from all over the world.

09:30 Key was on.12年6月5日火曜日

1. Introduction

4

50 years ago

weak neutrinos:νe, νμ, ντ

are not stable

νeνμντ

⎛

⎝

⎜⎜

⎞

⎠

⎟⎟=UPMNS

ν1ν2ν3

⎛

⎝

⎜⎜

⎞

⎠

⎟⎟

UPMNS: Pontecorvo–Maki–Nakagawa–Sakata matrix


Rich Physics from νe appearance [θ θ θ δCP Δ Δ Δ ]

CP violation

Matter effect

(Sterile neutrinos) or new physics5

UPMNS =1 0 00 c23 s230 −s23 c23

⎛

⎝

⎜⎜⎜

⎞

⎠

⎟⎟⎟

c13 0 s13e−iδ

0 1 0−s13e

iδ 0 c13

⎛

⎝

⎜⎜⎜

⎞

⎠

⎟⎟⎟

c12 s12 0−s12 c12 00 0 1

⎛

⎝

⎜⎜⎜

⎞

⎠

⎟⎟⎟

P (νμ → νe) = 4C213S213S223 · sin2 Δ31+8C213S12S13S23(C12C23 cos δ − S12S13S23) · cos Δ32 · sin Δ31 · sin Δ21−8C213C12C23S12S13S23 sin δ · sin Δ32 · sin Δ31 · sin Δ21+4S212C

213(C

212C

223 + S

212S

223S

213 − 2C12C23S12S23S13 cos δ) · sin2 Δ21

−8C213S212S223 ·aL

4Eν(1 − 2S213) · cos Δ32 · sin Δ31

+8C213S213S

223

a

Δm213(1 − 2S213) sin2 Δ31

0 1 2-0.06

-0.04

-0.02

0

0.02

0.04

0.06

TotalLeading 13)

Matter

CPVCPC(cos

Solar

Eν (GeV)

(sin22θ13=0.1,δ= /4)

295km

cij=cosθijsij=sinθij

leading term CP violating (flips sign for anti-ν)

Solar

Matter

( ) 2 2 223 231 sin 2 sin 1.27LP mEμ μ

ν ν θ ⎛ ⎞→ ≈ − Δ⎜ ⎟⎝ ⎠

Δij=Δmij (L/4Eν)


50 years ago

Discovery of the 2nd neutrino

6

1 year ago (~300km distance)

J. Steinberger@NEUTRINO 2012


Status of neutrino oscillation studies

In 2012, further solid confirmation of θ13≠0 from reactor experiments.

For CPV and Mass hierarchy, νμ→ νe appearance is essential.7

Before T2K••sinn2222θθ1330 @ ~1.? σ (solar ν +

KamLAND)

T2K@June 13th, 2011Six Electron Neutrino events are observed

with 1.5±0.3 BG events.p-value=0.007

θ13≠0

Appearance Signal


2. T2K ExperimentAfter March 11 earthquake, T2K Operation was restored and running from March 2012.

8

TokaiKamioka295 km

J-PARC Accelerator@Tokai

protonsπ, π, π, π, Κ

σ

Intense beamHuge Far detector High Resolution Near detectorΦνSK(Eν）

oscillation

ν, ν, ν, ν

Super-K@Kamioka

• High Power Accelerator• Intense and High Quality Neutrino Beam• High Resolution Near Detector• Huge Far Detector

ΦνND(Eν）

CERN NA61 Hadron prod. measurement


Intense & High Quality ν beam

98 Reconstructed energy (GeV)0 1 2 3 4 5 6

Num

ber

of e

vent

s

2

4

6

8

1012

14

16

18

20

No-disappearance hypothesis

Best-fit oscillation hypothesis

T2K Run 1+2 data

othesis

othesis

beam dump

target and hornstrip line

High Power ν beam production

•30 GeV ~1×1014 protons extracted every 2.5~3 sec. directed to the carbon target.•Secondary π+(and K+) focused by three electromagnetic horns (250kA/200kA)•νμ from mainly π+→μ++νμ

•νe in the beam come from K and μdecays

PHYSICAL REVIEW D 85, 031103(R) (2012)

• Off-axis (2.5 ˚) νμ beam ν

ν

T2K 2011 νμ disappearance


Data collected and Analyzed

10

up to 190 kWw/ >1×1014 protons per pulse

(world record)March 11, 2011Big Earthquake

RUN-1 RUN-2 RUN-3

Analysis by May 15th, 20122.56×1020 POT (Protons On Target)

RUN-1 (2010): 0.32×1020 POT

RUN-2 (2010-2011): 1.11×1020 POT

ND280 RUN-1+2 data used for oscillation analysis

RUN-3 (2012): 1.12×1020 POT

including 0.21×1020 POT with 200kA horn operation (13% flux reduction at peak)

ND280 RUN-3data was checked for consistency with RUN1+2.


ND280

11

• INGRID @ on-axis (0 degree)• ν beam monitor [rate, direction, and

stability]

• ND280 @ 2.5 degree off-axis Normalization of Neutrino Flux Measurement of neutrino cross sections.•Dipole magnet w/ 0.2T• P0D: π0 Detector• FGD+TPC: Target + Particle tracking• EM calorimeter• Side-Muon-Range Detector

Near Detector @ 280m from the target


Performance of ND280

1212

ν events interacted in P0D with tracks going through FGDs, TPCs and ECAL

TPC PID positive tracknegative track

a few electrons

muons muon+π

protons

ν event rate stability by INGRID

•INGRID [RUN 1-3 data]• ν rate stability• beam direction: • -0.01±0.33 mrad (x)• -0.11±0.37 mrad (y)

•ND280 [RUN 1-2 data]•excellent PID and tracking capability•identification of the neutrino interactions.


Neutrino Interactions in T2K(NEUT and GENIE )

• CC (Charged-Current) quasi elastic (CCQE)• ν + n → μ- + p (n in N)• CC (resonance) single π(CC-1π)• ν + n(p) → μ- + π+ + p(n) (n,p in N)• DIS (Deep Inelastic Scattering)• ν + N → μ- + mπ+/−/0 + N’• CC coherent π ( ν + A → μ- + π+ + A) • NC (Neutral-Current) copious process (NC-1π0, etc..)

• + Nuclear Effects

13

Total (NC+CC)

CC Total

CC quasi-elastic

DIS CC single π

NC single π0 σ/E

(10-

38cm

2 /G

eV)

Eν(GeV)

NEUT model

ννμ

proton

CCQE

• SIGNAL: reconstruct neutrino energy from lepton momentum and scattering angle.

a main background for νe


T2K-Far Detector: Super-Kamiokande

• Water Cherenkov detector with 50 kton mass (22.5 kton Fiducial volume) located at 1km underground

• Good performance (momentum and position resolution, PID, charged particle counting) for sub-GeV neutrinos. [Typical] 61% efficiency for T2K signal νe with 95% NC-1π0 rejection

• Inner tank (32 kton) :11,129 20inch PMT• Outer tank:1,885 8inch PMT

• Dead-time-less DAQ• GPS timing information is recorded

real-time at every accelerator spill• T2K recorded events: All interactions

within a ±500μsec window centered on the the neutrino arrival time.

14

39.3m

41.4

m

Atmospheric ν● Data− MC


4. T2K νe event selection

T2K Beam timing

Fully-Contained events (FC)

Vertex is in the Fiducial Volume ( FV)

1 Cherenkov Ring and Electron-like

Visible Energy > 100 MeV

No additional electron signal generated by the muon decay

15

FV

OD

ID

Expected ToF of ν = 985.132±0.002 μsec

Zoom-Up209 FC events

KS probability= 49.2%


16

151 events

RUN 1+2+3Data

MMC ExpectatioonsBG

2.556×1020 POTData

sin22θ13=0.1 sin22θ13=0 NO osc.(12μs window)

FC 209 213.6 199.7 429.6 0.034

FCFV 151 150.7 140.9 297.0 0.0042

　Single-ring 74 79.0 70.6 205.4 ---

μ-like (pμ>200MeV/c) 55 (54) 57.0 (56.7) 57.0 (56.7) 185.7 (184.6) ---

e-like (Ee>100MeV/c) 19 (18) 21.9 (20.0) 13.6 (11.8) 19.7 (13.6) ---

　Multi-ring 77 71.8 70.3 91.5 ---


17

Ring Counting

#Rings1 Ring

Multi-Ring

PID

1 Ring

electron-like

muon-like

PμEevis.

74 events

18 events 54 events

77 events


Further νe selection

18

#νe events

20

Invariant mass of assumed two rings (100MeV 18 8.50 11.47 1.49 4.03 5.94No decay-e 13 7.31 8.56 0.28 3.19 5.09

POLfit mass 10 6.82 3.67 0.07 2.21 1.39Eνrec

Clear Signal of νe appearance !!

The probability (p-value) to observe 10 or more events with 2.73±0.37 (sys.) BG events is 0.08% (3.2σ).

Confirm the T2K 2011 result [PRL 107, 041801 (2011)]!

We find the Evidence of “Electron Neutrino Appearance”.19

0.08%


5. Oscillation Analysis

20

Neutrino flux prediction w/CERN NA61 result

ND280 ννμ measurementsin CCQE and nonQE samples

Neutrino Cross SectionUncertainties

SK Detector/SelectionUncertainties

n

p

NFlux+Cross Section Fit

2200

Neutrino Cross SectionUncertainties

Osc. Fit: sinnnn2222222222θθθ13 [[δδCP scanned]

ND280 CC--ννe and NC--ππ0

measurements

Result

ν oscillation parameters fixed:• Δm122=7.6×10-5 eV2• Δm322=±2.4×10-3 eV2• sin22θ12=0.8704• sin22θ23=1.0


(GeV)E

-110 1 10

Frac

tiona

l Err

or

0

0.1

0.2

0.3TotalPion ProductionKaon ProductionSecondary Nucleon ProductionHadronic Interaction LengthProton Beam, Alignment and Off-axis AngleHorn Current & Field

FluxeRun 1+2+3b+3c SK

Neutrino flux prediction w/CERN NA61

21

νμ@SK νe@SK

Errors: ~15%

νμ and νe Flux Energy Correlations

νμ, νe, anti-νμ, anti-νe energy dependent errors with full correlations @SK and @ND280 are taken in the FIT!

Errors:

ND280 νμ measurements (w/ RUN-1+2 data)

22

• Good negative track in FV.• Upstream TPC veto• muon ID by TPCfor CCQE

• 1 FGD-TPC track• No decay-e in FGD

For CCQE selection40% eff. w/ 72% purity

# Events in Pμ vs. θμ are used in FIT to constrain the flux and ν cross sections (MC predictions at ND280 and SK).

CCQE sample

CCnQE sample

CCQE sample CCQE sample

CCnQE sample

(1.08×1020 POT)

● Data— MC w/o tuning--- MC after FIT


CCQE sample


cosθμ

CCQECC1π+CC1π0CCcohCCotherNCbkgd outside

CCQECC1π+CC1π0CCcohCCotherNCbkgd outside


Neutrino Cross Section Uncertainties(Model parameters used in the cross section FIT)

23

model parameters Before FIT After FIT

CCQE MA [GeV] 1.21±0.45 1.19±0.19

CC1π(resonance) MA [GeV] 1.16±0.11 1.14±0.10

Fermi momentum surface PF [MeV] 217±30 224.6±23.5

Spectral Function 0[off] - 1[on] 0.04±0.21

CC-other cross section shape 0.0±0.4 -0.05±0.35

CCQE E-dependence 1.0±0.11, 1.0±0.11, 1.0±0.11 0.94±0.09, 0.92±0.23, 1.18±0.25

CC1π(resonance) E-dep. 1.63±0.43, 1.0±0.4 1.67±0.28, 1.10±0.30

NC-π0 cross sections 1.19±0.43 1.22±0.40

CC-coherent π cross section 1−1 from other experiments

NC-coherent π cross section 1.0±0.3 from other experiments

NC other cross section 1.0±0.3 from other experiments

W shape in resonance model [MeV] 87.7±45.3 from other experiments

π-less Δ decay 0.0±0.2 from other experiments

CC-1π,rNC-1π0 energy shape 0.0±0.5 from other experiments

(*) Parameters that are correlated between ND280 and SK


Flux + Cross section FIT output

24

ND280 νμ Flux

SK νμ Flux SK νe Flux

Correlations


#Events Predictions at SK w/ Sys. error(NOTE: 10 νe events observed)

25

sin22θ13=0.1 sin22θ13=0.0

Total 9.07±0.93 2.73±0.37

νe signal 6.60 0.15

νe background (beam org.) 1.32 1.42

νμ background (~NCπ0) 1.02 1.02

anti-ν background 0.13 0.14

sin22θ13=0.1 sin22θ13=0.0

Flux+Xsec in T2K fit 5.7% 8.7%

Xsec (from other exp.) 7.5% 5.9%

SK + FSI 3.9% 7.7%

Total 10.3% 13.4%

#Events prediction Systematic Errors

sin22θ13=0.1 sin22θ13=0.0

Big improvement from the 2011 result: ~18%(sin22θ13=0.1) ~23% (sin22θ13=0.0)

sin22θ13=0.0


(GeV)Reconstructed E1.5 2 2.5 3 3.5 4 4.5 5 5.5 6

# of

Eve

nts

0

5

10

15

20

25

30

35

40

45Signal

0 w/ 0 no 0, no

0 no no Out of P0DData

ND280 CC-νe and NC-π0

26

f(νe)DATA/MC=0.85±0.18

FGD+TPC+ECAL νe

(Data-MCbg)/MCsig=0.91±0.26

P0D high energy νe

Invariant Mass (MeV)0 50 100 150 200 250 300 350 400 450 500

Eve

nts

/ (20

MeV

)

0

5

10

15

20

25

P0D NC-π0

Data/MC=0.81±0.21(CC normalization)

• Dominant backgrounds for Electron Neutrino Appearance are measured in ND280.• Measurements of both CC-νe and NC-π0 are

consistent with the MC prediction.

• Check the background events at ND280 for νe appearance.

poster 91-1 poster 115-1

poster 117-3


Oscillation Analysis FIT (3 methods)

Method-1: Maximum likelihood Fit w/ Rate + (pe, θe)

Method-2: Maximum likelihood Fit w/ Rate + reconstructed Eν

Method-3: Feldman&Cousins for Rate only

27

L(Nobs., x; o, f) = Lnorm(Nobs.; o, f) × Lshape(x; o, f) × Lsyst.(f)

Method-1

measurements, oscillation parameters systematic parameters

Signal

BG νe

NC BG

NC BG

BG νe

Method-2

Signal

BG νeNC BG

Data is fit to signal + 2 BG 1-D curves

Data is fit to signal + 4 BG 2-D curves


Method 1

6. Result

28

sin22θ13=0.104+0.060-0.045 (Nνebest-fit=9.27)0.036

Allowed Region (constant χ2 method)

29

normal hierarchy inverted hierarchy

13θ22sin

0 0.1 0.2 0.3 0.4

CP

Vδ

-2

0

2

68% C.L.90% C.L.Best fit

(2.556e20 POT)Run1+2+3 data

normal hierarchy2 eV-310×|=2.432mΔ|

13θ22sin

0 0.1 0.2 0.3 0.4C

PV

δ

-2

0

2

68% C.L.90% C.L.Best fit

(2.556e20 POT)Run1+2+3 data

inverted hierarchy2 eV-310×|=2.432mΔ|

sin22θ13=0.104 +0.060-0.045 sin22θ13=0.128 +0.070-0.055 @δCP=0@δCP=0

|Δm32|2=2.4×10-3eV2 |Δm32|2=2.4×10-3eV2

Preliminary


Results (method-2,3)

30

method-2 (w/ Eνrec) method-3 (F&C)

All three results are consistent.

)13(22sin23

22sin0 0.2 0.4 0.6

CP

-2

0

2

POT20102.556Normal HierarchyRuns I-IIIc Measurement

68% C.L.

90% C.L.

)13(22sin23

22sin0 0.2 0.4 0.6

CP

-2

0

2

POT20102.556Inverted HierarchyRuns I-IIIc Measurement

68% C.L.

90% C.L.

Δm322>0

Δm322

This result and 2011 result

31

• The result is consistent with the 2011 result and is improved.• The result with 2012 data only is consistent with 2011 result.

PreliminaryPreliminary


7. More T2K results and Prospect

32

(GeV)E0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

/GeV

)2

cm-3

8/E

(10

0.2

0.4

0.6

0.8

1

1.2

1.4

BNL 7ft

MINOS

NOMAD

SciBooNE data based on NEUTSciBooNE data based on NUANCENEUT prediction for SciBooNENUANCE prediction for SciBooNE

NEUT prediction for T2KGENIE prediction for T2KT2K data based on NEUT

T2K-PRELIMINARY

Total cross section given for a mean neutrino energy of 0.85 GeV, the horizontal bars represent 68% of the flux at each side of the mean energy

〈σCC〉φ = (6.73± 0.13(stat)± 0.99(syst))× 10−39 cm2

nucleons

〈σNEUTCC 〉φ = 7.28× 10−39cm2

nucleons

〈σGENIECC 〉φ = 6.69× 10−39cm2

nucleons

First T

2K cro

ss sect

ion me

asurem

ent

νμ νμ

θ θ

3122

32

3

3122

32

3

sin||||4)(

sin||1||41)(

UUP

UUP

),()R,()R()R()R,()R(R 312121131323231414224243434U

θ

event vertex beam z-position (cm)

-2000 -1000 0 1000 20000

20

40

60ODC

DATA

MC w/ osc.

MC w/o osc.

event vertex beam z-position (cm)

-2000 -1000 0 1000 20000

20

40

60

80 ODENDATA

MC w/ osc.

MC w/o osc.

event vertex SK z-position (cm)

-1000 0 10000

20

40

60

80ODC

DATA

MC w/ osc.

MC w/o osc.

event vertex SK z-position (cm)

-1000 0 10000

10

20

ODENDATAMC w/ osc.MC w/o osc.Empty Spill data (CR)

OD events helped check the T2K appearance indicationνe

T2K is the first experiment toshow an indication ofnon-zero θ13

However, events concentrated near

upstreamdetector wall

Looked at OD event vertex distribution for possible beam events entering from outside ID

Did not see any excess or deficit of OD events.

True Track is from OD

Fiducial Volume

Track Reconstructed as candidate ID event

νe

MC versus Data Comparisons

Old SKDETSIMNEUT (Tuned)

GCALOR

+-16O213 MeV/c

lab

+-12C --12C

Stage 1 – Local Reconstruction pendent reconstruction in each sub-detector, finding tracks and showers

beam

truct nts

P0D uses triangular bars for improved positional resolution

4.8mm

2.5mm

Data P0D resolution

Resolution for square bars of

same cross-section

FGDs are fiducial volume for Tracker region, but most interactions occur in other sub-detectors: accurate

reconstruction is essential to reduce this background

D fid i l l f T k i b t

MC Truth

ECals complement TPC PID, especially for selecting electrons in e analysis

Data/MC

••

σ

• δ

2

222

''12

2'2

22

1),(ln

)(2

)(exp2

1)(

E

mTTTtPL

dttPtt

tP

i

i

nn

•

•••

•

•

δT

• δ• δ

ν TOF160 - 1 T2K neutrino time of flight study

162 - 3 Reconstruction in the ND280 at T2K

82 - 1 An Optical Transition Radiation Monitor for the T2K Proton Beam Line

83 - 2Measurement of Pion and Kaon production cross sections withNA61/SHINE for T2K

84 - 3Hadron Production Measurements with the T2K Replica Target inNA61/SHINE for the T2K Neutrino Flux Prediction

85 - 1 Performance of the Muon Monitor in the T2K Experiment

86 - 2Improvement and recent status of the beam monitoring with T2K neutrinobeam monitor INGRID

87 - 3 Measurement of the flux averaged Inclusive Charged Current cross-section

115 - 1 Measurement of NC1π0 production using the ND280 P0D

116 - 2 Pion Final State Interactions in NEUT

117 - 3 Measurement of the νe flux of T2K’s beam in the tracker of ND280

118 - 1Measurement of CC inclusive cross-section on Iron in a few GeV neutrinobeam at the T2K

119 - 2Constraining neutrino interaction parameters in T2K using MiniBooNEdata

120 - 3 Measurement of the Muon Neutrino Spectrum at the T2K Near Detector

90 - 3 First Muon-Neutrino Disappearance Study with the T2K Off-Axis Beam

91 - 1 Measurement of the νe Component of T2K’s νμ Beam in the ND280 P0D

92 - 2 Sterile neutrino search at T2K using NC nuclear de-excitation gamma-rays

93 - 3 Outer Detector Events at T2K

94 - 1 T2K νe appearance analysis using energy spectrum

95 - 2 Recent Result of numu disappearance analysis in T2K experiment

π interactions

ND280 rec

onstructio

n

SK outer detector events

Sterile ν


Future Prospect

Results from data collected by June 2012 are expected soon.

Update on results from νμ disappearance coming shortly: measurement of the θ23 with the θ13 value from reactor experiments relevant to explore sub-leading terms.

Corrected data to increase with new runs at higher beam power.

~8E20 POT (2013) → ~1.2E21 POT (2014) → ~1.8E21 POT (2015)

More precise measurement of P(νμ→νe): a tool to assess sub-leading effects such as CP violation, matter effects, possible new physics manifesting from νe appearance.

33

P(νμ→νe)=sin2θ23sin22θ13sin2(1.27Δm322L/E) + CPV + matter effect. + ...


8. Summary

In 2011, 6 “electron neutrino appearance” candidate events were observed (p-value=0.007), which clearly indicated θ13≠0.

This year J-PARC resumed operation and T2K restarted physics data taking with ~190kW [maximum 200kW] beam power after recovering from the Great East Japan Earthquake of March 2011.

Based on 2.56×1020 POT collected by May 2012, a total of 10 “electron neutrino appearance” candidate events were observed. 2011 results are confirmed.

p-value=0.0008 (3.2σ)

sin22θ13=0.104 for Δm322=2.4×10-3eV2, δCP=0, θ23=π/4

The systematic error is now at the level of 10%.

We find Evidence for “Electron Neutrino Appearance”, which opens the window to access CP violation in the lepton sector.

34

+0.060-0.045


BackUp


Super-K


SK νe Vertex Distribution

37

(cm)0 200 400 600 800 1000 1200 1400 1600

0

1

2

3

4

5

6

dwall of FC Events for RUN1+RUN2+RUN3

DataeνSignal

eνBeam

eνBeam μνBeam

μνBeam

dwall of FC Events for RUN1+RUN2+RUN3

(cm)0 200 400 600 800 1000 1200 1400 1600

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

dwall of FC Events for RUN3

DataeνSignal

eνBeam

eνBeam μνBeam

μνBeam

dwall of FC Events for RUN3

(cm)0 500 1000 1500 2000 2500 3000

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Fromwall || to Beam of FC Events for RUN1+RUN2+RUN3

DataeνSignal

eνBeam

eνBeam μνBeam

μνBeam

Fromwall || to Beam of FC Events for RUN1+RUN2+RUN3

(cm)0 500 1000 1500 2000 2500 3000

0

0.5

1

1.5

2

2.5

3

3.5

Fromwall || to Beam of FC Events for RUN3

DataeνSignal

eνBeam

eνBeam μνBeam

μνBeam

Fromwall || to Beam of FC Events for RUN3

Figure 29: The Dwall and Fromwall beam|| distributions for νe candidates are shown above.The left column shows the two distributions for all the runs combined while the right columnsshow the distributions for RUN3. All νe event selection except the FV cut have been applied.The error bars on the data are statistical only.

)2 (cm2R0 500 1000 1500 2000 2500 3000

310×0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

of FCFV Events for RUN1+RUN2+RUN32R

DataeνSignal

eνBeam

eνBeam μνBeam

μνBeam

of FCFV Events for RUN1+RUN2+RUN32R

)2 (cm2R0 500 1000 1500 2000 2500 3000

310×0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

of FCFV Events for RUN32R

DataeνSignal

eνBeam

eνBeam μνBeam

μνBeam

of FCFV Events for RUN32R

z (cm)-1500 -1000 -500 0 500 1000 1500

0

0.5

1

1.5

2

2.5

3

3.5

z of FCFV Events for RUN1+RUN2+RUN3

DataeνSignal

eνBeam

eνBeam μνBeam

μνBeam

z of FCFV Events for RUN1+RUN2+RUN3

z (cm)-1500 -1000 -500 0 500 1000 1500

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

z of FCFV Events for RUN3

DataeνSignal

eνBeam

eνBeam μνBeam

μνBeam

z of FCFV Events for RUN3

Figure 30: The R2 and Z distributions for νe candidates are shown above. The left column showsthe two distributions for all the runs combined while the right columns show the distributionsfor RUN3. All νe event selections, including the FCFV cut, have been applied. The error barson the data are statistical only.


SK νe Vertex Distribution

38

RUN1+2 RUN3 RUN1+2+3

Dwall 22.9% 80.7% 21.5%

Fromwall beam|| 1.34% 47.3% 2.64%R2 + Z 10.5% 66.1% 17.2%

Table 17: This table shows the probabilities that where obtained from the KS-test and Toy-MCfor the Dwall, Fromwall beam||, and the R2 and Z distributions combined. For almost all casesbut Dwall, the RUN3 and combined run probabilities show a better agreement with uniformitythan the RUN1+2 data.


t. nakaya for the t2k collaboration results from t2k.pdf · t2k/j-parc recovery after the big...

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