Status of T2KTakashi Kobayashi

KEKFor T2K collaboration

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June 14, 2010Neutrino 2010@Athens, Greece

The T2K Collaboration

CanadaTRIUMFU. AlbertaU. B. ColumbiaU. ReginaU. TorontoU. VictoriaYork U.

FranceCEA SaclayIPN LyonLLR E. Poly.LPNHE Paris

GermanyU. Aachen

~500 members, 61 Institutes, 12 countriesItalyINFN, U. RomaINFN, U. NapoliINFN, U. PadovaINFN, U. Bari

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

PolandA. Soltan, WarsawH.Niewodniczanski,

CracowT. U. WarsawU. Silesia, KatowiceU. WarsawU. Wroclaw

RussiaINR

S. KoreaN. U. ChonnamU. DongshinU. SejongN. U. SeoulU. Sungkyunkwan

STFC/RALSTFC/Daresbury

USABoston U.B.N.L.Colorado S. U.Duke U.Louisiana S. U.Stony Brook U.U. C. IrvineU. ColoradoU. PittsburghU. RochesterU. Washington

SpainIFIC, ValenciaIFAE (Barcelona)

SwitzerlandU. BernU. GenevaETH Zurich

United KingdomImperial C. LondonQueen Mary U. L.Lancaster U.Liverpool U.Oxford U.Sheffield U.Warwick U.

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T2K (Tokai to Kamioka) experiment

High intensity nm beam from J-PARC MR to Super-Kamiokande @ 295km

Discovery of ne appearance Determine q13 Last unknown mixing angle Open possibility to explore CPV in lepton sector

Precise meas. of nm disappearance q23, Dm232

Really maximum mixing? Any symmetry? Anytihng unexpected?

132312sin ssse nn m prob. in term odd CP sinq12~0.5, sinq23~0.7, sinq13<0.2)

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Remarkable Features of T2K High intensity neutrino beam from J-PARC

First “Super beam” experiment w/ O(MW) beam Narrow spectrum tuned at the oscillation maximum.

First application of “Off-axis beam” (cf. BNL-E889 proposal)

Less background, High sensitivity World largest water Cherenkov detector SuperKamiokande

High efficiency for low energy Good PID (e/m) capability

Neutrino energy reconstruction by using Quasi-elastic (QE) interaction (nl+n l- + p) s~80MeV Oscillation pattern measurement BG due to miss-reconstruction of inelastic interaction

Greatly improved by using narrow spectrum

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>10times improvement3.75MWx107s

Expected Sensitivity of T2K

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Goal @ 3.75MWx107s: (sin22q23)~0.01,(Dm2

23) <1×10-4 [eV2]

nmne appearance nm 　 disappearance

CP=0

MINOS, PRL 101, 131802 (2008)

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2.5 deg Off-axis Peak ~600MeV Quasi-Elastic interaction dominate

Less Non-QE background Muon monitors @ ~120m

Muon > 5GeV Spill-by-spill monitoring of

direction/intensity Near detector @280m

On-axis detector “INGRID” Intensity and direction (profile)

Off-axis (toward SK direction) Absolute flux/spectrum/ne

Far detector Super-Kamiokande @ 295km

Experimental Setupp p n

120m0m 280m 295 km

on-axisoff-axis

2.5o

m-mon

n m fl

ux (a

rb. u

nit)

Near detectors

Super-Kamiokande

MC (GFULUKA)

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J-PARC Facility(KEK/JAEA ）

Bird’s eye photo in January of 2008

South to North

Neutrino Beams 　 (to Kamioka)

JFY2009 Beams

Main ring

JFY2008 Beams

3 GeV Synchrotron

CY2007 Beams

Linac

Design Intensity750kW

ConstructionJFY2001~2008

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Neutrino facility for T2K at J-PARCTarget

Primary beamline (superconducting)

Electromagnetic hornNeutrino monitor bld.

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Muon monitors

Fast Extracted (FX) beam from MR (30GeV) 6bunches (8 from Fall 2010) 581ns apart

Proton beam transport Superconducting combined function magnets

Graphite target (26mmfx90cm) 3 horns @ 320kA (250kA by summer) 110m of decay volume SK direction is given by GPS survey at 2mrad precision

Construction (JFY2004~2008) COMPLETED as scheduled!

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2 Near Detectors

Scintillator tracker & Iron sandwich

UA1 magnet(Donated From CERN)

INGRID & off-axis completed in 2009 (Except side ECAL) Side ECAL installation in Summer 2010

Commissioning completed

SMRDIn magnet yoke

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Far Detector: SK-IV

ICRR, Univ. of Tokyo

50kt Water Cherenkov detector operational since 1996 11129 20" PMTs in inner detector (ID), 1885 8" PMTs in outer

detector (OD) Readout electronics has been renewed in 2008 summer.

dead time less DAQ system SK is working very stably Beam related events are selected by event timing using GPS

system.

Milestones 1999: Nishikawa&Totsuka proposed to measure ne

appearance as a next critical step toward CP measurement 2001: “The JHF-Kamioka Neutrino Project” report

(hep-ex/0106019) April 2004:

Officially approved by Japanese Government and 5yr Construction started

T2K international collaboration officially formed March 2009: Construction completed as scheduled April 23, 2009: First neutrino beam production and

commissioning started January 2010: Data accumulation for oscillation search

started! Feb. 24, 2010: First T2K Event in Super-Kamiokande! 11

Beam commissioning

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Target size

Horizontal: 1mm

Vertical: 2mm

Beam orbit is tuned within 2mm from design orbit.(Critical for controlling beam loss)

SSEM inSSEM out

SSEM foil: 5x10-5 loss→ real loss << 0.5W @50kW

No significant beam loss w/o SSEM

Beam loss along proton beam line

OTR detector just in front of target worked very well!

OTR beamPotision meas.Linearity

Beam commissioning

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MUON MONITOR MEASUREMENTS

Horn focusing effect clearly seenAlighment &Targeting check

Beam wid. ~4mm(1s)

Target size Functionality of all components confirmed Beam commissioning COMPLETED

Linear upto 70kW within 1%

Started data taking for oscillation!

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70kW

50kW

Delivered # of protons: 2.34×1019 (Jan-May) Continuous run @ ~50kW level Trial upto 100kW done

(2010)

Proton beam stability Beam position on target have to be controlled < 1mm

To control direction of secondary beam within 1mrad To avoid destroying the target from non uniform thermal

stress on target (at higher power) Succeeded to control <1mm during long term operationCorrelation btw p beam positionon target vs MUMON center

1mrad

~3mm

Horn lens effectRMS 0.4mm

RMS 0.4mmCurrent

B

B

p beam

p+

p+

Beam direction & intensity stabilitymeasured by Muon monitor

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Beam direction is controlled well within 1mrad Secondary beam intensity (normalized by proton intensity) stable within 1%

(reflects stability of targeting, horn focusing, etc) Stable well within our physics requirements

Jan Feb Mar

Detector intrinsic resolution <1.5mm

Apr May

0

-10

10

Profi

le c

ente

r (c

m)

Mu(

Si)

Tota

l Q/Np

Jan Feb Mar Apr May

RMS/MEAN < 1% (whole period)

INGRID measurements

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Bunch structure clearly seen as expected Event rate is stable for wide range of intensity Beam direction well controlled within requirement (<1mrad)

Off-axis detector performances

Very small number of bad channels

Hit Efficiencies >99%For all layers (FGD)

32 0.4%

s~8%(400~500MeV/c)

dE/dx from TPC

Off-axis detector n measurements

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Event rate are stable

FGD cluster timing

FGD

ECAL

P0D

Super-Kamiokande Event Selection J-PARC neutrino events selected by event timing using GPS SK analysis is very well established

>20yrs of experiences w/ Water Cherenkov detector Event selection & cut values are fixed already

UNBIASED SELECTON Selection criteria

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For nm disappearance analysis For ne appearance search

Timing coincidence w/ beam timing (+TOF)

Fully contained (No OD activity)

Vertex in fiducial volume (Vertex >2m from wall)

Evis > 30MeV Evis > 100MeV

# of ring =1

m-like ring e-like ring

No decay electron

Inv. mass w/ forced-found 2nd ring < 105MeV

Enrec < 1250MeV

Observed SK events

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Event time distribution clearly show beam structure Observed # of Fully contained events: 22 (by Mid. May) Expected non-beam BG: <10-2evts

FCODLE

FC

LE: Low energy triggered eventsOD: Outer detector eventsFC: Fully contained events

SK events

Single-ring m-like event Two-ring event

Pink diamonds are placed on the wall in the beam direction starting from the reconstructed vertex.

Analysis Strategy Predict SK observations (nm,ne): Nm/e(En

rec,Posc) BASED ON T2K&NA61 measurements as precisely as necessary

Then compare w/ SK observation

Intensive analysis of beam, near detector, NA61 and SK are on going 23

NDNFSK R /

truerectruetruetruetrueexprec , nnnnnnn s EEfEEEPEEN SKSKoscSK (omitting integral of En

true)

Flux at SK Osc. Prob. Cross sect. Det. Eff. SK Det. Responce

Enrec: Reconstructed neutrino energy

Entrue: True neutrino energy

DNNDNDND N s obs

Far-to-near extrapolation factor

SK flux Flux at ND

Normalization & Spectrum from ND measurements

Hadron production measurement NA61

Hadron production measurement CERN NA61

Pilot run in 2007 and high statistics data in 2009 p (30GeV) + C (thin target 4% λI and T2K replica

target ) Preliminary results on p production from 2007

thin target data were released. They are being implemented in T2K beam MC.

Preliminary NA61 π+, 20% syst. error

Prelim

inary

MC=GFLUKA

Future plan Until end of June, 2010

~50kW Jul – Fall, 2010 (Summer shutdown)

New Kicker magnets and power supply installation (68bunch)

Horn power supply replacement (Old K2K New!) Remaining ECAL installation

After Nov. 2010 From ~100kW toward design power

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Summary Construction completed Mar.2009 as scheduled First beam on Apr.23, 2009 Data accumulation for oscillation search started in Jan. 2010

Continuous operation at ~50kW level Accumulated 2.34E19 protons (Until June 1st, 2010) Observed # of FC events: 22 (by Mid May)

After Summer: from ~100kW toward design power Intensive analysis going on to extract physics! Goal

Accumulate 0.75MW x 5x107sec (=3.75MWx107sec) Discover ne appearance

sin22q13 down to 0.018 (3s), 0.008 (90%CL) Precise measurement of nm disappearance

(Dm232)~1x10-4eV2, (sin22q23)~1%

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Posters on T2K1. Masashi Otani (Kyoto U.), “The Result from the T2K Neutrino Beam Monitor

INGRID”2. Suzuki Kento (Kyoto U.), “T2K Beam Study with the Muon Monitor”3. Tatsuya Kikawa (Kyoto U), “Development of the new T2K on-axis neutrino

detector INGRID proton module”4. Gavin Davies (Lancaster U.), “Understanding and Calibrating the Calorimeter

for the T2K Near Detector”5. Takatomi Yano (Kobe U.), “The Side Muon Range Detector for the T2K

experiment”6. Masahiro Shibata (KEK), “Commissioning of the neutrino beam facility for the

first superbeam experiment T2K”7. Georgios Christodoulou (U. of Liverpool), “T2K : Electron Neutrino Analysis

at the Near Detector (ND280)”8. Luigi Esposito (ETHZ), “NA61 data for T2K flux calculations”9. Tomasz Palczewski, “Particle production cross-sections by 30GeV protons ”10. Jeremy Maxime Argyriades (Geneva) “SHINE-NA61 experiment and

applications for neutrino fluxes”27