K2K and T2K experiments

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1 K2K and T2K experiments Issei Kato TRIUMF, Canada for the K2K and T2K collaborations Neutrino Oscillation Workshop 2006 at Conca Specchiulla,, Otranto, Italy

2 Outline K2K experiment, shortly What s updated from the previous results, and the final results T2K experiment Experimental setup What needs to be measured ND280 off-axis detectors Summary September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 2

3 K2K experiment KEK to Kamioka long baseline experiment Pure ν μ beam with <E ν > = 1.3 GeV and L=250 km To confirm neutrino oscillation seen in atmospheric neutrino observations Search for ν e appearance Brief history : civil construction and detector installation : physics run with SK-I and with SK-II 1998 June: the first event in SK 2002: indications for oscillation (0.47x10 20 pot) 2004: evidence for oscillation (0.89x10 20 pot) 2006: the final results (0.92x10 20 pot) September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 3

4 What s s updated? Near detector # of events ν spectrum ν interaction Extrapolation Far/near spectrum ratio Far detector (SK) # of events ν spectrum Full date set is used Far-to-near spectrum ratio Pion monitor measurements HARP results Published in Nucl. Phys. B732, 1-45 (2006) Neutrino interaction study No CC coherent π production Published in Phys. Rev. Lett. 95, (2005) For ν e appearance search, more sophisticated selection applied to reject NC-π 0 events Energy v.s. invariant mass of an event September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 4

5 Far/near ratio from HARP HARP Pion production (Al target, 12.9 GeV/c) mrad mrad Far/near spectrum ratio mrad mrad mrad mrad Far/near ratio is estimated using HARP results September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 5 Nucl. Phys. B732, 1-45 (2006)

6 Results for disappearance Best Fit (phys. Region) at (sin 2 2θ, Δm 2 ) = (1.0, 2.8x10-3 ev 2 ) # of events observed = 112 Expected (null osc.) = Expected (best fit) = hep-ex/ , will be soon published in Phys. Rev. D Data No oscillation Best fit Null Oscillation : % (4.3σ) Allowed region of Δm 2 at sin 2 2θ = x10-3 < Δm 2 < 3.5x10-3 ev 2 (90% C.L.) September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 6

Search for ν e appearance Invariant mass v.s. Energy # of events in the signal region = 1 +0.6 Expected B.G. = 1.7 (no oscillation case) Signal MC Published in Phys. Rev. Lett.

7 Search for ν e appearance Invariant mass v.s. Energy # of events in the signal region = Expected B.G. = 1.7 (no oscillation case) Signal MC Published in Phys. Rev. Lett. 96, (2006) 0.4 (ν μ int. = 1.3, beam-ν e = 0.4) ν μ background MC sin 2 θ μe < 0.13 at Δm 2 μe = 2.8x10-3 ev 2 September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 7

Feb. 2006 T2K experiment Under construction

presicely, to discover the θ 13 and beyond with

maximum by off-axis technique OA 2.0 OA 2.

8 Feb T2K experiment Under construction Ready for T2K Apr Tokai (J-PARC) to Kamioka neutrino experiment to determine θ 23 and Δm 23 presicely, to discover the θ 13 and beyond with intense neutrino beam tuned at the oscillation maximum by off-axis technique OA 2.0 OA 2.5 OA 3.0 OA 0 September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 8

9 T2K setup 2KM detector 0 m ~130 m 280 m possible future 2 km 295 km proton beam π μ-monitor 2.5 off-axis Decay tunnel 0 on-axis Super-K ND280 N-GRID Fully reconstructed!! 1 st horn & target ND280 off-axis detector ~0.3 events/ton/spill September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 9

Eν = p m To see its re-appearance mn E E Understanding of the ν μ spectrum and backgrounds (mainly CC1π and NC1π) is the key issue Towards search for ν e appearance Small

10 What needs to be measured? re-appearance oscillation max non-qe B.G. sin 2 2θ 13 = 0.1 Δm 2 =2.5x10-3 ev 2 # of events in 0.35~0.85 GeV Signal 103 Beam ν e BG 13 BG from ν μ 10 ν μ disappearance ν e appearance Towards precise measurements of ν μ disappearance With energy spectrum (CCQE events) μ ν Eν = p m To see its re-appearance mn E E Understanding of the ν μ spectrum and backgrounds (mainly CC1π and NC1π) is the key issue Towards search for ν e appearance Small signal in GeV region Understanding of the backgrounds (NC1π 0 and beam-ν e ) is the key issue September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 10 N l l m + p 2 l l 2 cos θ l

11 ND280m off-axis detectors To measure the neutrino spectrum UA1 Magnet (0.2T) Tracker (FGD+TPC) Side-MRD (SMRD) SMRD To estimate the background events Pi-zero detector (P0D) EM calorimeter (ECAL) + Tracker September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 11

Tracker FGD + TPC CC measurements Plastic scintillator 9.

backgrounds To select pure CCQE Select μ by negative track with small

12 Tracker FGD + TPC CC measurements Plastic scintillator 9.5mm ~1mm FGD + TPC with magnet For CC measurements Spectrum and backgrounds To select pure CCQE Select μ by negative track with small de/dx Momentum measured by TPC/SMRD Proton by de/dx v.s. momentum To select/reject CC π productions Tagging pions by Positive track in TPC (π + ) de/dx v.s. momenum Decay-e in FGD (10μs active window) Interaction in FGD EM/hadron clusters in ECAL (π 0 /π ± ) 30cm MPPC readout Micromegas for gas amplification September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 12

13 The tracker Particle ID by de/dx v.s. momentum TPC TPC TPC FGD FGD p p μ π Particle ID by decay-e For track stopping inside FGD π + p September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 13

$Side-MRD Relatively large fraction of muons going sideway. SMRD measures these muons energy by range SMRD events Light yield, p.e./mip 30 25 20 Scintillator slabs inserted in between$ 0 b (ns) 10 0.485 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 September 9-16, 2006 Neutrino 5Oscillation 10 15Workshop 20 25 2006 30 / Conca 35 40Specchiulla, Italy 14 a σ t (ns) = 15 5 a N p.e. -200-150 -100-50 0 50 100 150 + X, mm b Light yield (p.

0 b (ns) 10 0.485 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 September 9-16, 2006 Neutrino 5Oscillation 10 15Workshop 20 25 2006 30 / Conca 35 40Specchiulla, Italy 14 a σ t (ns) = 15 5 a N p.e. -200-150 -100-50 0 50 100 150 + X, mm b Light yield (p.

14 Side-MRD Relatively large fraction of muons going sideway. SMRD measures these muons energy by range SMRD events Light yield, p.e./mip Scintillator slabs inserted in between the iron plates of magnet yoke Scillator Slab: Length = 87 cm Width = 18 cm Thickmess = 10 mm S-shape grooves for WLS fiber readout: Depth = 4 mm Length = 2.5 m σ t (ns) 3.2 (ns) b (ns) September 9-16, 2006 Neutrino 5Oscillation 10 15Workshop / Conca 35 40Specchiulla, Italy 14 a σ t (ns) = 15 5 a N p.e X, mm b Light yield (p.e.) Beam test with 1.4 GeV/c pions Light yield p.e. Timing (σ t ) ns space resolution cm efficiency (MIP) > 99%

ECAL and P0D Backgrounds to ν e appearance Beam-ν e measurement ECAL surrounding the tracker Electron ID using EM shower in ECAL and de/dx in TPC NC π 0

7x10 4 NC1π 0 events/year ECAL with tracker can also do the job Exclusive NC1π 0 study But low efficiency (low stat.

15 ECAL and P0D Backgrounds to ν e appearance Beam-ν e measurement ECAL surrounding the tracker Electron ID using EM shower in ECAL and de/dx in TPC NC π 0 production by ν μ Pi-zero detector (P0D) Detector design optimized for NC-π 0 measurements With large statistics 1.7x10 4 NC1π 0 events/year ECAL with tracker can also do the job Exclusive NC1π 0 study But low efficiency (low stat.) ~800 NC1π 0 events/year ECAL Segmented plastic scintillators + Pb sandwitch Readout by WLS fiber + SiPM P0D Segmented plastic scintillators + Pb sandwitch with water target September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 15

16 NC1π 0 in P0D 0.5 GeV/c π 0 + undetected neutron 0.5 GeV/c π GeV/c proton September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 16

17 Requirements for systematics To estimate the neutrino beam properties with systematic uncertainty well below the SK statistical error Neutrino flux: < 5% Spectrum shape: width of shape, for example, < 10% Non-QE/QE: < 5 10% NC-1π 0, beam-ν e : < 10% SK energy scale: < 2% September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 17

T2K prospects Δm 2 [10-3 ev 2 ] 6 5 4 3 Precision of ν μ disappearance measurement T2K 5 years (5x10 21 pot), Stat.

2 1 K2K 68% K2K 90% K2K 99% SK L/E 90% 0 0.2 0.4 0.6 0.

18 T2K prospects Δm 2 [10-3 ev 2 ] Precision of ν μ disappearance measurement T2K 5 years (5x10 21 pot), Stat. only Sensitivity to ν e appearance T2K 5 years (5x1021 pot) Stat.+10% B.G. syst. 2 1 K2K 68% K2K 90% K2K 99% SK L/E 90% sin 2 (2θ) --68%CL --90%CL --99%CL Goal : δ(sin 2 2θ 23 ) ~ 0.01, δ(δm 2 23 ) < 1x10-4 ev 2 Sensitivity down to sin 2 2θ 13 ~0.005 September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 18

19 Summary and T2K schedule K2K confirmed the neutrino oscillation observed in atmospheric neutrino Null oscillation: < % (4.3σ) Allowed region: 1.9x10-3 < Δm 2 < 3.5x10-3 ev 2 at sin 2 2θ=1 (90%C.L.) T2K: the next generation neutrino experiment To measure Δm 2 23 and sin2 2θ 23 precisely To discover ν e appearance, measure the θ 13, and beyond T2K schedule: T2K schedule: Beam line construction started in April 2004 on schedule Start of ND280m detectors manufacturing Fall 2006 ND280 hall construction start April 2007 UA1 magnet installation May 2008 Complete ND280 building December GeV MR commissioning 2008 Begin installation of ND280 detectors January 2009 Neutrino beam line commissioning April 2009 T2K physics run 2009 September 9-16, 2006 Neutrino Oscillation Workshop 2006 / Conca Specchiulla, Italy 19

Recent Results from Alysia Marino, University of Colorado at Boulder Neutrino Flux Workshop, University of Pittsburgh, Dec 6 8,2012

Recent Results from Alysia Marino, University of Colorado at Boulder Neutrino Flux Workshop, University of Pittsburgh, Dec 6 8,2012 Outline T2K Beamline and Detectors Uncertainties from prior measurements