Results from T2K Alex Finch Lancaster University ND280 T2K 1 - - PowerPoint PPT Presentation

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Results from T2K Alex Finch Lancaster University ND280 T2K 1 - - PowerPoint PPT Presentation

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Results from T2K Alex Finch Lancaster University ND280 T2K 1 Contents T2K Overview Tokai Kamioka Neutrino Oscillations Results Muon neutrino disappearance Electron neutrino appearance Charged Current

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Results from T2K

Alex Finch Lancaster University ND280 T2K

1

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  • T2K

– Overview – Tokai – Kamioka

  • Neutrino Oscillations
  • Results

– Muon neutrino disappearance – Electron neutrino appearance – Charged Current inclusive cross section

  • Future Prospects

– Current Run – Future Running

Contents

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  • Observe νe appearance and measure θ13
  • Observe νμ disappearance and measure θ23
  • Measure ν cross sections
  • Search for exotic neutrinos

T2K Overview

Physics Goals

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T2K - Long Baseline Accelerator based Neutrino Experiment

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T2K Overview

Beam and Detectors

4 Tokai

ND280

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T2K Overview

Neutrino Beam

π→μν

118 m

  • ff-axis (2.5°)

(30 GeV from MR synchrotron)

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Charge Current Quasi-Elastic

What we’d like: What we have:

“Final State Interactions” confuse the picture

Nucleon changes but doesn’t break up.

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Super Kamiokande

(“SK”)

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Super Kamiokande events

8 Muon event Electron event

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ND280

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ND280 Events

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T2K Data – Run Periods

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2013/7/31

Long Shutdown →JAN 2014

? Earthquake

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Neutrino Oscillations

12 Slide from P. Litchfield PMNS=>Pontecorvo-Maki-Nakagawa-Sakata Δm2

21 ≡ Δm2 sol = 7.6×10−5 eV2

| Δm2

31| ≈ |Δm2 32| ≡ Δm2 atm=2.4×10−3 eV2

Θ13 = 9⁰ Θ12 = 34⁰ Θ23 = 45⁰

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Angle parameterisation

13 Slide from P. Litchfield

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14 Slide from P. Litchfield

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T2K Oscillation Analysis

Simulate Events in ND280. Tune beam and cross section parameters using ND280 data Tune using NA61 data Simulate events in SK Predict spectrum and fit for

  • scillation parameters.

Systematic errors include ND280 constraints. Simulate ν beam production Constraints from MiniBOONE etc. ND280 Measurements Super Kamiokande Measurements

Overview

NEUT and GENIE MCs Use event reweighting to model effect of varying parameters. 15

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T2K Oscillation Analysis

Simulate Events in ND280. Tune beam and cross section parameters using ND280 data Tune using NA61 data Simulate events in SK Predict spectrum and fit for

  • scillation parameters.

Systematic errors include ND280 constraints. Simulate ν beam production Constraints from MiniBOONE etc. ND280 Measurements Super Kamiokande Measurements

Overview

NEUT and GENIE MCs Use event reweighting to model effect of varying parameters. 16

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NA61 / SHINE

NA61 is a large acceptance hadron spectometer with excellent capabilities for momentum, charge and mass

  • measurements. The experimental facility

consists of Time Projection Chambers, Time

  • f Flight and Projectile Spectator Detectors.

Physics goals ... Hadron production reference measurements for neutrino (T2K) and cosmic-ray (Pierre Auger Observatory, KASCADE-Grande and KASCADE)

  • experiments. ...

Phys.Rev. C84 (2011) 034604

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T2K Oscillation Analysis

Simulate Events in ND280. Tune beam and cross section parameters using ND280 data Tune using NA61 data Simulate events in SK Predict spectrum and fit for

  • scillation parameters.

Systematic errors include ND280 constraints. Simulate ν beam production Constraints from MiniBOONE etc. ND280 Measurements Super Kamiokande Measurements

Overview

NEUT and GENIE MCs Use event reweighting to model effect of varying parameters. 18

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T2K Oscillation Analysis

Simulate Events in ND280. Tune beam and cross section parameters using ND280 data Tune using NA61 data Simulate events in SK Predict spectrum and fit for

  • scillation parameters.

Systematic errors include ND280 constraints. Simulate ν beam production Constraints from MiniBOONE etc. ND280 Measurements Super Kamiokande Measurements

Overview

NEUT and GENIE MCs Use event reweighting to model effect of varying parameters. 19

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What are ND280 Inputs?

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T2K Oscillation Analysis

Simulate Events in ND280. Tune beam and cross section parameters using ND280 data Tune using NA61 data Simulate events in SK Predict spectrum and fit for

  • scillation parameters.

Systematic errors include ND280 constraints. Simulate ν beam production Constraints from MiniBOONE etc. ND280 Measurements Super Kamiokande Measurements

Overview

NEUT and GENIE MCs Use event reweighting to model effect of varying parameters. 21

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  • Observe muon neutrinos from J-PARC in Super Kamiokande
  • Predict number using beam MC constrained by ND280

measurements

  • Fit reconstructed neutrino energy spectrum and thus
  • Measure sin22θ23, and Δm32

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Muon neutrino disappearance

Overview

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νμ Selection at Far Detector (SK)

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νμ Event Selection contd.

> 200 MeV/c Electron observed later in time than μ consistent with beng from decay of μ.

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Muon Neutrino Disappearance

Count number of muon neutrino events in Super Kamiokande 25 95% CC – of which 64% CCQE

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Muon Neutrino Disappearance

Plot spectrum as a function of reconstructed ν energy. Fit for oscillation parameters.

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Oscillation Fitting

Results

27 90% Confidence Level allowed region: 2.14 x 10-3 eV2/c4 < |Δm32 | < 2.76 x 10-3 eV2/c4 sin22θ23>0.957 Best fit values: |Δm32 | = 2.44 x 10-3 eV2/c4 sin22θ23 = 1.0

New MINOS result: combined fit of beam and atmospheric results http://uk.arxiv.org/abs/1304.6335 8th May 2013

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Latest MINOS Result Overlaid on T2K

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  • 2011 result

– Observed 6 events

  • (Run 1 and 2 data – before earthquake 11 March 2011)

– 0.03 <sin22θ13< 0.28

  • for δCP=0 and normal hierarchy.
  • Reactor results

– 29 Dec 2011 Double Chooz 0.017 < sin22θ13 < 0.16. ( 90% CL) – 8 March 2012 Daya Bay announces 5.2σ measurement of θ13 sin22θ13 = 0.092 ± 0.016 (stat) ± 0.005 (syst) Confirmed 1 month later by RENO See talk by Kwong Lau

  • Our new result

– Run1 + Run2 + Run 3

Electron Neutrino Appearance

Recent history

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Electron Neutrino

Candidate Selection (at SK)

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Electron Neutrino

Candidate Selection (continued) 11 Candidate Events

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νe candidate #11

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Effect of ND280 Constraint

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Electron Neutrino

Summary

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Electron Neutrino

Fit results

35 0.030 < sin22θ13< 0.175 ( 90%CL ) 0.038 < sin22θ13< 0.212 ( 90%CL )

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CC Inclusive Cross Section

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Efficiency = 50% Purity = 88%

Main backgrounds: Events not in FGD1 Neutral current

  • ND280 Run1 and 2 data
  • Detect νμ in FGD1 of ND280

– Good Data Quality – >0 -ve track in TPC – Track starts in FGD1 – dE/dx of -ve track consistent with μ – No activity upstream of FGD

  • Unfold to true μ p/θ bins
  • Convert to differential cross section
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CC Inclusive

Results (Binned)

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CC Inclusive

38 <σCC >φ=(6.93±0.13(stat)±0.85(syst)x10-39cm2/nucleon

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  • More data

–Plan is to collect sufficient data before long shutdown for a 5σ measurement of θ13

  • Improved reconstruction
  • More ND280 cross section measurements
  • Which will all help to produce more

accurate measurement.

Future Prospects

Current Run / Near Term

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  • More of the above and..
  • Anti neutrino running?
  • Synergies with NOVA...
  • Possible sensitivity to CP violation.

Future Prospects

Future Runs / Long Term

40 NOVA: Long baseline experiment Fermilab -> Ash River (810 km) => Larger matter effects than T2K Off Axis E=2GeV First beams now (Spring 2013) Detector completed this time next year Expect 5σ on θ13 by May 2014

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  • T2K is well on the way to achieving its original Physics Goals

– Electron neutrino appearance – Muon neutrino disappearance – Neutrino cross sections

  • Lots more to come in the next few years

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Summary

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BACKUP

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effects matter with ) ( and ) (

e e

P P    

 

 

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Systematic errors -νμ disappearance

Pulls of systematic parameters at the best fit point using two different fitting methods (histogram/ points) Total error envelope calculated as ±1σ spread of bin contents using 100k toy MC experiments generated with randomized systematic parameters. All systematic parameters and their correlations were taken into account.

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Results in 2012: νeflux

Data/MC = .845 ± .146 (stat) ± .107 (syst) νe events = 82.1 ± 14.2 (stat) ± 8.8 (syst)

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CC Inclusive

Unfold to find true bins of muon momentum and angle

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