1. Current* Neutrino Oscillation Experiments
PPAP Meeting
Birmingham
15 July 2009
Elisabeth Falk
University of Sussex
Def. current: running or under construction

2. Neutrino-oscillation experiments: what to measure, and how
Outline
Neutrino-oscillation experiments: what to measure, and how
Accelerator-based experiments
Reactor experiments
Conclusions and outlook
15/7/09
E. Falk, U. of Sussex

3. Neutrino Mixing Dm212 n2 n1 n3 Dm232 ne nt nm
What to measure, and how
Neutrino Mixing
Dm212 n2 n1 n3
Dm232 ne nt nm
Unknown CP-violating phase
Solar n + KamLAND: q12 = (34 ± 3)o
Dm212 = 7.6 x 10-5 eV2
Reactor n (CHOOZ):
sin2 2q13 < 90% CL
(or q13 <~ 10o)
Dm231 ~ Dm232
Atmospheric n +
MINOS, K2K:
q23 = (45 ± 7)o
Dm232 = 2.5 x 10-3 eV2
15/7/09
E. Falk, U. of Sussex

4. Accelerator-Based vs. Reactor Experiments
What to measure, and how
Accelerator-Based vs. Reactor Experiments
LBL accelerator experiments:
sin2 q12, Dm232:
Look for disappearance (nm  nm) as a fnc of L and E
Near detector to measure unoscillated spectrum
q13, δCP, sign(Dm232):
Look for appearance (nm  ne) in nm beam vs. L and E
Near detector to measure background nes (beam + mis-id)
P (nm  ne) = f (d, sign(Dm312))
Reactor experiments:
q13 only:
Look for disappearance (ne  ne) as a fnc of L and E
Near detector to measure unoscillated flux
P (ne  ne) independent of d; matter effects small
Accelerator-based and reactor experiments complementary
Two-detector experiment to reduce systematic errors:
Flux, cross-section and detector uncertainties minimised ND FD
MINOS, T2K, NOnA
Double Chooz, Daya Bay, RENO
15/7/09
E. Falk, U. of Sussex

5. Experimental Approach
What to measure, and how
Experimental Approach
(nm) disappearance measurements:
Measure unoscillated nm spectrum at Near Detector
Extrapolate using MC
Compare to measured spectrum at Far Detector
ne appearance measurements:
Measure ne spectrum at Far Detector
Near Detector to measure background nes (beam + mis-id)
Predict Far Detector background using MC
Unoscillated
Oscillated
Monte Carlo
nm spectrum
spectrum ratio
Monte Carlo
~ sin2 2q23
15/7/09
E. Falk, U. of Sussex
~ Dm232

6. Neutrino Beam Protons strike graphite target
Accelerator-based experiments
Neutrino Beam
NuMI
Protons strike graphite target
Magnetic horns focus secondary p/K
Decay of p/K produces (mostly) muon neutrinos
NuMI
15/7/09
E. Falk, U. of Sussex

7. Players: MINOS, T2K, NOnA Accelerator-based experiments MINOS:
NuMI (Fermilab) to Soudan mine, MN
735 km baseline
Magnetised sci/steel calorimeters
Taken beam data since 2005
Two more years of data-taking
Large UK involvement
All ana/working groups have UK co-convener(s)
Made significant h/w & DAQ contributions
T2K:
J-PARC (Tokai) to Kamioka mine
295 km baseline, off-axis
New beam
FD: Super-K (water Cerenkov)
Start data-taking in 2010
Large UK involvement
ND280 off-axis detector (P0D, ECAL, DAQ, ….)
NOnA:
NuMI (Fermilab) to Ash River, MN
810 km baseline, off axis
Upgrade beam power
“Totally active” tracking liquid sci calorimeters
Start data-taking in 2013
No UK involvement
15/7/09
E. Falk, U. of Sussex

8. MINOS Main physics results to date:
Accelerator-based experiments
MINOS
nm disappearance
Main physics results to date:
nm disappearance: |Δm232|=(2.43 ± 0.13) x 10-3 eV2 at 68% C.L sin2(2θ23) > 0.90 at 90% C.L.
Most precise result for |Δm232| to date
ne appearance:
1.5s excess (within realms statistical fluctuation):
Normal hierarchy (dCP = 0): sin2(2θ13) < 0.29 (90% C.L.)
Inverted hierarchy (dCP = 0): sin2(2θ13) < 0.42 (90% C.L.)
nm disappearance:
Study 7% nm component
See 1.9s fewer events than CPT-conserving
Neutral-current interaction rate:
Limit on sterile neutrinos: fs < 0.68 (90% C.L.)
ne appearance
15/7/09
E. Falk, U. of Sussex

9. Accelerator-based experiments
MINOS
Future plans:
Update all analyses with more than double the data set
Data in the can (3.2  7E20 POT)
Muon antineutrino running
Switch beam magnetic horns to focus p-
Start in September this year
Make the first direct measurement
Reduce uncertainty on Dm232 by an order of magnitude
nm mode for 2E20 POT, or until July 2010
15/7/09
E. Falk, U. of Sussexß

10. T2K Physics programme: Milestones: Phase I: Potential phase 2:
Accelerator-based experiments
T2K
Physics programme:
Phase I:
Discovery/measurement of q13
D(sin2 2q23) ~ 0.01 (1%) D|Dm232| < 1 x 10-4 eV (a few %) (90% CL)
Potential phase 2:
Search for CP violation
Milestones:
ND suite operational by end of 2009
Beam power ramped over next few years (2009: 30 kW; 2010: 100 kW; 2011: 300 kW; + “a few years”: 750 kW
Phase 1: total of 5E21 POT
15/7/09
E. Falk, U. of Sussex

11. Accelerator-based experiments
NOnA
Significant injection of funds via US stimulus package revived NOnA
Physics programme:
Optimised for ne appearance
An order of magnitude more sensitive than MINOS
Improve sin2 2q23 and |Dm232| by an order of magnitude (compared to MINOS)
Mass hierarchy (sign (Dm232))
Long baseline: only experiment sensitive to this
Milestones:
1 May 2009: FD groundbreaking
Autumn 2011: Start of beam upgrades (400 kW  700 kW)
2013: Data-taking with full FD
15/7/09
E. Falk, U. of Sussex

12. Measuring q13: ne Disappearance
Reactor experiments
Measuring q13: ne Disappearance ne ne
(nm,t)
Nuclear power station
Near Detector
d = m
Far Detector
d = km
Present limit from CHOOZ:
sin2(213) < 0.15 (90% C.L.) at
Dm231 = 2.5 x 10-3 eV2
Dominant source of
systematic error in CHOOZ:
Reactor neutrino spectrum
~ Cancels out with two detectors
15/7/09
E. Falk, U. of Sussex

13. The Detectors Example: Double Chooz Reactor experiments
Outer Veto: Plastic scintillator panels
n Target: 10 m3 liquid scintillator doped with 0.1% Gd
g Catcher: 23 m3 liquid scintillator
Buffer: 114 m3 mineral oil with ~400 PMTs
Inner Veto:
90 m3 liquid scintillator with 80 PMTs
Shielding: 15 cm steel
Prompt e+ signal
Eprompt = En – (Mn – Mp) + me
Inverse Beta Decay
Delayed n capture on Gd
(t ~ 30 ms) with emission
of g cascade ( E ~ 8 MeV)
15/7/09
E. Falk, U. of Sussex

14. Players: Double Chooz, RENO, Daya Bay
Reactor experiments
Players: Double Chooz, RENO, Daya Bay
RENO, Korea
Expected sin2213~0.03
250 ton-GWth
Double Chooz, France
Expected sin2213~0.03
85 ton-GWth
Small UK interest (Sussex, no longer funded)
Daya Bay, China
Expected sin2213~0.01
1400 ton-GWth
Main differences:
Reactor power/no of cores
Configuration cores vs. detectors; no. of detectors
Detector target mass
15/7/09
E. Falk, U. of Sussex

15. Status and Expected Milestones*
Reactor experiments
Status and Expected Milestones*
Double Chooz
RENO
Daya Bay
N and F tunnels completed
2009
2010
2011
2012
2013
2014
2009
2010
2011
2012
2013
2014
2009
2010
2011
2012
2013
2014
Near Hall occupancy
ND hall + tunnel construction begins
ND and FD commissioning
First detector complete;
start dry run
ND and FD ready for data-taking
FD ready for
data-taking
Near Hall ready for
data-taking
Far Hall ready for
data-taking; Ling Ao Hall ready a bit earlier
sin2 2q13 ~ 0.06
ND ready for data-taking
sin2 2q13 ~ 0.03 ???
sin2 2q13 ~ 0.03
sin2 2q13 ~ 0.01
15/7/09
* DC schedule includes my estimated delays – not official, so don’t quote it! RENO, DB official schedules, but at least DB will likely be delayed by a few months
E. Falk, U. of Sussex

16. Comparison of q13 Sensitivities
M. Mezzetto, Venice, March 2009
15/7/09
E. Falk, U. of Sussex

17. Comparison of q13 Sensitivities
M. Mezzetto, Venice, March 2009
15/7/09
E. Falk, U. of Sussex

18. Conclusions and Outlook
Past and present experiments have pinned down q13, Dm212, q23, Dm232
MINOS recently announced 1.5s result for q13
T2K and reactor experiments come on-line within ~a year from now
Next 5 years will see sensitivity to sin2 2q13 to ~0.01, plus order of magnitude improvement on q23 and Dm232
Need combination of different baselines + reactor to resolve q13, δCP, sign (Dm232)
Would be difficult to search for δCP if sin2 2q13 < 0.01
15/7/09
E. Falk, U. of Sussex

19. Reactor Experiment Howto: Improve on Chooz
CHOOZ : Rosc = 1.01 ± 2.8% (stat) ± 2.7% (syst)
Statistics
More powerful reactor (multi-core)
Larger detection volume
Longer exposure
Experimental error: n flux and cross-section uncertainty
Multi-detector
Identical detectors
Reduce inter-detector systematics (normalisation, calibration...)
Background
Improve detector design
Increase overburden
Improve knowledge of background by direct measurement
Larger S/B
Reach ~1% precision
E. Falk, U. Sussex

20. Double Chooz Systematic Uncertainties
n energy, Dt, (distance e+ - n)
E. Falk, U. Sussex

21. Baselines and Reactor Power
Reactor experiments
Baselines and Reactor Power
Double Chooz
Daya Bay
RENO OK
P = 8.2 GWth/2 cores
L = 1.05 km
P = 11.6 GWth/4 cores
~2011:
17.4 GWth/6 cores
L ~ 1.8 km
P = 16.1 GWth/6 cores
L ~ 1.4 km
15/7/09
E. Falk, U. of Sussex

22. Daya Bay and Ling Ao Nuclear Power Plant
LingAo II NPP 2.9GW2 Under construction (2010)
LingAo NPP 2.9GW2
Daya Bay NPP 2.9GW2

23. Reactor experiments
Daya Bay Run Plan
DYB (40 t)
LA (40 t)
Far (80 t)
Istall first two detectors in DB Near Hall within a year from now
Take data (engineering run) while Ling Ao and Far Halls completed
Additional detectors deployed in pairs, one in Ling Ao and one in Far Hall, as they become ready – except last pair
One detector to be moved from Near to Far Hall
Last pair deployed in Near + Far Halls
Run for three years
Publish OK
15/7/09
E. Falk, U. of Sussex

24. Daya Bay: Redundancy
Measuring sin2213 to 0.01 need to control systematic errors very well.
We believe that the relative (near/far) detector systematic error could be lowered to 0.38%, with near/far cancellation and improved detector design.
Side-by-side calibration: Event rates and spectra in two detectors at the same near site can be compared  How IDENTICAL our detectors are?
Detector swapping: Daya Bay antineutrino detectors are designed to be MOVABLE. All detectors are assembled and filled with liquids at the same place. Detectors at the near sites and the far site can be swapped, although not necessary to reach our designed sensitivity, to cross check the sensitivity and further reduce the systematic errors.
DYB (40 t)
LA (40 t)
Far (80 t)

25. Comparison of q13 Sensitivities
Reactor experiments
Comparison of q13 Sensitivities
Daya Bay
Double Chooz
sin22q13 limit
ssys= 0.6%
Far+Near Detectors
ssys= 2.6%
Far Detector
only OK
2010
2011
2012
2013
2014
2015
15/7/09
E. Falk, U. of Sussex

26. Comparison of q13 Sensitivities
M. Mezzetto, Venice March 2009
Assumptions:
DC to start end of 2009; ND 1.5 yrs later
More likely 2nd quarter of 2010 (my estimate)
DB to start mid 2011
From C. White: Schedule slipping by a few months
T2K: 0.1 MW in 2010; MW in 2011; MW thereafter
From D. Wark: 0.1 MW in 2010; 0.3 MW in 2011; ramp to 0.75 MW over a few years
MINOS, OPERA: sensitivity as per proposal, scaled by POT OK
15/7/09
E. Falk, U. of Sussex

27. Overview Long baseline Fermilab  735 km  Soudan
MINOS
Overview
Long baseline Fermilab  735 km  Soudan
Near detector at Fermilab
Measure beam composition, energy spectrum
Far detector in Minnesota
Search for and study oscillations
Test the nm  nx oscillation hypothesis
Measure precisely |Dm232| and sin2 (2q23)
Search for sub-dominant nm  ne oscillations
Sensitive to q13
Other MINOS physics:
Search for sterile neutrinos, CPT/Lorentz violation
Compare nm, nm oscillations
Studies of cosmic rays and atmospheric neutrinos
Neutrino interaction studies in the Near Detector
15/7/09
E. Falk, U. of Sussex

28. Muon-Neutrino Disappearance Analysis
MINOS
Muon-Neutrino Disappearance Analysis
Strong energy-dependent spectrum distortion
Spectrum fit with two-flavour oscillation hypothesis
Fit constrained to physical region + includes three largest systematics
Results: |Δm232|=(2.43 ± 0.13) x 10-3 eV2
at 68% C.L.
sin2(2θ23) > 0.90
at 90% C.L.
PRL (2008)
Most precise measurement of |m232| to date
15/7/09
E. Falk, U. of Sussex

29. Antimuon-Neutrino Disappearance Analysis
MINOS
Antimuon-Neutrino Disappearance Analysis
Measure |Δm232|, sin2(2θ23)
Test CPT
FNAL Wine & Cheese three weeks ago
nm CC events are 7% of beam
Mis-ID muon and NC backgrounds relatively larger
As CC analysis, but with extra cuts
Track-length likelihood, charge-sign significance
Oops, the spectrum plot isn’t for the data, only for the prediction!!
15/7/09
E. Falk, U. of Sussex

30. The Future If the excess persists If the excess goes away
All these analyses have used 3x1020 of the 7x1020 protons-on-target that have been recorded
As of this June’s summer shutdown
Over the next year, the analyses will be updated with the increased dataset
Using the blind analysis policy on the new data
Graphs below show the θ13 sensitivity for 7x1020 PoT
If the excess persists
If the excess goes away
16th-22nd July 2009
Justin Evans

31. Electron-Neutrino Appearance Analysis
MINOS
Electron-Neutrino Appearance Analysis
CC Event
Sub-dominant neutrino oscillations
P(νμ→νe) ≈ sin2θ23 sin22θ13 sin2(1.27Δm231L/E)
Also CPv and matter effects: not shown here but included in fit
ANN algorithm to select ne events
Background measured in ND
NC events, high-y nm CC, beam ne, oscillated nt at FD
Data-driven technique: compare horn on/off data
Predict FD background from measured ND background + MC
NC Event
eCC Event
15/7/09
E. Falk, U. of Sussex

32. Electron-Neutrino Appearance Analysis
MINOS
Electron-Neutrino Appearance Analysis
Far Detector spectrum obtained after blind analysis
Expected background: 27 ± 5(stat) ± 2(syst)
Contours from Feldman-Cousins method
Fit to number of events
Observed events: 37
Results:
Normal hierarchy (dCP = 0): sin2(2θ13) < 0.29 (90% C.L.)
Inverted hierarchy (dCP = 0): sin2(2θ13) < 0.42 (90% C.L.)
1.5s excess
Well within realms of statistical fluctuation
15/7/09
E. Falk, U. of Sussex

33. Neutral Current Analysis
MINOS
Neutral Current Analysis
General NC analysis overview:
All active neutrino flavours participate in NC interaction
Mixing to a sterile ν will cause a deficit of NC events in Far Detector
Assume one sterile neutrino and that mixing between νμ, νs and ντ occurs at a single Δm2
Survival and sterile oscillation probabilities become:
(αμ,s = mixing fractions)
Simultaneous fit to CC and NC energy spectra yields the fraction of νμ that oscillate to νs:
Say that new results are immient (what stats?)
15/7/09
E. Falk, U. of Sussex

34. Future Plans Update all analyses with more than double the data set
MINOS
Future Plans
Update all analyses with more than double the data set
Muon antineutrino possibilities
Switch beam magnetic horns to focus p-
MINOS can make the first direct measurement
Reduce uncertainty on Dm232 by an order of magnitude
Introduce one or two slides on numubar ana
15/7/09
E. Falk, U. of Sussex

35. Main Measurements: sin2q13
T2K
Main Measurements: sin2q13
Simulated SK spectrum
Use CCQE: ne + n  e- + p
Main backgrounds:
Beam ne contamination
NC p0 events
15/7/09
E. Falk, U. of Sussex

36. Main Measurements: sin2q23, Dm232
T2K
Main Measurements: sin2q23, Dm232
Use CC quasi-elastic events: nm + n  m- + p
Background from non-CCQE interactions
Dm322
sin22q23
nm disappearance
Precision prospect: D (sin22q23) ~ 0.01 (1%) D (Dm232) < 1 x 10-4 eV2 (a few %) at 90% C.L.
@ Dm2 ~ 2.5 x 10-3 eV2
15/7/09
E. Falk, U. of Sussex

37. J-PARC Accelerator Complex
T2K
J-PARC Accelerator Complex
Protons to 30 GeV on 23/12/08 Commissioning is on time
Commissioned, in use for material & life science
n beam-line components Commissioning in progress
Commissioned, in use for material & life science
15/7/09
E. Falk, U. of Sussex
Neutrino Beam Line

38. T2K
Near Detectors at 280 m
On- and off-axis detectors 280 m downstream of target
Understand the neutrino beam before oscillations occur
T2K timeline
Apr 09: Beam-line commissioning 10 days
Summer-autumn 09: Install INGRID & ND280
Oct 09: Restart beam commissioning
Dec 09-June 10: Physics run
Aim to improve CHOOZ limit
ND 280: Off-axis detectors
inside UA1 magnet
On-axis: INGRID
Scintillator/iron
modules
15/7/09
E. Falk, U. of Sussex

39. Beam Power Projections
T2K
Beam Power Projections
April 1, 2009
15/7/09
E. Falk, U. of Sussex

40. T2K
Discovery Potential
15/7/09
E. Falk, U. of Sussex