PPAP Meeting Birmingham 15 July 2009 Elisabeth Falk University of Sussex Def current running or under construction Outline Neutrinooscillation experiments what to measure and how Acceleratorbased experiments ID: 792714
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Slide1
Current* Neutrino Oscillation Experiments
PPAP MeetingBirmingham15 July 2009Elisabeth FalkUniversity of Sussex
Def. current: running or under construction
Slide2OutlineNeutrino-oscillation experiments:
what to measure, and howAccelerator-based experimentsReactor experimentsConclusions and outlook15/7/09E. Falk, U. of Sussex
2
Slide3Neutrino Mixing15/7/09
E. Falk, U. of Sussex3
Solar
n
+ KamLAND:
q
12
= (34
± 3
)
o
D
m
2
12
= 7.6
x
10
-5
eV2
Atmospheric n + MINOS, K2K: q23 = (45 ± 7)oDm232 = 2.5 x 10-3 eV2
Unknown CP-violating phase
Reactor
n
(CHOOZ):sin2 2q13 < 0.11 @ 90% CL(or q13 <~ 10o)Dm231 ~ Dm232
D
m212
n2
n1
n
3
D
m
2
32
n
e
n
t
n
m
What to measure, and how
Slide4Accelerator-Based vs. Reactor Experiments
Reactor experiments:q13 only:Look for disappearance (ne ne
) as a fnc of L and ENear detector to measure unoscillated flux
P
(
n
e
n
e
) independent of
d
; matter effects small
15/7/09
E. Falk, U. of Sussex
4
ND
FD
LBL accelerator experiments:
s
in2 q12, D
m232:Look for disappearance (
nm
nm) as a fnc of L and
ENear detector to measure unoscillated spectrumq13, δCP, sign(Dm232):Look for appearance (nm ne) in nm beam vs. L and ENear detector to measure background nes (beam + mis-id)P (nm n
e) =
f (d, sign(Dm312
))Accelerator-based and reactor experiments complementary
MINOS, T2K, NOnADouble Chooz, Daya Bay, RENO
What to measure, and how
Slide5Experimental Approach(
nm) disappearance measurements:Measure unoscillated nm spectrum at Near DetectorExtrapolate using MCCompare to measured spectrum at Far Detector15/7/09E. Falk, U. of Sussex
5
spectrum ratio
Monte Carlo
Unoscillated
Oscillated
Monte Carlo
n
m
spectrum
What to measure, and how
n
e
appearance measurements:
Measure
n
e
spectrum at Far Detector
Near Detector
to measure background
n
e
s (beam + mis-id)
Predict Far
Detector background using MC
~ sin
2
2
q23~ Dm2
32
Slide6Neutrino BeamProtons strike graphite target
Magnetic horns focus secondary p/KDecay of p/K produces (mostly) muon neutrinos15/7/09E. Falk, U. of Sussex
6
Accelerator-based experiments
NuMI
NuMI
Slide7Players: MINOS, T2K, NO
nAMINOS:NuMI (Fermilab) to Soudan mine, MN735 km baselineMagnetised sci/steel calorimetersTaken beam data since 2005Two more years of data-takingLarge UK involvementAll ana/working groups have UK co-convener(s)Made significant h/w & DAQ contributions
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E. Falk, U. of Sussex
7
Accelerator-based experiments
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, ….)
NO
n
A:
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
Slide8MINOS
Main physics results to date:nm disappearance: |Δm232
|=(2.43 ± 0.13) x 10-3
eV
2
at 68% C.L.
sin
2
(2θ
23
) > 0.90 at 90% C.L
.
Most precise result
for
|Δm
2
32
| to date
n
e 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.)n
m disappearance:Study 7% nm component See 1.9s fewer events than CPT-conservingNeutral-current interaction rate:
Limit on sterile neutrinos:fs < 0.68 (90% C.L.)
15/7/09E. Falk, U. of Sussex8Accelerator-based experimentsnm disappearancene appearance
Slide9MINOS
Future plans:Update all analyses with more than double the data setData in the can (3.2 7E20 POT)Muon antineutrino runningSwitch beam magnetic horns to focus p-Start in September this yearMake the first direct measurementReduce uncertainty on Dm232 by an order of magnitude
nm mode for 2E20 POT, or until July 2010
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E. Falk, U. of Sussexß
9
Accelerator-based experiments
Slide10T2KPhysics programme:
Phase I:Discovery/measurement of q13D(sin2 2q23) ~ 0.01 (1%)D|Dm232| < 1 x 10-4 eV (a few %)
(90% CL)Potential phase 2:Search for CP violationMilestones: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
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E. Falk, U. of Sussex
10
Accelerator-based experiments
Slide11NO
nASignificant injection of funds via US stimulus package revived NOnAPhysics programme:Optimised for ne appearanceAn order of magnitude more sensitive than MINOS
Improve sin2 2q23 and |
D
m
2
32
| by an order of magnitude (compared to MINOS)
Mass hierarchy (sign (
D
m
2
32
))
Long baseline: only experiment sensitive to
this
Milestones:
1 May 2009: FD groundbreakingAutumn 2011: Start of beam upgrades (400 kW 700 kW)2013: Data-taking with full FD
15/7/09E. Falk, U. of Sussex
11Accelerator-based experiments
Slide12Dominant source of systematic error in CHOOZ:Reactor neutrino spectrum
~ Cancels out with two detectorsMeasuring q13: ne Disappearance
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E. Falk, U. of Sussex
12
Reactor experiments
Nuclear power station
Far Detector
d = 1 - 1.8 km
n
e
n
e
Present limit from CHOOZ:
sin
2
(2
13
) < 0.15 (90% C.L.) at
D
m
231 = 2.5 x 10-3 eV2
Near Detector
d = 300 - 400 m
(
nm,t)
Slide13The Detectors15/7/09
E. Falk, U. of Sussex13
Prompt e
+
signal
E
prompt
= E
n
– (M
n
– M
p
) + m
e
Delayed n capture on Gd
(t ~ 30 ms) with emission
of g cascade ( E ~ 8 MeV)
Outer Veto:
Plastic scintillator panelsn Target:
10 m3 liquid scintillatordoped with 0.1% Gdg Catcher:23 m3 liquid scintillatorBuffer:114 m3 mineral oil with~400 PMTs
Inner Veto:90 m3 liquid scintillatorwith 80 PMTsShielding:15 cm steel
Reactor experiments
Example: Double Chooz
Inverse Beta Decay
Slide14Players: Double Chooz, RENO, Daya Bay15/7/09
E. Falk, U. of Sussex14Reactor experiments
Double Chooz, France
Expected sin
2
2
13
~
0.03
85 ton-GW
th
Small UK interest
(Sussex, no longer funded)
Daya Bay, China
Expected sin
2
2
13
~
0.011400 ton-GWthRENO, KoreaExpected sin22
13~
0.03250 ton-GWth
Main differences:
Reactor power/no of coresConfiguration cores vs. detectors; no. of detectorsDetector target mass
Slide15Status and Expected Milestones*15/7/09
E. Falk, U. of Sussex15Reactor experiments
2009
2010
2011
2012
2013
2014
2009
2010
2011
2012
2013
2014
2009
2010
2011
2012
2013
2014
Double Chooz
RENO
Daya Bay
* 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
ND and FD ready
for data-taking
N and F tunnels
completed
ND and FD
commissioning
sin
2
2
q
13
~ 0.03 ???
First detector complete;
start dry run
Near Hall ready for
data-taking
Far Hall ready for
data-taking;
Ling Ao Hall ready a
bit earlier
Near Hall occupancy
sin
2 2q13 ~ 0.01
FD ready for data-taking
sin
2 2q13 ~ 0.06
ND ready for
data-taking
sin
2
2
q
13
~ 0.03
ND hall + tunnel
construction begins
Slide16Comparison of q13 Sensitivities
15/7/09E. Falk, U. of Sussex
16
M. Mezzetto, Venice, March 2009
Slide1715/7/09
E. Falk, U. of Sussex17Comparison of q
13 Sensitivities
M. Mezzetto, Venice, March 2009
Slide18Conclusions and OutlookPast and present experiments have pinned down
q13, Dm212, q23, Dm232MINOS recently announced 1.5s result for q13T2K and reactor experiments come on-line within
~a year from nowNext 5 years will see sensitivity to sin2 2q13 to ~0.01,
plus order of magnitude improvement on
q
23
and
D
m
2
32
Need combination of different baselines + reactor to resolve
q
13
,
δ
CP
, sign (Dm232)Would be difficult to search for δCP if sin2
2q13 < 0.0115/7/09
E. Falk, U. of Sussex18
Slide19E. Falk, U. Sussex19
Reactor Experiment Howto: Improve on ChoozStatisticsMore powerful reactor (multi-core)Larger detection volumeLonger exposureExperimental error:
n flux and cross-section uncertaintyMulti-detectorIdentical detectors
Reduce inter-detector systematics (normalisation, calibration...)
Background
Improve detector design
Increase overburden
Improve knowledge of background by direct measurement
Larger
S
/
B
CHOOZ :
R
osc
= 1.01 ± 2.8% (stat) ± 2.7% (syst)
Reach ~1% precision
Slide20E. Falk, U. Sussex20
Double Chooz Systematic Uncertainties
n energy,
D
t, (distance e
+
- n)
Slide21Baselines and Reactor Power15/7/09
E. Falk, U. of Sussex21Reactor experiments
Double Chooz
RENO
Daya Bay
P = 16.1 GW
th
/6 cores
L ~ 1.4 km
P = 8.2 GW
th
/2 cores
L = 1.05 km
P = 11.6 GW
th
/4 cores
~2011:
17.4 GW
th
/6 cores
L ~ 1.8 km
Slide22Daya Bay and Ling Ao Nuclear Power Plant
Daya Bay NPP 2.9GW
2
LingAo NPP 2.9GW
2
LingAo II NPP 2.9GW
2
Under construction (2010)
Slide23Daya Bay Run PlanIstall first two detectors
in DB Near Hall within a year from nowTake data (engineering run) while Ling Ao and Far Halls completedAdditional detectors deployed in pairs, one in Ling Ao and one in Far Hall, as they become ready – except last pairOne detector to be moved from Near to Far HallLast pair deployed in Near + Far HallsRun for three yearsPublish
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23
Reactor experiments
DYB (40 t)
LA (40 t)
Far (80 t)
Slide24Daya Bay: Redundancy
Measuring sin2213 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)
Slide2515/7/09E. Falk, U. of Sussex
25Reactor experiments
2010
2011
2014
2013
2012
2015
sin
2
2
q
13
limit
Far Detector
only
Far+Near Detectors
s
sys
= 2.6%
s
sys
= 0.6%
Comparison of
q
13 SensitivitiesDaya BayDouble Chooz
Slide26Comparison of
q13 Sensitivities15/7/09E. Falk, U. of Sussex
26
M. Mezzetto, Venice March 2009
Assumptions:
DC to start end
of 2009; ND 1.5 yrs later
More likely 2
nd
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;
0.45
MW in 2011;
0.75 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
Slide27Overview
Long baseline Fermilab 735 km SoudanNear detector at FermilabMeasure beam composition, energy spectrumFar detector in MinnesotaSearch for and study oscillationsTest the nm
nx oscillation hypothesisMeasure precisely |
D
m
2
32
| and
sin
2
(2
q
23
)
Search for sub-dominant
n
m
ne oscillationsSensitive to q13Other MINOS physics:Search for sterile neutrinos, CPT/Lorentz violation
Compare nm, nm oscillationsStudies of cosmic rays and atmospheric neutrinos
Neutrino interaction studies in the Near Detector15/7/09
27E. Falk, U. of SussexMINOS
Slide28Muon-Neutrino Disappearance Analysis
Strong energy-dependent spectrum distortionSpectrum fit with two-flavour oscillation hypothesisFit constrained to physical region + includes three largest systematicsResults:|Δm2
32|=(2.43 ± 0.13) x 10
-3
eV
2
at 68% C.L.
sin
2
(2θ
23
) > 0.90
at 90% C.L.
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28
PRL
101
131802 (2008)Most precise measurement of |m232
| to date MINOS
Slide29Antimuon-Neutrino Disappearance Analysis
Measure |Δm232|, sin
2(2θ
23
)
Test CPT
FNAL Wine & Cheese three weeks ago
n
m
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
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29
MINOS
Slide3016th-22nd July 2009
30Justin EvansThe FutureAll these analyses have used 3x10
20 of the 7x1020 protons-on-target that have been recordedAs 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
θ
13
sensitivity for 7x10
20
PoT
If the excess persists
If the excess goes away
Slide31Electron-Neutrino Appearance Analysis
Sub-dominant neutrino oscillationsP(νμ→
νe) ≈ sin
2
θ
23
sin
2
2
θ
13
sin
2
(1.27
Δ
m
2
31
L/E)
Also CPv and matter effects: not shown here but included in fit
ANN algorithm to select ne eventsBackground measured in NDNC events, high-y nm CC, beam ne, oscillated nt at FDData-driven technique: compare horn on/off dataPredict FD background from measured ND background + MC 15/7/09E. Falk, U. of Sussex
31
CC Event
NC Event
eCC EventMINOS
Slide32Electron-Neutrino Appearance Analysis
Far Detector spectrum obtained after blind analysisExpected background: 27 ± 5(stat) ±
2(syst)Contours from Feldman-Cousins methodFit to number of eventsObserved events:
37
Results:
Normal hierarchy (
d
CP
= 0):
sin
2
(2θ
13
) < 0.29 (90% C.L.)
Inverted hierarchy (
d
CP
= 0): sin2(2θ
13) < 0.42 (90% C.L.)1.5s
excessWell within realms of statistical fluctuation15/7/09E. Falk, U. of Sussex32MINOS
Slide33Neutral Current Analysis
General NC analysis overview:All active neutrino flavours participate in NC interactionMixing to a sterile ν will cause a deficit of NC events in Far DetectorAssume one sterile neutrino and that mixing between νμ, νs
and ντ occurs at a single Δm2
Survival and sterile oscillation probabilities become:
(α
μ,s
= mixing fractions)
15/7/09
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33
Simultaneous fit to CC and NC energy spectra yields the fraction of ν
μ
that oscillate to
ν
s
:
MINOS
Slide34Future PlansUpdate all analyses with more than double the data set
Muon antineutrino possibilitiesSwitch beam magnetic horns to focus p-MINOS can make the first direct measurementReduce uncertainty on Dm232 by an order of magnitude15/7/09
E. Falk, U. of Sussex
34
MINOS
Slide35Main Measurements: sin2q13
Use CCQE: ne + n e- + pMain backgrounds:Beam n
e contaminationNC p0 events
15/7/09
E. Falk, U. of Sussex
35
T2K
Simulated SK spectrum
Slide36Main Measurements: sin2q23,
Dm232Use CC quasi-elastic events:nm + n
m- + p
Background from non-CCQE interactions
15/7/09
E. Falk, U. of Sussex
36
T2K
D
m
32
2
sin
2
2
q
23
n
m
disappearance
Precision
prospect:
D
(sin
22q23) ~ 0.01 (1%)D (Dm232) < 1 x 10-4 eV2 (a few %) at 90% C.L.@ Dm2 ~ 2.5 x 10
-3
eV2
Slide37J-PARC Accelerator Complex
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37
T2K
Commissioned,
in use for material & life science
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
Neutrino Beam Line
Slide38Near Detectors at 280 mOn- and off-axis detectors 280 m downstream of target
Understand the neutrino beam before oscillations occurT2K timelineApr 09: Beam-line commissioning 10 daysSummer-autumn 09: Install INGRID & ND280Oct 09: Restart beam commissioningDec 09-June 10: Physics runAim to improve CHOOZ limit15/7/09
E. Falk, U. of Sussex
38
On-axis: INGRID
Scintillator/iron
modules
ND 280: Off-axis detectors
inside UA1 magnet
T2K
Slide39Beam Power Projections15/7/09
E. Falk, U. of Sussex39
April 1, 2009
T2K
Slide40Discovery Potential15/7/09
E. Falk, U. of Sussex40
T2K