NeSSiE and the quest for sterile
neutrinos
by
Giovanni Marsella,
Università del Salento and INFN
(for the NESSiE collaboration)
Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy)
September 7-14, 2014
1
Outline
• The “sterile” issue at 1 eV mass scale
• The FNAL proposals
• The CERN neutrino platform: WA104-NESSiE
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The NESSiE Collaboration
Neutrino Experiment with SpectrometerS in Europe
Neutrino Experiment with SpectrometerS in FERMILAB
Make a conclusive experiment to clarify the nm
disappearance behavior at 1 eV scale,
by using spectrometers to allow
muon charge and momentum measurement
Spectrometers at a neutrino beam. Extended studies:
- SPSC-P-343, arXiv:1111.2242
- SPSC-P347, arXiv:1203.3432
- ESPP, arXiv:1208.0862
- LOI CENF: https://edms.cern.ch/nav/P:CERN-0000096725:V0/P:CERN-0000096728:V0/TAB3
- L. Stanco et al., AHEP 2013 (2013) ID 948626, arXiv:1306.3455v2
- FNAL-P-1057, arXiv:1404.2521
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The NESSiE Collaboration
INFN and Physics Departments (Italy),
Lebedev Institue (Russia).
MSU (Russia),
Boskovic Institute (Croatia),
CERN.
All these groups have long experience
in Neutrino Physics and Hardware
(Chorus, Macro, Nomad, Opera, T2K …)
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The “sterile” issue
From masses to flavours:
n e  U e1 n 1  U e 2 n 2  U e3 n 3
n m  U m1 n 1  U m 2 n 2  U m 3 n 3
n   U 1 n 1  U 2 n 2  U 3 n 3
U is the 3 × 3 Neutrino Mixing Matrix
mixing given by 3 angles, q23, q12, q13
transition amplitudes driven by
∆m2solar = ∆m221
∆m2atm = |∆m231| ≈ |∆m232|
The wonderful frame pinpointed for the 3 standard neutrinos,
beautifully adjusted by the q13 measurement, left out some
relevant questions:
- Leptonic CP violation
- Mass values
- Dark Matter
- Anomalies and discrepancies in several results
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The “sterile” issue (cnt’d)
The previous picture is working wonderfully.
So it should stay whenever extensions are allowed !
Exploit 3+1 or even 3+2 oscillating models, by adding one or more “sterile” neutrinos
APPEARANCE
DISAPPEARANCE
when
with
and
and
for APPEARANCE
for DISAPPEARANCE
Sterile neutrino: not weakly interacting neutrinos (B. Pontecorvo, JETP, 53, 1717, 1967)
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The “sterile” issue (cnt’d)
 Experimental hints for more than 3 standard neutrinos, at eV scale
 Strong tension with any formal extension of 3x3 mixing matrix
ne disappearance
ne appearance
Reactor anomaly ~2.5σ
Re-analysis of data on antineutrino flux from reactor
short-baseline (L~10-100 m)
shows a small deficit of
Accelerator anomaly ~3.8σ
Appearance of anti-νe in a anti-νμ
beam (LSND). A.Aguilar et al. LSND
R=0.943 ±0.023
Confirmed (?) by miniBooNE (which
also sees appearance of νe in a νμ
beam) A.Aguilar et al. (MiniBooNE
G.Mention et al, Phys.Rev.D83, 073006
(2011) , A.Mueller et al. Phys.Rev.C 83,
054615 (2011).
Gallex/SAGE anomaly ~3σ
Deficit observed by Gallex in
neutrinos coming from a 51Cr
and 37Ar sources
Collaboration Phys.Rev.D 64 112007 (2001).
Collaboration) Phys.Rev.Lett. 110 161801 (2013)
?? Where is nm disappearance ??
R = 0.76+0.09 −0.08
C. Giunti and M. Laveder, Phys.Rev.
C83, 065504 (2011), arXiv:1006.3244
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Possible explanation: mixing of the active flavours with a sterile neutrino ∆m2 ~ 1 eV2
But there are STRONG tensions between
ne (appearance and disappearance) and nm disappearance
What is the community undergoing ?
Many proposals and experiments
to confirm the anomalies.
SK 2014
Mass scale (PHASE)
(by J. Kopp at Neutrino2014 and references therein)
Why not directly going to
measure the nm disappearance ?
MINOS(2014)
Mixing (AMPLITUDE)
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Prospects for the measurement of
nm disappearance at the FNAL-Booster
FNAL-P-1057 and arXiv:1404.2521
Submitted to FNAL-PAC:
BOOSTER BEAM
The NESSiE Collaboration
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Key-points of the proposal:
1.
The muon-neutrino disappearance is mandatory
- either in case of null result on electron-neutrino
(the sterile possibility might still be there due to interference modes
and data mis-interpretation)
- or in case of positive result
(to address the correct interpretation of sterile,
see current tension between appearance/disappearance)
2.
Standalone measurement of muon-neutrinos
(fully compatible with upstream LAr, or, in case, a small active scintillator target
may be foreseen at Near-site for NC/CC and absolute rate control)
3.
Interplay between systematic and statistical errors:
optimized configuration for Near and Far site
4.
IDENTICAL near and far detector
(the same iron slab will be cut in two pieces to be put corresponding in the Near and the Far)
5.
No R&D/refurbishing/upgrade: robustness of the program
(80% of re-used well proven detectors, straightforward extension;
100 kWatt needed for each site)
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Careful study of the FNAL-Booster neutrino beam,
based on previous knowledge from MiniBooNE, SciBooNE and
data obtained by HARP and E910.
- full simulation of the beam with GEANT4 and FLUKA
(from proton to neutrinos)
- detailed systematic error source analysis
(use of Sanford-Wang parametrization)
- Several configurations analyzed, on/off-axis including MicroBooNE site
and different detector sizes
Far site
Near site
A possibility
Near: SciBooNE enclosure
Far: NOvA surface building
meters
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Near-site Far Near-off
Far Near-size Far
chosen
configuration
Near almost on axis
Far on surface,
Full “NESSiE” configuration
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n m CC / 0.1 GeV / 6.6 ´ 1020 pot
Near site
50000
CC
CCQE
enuTot
Entries
Mean
RMS
40000
30000
72611
1.147
0.6366
Eneutrinos
20000
10000
Far site
n mCC / 0.1 GeV / 6.6 ´ 1020
0
0
0.5
1
1.5
2
2.5
70000
3
3.5
4
4.5
5
n m energy (GeV)
CC
CCQE
60000
50000
pmuTot
Entries
72611
Mean
0.6665
RMS
0.5065
pmuons
40000
30000
20000
10000
0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
m momentum (GeV)
ABSOLUTE nb. interactions in the FAR fiducial volume, 3 years data taking13
Sensitivity
from here (now)
to here (NESSiE)
with strong cuts
plus statistical error
plus systematics only
on pm reconstruction
MINOS (Neutrino 2014)
gure 32: The sensitivity plot (t 90% C.L.) for the negative-focussing option assuming 3.5×106
with and without the air magnet option. Black (red) line: νµ (νµ )exclusion limit. Note that the
ntribution
thesensitivity
magnetic plot
field(tin90%
air to
the sensitivity
has not being include
yet. Blue3.5×10
(green)6
gure 32: of
The
C.L.)
for the negative-focussing
optiond,assuming
e:with
old and
(recent)
exclusion
on option.
νµ fromBlack
previous
cent ([43])me
asurements.The
without
the airlimits
magnet
(red)(CDHS
line: )νµand
(νµre
)exclusion
limit.
Note that the
o filled areof
as the
correspond
the in
present
limitshas
on not
the bνeing
CCFR
([44]
and(gre
Miniµ from
ntribution
magnetictofield
air toexclusion
the sensitivity
include
d, yet.
Blue
en)
oNE
experiments
(atlimits
90% C.L.).
e: old[16]
(recent)
exclusion
on νµ from previous (CDHS) and recent ([43])measurements.The
o filled areas correspond to the present exclusion limits on the νµ from CCFR ([44] and MinioNE [16] experiments (at 90% C.L.).
Three independent
analyses, with different
statistical approaches
a full simulation
and a careful treatment
of 1% systematics error
48
48
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The CERN Neutrino Platform:
WA104-NESSiE
Precision measurement of muon momentum &
charge in the 0.5 GeV - 10 GeV range
- relevant to disentangle ν anomalies in ν / anti-ν channels
- relevant in LBL exps to limit ν / anti-ν related systematics
Proposed strategy
A) The “conservative” approach
Air Core Magnet spectrometer coupled to Iron Core Magnet
spectrometer – Coupling to upstream LAr TPC
B) The advanced solution (R&D)
- Superconducting ACM spectrometer – Coupling to upstream LAr TPC
-Magnetization of Large Volume LAr-TPC
WA104 -NESSiE R&D program
• First step - construction and operation of 13/39 ACM coils
• R&D on Tracking Detectors in Magnetic Field
- Scintillator bars + SiPM in analog and digital readout
- Other tracking devices (RPC in analog readout)
• Charged beam tests
- charge and momentum measurement
- Test on LAr-TPC –ACM matching
• Cold ACM in NbTi : design, simulation, demonstrator
•MgB2 Conductor: R&D actvity
Synergy with LAr –TPC magnetization.
The Air Core Magnet
getting rid of multiple scattering at low energy
Design constrained by
-Low power consumption
-Low “budget” of material along the beam
-Low cost
-Large magnetized volume
-Large acceptance
Optimized parameters
Field Volume Depth 130 cm
 Magnetic Field ~ 0.1 T
Aluminum Conductor
 1 mm Tracking Detector Resolution
z
x
y
SC Air Core Magnet
Cold ACM Bending Power
Assuming:
Normal incidence
Toroid width 130 cm
Uniform magnetic field
Superconductor Materials:
The choice
à la Atlas
Cryostat
1.5 m
Superconducting Coil
NbTi: proven successful technology –
Operating at 4 K
Exploring new materials as MgB2
(operating at 20 K). Long term R&D required
-cabled conductor development
-coil winding technology
-demonstration coils
-qualification of coil operation
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Thank you !
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BACKUP
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Resolutions:
Sensitivities from the actual
NESSiE configurations
(full simulation, with neutrino beam)
Charge-ID measured by iron slabs
(ICM: blue line)
Momentum measured by range (ICM)
up to 3.5 GeV,
then ≈30% are provided
(goal ≥ 250 MeV)
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DATA COLLECTION
absolute number of nm CC interactions, seen by the Near detector at 110 m,
either in the En or the pm variables, normalized to the expected luminosity
in 3 years of data taking at FNAL–Booster, or 6.6 × 1020 p.o.t.
(full simulation including RPC digitalization, muon momentum resolution 10%)
Number of events in 3 year (6.6 x 1020 pot)
Trigger
NEAR
FAR
num. planes ≥ 2
5.1 x 106
2.8 x 105
num. planes ≥ 3
4.1 x 106
2.3 x 105
num. planes ≥ 5
2.7 x 106
1.5 x 105
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Schedule and Costs
A bit aggressive, but reliable schedule
based on successful OPERA experience
Both Near and Far
(new Electronics, new DAQ, 2 x coil number)
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2014
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