1. NESSiE and Muon Detection in magnetized Detectors
ICFA Neutrino European Meeting
January 8-10, 2014
APC, Paris Diderot University, France
NESSiE and Muon Detection in magnetized Detectors
S. Dusini – INFN Padova
On behalf of NESSiE Collaboration

2. ICFA Neutrino European Meeting - Paris 2014
SNO
SK & T2K
Borexino
MINOS
KamLAND
Daya Bay
OPERA
CHOOZ
… and many more
MACRO
In the last two decades of experimentation a vast number of results in neutrino physics have created a clear pictures of neutrino oscillations consistent with the mixing of three physical neutrino νe,νμ and ντ with three mass eigenstates ν1,ν2 and ν3.
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

3. ICFA Neutrino European Meeting - Paris 2014
…but some anomalies in the region Δm2 ~ eV2
(* significance of deviation from null hypo.)
Laveder©
Gallium ( ~2.8σ)*
Reactor (~ 2.7σ)*
Th. Lasserre – ICFA 2014
2013 result: μ = ± 0.024, 2.7σ deviation from unity
Predominantly from single detector experiments.
Disappearance signal from anti-νe and νe
Appearance signal from anti-νe
measurements “mistakes” or oscillation between active and non-active neutrinos with Δm2new ≈ 1 eV2 ?
 SHORT BASELINE projects
LSND (~ 3.8σ)*
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

4. ICFA Neutrino European Meeting - Paris 2014
SBL 3+1 neutrino model
νe & anti-νe disapperance
νe & anti-νe appearance
C.Polly – Neutrino 2012
T.Schwetz – Neutrino 2012
SBL reactor + Gallium allowed (95% CL)
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

5. Effective SBL oscillation prob. in 3+1 schema
Effective two state oscillation with new Dm2 frequancy : no CP violation
Appearance
Disappearance
Appearance and disappearance are correlated by the Ua4 term
Coupled measurements
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

6. 3+1 Global fit
Kopp, Machado, Maltoni, Schwetz, JHEP 1305 (2013) 050
Giunti, Laveder, Y.F. Li, H.W. Long, PHYS.REV. D88, (2013)
Parameter of goodness of fit
Not unanimous consensus on the incompatibility between appearance and disappearance, but clear tension among the two set of measurements
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

7. ICFA Neutrino European Meeting - Paris 2014
How to disentangle all the anomalies ?
Measure both νμ disappearance and νe appearance
Measure NC disappearance
 Short Baseline Neutrino Beam
2 sites with as much as possible similar detectors
L/E matching at Δm2∼1 eV2
νμ disappearance is a key feature of the interpretation of the anomalies in terms of sterile neutrinos
Detector requirements:
Measure muons in a wide range (0.4 – 8 GeV)
Measure muon charge (useful in case of discovery but also to exclude more exotic scenarios)
Low systematics and high statistic (small mixing expected)
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

8. ICFA Neutrino European Meeting - Paris 2014
L. Stanco et al., arXiv:
Past reference:
P. Bernardini et al., NESSiE Coll., CERN-PS SPSC-P /10/2011 arXiv: v1
M. Antonello et al. ICARUS-NESSiE Coll. Technical proposal. SPSC-P-347 arXiv:
M. Antonello et al. ICARUS-NESSiE Coll. Contribution to the European Strategy for ParticlePhysics. Krakow September /09/2012 arXiv: v2
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

9. CERN Neutrino Facility
Near site L ~460 m
Far site L ~ 1600 m
SPS p beam: 100 GeV ν beam ~ 2 GeV
4.5·1019 pot/year
interactions/spill = 5 / 0.65 at near /far (2·1013 p/spill with “+” polarity)
Near detector facility
~460 m from target
Far detector facility
~1600 m from target
Target area
Primary beam extraction from TT20
5 mrad slope, -3 m at far
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

10. ICFA Neutrino European Meeting - Paris 2014
Tentative CERN and n CC spectra
Near and Far beam spectra nearly equal -> lower beam systematics
L/E ~ O(1) m/eV
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

11. ICFA Neutrino European Meeting - Paris 2014
NESSiE Detector Concept
NESSiE (Neutrino Experiment with SpectrometerS in Europe)
Goal:
Allow charge separation and momentum measurement of as many mouns as possible escaping from LAr ( large statistic <-> low sin22θ )
Go as low as possible in muon momentum ( low momenta <-> low Δm2 )
Massive iron magnet as target for independent (wrt LAr) νμ disappearance measurement.
Solution:
Air-core magnets for low momentum mouns escaping LAr (Eμ < 0.5 GeV/c in NESSiE <-> <Eν> < 1 GeV in LAr)
Downstream massive iron dipolar magnet for an extension to higher momenta
Charge measurement to control systematics in anti-neutrino run
Statistics
Spectrum
Δm2
sin2 2θ
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

12. ICFA Neutrino European Meeting - Paris 2014
Performance for the present
NESSiE configuration
(full simulation, with neutrino beam)
Iron-Core Magnet (ICM): refurbishment of OPERA
Goal: muons from (0.3–0.5 GeV) up to 8–10 GeV
ICM+ACM: ~ 30% n
by range in ICM
~ 4.5%
Air-Core Magnet (ACM): new design (see WA104 talk tomorrow)
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

13. ICFA Neutrino European Meeting - Paris 2014
Observable event topologies in NESSiE
LAr + NESSiE νμCC events: neutrino interaction in the LAr detector
NESSiE is used to measure muon momentum and charge extending LAr “active” mass. n
NESSiE νμCC events: neutrino interactions in the iron magnet
Independent νμ disappearance with large statistic (fiducial Mnear/far = 330/770 ton )
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

14. νμ disappearance with LAr+NESSiE events
For an important fraction (~ 30 ÷ 50 %) of νμCC events in LAr the muon reach NESSiE
With charge separation independent νμ and anti-νμ disappearance search
Signals for one year in negative focusing
Test point: Δm2 = 1.6 eV2, sin22θ = 0.03
n rec. energy
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

15. ICFA Neutrino European Meeting - Paris 2014
νμ disappearance with spectrometers only
The large mass of the near (330 ton) and far (770 ton) NESSiE iron magnets allow to measure the νμ disappearance with spectrometer ONLY
NEAR neg foc.
NEAR pos. foc.
FAR neg.foc.
FAR pos. foc. νμ
1150 K
3600 K
94 K
280 K
nm-bar
1100 K
300 K
89 K
22 K
With a near/far detectors setup the most sensitive discrimination variable is the double ratio
cancellation of cross section and detector systematics
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

16. ICFA Neutrino European Meeting - Paris 2014
νμ disappearance with spectrometers only
In a coarse iron detector the neutrino energy reconstruction is more difficult and subject to systematics.
<Eν> ~ 2 GeV the QEL events are dominant  strong correlation between Eν and Pμ in νμ CC events
 muon momentum can be use as discriminating variable
sin22θ = 0.1
The observed double ratio R can be tested against the null-hypo R=1.
No need to unfold Eν
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

17. NESSiE νμ disappearance exclusion region
CENF in positive focusing run
MiniBooNE and SciBooNE 90% CL νμ dis. Phys. Rev. D85, (2012), arXiv:
95% CL null-oscillation exclusion region
95% CL
Ultimate performance of NESSiE (no sys) extend by more then one order of magnitude the sensitivity in sin(2θμμ).
With 1% uncorrelated sys. err.
 competitive
L. Stanco et al., Adv. High Energy Phys. 2013, (2013), arXiv: v2
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

18. ICFA Neutrino European Meeting - Paris 2014
NESSiE νμ disappearance exclusion region
The muon charge determination allows a clear separation of νμ and anti-νμ in negative-focusing beam mode and the large and the simultaneous measurements of νμ and anti-νμ disappearance.
NEAR neg foc.
FAR neg.foc. νμ
1150 K
94 K
nm-bar
1100 K
89 K
95% CL
MiniBooNE - SciBooNE 90% CL anti-νμ dis. Phys.Rev. D86, (2012), arXiv:
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

19. ICFA Neutrino European Meeting - Paris 2014
Conclusions
The sterile neutrino interpretation of reactor/galium/LSND anomalies are still open.
A two site νμ disappearance measurement at SBL is mandatory to fully disentangle the "sterile" anomalies or to interpret them
The NESSiE muon spectrometer design (Near+Far) on the CENF neutrino beam would extend νμ disappearance down to 10-3
NESSiE: large and experienced community (knowledge, motivation, largeness)
favorable time scale and small funding thanks to the use of existing detectors (or reasonable extensions)
S. Dusini
ICFA Neutrino European Meeting - Paris 2014

20. ICFA Neutrino European Meeting - Paris 2014
S. Dusini
ICFA Neutrino European Meeting - Paris 2014