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byGiovanni Marsella,

Università del Salento and INFN(for the NESSiE collaboration)

NeSSiE and the quest for sterile neutrinos

Neutrino Oscillation Workshop - Conca Specchiulla (Otranto, Lecce, Italy)September 7-14, 2014

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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

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

Make a conclusive experiment to clarify the nm disappearance behavior at 1 eV scale,

by using spectrometers to allowmuon charge and momentum measurement

Neutrino Experiment with SpectrometerS in Europe

Neutrino Experiment with SpectrometerS in FERMILAB

or

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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” issueFrom masses to flavours:

332211

332211

332211

UUU

UUU

UUU eeee

U is the 3 × 3 Neutrino Mixing Matrixmixing given by 3 angles, q23, q12, q13

transition amplitudes driven by ∆m2

solar = ∆m221

∆m2atm = |∆m2

31| ≈ |∆m232|

The wonderful frame pinpointed for the 3 standard neutrinos, beautifully adjusted by the q13 measurement, left out somerelevant 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

Sterile neutrino: not weakly interacting neutrinos (B. Pontecorvo, JETP, 53, 1717, 1967)

APPEARANCE

DISAPPEARANCE

with

for APPEARANCE

for DISAPPEARANCE

when and

and

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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

Reactor anomaly ~2.5σ Re-analysis of data on anti- neutrino flux from reactor short-baseline (L~10-100 m) shows a small deficit of R=0.943 ±0.023 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 R = 0.76+0.09 −0.08 C. Giunti and M. Laveder, Phys.Rev. C83, 065504 (2011), arXiv:1006.3244

Accelerator anomaly ~3.8σ Appearance of anti-νe in a anti-νμ beam (LSND). A.Aguilar et al. LSND Collaboration Phys.Rev.D 64 112007 (2001).

Confirmed (?) by miniBooNE (which also sees appearance of νe in a νμ beam) A.Aguilar et al. (MiniBooNE Collaboration) Phys.Rev.Lett. 110 161801 (2013)

ne disappearance ne appearance

?? Where is nm disappearance ??

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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

(by J. Kopp at Neutrino2014 and references therein)

What is the community undergoing ?

Many proposals and experimentsto confirm the anomalies.

Why not directly going to measure the nm disappearance ?

SK 2

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Mixing (AMPLITUDE)

Mas

s sc

ale

(PH

ASE)

MINOS(2014)

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FNA

L-P-1

05

7 a

nd

arX

iv:1

40

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Subm

itted

to F

NAL

-PAC

:

Prospects for the measurement ofnm disappearance at the FNAL-Booster

The NESSiE Collaboration

BOO

STER

BEA

M

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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 targetmay 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 siteand different detector sizes

A possibilityNear: SciBooNE enclosureFar: NOvA surface building

Far site

Near site

meters

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Near-site Far Near-off Far Near-size Far

chosenconfiguration

Near almost on axisFar on surface,Full “NESSiE” configuration

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Near site

Far site

Eneutrinos

pmuons

ABSOLUTE nb. interactions in the FAR fiducial volume, 3 years data taking

MINOS (Neutrino 2014)

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from here (now)

to here (NESSiE)

a full simulationand a careful treatmentof 1% systematics error

Sensitivity

with strong cutsplus statistical errorplus systematics onlyon pm reconstruction

Three independent analyses, with different statistical approaches

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The CERN Neutrino Platform: WA104-NESSiE

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

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

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.

Design constrained by

-Low power consumption-Low “budget” of material along the beam-Low cost-Large magnetized volume-Large acceptance

The Air Core Magnet

Optimized parameters

Field Volume Depth 130 cm

Magnetic Field ~ 0.1 T

Aluminum Conductor

1 mm Tracking Detector Resolution

yz

x

getting rid of multiple scattering at low energy

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Assuming:Normal incidenceToroid width 130 cm Uniform magnetic field

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

Cold ACM Bending Power

Superconductor Materials: The choice

Cryostat

Superconducting Coil1.5 m

SC Air Core Magnetà la Atlas

Thank you !

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BACKUP

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Resolutions:

Momentum measured by range (ICM)up to 3.5 GeV, then ≈30% are provided

(goal ≥ 250 MeV)

Sensitivities from the actualNESSiE configurations(full simulation, with neutrino beam)

Charge-ID measured by iron slabs (ICM: blue line)

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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 luminosityin 3 years of data taking at FNAL–Booster, or 6.6 × 1020 p.o.t. (full simulation including RPC digitalization, muon momentum resolution 10%)

DATA COLLECTION

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 schedulebased on successful OPERA experience

Both Near and Far

(new Electronics, new DAQ, 2 x coil number)

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2014