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Near Detector at a Neutrino FactoryNear Detector at a Neutrino FactoryNear Detector at a Neutrino FactoryNear Detector at a Neutrino Factory
Chuzenji Lake, Nikko, Japan. 10 November 2005
Paul SolerUniversity of Glasgow/RAL
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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ContentsContents
1. Physics motivation Neutrino Factory1.1 Neutrino oscillations1.2 Neutrino factory1.3 Neutrino factory physics reach
2. Near Detector at a Neutrino Factory2.1 Flux normalization2.2 Cross-sections2.3 Parton Distribution Functions2.4 Charm production2.5 Sin2w
3. Near detector requirements4. NOMAD-STAR, an R&D prototype5. Near detector ideas
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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1.1 Neutrino Oscillations1.1 Neutrino Oscillations Neutrino oscillations well established Neutrino flavour mixing: Pontecorvo-Maki-Nakagawa-Sakata
(PMNS) matrix
Atmospheric neutrinos: SuperKamiokande
1)2(sin45 232
23
23223 102.3 eVm
3
2
1
U
e
ijijijij sandcwhere
cs
sc
iδecs
sccs
sc
U
sin,cos
0
010
0
00
010
001
0
0
001
100
0
0
1313
1313
2323
23231212
1212
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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1. Neutrino Oscillations1. Neutrino Oscillations
Solar neutrinos (SuperKamiokande, Sudbury, Chlorine and Gallium Experiments) and KamLand reactor experiment:
1.3446.0tan 1210.007.012
2
256.05.0
212 109.7 eVm
Sudbury KamLand
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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1. Neutrino Oscillation fits1. Neutrino Oscillation fits
Consistent picture emerging Global fit provides 23, 12, m12
2 and m232
13 not known, mass hierarchy not known,CP violation phase not known.
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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1.2 Neutrino Factory1.2 Neutrino Factory Matter-antimatter asymmetry
of the universe: baryogenesis (CP violation in quark sector), leptogenesis (CP violation in lepton sector)
e
e
e
e
Conceptual design: neutrinos produced from muon decay in storage ring. Rate calculable by kinematics of decay (Michel spectrum)
Neutrino factory: very long baseline oscillation experiments to measure 13, mass hierarchy and leptonic CP violation
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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1.3 Neutrino Factory physics reach1.3 Neutrino Factory physics reach Far detector (3000-7000 km) can
search for “wrong-sign” muons in appearance mode (for example, Large Magnetic Detector)
Background: charm production, charge misidentification.
Qt = P sin2 cut eliminates backg at 10-6
Large Magnetic Detector
iron (4 cm) + scintillators (1cm)
beam20 m
20 m
B=1 T
40KT40KT
e
e
50%
50%
wrongwrongsignsignmuonmuon
e
detectordetector
not detected
De
e
De e
NC
CC
Hadron decay
Other Detectors: liquid argon TPC, water Cherenkov, emulsion can search for either e, or appearance
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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1.3 Neutrino Factory physics reach1.3 Neutrino Factory physics reach Can detect sign of m2
32 due to matter effects
Determine 13 and CP phase simultaneously: need ~1021 muons/year
Optimal CP phase sensitivity ~6000 km but
can obtain >5 sensitivity for ~1000-8000 km
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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2. Near detector aims2. Near detector aims To achieve physics goals of neutrino factory, need to establish near
detector for near/far ratio. Long baseline neutrino oscillation systematics:
– Flux control and measurement for the long baseline search.– Neutrino beam angle and divergence– Beam energy and spread– Control of muon polarization– Measurement of charm backgrounds
Near detector neutrino physics:– Cross-section measurements: DIS, QES, RES scattering– sin2W - sin2W ~ 0.0001– Parton Distribution Functions, nuclear shadowing S from xF3 - S~0.003 _– Charm production: |Vcd| and |Vcs|, D0/ D0 mixing– Polarised structure functions– polarization– Beyond SM searches General Purpose Detector(s)!!
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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2.1 Flux normalisation (cont.)2.1 Flux normalisation (cont.)
e
e
e
e
Neutrino beams from decay of muons:
Spectra at Production (e.g. 50 GeV) Number CC interactions
Polarisation dependence
P=+1: gone!
Need to measure polarization!!
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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2.1 Flux normalisation (cont.)2.1 Flux normalisation (cont.)
Rates:— E = 50 GeV
— L = 100 m, d = 30 m— Muon decays per year: 1020
— Divergence = 0.1 m/E
— Radius R=50 cm
100 m
E.g. at 25 GeV, number neutrino
interactions per year is:
20 x 106 in 100 g per cm2 area.
With 50 kg 109 interactions/yr
Yearly event rates
High granularity in inner region
that subtends to far detector.
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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2.1 Flux normalisation (cont.)2.1 Flux normalisation (cont.) Neutrino flux normalisation by measuring: Signal: low angle forward going muon with no recoil Calculable with high precision in SM
Same type of measurement as for elastic scattering on electrons:
ee
)(2)( 2
22
22
LABinEmG
mq
msG
dy
edeF
W
WFCC
2412
104.02
)( cmGeV
EEmGe eF
CC
ee ee
)()(
ee )()(
)1(22 ymE ee
E.g. CHARM II obtained value of sin2W from this
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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2.2 Cross sections2.2 Cross sections Measure of cross sections in Deep Inelastic (DIS), Quasi-
Elastic (QE) and Resonance Production (RES). Coherent background to many interactions) Different nuclear targets: H2, D2
Nuclear effects, nuclear shadowing, reinteractions
With modest size targets
can obtain very large
statistics
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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2.3 Parton Distribution Functions(s)2.3 Parton Distribution Functions(s) Unpolarised and Polarised
Structure functions S from xF3 - S~0.003 Sum rules: e.g. Gross-Llewelyn
Smith polarization: spin transfer from
quarks to — NOMAD best data— Neutrino factory 100 times
more data
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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mixing: doubly Cabbibo suppressedSM very small, new physics
Babar: Rmix<4x10-3 (90% CL) hep-ex/0408066
2.4 Charm Production2.4 Charm Production Charm production: Measure of Vcd and strange quark content nucleon
Measure charm vs pt (background to oscillations) 6-7% of cross-section at 20 GeV3% CC events:
about 3x107 charm states per year
...,,,, 00 csDDDD
McFarland
00 DD
Clean tagged sample
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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2.5 sin2.5 sin22 ww
Elastic scattering off electrons:
Deep inelastic scattering: NC/CC Good statistical accuracy on sin2W (~0.5x10-4) but hadron uncertainties dominate
sin2W ~ 0.0001
ee ee ,
)(
,
)(
2231241106.1)( cmgg
GeV
Ee RLCC
36.0)()(
)()(
eCCCC
eNCNCR
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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High granularity in inner region that subtends to far detector. Very good spatial resolution: charm detection Low Z, large Xo Electron ID Does the detector have to be of same/similar technology as far detector?
3. Near detector requirements3. Near detector requirements
Does not need to be very big (eg. R~50-100 cm)
Possibilities:— silicon or fibre tracker in a
magnet with calorimetry, electron and muon ID
(eg. NOMAD-STAR??)— Liquid argon calorimeter:
problems with rate
NOMAD-STAR (Silicon TARget)
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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4. NOMAD-STAR4. NOMAD-STAR R&D in NOMAD for short baseline detector based on silicon:
NOMAD-STAR (NIMA 413 (1998), 17; NIMA 419 (1998), 1; NIMA 486 (2002), 639; NIMA 506 (2003), 217.)
Total mass: 45 kg of B4C target (largest density for lowest X0)
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Aim of NOMAD-STAR: reconstruct short lived particles in a neutrino beam
to determine capabilities detection: use impact parameter signature of charm decays to mimic
impact parameter ~ 62 m, normal charged current (CC) interactions ~30 m
4. NOMAD-STAR4. NOMAD-STAR
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Longest silicon microstrip detector ladders ever built: 72cm, 12 detectors, S/N=16:1
Detectors: Hamamatsu FOXFET p+ on n, 33.5x59.9 mm2, 300 m thick, 25 m pitch, 50 m readout
VA1 readout: 3 s shaping
4. NOMAD-STAR4. NOMAD-STAR
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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4. NOMAD-STAR4. NOMAD-STAR
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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CC event
Primary vertex
Secondary vertex
4. NOMAD-STAR4. NOMAD-STAR
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Most chips stable, but some chips showed varying level of noise
Maybe the same as charge build-up seen in Babar?
4. NOMAD-STAR4. NOMAD-STAR
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Increase noise in some ladders affected some efficiencies: compensated by clustering algorithm with cuts as function of ladder
4. NOMAD-STAR4. NOMAD-STAR
S/N
16
10
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Vertex resolution: y = 19 m Impact parameter resolution: 33 m
Double vertex resolution: 18 m from Ks reconstruction
Pull:~1.02
x~33 m
4. NOMAD-STAR4. NOMAD-STAR
x~18 m z~280 m
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Charm event reconstruction:– Implementation of Kalman filter – Constrained fit method to extract charm signatures
Used NOMAD-STAR to search for charm events: marginal statistical accuracy, but was a good proof of principle
4. NOMAD-STAR4. NOMAD-STAR
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Efficiency very low: 3.5% for D0, D+ and 12.7% for Ds+ detection because
fiducial volume very small (72cmx36cmx15cm), only 5 layers and only one projection.
From 109 CC events/yr, about 3.1x106 charm events, but efficiencies can be improved.
4. NOMAD-STAR4. NOMAD-STAR
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Passive target can provide target mass, but affects vertex and tracking reconstruction efficiency due to scatters
Improve efficiency by having fully active silicon target. For example: 52 kg mass can be provided by 18 layers of Si 500 m
thick, 50 x 50 cm2 (ie. 4.5 m2 Si) Optimal design: fully pixelated detector (could benefit from Linear
Collider developments in MAPS, DEPFET or Column Parallel CCD). Could also be with 3D detectors or silicon strips.
Other technologies:– Liquid argon TPC in a magnetic field: maybe rate is a problem – Scintillating fibre tracker– Standard gas TPC with target (likeT2K near detector), …
International Scoping Study (ISS) for a neutrino factory (July 2005 to August 2006): aim to define the scope of physics parameters, neutrino factory machine technology and detector technology needed to launch a full design study 2007-2010. Near detector will be considered within detector working group.
5. Near Detector Ideas 5. Near Detector Ideas
Vertex 2005, Chuzenji Lake, Nikko, Japan. 10 November 2005
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Vertex for CP.
Conclusion Haiku: unique form of very compact and succint
Japanese poetry that captures the essence and beauties of nature.
Haiku poems consist of 3 verses of 5 syllables, 7 syllables and 5 syllables. Maximum exponent of Haiku poetry: Basho Matsuo (17th century).
My own (humble) attempt at a Haiku poem:Leptogenesis,
Oscillations to find,