AnnaritaBuonaura,AntoniaDiCrescenzo– University ofNaples &INFN
14/06/2016– 8° SHiPCollaborationMeeting
8thSHiPCollaborationMeeting- London 13-15/06/2016
Configurationofthe
tauneutrinodetector
1
Hanspresentationyesterday
μflux
8thSHiPCollaborationMeeting- London 13-15/06/2016
NewMuon ShieldConfiguration
2
Maximumpossible sizesoftheneutrino detectorinthetransverseplaneatthe
beginning of ourregion, atthezofthefirstdrifttubeassuming itatthesame
distanceasinTPandatthebeginning ofthedecayvolume.
Δz fromtarget(m)
z (m)
Δx (m)
Δy (m)
35.1
-35
1.7
3.32
40.1
-30
1.9
3.8
45.1
-25
2.1
4.2
Nottoscale
2.5m
TT4
5m
4.2m
3.8m
3.3m
z(TT4)=3540cm
z(Target)=-7010cm
z=-3500cm
Startofν
targetregion
z=-3000cm
1st DriftTube
z=-2500cm
Endof ν
targetregion
z
8thSHiPCollaborationMeeting- London 13-15/06/2016
Newsizesfortheν detector
3
Sizesforν detector inthe
transverseplane
Bytakingalook atthetransverseplaneatthebeginning oftheneutrino detector
region, assuming aν targetof0.8x1.6m2:
1.7m
0.55m
ν target
0.8m
1.6m
3.3m
0.8m
Inthese80cm,thereshould be
placed:
- Read-outelectronicsofTarget
Trackerplanes
- Cooling system
- Magnetcoils
- Returnfield
Goliathmagnetwouldnotfitanymore.
Newmagnetprojecttobedone
4
Differentoptionsunderstudy
ByD.Tommasini
• Dimensions similartothoserequired
forthisnewconfiguration
• Noteasytoperform targetextraction
forthetargetreplacement
8thSHiPCollaborationMeeting- London 13-15/06/2016
NewMagnetLayout
5
Differentoptionsunderstudy
SideView
Incomingν flux
•
•
•
•
•
•
•
•
•
•
Magnet field 1.2T
Magnet gap height 1m
Radius of coil center = distance of coil centers 1.45m
Coil cross section 0.4m x 0.4m
Current 3570A
Total power 0.57MW
Cover plate 4.5m 4.5m 0.5m
Column cross section 1.1x1.1m2 - 0.6x0.6m2
Outer flux return 2.3m x 0.5m x 0.25m
Total magnet size 4.5m x 4.5m x 3m
Stilltobeoptimized
Topview
ByWalterSchmidt-Parzefall
• Horizontalmagneticfield
• Allowsextractionofthetargetfrom
thetop
8thSHiPCollaborationMeeting- London 13-15/06/2016
NewMagnetLayout
Incomingν flux
6
Newdetectorlayout
Startedfrom Walteridea:shrinked thex/y
dimensions sotofitintheallowedregion
Openingallowingthe
extractionofthetarget
3.2m
3.8m
8thSHiPCollaborationMeeting- London 13-15/06/2016
ImplementationinGeant4performedbyA.DiCrescenzo
7
y
x
z
Newdetectorlayout
Targetextractionfrom thetop
SIDEVIEW
Incoming ν flux
3.8m
3.2m
y
4.5m
z
Neutrinotarget
Neutrinotarget
4.76m
Magneticspectrometer
10m Magneticspectrometer
8thSHiPCollaborationMeeting- London 13-15/06/2016
ImplementationinGeant4performedbyA.DiCrescenzo
8
•
•
•
•
6 columns (along x direction)
12 rows (along y direction)
11 walls (along z direction)
12 layers of Target Trackers
(upstream layer acting as veto)
1.6m
Totaldimensions: 0.8x1.6x2m3
Incoming ν flux
8thSHiPCollaborationMeeting- London 13-15/06/2016
Neutrinotarget
9
Fluxesofincomingneutrinos
Neutrino spectraproduced byThomas andextrapolatedatzoftheneutrino target
Incomingν ontarget
NewConfig
Incomingν spectra
TP
Flux
<E>(GeV)
Flux
<E>(GeV)
νμ
9.6x1016
6.7
5.2x1016
8
νe
6.6x1015
18.8
3.6x1015
28
ντ
3.1x1014
24.6
1.5x1014
28
νμ-bar
7.8x1016
6.3
4.0x1016
8
νe-bar
4.5x1015
29.2
1.4x1015
27
ντ-bar
3.1x1014
23.6
1.5x1014
26
WithrespecttoTP
• Gainonincomingντ fluxof≈factor2partiallycompensatedbylowermean
energy
10
FluxesofCCinteractingneutrinos
Interactingν ontarget
NewConfig
SpectraofCCinteractingν
TP
Flux
<E>(GeV)
Flux
<E>(GeV)
νμ
1.9x106
26.1
1.7x106
29
νe
3.4x105
49.8
2.5x105
46
ντ
9.1x103
55.3
7.6x103
59
νμ-bar
6.8x105
20.7
6.7x105
28
νe-bar
1.6x105
57.2
9.0x104
46
ντ-bar
4.5x103
55.3
3.9x103
58
WithrespecttoTP
• ≃ 1.2 thenumber ofCCinteractionsfromντ andanti-ντ
• Neutrino interactionsforthefollowing studieshavebeen performed withNuAge tuned versionwithNOMADneutrino data(A.Chukanov)
11
8thSHiPCollaborationMeeting- London 13-15/06/2016
DETECTOR
PERFOMANCES
12
The main background source in ντ and anti-ντ searches is the charm production in
anti-νμCC (νμ CC) and anti-νe CC (νe CC) interactions, when the primary lepton is
not identified.
Expectedν-inducedcharmfractionand
yieldin5yearsrun(NEWCONFIG)
SIGNAL
ντ
τ
-
μ-,h-
BACKGROUND
Flux
<E>(GeV)
charm/CC(%)
νμ
6.6x104
46.5
3.5
νe
2.1x104
60.2
6.2
νμ-bar
2.0x104
39.5
3.0
νe-bar
1.1x104
66.3
6.6
(TPCONFIG)
Flux
<E>(GeV)
charm/CC(%)
νμ
6.8x104
46.5
4.1
νe
1.5x104
57.0
6.0
νμ-bar
2.7x104
43.4
4.1
νe-bar
5.4x103
56.7
6.0
8thSHiPCollaborationMeeting- London 13-15/06/2016
Backgroundsources
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Muons produced inνμ CCinteractionswithcharmproduction inthetarget
• 73%reachtheSpectrometerwithout enteringthetargetMagnet(A)
• 1% stopintheneutrino target
• 3% exitlaterallyfrom theneutrino target
• 23%enterintheDavidMagnet
• 1% absorbed intheDavidIron(B)
• 22%exitfromDavid
• 17%reachthefirstDTTplane
• 5%don’t reachthefirstDTTplane
DTTplanes
Incoming ν
A
TARGET
B
8thSHiPCollaborationMeeting- London 13-15/06/2016
Muon Identification
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Muons produced inνμ CCinteractionswithcharmproduction inthetarget
• 73%reachtheSpectrometerwithout enteringthetargetMagnet(A)
• 1% stopintheneutrino target
• 3% exitlaterallyfrom theneutrino target
DTT
• 23%enterintheDavidMagnet
• 1% absorbed intheDavidIron(B)
• 22%exitfromDavid
• 17%reachthefirstDTTplane
• 5%don’t reachthefirstDTTplane
Target
DTTplanes
Incoming ν
A
TARGET
B
8thSHiPCollaborationMeeting- London 13-15/06/2016
Muon Identification
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Requirements:
1. trackcrossing 3RPClayersintheARM1oftheMagneticSpectrometer
2. trackcrossing theGoliath IronandreachingatleastthefirstDTTplane
TheusageoftheDriftTubeTrackerplaneforthemuon identification incase2.
increasesthemuon identification efficiencyofabout2%
μ+ inanti-νμcc charm
τ - → μ-
Primarymuon identification efficiency
ε1ryμID =90%
Decaymuon identification efficiency
ε2ryμID =89%(90%)
()=valuesfromTP
8thSHiPCollaborationMeeting- London 13-15/06/2016
Muon Identification
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Only topological selection considered (primary lepton identification and charge
measurement)
Example: evaluationofsignalandbackground intheτ - →μ- decaychannel
TPConfiguration
NewConfiguration
SIGNAL
EVENTS
CHARM
BKG
S/B
RATIO
τ - → μ-
570
30
19
8.8
τ - → h-
990
80
12
66
4.8
τ - → 3h-
210
30
7
275
8.8
TOTAL
1770
140
13
SIGNAL
EVENTS
CHARM
BKG
S/B
RATIO
τ - → μ-
774
59
13.2
τ - → h-
1326
151
τ - → 3h-
313
TOTAL
2413
8thSHiPCollaborationMeeting- London 13-15/06/2016
SignalandBackgroundexpectation
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Startedstudiestounderstand implicationsofmuon shield optimization onthetau
neutrino detectorside.
xandydimensions ofthespaceclearedfromthemuon fluxsmallerwrt TP
• Notpossible tousetheGoliathMagnetanymore
• Layoutssuggested byD.Tommasini andW.Schmidt-Parzefall
• Optimizationstilltobedone
• Realisticbutnotrefined implementation inGeant4
• Neutrino targetlayoutoptimized sotohave~thesamenumber ofneutrino
interactionsasthose quotedintheTP
NEXTSTEPS
• Moreneutrino statisticneededtoperform amoreaccurateestimateofincoming
neutrino flux
• Implementation inFairSHIP
8thSHiPCollaborationMeeting- London 13-15/06/2016
Conclusions
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19
8thSHiPCollaborationMeeting- London 13-15/06/2016
8thSHiPCollaborationMeeting- London 13-15/06/2016
BACKUP
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Performed withtheMagneticSpectrometerandtheCompactEmulsion Spectrometer
Hadrons:MeasuredmainlyinCES
Efficienciesforcorrectchargeassignment
Misidentification probabilities
εhcharge =68%(70%)
ε3hcharge =45%(49%)
ωhcharge =0.5%
ω3hcharge =1%
Muons :MeasuredmainlyintheMagnetic Spectrometer
Efficiencyforcorrectchargeassignment
εμcharge =93%(94%)
Misidentification probability
ωμcharge =1.5%
()=valuesfromTP
8thSHiPCollaborationMeeting- London 13-15/06/2016
ChargeMeasurement
21
Identificationofντ andντ interactionsrequires, asafirststep,thedetectionof
both theneutrino interactionandtheτ decayvertices
EventLocation
Procedureaiming atreconstruction ofthe
neutrino interactionvertex.
⇒ Vertex1mmfarfrom thetransverseedgesand
5mmfrom thedownstreamedgeof thebrick
⇒ Presenceofleastonetrackwithamomentum
lagerthan1GeV/cattachedtotheprimary
vertex,withaslopetanθ <1
Decaysearch
Procedureaiming atthedetectionoftheτ
decayvertex.
⇒ Kinkangle>20mrad
⇒ Impactparameter>10µm
IP
θkink
8thSHiPCollaborationMeeting- London 13-15/06/2016
Verticesidentificationefficiencies
22
Identificationofντ andντ interactionsrequires, asafirststep,thedetectionof
both theneutrino interactionandtheτ decayvertices
Geometricalefficiencyντ CC: 96%
Locationefficiencyντ CC: 85.7%(87%)
DecaySearchefficienciesντ CC:
τ ->μ:
τ ->1h:
τ ->3h:
τ ->e:
73.4%(72%)
74.4%(74%)
89.7%(76%)
71.8%(67%)
Totalefficienciesντ CC: εTot =εGeom xεLoc xεDS
τ ->μ:
τ ->1h:
τ ->3h:
τ ->e:
60.4%(60%)
61.2%(62%)
73.8%(63%)
59.0%(56%)
8thSHiPCollaborationMeeting- London 13-15/06/2016
Verticesidentificationefficiencies
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()=valuesfromTP