E - GDR neutrino

Etat d’avancement du projet
OPERA/CNGS
D.Duchesneau
LAPP, Annecy
• Introduction
• CNGS beam-line
• OPERA experiment:
– status of construction
– Physics performance
• Conclusion
Réunion du GDR ν
CPPM, 14 mars 2005
CNGS/OPERA program:
In the CERN high energy νµ beam
(CNGS):
• search for ντ appearance at the Gran Sasso laboratory (732 km
from CERN)
Answer unambiguously on the origin of the ν oscillations
observed at the atmospheric ∆m2 scale
• search for νµ → νe and put new constraints on θ13
Most recent atmospheric results:
Super-Kamiokande :
(hep-ex/0501064):
SK L/E analysis :
PRL 93 (2004) 101801:
Best fit: ∆m2 = 2.1 10-3 eV-2 and sin22θ = 1.0
1.5 < ∆m2 < 3.4 x 10-3 eV2 at 90% CL
Best fit: ∆m2 = 2.4 10-3 eV-2 and sin22θ = 1.0
1.9 < ∆m2 < 3.0 x 10-3 eV2 at 90% CL
CNGS: beam optimized for ντ appearance
For 1 year of CNGS operation in
shared mode:
“Off-peak”:
200 days/year ; ε = 55%
4.5 x 1019 pot/year
νµ CC / kton
2900
νµ NC / kton
875
< E >ν ( GeV )
17
(νe + νe) / νµ
0.85 %
νµ / νµ
2.1 %
ντ prompt
negligible
OPERA: ~ 30 evts/day
For ∆m2=2.4x10-3 and maximal mixing
expect 16 ντ CC/kton/year at Gran Sasso
Status of the project:
Civil engineering is
completed (June 2003)
Hadron stopper and decay tube
installed (June 2004)
Installation of the services going on
until June 2005
Hadron stop: Sept. 2003
Target chamber: June 2003
Decay tube: 998 m
vacuum tested April 2004
Proton beam and target chamber installation: second semester 2005
Inner Conductor of the Horn
Inner Conductor of the Reflector
June 2003 at LAL
with the Outer Conductor
Delivered to CERN Feb. 2005
April 2004 at CERN
Work to complete by CERN
First beam to Gran Sasso in spring 2006
Gran Sasso National Laboratory: ( Italy, 120 km from Rome)
Underground laboratory:
1400 m
good cosmic ray shielding
1 cosmic/m2/hr
3 large experimental halls
(100m x 18m x 18m)
directed towards CERN
Hall B
ICARUS
Borexino
HallC
OPERA
Belgium
IIHE(ULB-VUB) Brussels
Bulgaria
Sofia University
COLLABORATION
China
IHEP Beijing, Shandong
Croatia
Zagreb University
France
‰ July 2000:
Experiment proposal
‰ May 2003
Start construction
‰ Summer 2006
First beam expected
LAPP Annecy, IPNL Lyon, LAL Orsay, IRES Strasbourg
Germany
Berlin, Hagen, Hamburg, Münster, Rostock
Israel
Technion Haifa
Italy
Bari, Bologna, LNF Frascati, L’Aquila, LNGS, Naples, Padova, Rome, Salerno
Japan
Aichi, Toho, Kobe, Nagoya, Utsunomiya
Russia
INR Moscow, ITEP Moscow, JINR Dubna, Obninsk
36 groups
~ 165 physicists
Switzerland
Bern, Neuchâtel
Turkey
METU Ankara
Newcomer in 2005:
Tunis group
γ . cτ < 1 mm
ντ
π,
e,
µ
Experimental signature for ντ appearance:
τ
νe νµ
ντ
p,n,π,K...
τ decay modes:
µ- ν τ ν µ
h- ντ nπο
e- ντ νe
π+ π- π- ντ nπο
ΒR 17.4 %
49.5 %
17.8 %
15.2 %
detect and identify the ντ CC events
OPERA: direct observation of τ decay topology
¾ See the τ decay kink or multiprong topology at sub-millimetre
distance of the ν interaction vertex
requires nuclear emulsions: ~ µm granularity
needs large target mass: Emulsion Cloud Chamber technique
¾ Reject efficiently main topological background: charm production
prompt µ at primary vertex
wrong sign assignment at secondary vertex
pt imbalance criteria
250 evts/year
OPERA: CERN experiment CNGS1
direct ντ observation by
DONUT in 2000
use photographic emulsions
alternate emulsion films with lead sheets (ECC concept)
plastic base 200 µm thick
Modular detector: basic unit brick
1 mm
ν
8cm
12.5cm
10X0
56 Pb sheets (1mm)
57 FUJI emulsion films
1 changeable sheet
τ
ν
Pb
emulsion layers (50 µm thick)
206 336 bricks are needed → target mass: 1.8 ktons
1.8 kton detector at Gran Sasso (Hall C)
µ spectrometer: Dipolar magnet + RPC chambers
Precision tracker: Drift tubes
B=1.6 T
ν
brick
(56 Pb/Em. “cells”)
Target Trackers
Pb/Em. target
• 2 SuperModules
• 31 walls/SuperModule
• 52x64 bricks/wall
• 206 336 bricks
module
brick wall
scintillator
strips
8 cm
(10X0)
Status of construction
Technical layout in Hall C
1st SM
2nd SM
~ 10 m
~20 m
~ 10 m
Muon spectrometer
Fe
Total Fe
weight
~ 1 kton
RPC
22 planes of 21
chambers
2.9 m x 1.1m
copper strips
6 planes of drift tubes
B= 1.55 T
(5 cm)
Bakelite RPC:
Precision tracker
8.2 m
12 Fe
slabs
in total
coil
•Tube : vertical , φ = 38
slabs
base
•efficiency: 99.1%
installation started: may 2003
miss ≈ ( 0 . 1÷0 . 3 )%
ε charge
∆p/p < 20% for p<50 GeV
mm, length 8 m , wire φ =
50 µm
• Plane: 4 staggered
layers, each with 168 tubes
• resolution: < 300 µm
µId > 95%
(with Target Tracker)
Hall C in Gran Sasso:
July 2003
Assembly frame for vertical slabs
OPERA magnet assembly
coil
Antiseismic structure
Base magnet 2
Magnet Assembly in Hall C september 2003
June 2004
• Magnet
SM1 completed June
2004
• Magnet SM2 partially
assembled, should be completed
in April 2005
Drift tube module
RPC:
1160 chambers produced + all needed strips for the 2 SM
•Mechanical test, gas tightness
•HV, electrical tests in Ar
•Noise, Efficiency with cosmics
Gas and HV tests repeated in Hall C
Precision tracker:
full size prototype
(Hamburg)
Mass production started in January 2005
Installation: 48 modules in April 2005 and 48 modules in
August 2005
8m
Target tracker:
• Plastic scintillator strips: 6.7 m x 2.5 cm x 1 cm
•AMCRYS-H (Kharkov) readout by Kuraray WLS
optical fibres + Hamamatsu PMT 64 channels
• X and Y planes of 256 strips
ν
•Target Tracker tasks :
- trigger (ε > 99%)
- brick finding: εbrick = 70-80%
- initiate muon tagging
Module assembly in Strasbourg (IRES)
Target tracker production:
• 235 modules already produced (~50%)
• 220 modules already calibrated,
• 832 PMTs delivered (80%)
Mounting and storing in Hall C (Aug 2004)
Commissioning of the electronics (FE chips LAL) and DAQ (IPNL) at
LNGS in progress
•Mechanical Structure Extended,
completed for SM1 August 2004
• Target Section SM1 startedSept 2004
OPERA Hall C : september 04
Target walls: mass production going on.
Rate: 2 half-walls/week
December 04: first brick
wall installed in Hall C
• Installation procedure needs
optimisation
• Target installation paused
• Some modifications in support
structure foreseen
• Target Installation should
resume beginning of May 2005
The Bricks:
Germany
Japan
100mm
LEAD
12 million plates
125mm
Emulsion films
12 million sheets
Italy
In Gran Sasso underground area: automatic Piling and packaging
2 bricks/mn → 1 year production
Fuji Emulsion Films
• Mass production started April 2003 (~150 000 m2)
• Already 50% produced. To be completed in autumn 2005
• Refreshing done in the Tono Mine in Japan to erase
cosmic ray tracks before transportation
o
30 C, 95% RH
3 days
• batch sent to LNGS every 2 months
starting January 2005
•Already 2.2 million refreshed Fuji
films received and stored in Gran
Sasso (~20%)
Lead
Low radioactivity lead (Boliden) Pb +2.5 % Sb
•Thickness control: 1000 µm +− 10µm)
(~107 plates to be produced for OPERA)
Brick Assembly Machine (BAM)
Hall A
Lead from Boliden
Hall B
• Construction started in Tecno-Cut firm
• BAM site in preparation at Gran Sasso
• Aug-Sept 2005: Delivery and assembly
at Gran Sasso
• Dec 2005-Dec 2006: Brick mass
production: 1000 /day
Brick Manipulators (LAPP):
• Full test in Annecy in 2005
• Installation in Gran Sasso in
autumn
• Start filling the walls Dec 2005
Annecy, January 2005
Automatic Scanning: Nagoya and Europe R&D efforts
S-UTS prototype at Nagoya
European station
Bari, Bern, Bologna, Lyon, Napoli,
Neuchatel, Roma, Salerno
500 fps
CMOS
camera
Dedicated hardware
Hard coded
algorithms
Commercial hardware
Software algorithms
15 microscopes working
Scanning speed ~ 20 cm2/h/side
Single side microtrack finding efficiency ~ 95%
• Fast CCD camera (3 k frames/sec)
• Continuous movement of the X-Y stage
Sheet-to-sheet alignment (8 GeV/c πs) ~ 0.5 µm
Angular resolution ~ 2 mrad
νµ → ντ search
Exploited τ decay channels
τ → e “ long decays ”
τ → µ “ long decays ”
τ → h “ long decays ”
kink angle
θkink > 20
mrad
ε.BR = 2.8-3.5%
τ→ e “ short decays ”
τ → µ “ short decays ”
impact
parameter
I.P. > 5 to
20 µm
ε.BR = 0.7-1%
Expected number of background events after 5 years:
τ→e
Charm background
.210
τ→µ
.010
τ→h
.162
total
.382
Large angle µ scattering
.116
Hadronic background
.093
.116
.209
.219
.278
0.707
Total per channel
.210
.116
νµ → ντ search
full mixing, 5 years run @ 4.5x1019 pot / year
¾New Brick finding strategy: eff. gain +10%
¾ Including the τ → 3 prongs (ε.BR = 1.0%): eff. gain +10%
channel
e
µ
h
3h
total
Signal (∆m2 (eV2))
1.9 10-3 2.4 10-3 3.0 10-3
2.7
4.3
6.7
2.2
3.6
5.6
2.4
3.8
5.9
0.7
1.1
1.7
8.0
12.8
19.9
ε.BR Background
3.7%
3.1%
3.3%
1.0%
11.1%
0.23
0.23
0.32
0.22
1.00
Improvements under study
¾ Reduction of the number of background events (~30%):
‰ improve π/µ id. (low p) using dE/dx vs range: reduce the
charm background
‰ New measurement of the large angle µ scattering
‰ New estimates of the hadronic background using Chorus data
4σ discovery potential and sensitivity versus Beam Intensity
Opera with beam
upgrade and 30%
90 % CL
Sensitivity F&C
BCK reduction
Opera, with beam
upgrade (1.5)
Opera nominal
(but with 3pi and
new BF )
SK 90% CL
(L/E analysis)
Opera with 30%
bck reduction
νµ → νe search:
Assuming ∆m122 << ∆m232 = ∆m132 = ∆m2, in the 3 flavour ν oscillation framework
P(νµ -> ντ)= cos4θ13 sin22θ23 sin2(1.27 ∆m2 L/E)
subleading transition
P(νµ -> νe)= sin2θ23 sin22θ13 sin2(1.27 ∆m2 L/E)
•look for an excess of νe CC events
νe beam
νµ → νe
ν µ → ντ
Events
Both oscillations
distort Evis at low
energy
Events
•take into account electron event from νµ → ντ , τ → eντνe
NC
νe beam
νµ → νe
ν µ → ντ
NC
Fit oscillation
components
simultaneously
sin22θ13
Visible Energy (GeV)
use Evis, PTmiss, Eel
sin22θ13
Missing pT (GeV)
νµ → νe expected signal and background 5 years: 2.25x1020 pot
θ13 sin2 2θ13 Signal νµ−>ντ , νµ CC νµ NC νe CC
(deg)
νµ−>νe τ −> eντνe
9
0.095
9.3
4.5
1.0
5.2
18
7
0.058
5.8
4.6
1.0
5.2
18
5
0.030
3.0
4.6
1.0
5.2
18
∆m223 (eV2)
OPERA sensitivity to θ13
Preliminary
4.50
1019
pot/yr
6.76 1019 pot/yr
sin22θ13
syst. on the νe contamination up to 10%
Limits at 90% CL for
∆m2 = 2.5x10-3 eV2 full mixing
CHOOZ
OPERA
sin2 2θ13
<0.14
<0.06
θ13
110
7.10
Conclusions
CNGS beam: on schedule → expect to start in June 2006
OPERA: construction and installation is progressing
→ should be ready to record ν events in 2006
Physics with CNGS:
νµ → ν τ :
• first evidence for ντ appearance signal after a few years
• expect 13 τ events after 5 years with 1.0 background event
at ∆m2 ~ 2.4 10-3 eV2
• studies to improve efficiency and to reduce background are
going on
νµ → ν e :
• high detector capabilities to explore this channel
• θ13 limit down to 70
• sensistivity on θ13 with a dependence on δCP different from T2K
The End