seminar OPERA apr 04

1
Overview for an European Strategy for neutrino
Physics Yves Déclais CNRS/IN2P3/UCBL IPN Lyon
CHIPP Neutrino CH June 22th - Neuchatel

• Measuring the neutrino mixing matrix
• Reactor experiments
• NUMI off axis
• Combined sensitivity for JPARC, NUMI and reactors
• Conclusions

2
Neutrino Oscillation 3 neutrinos formalism
3
The oscillation probability including matter
effect
All effects are driven by ?13 !
Neutrinos Anti Nu -
dominant  on peak 
4
Neutrino Mixing Matrix Study which Road Map
5
Nuclear reactors as neutrino source
6
Backgrounds in reactor neutrinos experiment
7
How to improve the sensitivity

• Reactor exp. Disappearance exp.
• compare total flux (and spectrum) with the
• no- oscillation hypothesis
• one depends on systematic uncertainties, like
• absolute source strength,
• cross section,
• detection efficiency,
• fuel development
  over time...

• Basic idea
• use 2 identical detectors to cancel
  uncertainties on neutrino flux and cross sections
• excellent monitoring of calibrations and
  efficiencies (including analysis cuts)
• to reduce the systematics on detectors
• large statistics to see small effects

8
Proposed sites
Site Power (GWthermal) Baseline Near/Far (m) Shielding Near/Far (mwe) Sensitivity 90 CL
Krasnoyarsk, Russia 1.6 115/1000 600/600 0.03
Kashiwazaki, Japan 24.0 300/1300 150/250 0.02
Double Chooz, France 8.4 150/1050 30/300 0.03
Diablo Canyon, CA 6.7 400/1700 50/700 0.01
Angra, Brazil 5.9 500/1350 50/500 0.02
Braidwood, IL 7.2 200/1700 450/450 0.01
Daya Bay, China 11.5 250/2100 250/1100 0.01
Many Sites have been investigated as potential
hosts to a reactor neutrino experiment. This is
appropriate since getting the cooperation of the
reactor company is the main challenge.
9
Double-Chooz site
Far detector using existing infrastructure
from the previous experiment _at_ 1050 m
2 identical detectors ?goal srelative ? 0.6

• LOI hep-ex/0405032
• detector cost 7.5 Meuros
• civil engineering 5 Meuros (not studied)
• LOI accepted
• need for a proposal within 6 months

Near detector _at_100-200 m from the nuclear
cores in discussion with EDF
10
Double CHOOZ detector structure

• Performances (expected)
• S/B 10 ? 100
• target 5.5 ? 12.7 m3
• analysis errors 1.5 ? 0.2

• But the changes would probably worsen the bkgd
• large increase of passive material (including
  high Z)
• active target less protected
• due to the increase of the target volume

11
Double CHOOZ Gd loaded scintillator
Warning long term stability and acrylic vessel
damage
12
Double CHOOZ close detector

• similar conditions to PaloVerde (46 mwe)
• large dead time for muon veto 50
• can a massive detector work at such a shallow
  depth ?
• PaloVerde and Bugey was segmented
• and used dedicated signature for neutron and
  positron

13
Double CHOOZ Background and signal
Ratio at the far detector
The baseline is too short to see the L/E pattern

• no direct measurement
• accidental miscorrection
• may mimic or suppress an effect
• fake neutron capture signal rate underestimated

14
Reactor experiment sensitivity
15
Double CHOOZ sensitivity
To be conclusive a reactor experiment which
intend to reach few 10-2 in sin22? should be
able to show an L/E effect according to the
value of dm2 ( which will be known at a high
level of accuracy ) and to the disappearance
rate measured
16
NUMI off-axis
17
NOVA detector TASD
160 M
?e n ? p e- p0
18
Goals of the NO?A experiment

• sensitivity to sin2(2?13) down to 0.01
• measurement of sin2(2?23) to 2 accuracy
• contribute to resolution of mass hierarchy via
  matter effect
• contribute to study CP violation in the neutrino
  sector

• NC background reduced by a narrow band beam (off
  axis)
• increase mass with cost/kiloton reduced by a
  factor 3
• sampling 1/3 X0 per plane for better electron id
• choose long baseline to enhance matter effects

For 5years _at_ 4 1020 pot/year, 50kton detector,
sin2(2?13) 0.1
?µ CC NC Beam ?e signal
Beam unoscillated 22858 10594 229
Beam oscillated 5758 10593 229 853
After cuts 3.6 15.4 19.1 175
19
Nova tentative schedule
MINOS run ? (goal 16. E20 pot

• 5 M/year to improve proton intensity
• Booster cycle 3 ? 7-10 hz
• decrease losses

20
N0?A sensitivity
21
MassHierarchy
22
CPViolation
23
Reactor contribution to CP violation (Shaewitz)

• Input
• sin22?130.058
• dCP 270
• sin22?231?0.06

24
The ?23 Degeneracy Problem
25
Solving the ?23 degeneracy with reactor (Shaewitz)

• Input
• sin22?130.058
• dCP 270
• sin22?231?0.06

26
European Strategy (Venice , december 03)4 phases
program for q13 and d

• CNGS/MINOS (2005-2010)
• 2) JPARC and Reactor(?) (2008-2013)
• 3) Superbeam/betabeam (gt2014 )
• 4) Neutrino factory (gt2020 )

• Are Phase 3 (and 4) needed in case of a signal
  seen in JPARC
• Can we disentangle all parameters with the
  superbeam /betabeam option
• Should we go directly to phase 4 in case of no
  signal seen in JPARC
• shift in time for Superbeam/betabeam due to
  funding profile in Europe
• is the low energy the optimum choice to measure
  T13 , d , sign(?m2)
• the choice on the strategy defines not only the
  needed RD on accelerators
• but also for the detectors

In any case a MW machine is central
27
Concluding on european activities (and dreams )
could be provided by Nuclear physics
SPL 330
EURISOL 200
PS/SPS upgrade 70
Decay Ring 340
Super beam 70
UNO like detector 500
Grand total 1510

• Concluding remarks by CERN management at MMW
• CERN will reimburse LHC loan up to 2011
• in 2008 new round of negotiations with members
  state
• for support for new RD (not only neutrinos )
• CERN machines (quite old) upgrade will cost
• Staff number will decrease from 2500 ? 2000 in 5
  years

More international coordination is mandatory
Cost in Meuros no manpower, no contingencies
The choice will imply consequences on Machines
AND Detectors RD