Experimental procedure

1
q13 at CNGS
D.Duchesneau LAPP, Annecy

• Introduction
• Experimental procedure
• Beam characteristics and systematic
• OPERA and ICARUS performances
• Conclusion

GDR Neutrino Lyon, September 20th 2005
2
Mesure de q13
Pour les projets de Long Baseline
Dans le vide
négligeable en LBL pour L/Elt max. atm.
Auquel doit sajouter les effets de matière P(nm
? ne ) augmente pour la hiérarchie normale et
diminue pour la hiérarchie inverse
Attention les effets dus à q13 et à d sont
indissociables avec une simple mesure de P(nm ?
ne ) ? paramètres sont corrélés
3
nm ? ne search at CNGS

• CNGS beam is off-peak 732km, ltEgt 17 GeV
• P4 term dominates over P3 sensitivity on q13 has
  a different dependence on dCP
• P4 changes sign with Dm312 sensitivity depends
  of mass hierarchy

?m2 gt 0
?m2 lt 0
This hierarchy dependence is not there for the
on peak projects.
Matter effect is small.
4
nm ? ne search at CNGS
Experimental method

• signal look for an excess of low energy ne CC
  events

Background

• ne beam contamination higher visible energy
• oscillation nm ? nt , t ? entne missing Pt,
  kink in long decays
• nm NC events with p0 identified as electrons,
  CC where m is not identified missing Pt, e/g
  separation, low energy electrons

Requirements

• knowledge of the ne and nm fluxes, beam spectra.
• particle identification, reconstructed event
  properties, event topologies

5
CNGS beam optimized for nt appearance
For 1 year of CNGS operation in shared mode
Off-peak
200 days/year e 55 4.5 x 1019 pot/year
?? CC / kton 2900 ?? NC / kton
875 lt E gt? ( GeV )
17 ?? / ?? 2.1 ?t
prompt negligible
For Dm22.4x10-3 and maximal mixing expect 16 nt
CC/kton/year at Gran Sasso
OPERA 30 evts/day
6
CNGS Beam energy spectra at Gran Sasso
ne sources m gnm e ne K gp0 e ne K0 gp-e ne
ne
nm
m
mainly from m decay
p
K0
K
K
ne
http//www.mi.infn.it/psala/Icarus/cngs.html
Event rate normalized to 1019 pot and 1kton
(?e ?e) / ?? 0.85
7
Neutrino beam systematics
Total normalisation uncertainty for both nm and
ne 4

• p and K production at the target 3.8
• Particle reinteraction along the beam line 1.1
• Proton beam positionoptics 0.8

Uncertainties on n fluxes
ne
nm
Uncertainty on nm/ne large cancellation due to
p origin of both flavours 3.1
nm/ne
derived from previous measurements and studies
with WANF experiments
Ref A. Ferrari et al. hep-ph/0501283
8
OPERA in Gran Sasso (Hall C)
206 336 lead emulsion bricks ? target mass 1.8
ktons
1st SM
2nd SM
10 m
10 m
20 m
9
Emulsion bricks
TEST experiment at CERN PS

• Electron Identification
• Method based on shower identification and on MCS
  of the track (e and p losses different)
• ee 90 ,

• Energy measurement
• count the number of track segments into a cone of
  50 mrad along the electron track
• Resolution _at_ few GeV

Excellent capabilities for t ?e decays and
search for nm ? ne appearance
10
nm ? ne search OPERA and ICARUS similar method

• Kinematical cuts (OPERA)
• Eelectrongt 1GeV
• Visible Energy lt 20 GeV
• Missing Pt lt 1.5 GeV

Assume no CP and no matter effect P(nm -gt nt)
cos4q13 sin22q23 sin2(1.27 Dm2 L/E) P(nm -gt ne)
sin2q23 sin22q13 sin2(1.27 Dm2 L/E)

• take into account electron event from nm ? nt , t
  ? entne

OPERA
Both oscillations distort Evis at low energy
Fit oscillation components simultaneously
sin22q13
use Evis, PTmiss, Eel
11
nm ? ne expected signal and background
5 years 2.25x1020 pot
syst. on the ne contamination up to 5
OPERA sensitivity to q13
Limits at 90 CL for ?m2 2.5x10-3 eV2
full mixing
Ref Komatsu et al. J. Phys. G29 (2003) 443.
12
q13 sensitivity as a function of pots
OPERA sin22q13 as a function of the pots
Ref P. Migliozzi, NuFact05
13
ICARUS in Gran Sasso (Hall B)
gradual mass increase
Cloning T600 module to reach a sensitive mass of
2.35ktons
n
Situation before june 2005
Numbers quoted 1 year of T600 4 years of T1800
14
Detector performance
Pictures from T600 technical run
EM and hadronic showers are identified and fully
sampled
Total energy obtained from charge integration
Excellent calorimeter with very good E resolution
EM showers
265 cm
142 cm
Hadronic showers
Hadronic interaction
Run 308, Event 160 Collection Left
15
nm ? ne search
ICARUS T1800
Evis spectra ?m223 2.5 10 -3 eV2 Sin2(2?13)
0.14 (CHOOZ limit) 25 oscillated events
Fit 2 oscillation components simultaneously
sin22q13
use Evis, PTmiss, PTel
Ref ICARUS document SPSC-2002-027 private
communication
16
nm ? ne search
Expected sensitivity to q13
Limits at 90 CL for ?m2 2.5x10-3 eV2
full mixing
ICARUS T1800
90 confidence level Full CNGS std. 1y t600
4y t1800 Dashed CNGS x 1.5 5 systematic
error on background
17
nm ? ne search at CNGS
expected signal and background
5 years 2.25x1020 pot
OPERA
ICARUS T1800
?m2 2.5x10-3 eV2
18
Conclusions

• nm ? ne
• high detector capabilities to explore this
  channel
• q13 limit down to 70
• sensistivity on q13 with a dependence on dCP
  different from T2K

Beam systematics lt 5 Sensitivity completely
dominated by statistics
More refined studies to perform include CP
violation , matter effect, full simulation
CNGS beam on schedule ? expect to start in June
2006
OPERA construction and installation is
progressing ? should be ready to record n
events in 2006
ICARUS successful demonstration of the principle
withT600 Hall B T600 in 2006 T1200
19
ICARUS project Realization of a 6001200 ton
LAr TPC at LNGS main goal Detect CNGS
neutrinos for a ?? appearance search in the
parameter region of atmospheric neutrino
oscillations (CNGS2 experiment). . Private
communication with Andre Recent event The INFN
President has recently communicated to the ICARUS
Collaboration the intention not to allocate the
20 MEuro for the T1200 construction. One
motivation is the anticipated delay of the T1200
construction and commissioning for CNGS physics.
Given the INFN role of main funding agency this
implies "de facto the phasing-out of the CNGS2
program. At the same time, INFN encouraged the
Collaboration to proceed along with the proposal
of a future program focused on the realization of
a large mass (5 kton) LAR TPC based on a single
tank, monolithic-design to be possibly installed
in the LNGS territory, as a scalable test module
in view of a larger mass facility, in
particularly meant for proton decay searches. In
the case of a sensible proposal, the above
mentioned 20 MEuro contribution could be likely
reassigned for the funding of the new project. In
parallel, INFN welcomes and intends to support
the commissioning of the existing T600 module
(already at LNGS) to mainly act as a demonstrator
of the technique in view of future
implementations.
Remarks - No official communication of the INFN
decision has been forwarded yet to the SPS and
LNGS scientific committees, regulating the
execution of the CNGS2 experiment. - The ICARUS
Collaboration (and in particular the Italian INFN
groups) has not yet defined a follow-up strategy.
20
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The End
22
sensitivity vs dCP
?m2 lt 0
?m2 gt 0
There are dCP values for which the sensitivity on
q13 is even better than the one computed in the
2-flavor approximation (dCP0).
23
Mesure de q13
Pour les projets de Long Baseline
Dans le vide
négligeable en LBL sur max. atm.
Auquel doit sajouter les effets de matière P(nm
? ne ) augmente pour la hiérarchie normale et
diminue pour la hiérarchie inverse
Attention les effets dus à q13 et à d sont
indissociables avec une simple mesure de P(nm ?
ne ) ? paramètres sont corrélés
24
On peak ? Off peak
P. Migliozzi and F. Terranova hep-ph/0302274
On/off peak
25
On peak ? Off peak

• On-peak
• O1 (leading term) and O2 (sin? )
• are dominant
• at high energy and larger distances
• larger matter effects ? sign(?m231)

• Off-peak
• O1 (leading term) and 03 (cos?)
• O3 is CP even or odd under
• ?m231 ? -?m231transformation

26
T1800 configuration
27
T600 in Hall B March 2005
28
ICARUS nm ? nt search
other channel t ? rnt with r- ? p-po
main background nm NC ? missing pt
use isolation criteria QT
nm
nt
p-
nm
QT
nm
QT
ptot
ptot
T1800 detector (1 year 0.47 kton4 years 1.4 kton
active LAr)
5 years 2.25x1020 pot
29
nm ? ne
Similar approach in both experiments
OPERA
Both oscillations distort Evis at low energy
Fit oscillation components simultaneously
use Evis, PTmiss, Eel
sin22q13
sensitivity to q13
syst. ne contamination up to 10
Limits at 90 CL for ?m2 2.5x10-3 eV2
full mixing
30
nm ? ne search at CNGS
in the 3 flavour n oscillation framework
Assuming Dm122 ltlt Dm232 Dm132 Dm2, P(nm -gt
nt) cos4q13 sin22q23 sin2(1.27 Dm2 L/E) P(nm -gt
ne) sin2q23 sin22q13 sin2(1.27 Dm2 L/E)
subleading transition

• look for an excess of ne CC events and take into
  account nm ? nt , t ? entne

expected signal and background
5 years 2.25x1020 pot
OPERA