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Introduction Experimental procedure Beam characteristics and systematic OPERA and ICARUS performances Conclusion D.Duchesneau LAPP, Annecy GDR Neutrino Lyon, September 20 th 2005 “ ” at CNGS
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Mesure de 13 Pour les projets de Long Baseline: Auquel doit s’ajouter les effets de matière: P( e ) augmente pour la hiérarchie normale et diminue pour la hiérarchie inverse Attention: les effets dus à 13 et à sont indissociables avec une simple mesure de P( e ) paramètres sont corrélés négligeable en LBL pour L/E< max. atm. Dans le vide
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e search: at CNGS m 2 > 0 m 2 < 0 CNGS beam is ‘off-peak’: 732km, = 17 GeV P 4 term dominates over P 3 : sensitivity on 13 has a different dependence on CP P 4 changes sign with m 31 2 : sensitivity depends of mass hierarchy Matter effect is small. This hierarchy dependence is not there for the ‘on peak’ projects.
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Experimental method: signal: look for an excess of low energy e CC events Background: e search: at CNGS e beam contamination: higher visible energy oscillation , e e : missing Pt, kink in long decays NC events with 0 identified as electrons, +CC where is not identified: missing Pt, e/ separation, low energy electrons Requirements: knowledge of the and fluxes, beam spectra. particle identification, reconstructed event properties, event topologies
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CNGS: beam optimized for appearance For 1 year of CNGS operation in shared mode: For m 2 =2.4x10 -3 and maximal mixing expect 16 CC/kton/year at Gran Sasso CC / kton 2900 NC / kton 875 ( GeV ) 17 / 2.1 % prompt negligible 200 days/year ; = 55% 4.5 x 10 19 pot/year OPERA: ~ 30 evts/day “Off-peak”:
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CNGS Beam energy spectra at Gran Sasso mainly from + decay e sources: + e + e K + 0 e + e K 0 - e + e http://www.mi.infn.it/~psala/Icarus/cngs.html Event rate normalized to 10 19 pot and 1kton e ( e + e ) / ~ 0.85 % e ++ K+K+ K0K0 K+K+ ++
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Neutrino beam systematics: Ref: A. Ferrari et al. hep-ph/0501283 Uncertainties on fluxes derived from previous measurements and studies with WANF experiments Total normalisation uncertainty for both and e ~ 4 % and K production at the target: 3.8 % Particle reinteraction along the beam line: 1.1 % Proton beam position+optics: 0.8 % Uncertainty on / e : large cancellation due to origin of both flavours ~3.1% e / e
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1 st SM 2 nd SM ~ 10 m ~20 m ~ 10 m OPERA in Gran Sasso (Hall C) 12.5cm 8cm 206 336 lead emulsion bricks target mass: 1.8 ktons
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5X 0 ( ~ ½ brick) 1 mm 5 cm Electron Identification Method based on shower identification and on MCS of the track (e and losses different) e ~ 90 %, Energy measurement count the number of track segments into a cone of 50 mrad along the electron track Resolution @ few GeV Emulsion bricks: Excellent capabilities for e decays and search for e appearance TEST experiment at CERN PS
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NC e e beam Events Visible Energy (GeV) e search: OPERA and ICARUS similar method take into account electron event from , e e Both oscillations distort E vis at low energy Fit oscillation components simultaneously use E vis, P T miss, E el sin 2 2 13 NC e e beam Events Missing p T (GeV) Kinematical cuts (OPERA): E electron > 1GeV Visible Energy < 20 GeV Missing Pt < 1.5 GeV OPERA Assume no CP and no matter effect: P( -> )= cos 4 13 sin 2 2 23 sin 2 (1.27 m 2 L/E) P( -> e )= sin 2 23 sin 2 2 13 sin 2 (1.27 m 2 L/E)
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Limits at 90% CL for m 2 = 2.5x10 -3 eV 2 full mixing 5 years: 2.25x10 20 pot syst. on the e contamination up to 5% Preliminary sin 2 2 13 m 2 23 (eV 2 ) 4.50 10 19 pot/yr 6.76 10 19 pot/yr e expected signal and background OPERA sensitivity to 13 Ref: Komatsu et al. J. Phys. G29 (2003) 443.
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13 sensitivity as a function of pot’s OPERA sin 2 2 13 as a function of the pots Ref: P. Migliozzi, NuFact05
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ICARUS in Gran Sasso (Hall B) Cloning T600 module to reach a sensitive mass of 2.35ktons Numbers quoted: 1 year of T600 + 4 years of T1800 gradual mass increase T1200 Unit (two T600 superimposed) Not yet included in infrastructure design but ultimate goal: T3000+muon spectrometer ≈ 95 m T1200 Unit (two T600 superimposed) money available for tendering of cryostats, inner mechanics and readout electronics: Should be completed by end of 2007 transported to LNGS: to be installed in 2005 Should be completed by autumn 2006 First Unit T600 + Auxiliary Equipment Situation before june 2005
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Run 308, Event 160 Collection Left 265 cm 142 cm 176 cm 434 cm Shower Hadronic interaction Pictures from T600 technical run: Detector performance: EM and hadronic showers are identified and fully sampled Total energy obtained from charge integration Excellent calorimeter with very good E resolution EM showers: Hadronic showers:
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e search: Fit 2 oscillation components simultaneously use E vis, P T miss, P T el sin 2 2 13 ICARUS T1800 Evis spectra Δm 2 23 =2.5 10 -3 eV 2 Sin 2 (2θ 13 )= 0.14 (CHOOZ limit) 25 oscillated events Ref: ICARUS document SPSC-2002-027 + private communication
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90% confidence level Full = CNGS std. 1y t600 +4y t1800 Dashed = CNGS x 1.5 5% systematic error on background Limits at 90% CL for m 2 = 2.5x10 -3 eV 2 full mixing Expected sensitivity to 13 e search: ICARUS T1800
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e search: at CNGS expected signal and background 5 years: 2.25x10 20 pot OPERA ICARUS T1800 m 2 = 2.5x10 -3 eV 2
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Conclusions CNGS beam: on schedule expect to start in June 2006 e : high detector capabilities to explore this channel 13 limit down to 7 0 sensistivity on 13 with a dependence on CP different from T2K OPERA: construction and installation is progressing should be ready to record events in 2006 ICARUS: successful demonstration of the principle withT600 Hall B: T600 in 2006 + T1200 ……… Beam systematics < 5% Sensitivity completely dominated by statistics More refined studies to perform: include CP violation, matter effect, full simulation
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ICARUS project: Realization of a 600+1200 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.
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The End
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sensitivity vs CP There are CP values for which the sensitivity on 13 is even better than the one computed in the 2-flavor approximation ( CP =0). m 2 > 0 m 2 < 0
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Mesure de 13 Pour les projets de Long Baseline: Auquel doit s’ajouter les effets de matière: P( e ) augmente pour la hiérarchie normale et diminue pour la hiérarchie inverse Attention: les effets dus à 13 et à sont indissociables avec une simple mesure de P( e ) paramètres sont corrélés négligeable en LBL sur max. atm. Dans le vide
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On peak Off peak P. Migliozzi and F. Terranova hep-ph/0302274 On/off peak
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On peak Off peak On-peak O1 (leading term) and O2 (~sin ) are dominant at high energy and larger distances larger matter effects sign( m 2 31 ) Off-peak O1 (leading term) and 03 (~cos ) O3 is CP even or odd under m 2 31 - m 2 31 transformation O1O1 O2O2 O3O3 O4O4 O1O1 O2O2 O3O3 O4O4
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T1800 configuration
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T600 in Hall B: March 2005
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5 years: 2.25x10 20 pot T1800 detector (1 year 0.47 kton+4 years 1.4 kton active LAr) ICARUS: search other channel: with main background: NC missing p t p tot QTQT QTQT use isolation criteria: Q T
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NC e e beam Events Visible Energy (GeV) Limits at 90% CL for m 2 = 2.5x10 -3 eV 2 full mixing syst. e contamination up to 10% Preliminary sin 2 2 13 m 2 23 (eV 2 ) 4.50 10 19 pot/yr 6.76 10 19 pot/yr e sensitivity to 13 Both oscillations distort E vis at low energy Fit oscillation components simultaneously use E vis, P T miss, E el sin 2 2 13 Similar approach in both experiments OPERA
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e search: at CNGS in the 3 flavour oscillation framework Assuming m 12 2 << m 23 2 = m 13 2 = m 2, P( -> )= cos 4 13 sin 2 2 23 sin 2 (1.27 m 2 L/E) P( -> e )= sin 2 23 sin 2 2 13 sin 2 (1.27 m 2 L/E) subleading transition look for an excess of e CC events and take into account , e e expected signal and background 5 years: 2.25x10 20 pot OPERA
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