the In order to be sure that the - PowerPoint PPT Presentation

INTRODUCTION We know that in Nature there are three kinds of neutrinos and in particular atmospheric neutrinos show a deficit of ν ν ν ν µ µ µ µ This effect, found first by the SuperKamiokande and confirmed by many other experiments (for example by MACRO and K2K), has been deeply studied. So, the disappearance of muon neutrinos seems doubtless stated . Moreover, the experimental data agree very well with the hypothesis of ν ν ν µ ν ν ν µ → → ν → → → → ν τ ν ν ν ν ν ν → → ν ν τ oscillations. oscillations. µ µ µ µ µ µ τ τ τ τ τ τ However, the experiments performed until now do not allow to observe the particle that should be produced in the oscillation: ν ν τ the ν ν ν ν ν ν τ τ τ τ τ τ τ In order to be sure that the oscillation ν ν ν ν ν µ → ν → → → ν ν τ ν ν τ is ν ν ν µ → → → → ν ν ν µ τ µ µ µ µ µ τ τ τ τ τ the right explanation of the data, we need the direct observation of the ν ν ν τ ν ν ν ν ν τ τ τ τ τ τ τ MTM Bologna, 17/6/ 2005

ν ν τ the ν ν ν ν ν ν …….. to “see” τ τ τ τ τ τ τ The OPERA experiment The OPERA experiment MTM Bologna, 17/6/ 2005

Physics motivations Physics motivations Provide unambiguous evidence for Provide unambiguous evidence for ν ν µ ν ν → → → ν → ν ν ν ν τ ν ν ν ν µ → → → → ν ν ν oscillations τ oscillations µ µ µ µ τ τ τ τ µ µ τ τ in the parameter region indicated by in the parameter region indicated by atmospheric neutrino data atmospheric neutrino data by searching for by searching for ν ν ν ν ν ν τ ν ν appearance τ appearance τ τ τ τ τ τ in the CNGS ν ν ν µ ν ν ν ν ν beam in the CNGS µ beam µ µ µ µ µ µ τ decay ν τ ν ν ν ν ν ν ν appearance signature: τ appearance signature: τ τ τ τ τ τ τ τ τ τ ~ 0.6 mm ν τ ν detection of ν ν ν ν ν ν CC interactions detection of τ CC interactions τ τ τ τ τ τ and direct observation of and direct observation of ν τ ν ν ν τ τ τ τ decay topology τ τ τ τ decay topology τ τ τ MTM Bologna, 17/6/ 2005

Beam to LNGS in May 2006 The CNGS Beam Beam to LNGS in May 2006 The CNGS Beam <E ν ν µ ν ν ν ν ν ν > 17 GeV GeV <E µ > 17 µ µ µ µ µ µ L = 732 km ν ν τ ν ν ν ν ν ν prompt τ prompt negligible negligible τ τ τ τ τ τ Expected ν ν τ ν ν ν ν ν ν Expected τ CC interactions/year: CC interactions/year: ~25 25 τ τ τ τ τ τ 2 = 2.4x10 3 eV ( ∆ ∆ m ∆ ∆ ∆ ∆ ∆ ∆ m 2 = 2.4x10 - -3 eV 2 2 , maximal mixing) , maximal mixing) ( MTM Bologna, 17/6/ 2005

The O Oscillation scillation P Project roject The with E Emulsion mulsion t tR Racking acking A Apparatus pparatus with In order to detect the decays In order to detect the decays of the τ τ particles produced in τ τ τ τ τ τ particles produced in CC interactions CC interactions of the ν ν τ ν ν ν ν µ ν ν of ν ν ν ν s from ν ν ν ν ‘s from oscillations of τ ‘ µ oscillations τ τ τ µ µ µ τ τ τ µ µ µ a high- -resolution tracking detector is required resolution tracking detector is required a high Nuclear emulsions Nuclear emulsions • 3D particle reconstruction • 3D particle reconstruction • Sub • Sub- -micron spatial resolution micron spatial resolution • High granularity (~300 • High granularity (~300 hits hits /mm) /mm) Modular detector basic unit (BRICK): sequence of lead/emulsions MTM Bologna, 17/6/ 2005

hybrid set- -up: up: hybrid set Detector structure Detector structure visual + electronic detection visual + electronic detection techniques techniques 2 super- -modules modules 2 super muon spectrometer + muon spectrometer + target walls target walls 52x64 bricks 52x64 bricks TOTAL > 220000 bricks 10m 10m 10m 10m 20m 20m MTM Bologna, 17/6/ 2005

Automatic microscopes for emulsion scanning Automatic microscopes for emulsion scanning European Scanning European Scanning System System running in : running in : Bari, Bern, Bologna, Lyon, Napoli, Neuchâtel, Roma, Salerno S- -UTS UTS (Nagoya) (Nagoya) S High speed CCD Camera (3 kHz) Piezo-controlled objective lens Synchronization of objective lens and stage Constant speed stage Scanning speed ~ 20 cm 2 /h/side Single side track finding efficiency ~ 95% Sheet-to-sheet alignment (8 GeV/c) ~ 0.5 µ µ m µ µ Angular resolution ~ 2 mrad MTM Bologna, 17/6/ 2005

Automatic emulsion scanning Automatic emulsion scanning Field of view Field of view 16 tomographic tomographic images images 16 2D Image Image 2D processing processing 3D reconstruction of particle tracks 3D reconstruction of particle tracks Vertex reconstruction Passing-through Track segments found tracks rejection in 8 consecutive plates Connected tracks with >= 2 segments MTM Bologna, 17/6/ 2005

Conclusions Conclusions • A complex modular detector, using visual and electronic detecti • A complex modular detector, using visual and electronic detection on techniques, has been designed techniques, has been designed • The detector construction and installation at LNGS are The detector construction and installation at LNGS are well underway well underway • Impressive progress in emulsion scanning automation has been ac • Impressive progress in emulsion scanning automation has been achieved hieved after challenging R&D challenging R&D after The OPERA experiment will start running in May 2006 06 The OPERA experiment will start running in May 20 to unambiguously confirm ν ν ν µ ν ν ν ν ν µ → → ν → → → → → → ν ν ν τ ν ν ν ν to unambiguously confirm τ oscillations oscillations µ µ µ µ µ µ τ τ τ τ τ τ MTM Bologna, 17/6/ 2005

fine fine

ν ν ν ν µ → → → ν → ν ν τ ν ν ν ν ν ν µ → → → → ν ν ν oscillation search τ oscillation search µ µ µ τ τ τ µ µ µ τ τ τ Signal τ τ decay τ τ Background channels 2 = 1.9 x 10 -3 eV 2 2 = 2.4 x 10 -3 eV 2 2 = 3.0 x 10 -3 eV 2 ∆ ∆ ∆ m ∆ ∆ ∆ ∆ ∆ ∆ m ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ m m 2 m 2 m 2 19.9 1.0 8.0 12.8 ALL Main background sources: charm production and decays hadron re-interactions in lead large-angle muon scattering in lead MTM Bologna, 17/6/ 2005

LNGS – – Gran Sasso Gran Sasso National Laboratory National Laboratory LNGS rock thickness 1400m (3800 m.w.e.) cosmic muon flux: ∼ ∼ ∼ ∼ 1/m 2 /h Hall B ICARUS BOREXINO Hall C OPERA (CNGS1) MTM Bologna, 17/6/ 2005

ν µ ν → ν → ν ν e ν ν → → ν ν ν ν ν ν µ → → → → ν ν ν oscillation search e oscillation search µ µ µ µ µ µ ∆ m ∆ 2 = 2.5 x 10 -3 eV 2 Θ Θ 23 ∆ ∆ ∆ ∆ ∆ ∆ Θ Θ Θ Θ Θ Θ m 23 2 23 = 45 = 45° ° 23 nominal CNGS beam 5 years ������ �� �� � Combined fit of E Combined fit of E e e , , E E vis vis , (pt) , (pt) miss miss 90% C.L. limits on sin 2 (2 Θ Θ Θ Θ 13 ) and Θ Θ 13 : Θ Θ (2 Θ Θ Θ Θ Θ 13 Θ )<0.06 Θ Θ Θ 13 Θ Θ Θ Θ Θ Θ Θ sin 2 2 (2 < 7.1º º sin 13 )<0.06 13 < 7.1 hep-ph/0210043

The OPERA Collaboration The OPERA Collaboration Belgium IIHE (ULB-VUB) Brussels Bulgaria Sofia China IHEP Beijing, Shandong Croatia IRB Zagreb France LAPP Annecy, IPNL Lyon, LAL Orsay, IRES Strasbourg Germany Berlin Humboldt, Hagen, Hamburg, Münster, Rostock Israel Technion Haifa Italy Bari, Bologna, LNF Frascati, L’Aquila, LNGS, Naples, Padova, Rome La Sapienza, Salerno Japan Aichi, Kobe, Nagoya, Toho, Utsunomiya Russia INR Moscow, ITEP Moscow, JINR Dubna, Obninsk Switzerland Bern, Neuchâtel Turkey METU Ankara

Signal Background ∆ ∆ m ∆ ∆ 2 = 1.9 x 10 -3 eV 2 ∆ ∆ m ∆ ∆ 2 = 2.4 x 10 -3 eV 2 ∆ ∆ m ∆ ∆ 2 = 3.0 x 10 -3 eV 2 ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ m 2 m 2 m 2 6.6 (10.0) 10.5 (15.8) 16.4 (24.6) 0.7 (1.1) Old analysis Old analysis 8.0 (12.1) 12.8 (19.2) 19.9 (29.9) 1.0 (1.5) New analysis New analysis full mixing, 5 years run @ 4.5x10 19 pot / year (…) CNGS beam intensity increase (x 1.5) Comments on background - - possible improvements possible improvements: Comments on background � π π π π / µ µ µ µ separation at low energy by dE/dx in emulsion (charm background reduction) � extensive comparison of FLUKA with GEANT4/CHORUS data (reduction of the uncertainty on hadron re-interaction calculations, based on FLUKA, 50% systematic error assumed) � experimental measurement of large-angle muon scattering WIN05, Delphi, June 6-11, 2005