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Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,Neutrino and Charm Physics with CHORUS,Francesca Spada,NIKHEF Annual Scientific Meeting-13/12/2001,CHORUS Emulsion Physics,Measurement principles,Neutrino interactions take place in a target/detector of nuclear emulsions,direct observation of short lived particle decays,770 Kg of nuclear emulsions divided in 4 stacks perpendicular to the beam,Very high spatial resolution(1m)with 300,tridimensional,hits/mm,Suitable to detect the decay signature:,Interaction vertex,Short,t,or charm path 1 mm,A,kink,as decay topology,Oscillation physics:search for,n,t,appearance in a pure,n,m,beam,n,m,energy well above,t,production threshold,An electronic detector reconstructs the kinematics and allows trace-back to the interaction vertex in emulsion,CHORUS was exposed during 4 years to the WBB from SPS at CERN,5,.,10,19,POTs leading to 840,000,n,CC interactions in emulsion,E,protons,=450 GeV,Intense,n,beam with E,n,27 GeV,Prompt,n,t,unavoidable but negligible,(0.1 bg events expected in total),The CERN,neutrino,beam,Reminder,Active target:,nuclear emulsion target,scintillating,fibre,tracker,Air-core magnet+tracker:,Hadron,momentum(up to 20,GeV,),D,p,/,p,=0.035,p,(,GeV,),0.22,Lead and,fibre,Calorimeter:,D,E/E=32%/,E(hadrons),=,14%/,E(electrons),Dq,hadrons,=60,mrad,10,GeV,Muon,spectrometer:,D,p,/,p,=10 15%up to 70,GeV,A,ctive target,Calorimeter,Spectrometer,Air-core,magnet,Honeycomb Chambers,4-Target setup,The CHORUS detector,Hybrid emulsion/electronic tracking,CCD image:120150 m,Focal depth:3 m,Take 16 tomographic,images per plate at,different focal depths,Shift each plane,by the angle given,in predictions,Sum up the ph.,A track is recognized,as a peak,The most upstream 100 m of each plate are scanned,Emulsion data acquisition,The Nagoya Track Selector,Emulsion data acquisition,The Nikhef/CERN scanning facility,sin,2,(2,q,),D,m,2,eV,2,0.6 eV,2,Design purpose:,Oscillation physics at large mass square(Dm2 eV2)and small mixing(sin2(2q)10-4),Current limit on oscillation:,Pt 80,Kevents,the current sample of 164,Kevents,(scan-back started),For each(old and new)located event,full event analysis in the vertex region(data-taking started,current speed is 10,Kevents,/month),Improvement of oscillation search to reach the proposal sensitivity,We will have a big sample of events fully analyzed in the vertex region,Unbiased study of charm production in neutrino interactions,About 600 charm events already identified,NETSCAN,An innovating scanning technique!,Use already located events,Pick up,all track segments,in an 8-plates deep fiducial volume,around scan-back track,Decay search is not limited to the scan-back track,Offline analysis of emulsion data,Track segments from 8 plates overlapped,At least 2-segment connected tracks,Eliminate passing-through tracks,Reconstruct full vertex topology,Fiducial,Volume,Charm physics with CHORUS,D,0,production,Sample:25,693 events analyzed with Netscan,Charm selection:,based on Impact Parameter analysis,and track matching in the Target Tracker,Purity:63%,(background:2ry interactions,d,rays,g,conversions,low momentum tracks),After manual scanning,283 D,0,candidates,Efficiency:58%on V2,70%on V4,Expected bg 9 events(mainly K,0,and,L,0,decays),s,(D0)/,s,(CC)=(1.990.130.11)10,-2,Interaction,vertex,Decay,vertex,D,0,TT-matched,tracks,CHORUS,E531,PRELIMINARY!,Charm physics with CHORUS,Associated,c,production,From a dedicated search:,We observed a candidate event for associated charm production,Event topology in emulsion:,V2,+,Kink,30,29,21,2,1,3,790 m,V2,decay of a D,0,1-kink parent(flight 1010 m),2-kink daughter(flight 7560 m)undergoing kink or 2ry interaction,3-ionization 3xMIP,proton(780 MeV from multiple scattering),Candidate for(neutral+charged)double charm production,Background evaluation under work,(,),Charm physics with CHORUS,Charmed hadron fractions,Charm physics with CHORUS,Works in progress,Bm,charm in antinu,Double charm search,?,Conclusions,
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