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ICHEP 2000, Osaka August 2000

Measurement of. n -N Differential cross-sections. and. Structure functions. using the. CHORUS lead calorimeter at CERN. ICHEP 2000, Osaka August 2000. Rolf Oldeman (NIKHEF, Amsterdam) for the CHORUS collaboration. Experimental setup. lead/scintillating fiber calorimeter-target.

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ICHEP 2000, Osaka August 2000

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  1. Measurement of n-N Differential cross-sections and Structure functions using the CHORUS lead calorimeter at CERN ICHEP 2000, Osaka August 2000 Rolf Oldeman (NIKHEF, Amsterdam) for the CHORUS collaboration

  2. Experimental setup lead/scintillating fiber calorimeter-target magnetized iron muon spectrometer 450 GeV protons(SPS) p,Kn focussing magnets beryllium target 300 m decay tunnel CHORUS detector WANF neutrino beamline

  3. A typical event Detector resolution: Kinematic variables:

  4. n beam CHORUS 1998 DIS data n beam Triggered & selected: 3638k 1032k After cuts: 1125k 234k fiducial volume: 15.1 ton right sign muon (contamination:2%, 32%) pm > 4 GeV qm < 300 mrad Ehad < 100 GeV 10 < En < 200 GeV Applied cuts:

  5. total snN total snN /snN snN(E) snN /snN(E) Differential n-N cross-sections binning in (En,x,y): 10<En<200GeV 10 bins 0.01<x<0.7 11 bins 0.05<y<0.95 9 bins use: systematic uncertainties: Dominant! Ehad scale Ehad offset pm scale pm offset 5% 150 MeV 2.5% 150 MeV 2.1% 1.4% 1%/100GeV 0.5%/100GeV

  6. n cross-section results Example En=55 GeV xbj=0.275 n 1.5 1.0 (10-38cm2GeV-1) 0.5 0 1 y First high statistics nN data on a lead target! Numerical tables at choruswww.cern.ch/~oldeman

  7. Structure function extraction Binning E,x,y to x,Q2,y Isoscalarity correction Radiative corrections (Bardin)

  8. n Extracting 6 structure functions Large statistical errors Very strong correlations. Especially 2xF1,xF3 n Need large range in y  limited # of x,Q2 bins satisfy

  9. Extracting 3 structure functions Assume: Reasonable correlations 10x smaller statistical error  measure R(x,Q2):

  10. Results on R(x,Q2) SLAC R1990

  11. ‘Classical’ 2-structure function extraction Use R(x,Q2) = SLAC R1990 (20%) Reduced statistical error Small correlation

  12. Measured structure functions F2(x,Q2) and xF3(x,Q2) LO model

  13. F2(x,Q2) Comparison with CCFR and CDHSW Consistent with CCFR Inconsistent with CDHSW

  14. xF3(x,Q2) Comparison with CCFR and CDHSW Mostly consistent (except high-x)

  15. Conclusions First high statistics neutrino data on a lead target Differential cross-section measured Structure functions F2(x,Q2), xF3(x,Q2) and R(x,Q2) measured Consistent with CCFR, discrepancy with CDHSW

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