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Kinematics Related Systematic Uncertainties via MCEEP

Kinematics Related Systematic Uncertainties via MCEEP. P.E. Ulmer Old Dominion University 12/11/02 Hall A Analysis Workshop. Breaking News: Cross sections depend on kinematics! Uncertainties run wild!. Coincidence cross section can vary strongly with kinematics.

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Kinematics Related Systematic Uncertainties via MCEEP

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  1. Kinematics RelatedSystematic Uncertainties via MCEEP P.E. Ulmer Old Dominion University 12/11/02 Hall A Analysis Workshop

  2. Breaking News:Cross sections depend on kinematics! Uncertainties run wild! • Coincidence cross section can vary strongly with kinematics. • Results in systematic uncertainties: • need to evaluate changes in cross section for variations of kinematical quantities. • Account for kinematical constraints: • For example, fixed missing mass. • May include constraints from various calibration measurements, such as H(e,e’p) • Must acceptance average derivatives. • It’s a snap with new MCEEP tools: • Cross sections handled at present. • Other observables could be added easily. • Satisfaction guaranteed or your money back.

  3. Process MCEEP Ntuple: Get cross sections for variations of kinematical quantities Determine cross section derivatives and total uncertainty, including any kinematical correlations Procedure MCEEP Hbook file

  4. Process NtupleFortran Program: systerr • Start with MCEEP Ntuple, containing Transport coordinates at target • Vary nine quantities, in turn: (beam, scatt. electron, ejectile) x (delta, phi, theta) • Produce new Ntuple, consisting of original variables plus 10 cross sections (nominal and nine “shifted”). • Program links to MCEEP subroutines and has access to its physics models.

  5. Acceptance AveragePAW: systerr.kumac • Error sum: positive definite quantity • Must first acceptance average. • Sum the “weights”: • Produce vectors of summed cross sections (10 in total). • Bin vectors in terms of any kinematical quantity within Ntuple. • Diagnostic histograms: • Fractional derivatives of cross section with respect to each of the nine varied kinematical quantities.

  6. Combine Errors Fortran Program: toterr • Produce cross section uncertainty, given kinematical uncertainties and correlations. For each bin, form:

  7. More Information • www.physics.odu.edu/~ulmer/mceep/mceep.html • Includes: • Sources • Installation Instructions • User manual • In particular, see: ~/mceep/systerr/README • JLAB-TN-02-015 Systematic Uncertainties in E89-003 (K. Fissum & P.E. Ulmer) See: http://hallaweb.jlab.org/publications/Technotes/files/2002/02-015.ps

  8. Figures Both figures are based on Experiment E94-004 D(e,e’p)n cross section vs. Pm • Cross section derivatives for each of the nine quantities: • Kinematics centered on Pm=100 MeV/c • Units: fractional derivatives per 1 mr or per 10^-3 in momentum. • Total error vs. Pm • All kinematics for E94-004 included, from Pm=0 to Pm=500 MeV/c (central values) • Uncorrelated analysis • Correlated analysis: assumes constraints from 1H(e,e’p)

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