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Zero Suppression Study with a fast MC. John Krane Iowa State University. Calorimeter Task Force 1 October, 2002. Goals. Run 1k events in a few seconds (actual is currently 15k jets/min) Simulate jet energy profiles Longitudinal Ncells in each layer Simulate noise
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Zero Suppression Studywith a fast MC John Krane Iowa State University Calorimeter Task Force 1 October, 2002
Goals • Run 1k events in a few seconds(actual is currently 15k jets/min) • Simulate jet energy profiles • Longitudinal • Ncells in each layer • Simulate noise • Simulate arbitrary ZSP scheme John Krane -- Iowa State University
Method • Study 100 GeV jets and scale down • Relatively free of noise pathology • Copious • Get Ncells per layer (Draw from Gaussian from data) • Get Efrac for each cell in lyr(Draw from histogram of E/cell in each layer, from data) • Get energy per layer for CC jets(Draw from histogram of E/lyr from data,scale this down) John Krane -- Iowa State University
Method, continued • Add noise (Robert’s .rcp provides sigmas) to jet cells and then suppress • Add noise to all other cells in jet cone and then suppress • Suppression can be 1.5s, 2.5s, or different s for different layers My noise is slightly asymmetric…also I am using negative E John Krane -- Iowa State University
Simulated jets have medium ET, mean is 47 GeV, mode is ~40 GeV (Could make ETcuts but don’t) John Krane -- Iowa State University
Several GeV consist entirelyof noise …but most jets have zero noise (2.5 s zsp) John Krane -- Iowa State University
Jet Reso 2.5 s zsp requiressmaller correctionfor noise …but note the asymmetric shape! Results in a long tailon dijet resolutions difficult analysiscould result from myasymmetric noise John Krane -- Iowa State University
ZSP schemes • 1.5 s zsp • 2.5 s zsp • 1.5 in low-noise layers (2,3,4,5,6,7)and 2.5 elsewhere • 1.5 in low-occupancy layers (12,13,15)and 2.5 elsewhere John Krane -- Iowa State University
Cut hard on noisy layers More reso First look indicatesthe blue line is fairly Gaussian in shape, but this might be a fitting oddity…will look more carefully Cut hard on populous layers John Krane -- Iowa State University
Zsp choice makeslarge diff in MC Blue line is a clever(i.e. counter-intuitive)choice for reso, andnaturally good for the occupancy John Krane -- Iowa State University
CHF Started checking to see if jet cut variables looked familiar… John Krane -- Iowa State University
Summary • Fast ZSP Monte Carlo is working • Will study jet variables to check accuracy • Can improve noise sim with direct histograms • Ignoring possible correlation between E and Ncells • Could try different ET regime, h ranges • Need suggestions for ZSP schemes • Tried two variable-s schemes (suppress noisy layers, suppress high-occupancy layers) • Decide what variables to optimize (How should I simulate the MET? Systematic noise?) John Krane -- Iowa State University