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Neutrino search using full waveform information. Dmitry Chirkin, LBNL. Reconstruction methods. Feature Extractor: Simple single-peak feature-extraction: first peak, total charge Multi-peak unfolding-based feature-extraction Rime: simple 5-parameter reconstruction
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Neutrino search using full waveform information Dmitry Chirkin, LBNL
Reconstruction methods Feature Extractor: • Simple single-peak feature-extraction: first peak, total charge • Multi-peak unfolding-based feature-extraction Rime: • simple 5-parameter reconstruction • joint 6-parameter reconstruction • Ice-layered model • bulk ice model
rllh Cut at 8
Closest approach to COGxy cut at 40
Zenith angle reconstructed uncertainty cut at 20
Reconstructed energy cut variables cut at 0.5 cut at 0.7
Angular resolution no convenient parameterization of angular resolution was found Angular resolution is defined as the value below which are 2/3 of the histogram entries
Cuts optimization For all of the cut variables: tighter cuts improve angular resolution Optimization: for a given fraction of data left, find the cuts which produce the subset with the best angular resolution Method 1: Simply go through all possible combinations and evaluate the angular resolution. For N=20 parameters and initial MC set of M events and fraction r, this will require to go through O(C(N,rM+N)) combinations Method 2: for a given reduction of fraction of events dr estimate the improvement of the angular resolution dA (by removing M*dr events with largest cut values, which reduce the cut by dC). Then, using the “fastest decent”, use dr*(dA/dr) to find the optimum cut value for each cut variable.
Cut optimization Starting from initial cuts or no initial cuts, the method converges to the same result at small enough fraction of events left
Correlated parameters Although many of the cut parameters are correlated, the method works: e.g., for 2 completely same parameters, dC/dr will be the same
Cut matrix For each Nch from 6 to 100 1ppw Angular resolution Nppw Fraction of events left