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Some Examples of IDS unfolding & Bin-to-bin corrections. Bogdan MALAESCU CERN 02/12/2010. Outlook. Example with experimental data: IDS & Bin-to-bin More complex example: IDS & Bin-to-bin (with iterations) Another example for (iterative) Bin-to-bin Conclusions.
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Some Examples of IDS unfolding & Bin-to-bin corrections Bogdan MALAESCU CERN 02/12/2010
Outlook • Example with experimental data: IDS & Bin-to-bin • More complex example: IDS & Bin-to-bin (with iterations) • Another example for (iterative) Bin-to-bin • Conclusions
Application for Experimental Data: IDS & Bin-to-bin pp • Resolution + FSR • Unfolding performed in one step (UR1) (iteration effect (UR2) is negligible) mm • Mainly FSR • Unfolding performed in one step (UR1) (iteration effect (UR2) is negligible) Number of events • Resolution • Main correction on the f at 1st step (UR1) • Result obtained after one iteration (UR2) (iteration effect important for new structures at high mass) KK Unfolding (resolution+FSR) From kinematic fits MXX(GeV/c2)
IDS method tested for a complex example Original reconstructed MC Corrected spectrum Original generated MC + New structures Data The method simultaneously treats all the problems described before
Bin-to-bin method tested for a complex example: 2 iterations
Bin-to-bin method tested for a complex example: 3 iterations
Bin-to-bin method tested for a complex example: 4 iterations
Bin-to-bin method tested for a complex example: 5 iterations Problem (fluctuations)
Bin-to-bin method tested for a simple example: fluctuations due to numerical instabilities (not new structures) 1st step 5 iterations
Bin-to-bin method - another example: no bias 1st step 5 iterations
Bin-to-bin method - another example: with bias 1st step 5 iterations
Conclusion • IDS method treats in a stable way complex problems • The bin-to-bin method would also need iterations to treat problems with data/MC differences • Numerical instabilities produce large fluctuations when iterating the bin-to-bin method, without regularization