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Add a looser vertion of tau2muphi stripping line

Domenico Riccardi requested to merge RD_Tau2MuPhi_2018-patches into RD_2018-patches

This merge request is related to the proposal to enlarge the mass window of the reconstructed invariant tau-mass in the existing StrippingLFVTau2PhiMuLine. Specifically, I made some changes to the code to include the peak of the D_s -> phi pi decay (where the pion in the final state is misidentified as a muon) within the mass window.

In the previously linked file, there are multiple stripping lines, so I created a new Python script that includes only my line with the new name "Tau2MuPhiLine".

I tested my line using the procedure descripted here, and the test was successfully completed. The obtained values for the retention and timing of my line are 0.067% and 0.045 ms/evt (obtained running on 100k events, as you can see in the log file attached StripTest.log - 2018 data). Other tests to compare the rate of the new line with the previous one are currently underway, and I will report the results as soon as possible (see comments for updates).

I expect that the new rate is approximately 1/4 higher than the old one because I have performed an extrapolation of the shape and quantification of events in the region added (up to 2020 MeV) using the 2018 MagDown Real Data sample stripped with the old line, as shown in the attached figure where the region of interest is coloured in orange. new_region The total number of events expected to be added to this Data sample is approximately 2.6M, of which 1.9M are from the background defined by the red curve (combinatorial + physical bkg) and 0.7M are attributed to D_s -> phi pi decays.

UPDATE

The final rates are:

  • Test with 2018 data
StrippingReport                                                INFO Event 100000, Good event 100000
 |                                              *Decision name*|*Rate,%*|*Accepted*| *Mult*|*ms/evt*|
 |_StrippingGlobal_                                            |  0.0670|        67|       |   4.509|
 |_StrippingSequenceStreamLeptonic_                            |  0.0670|        67|       |   4.500|
 |!StrippingTau2MuPhiLine                                      |  0.0670|        67|  1.015|   3.815|
 |!StrippingTau2MuPhiLine_TIMING                               |  0.0670|        67|  1.015|   0.026|
  • Test with 2017 data
StrippingReport                                                INFO Event 100000, Good event 100000
 |                                              *Decision name*|*Rate,%*|*Accepted*| *Mult*|*ms/evt*|
 |_StrippingGlobal_                                            |  0.0680|        68|       |   4.229|
 |_StrippingSequenceStreamLeptonic_                            |  0.0680|        68|       |   4.219|
 |!StrippingTau2MuPhiLine                                      |  0.0680|        68|  1.044|   3.561|
 |!StrippingTau2MuPhiLine_TIMING                               |  0.0680|        68|  1.044|   0.025|
  • Test with 2016 data
StrippingReport                                                INFO Event 100000, Good event 100000
 |                                              *Decision name*|*Rate,%*|*Accepted*| *Mult*|*ms/evt*|
 |_StrippingGlobal_                                            |  0.0410|        41|       |   3.562|
 |_StrippingSequenceStreamLeptonic_                            |  0.0410|        41|       |   3.551|
 |!StrippingTau2MuPhiLine                                      |  0.0410|        41|  1.049|   2.962|
 |!StrippingTau2MuPhiLine_TIMING                               |  0.0410|        41|  1.049|   0.025|

FYI @yusong @mbirch @yitang @lpica

Edited by Domenico Riccardi

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