lcfi package and flavour tag @ 3tev
DESCRIPTION
LCFI Package and Flavour Tag @ 3TeV. Tomáš Laštovička Institute of Physics AS CR CLIC WG3 Meeting 9/6/2010. LCFI Package. Used for jet flavour tagging and secondary vertex reconstruction. Topological vertex finder ZVRES. Standard LCIO input/output - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/1.jpg)
LCFI Package and Flavour Tag @ 3TeV
Tomáš Laštovička
Institute of Physics AS CR
CLIC WG3 Meeting 9/6/2010
![Page 2: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/2.jpg)
Page 2
LCFI Package
Used for jet flavour tagging and secondary vertex reconstruction. Topological vertex finder ZVRES. Standard LCIO input/output
– Marlin environment (used for both ILD/SiD)
Flavour tagging based on Neural Nets.– Combine several variables…
Probability Tubes
Vertex Function
![Page 3: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/3.jpg)
Page 3
NN Input Flavour Discriminating Variables
There are 14 flavour discriminating variablesR- and Rz- significance for 2 tracks with the highest impact parameter significance in R
(“leading tracks”)
Relative momenta of the leading tracks (relative to jet energy)
Joint Probability in R and Rz
Decay length and decay length significance (relative to jet energy)
Pt-corrected vertex mass
Secondary vertex probability
Relative total momentum of non-primary vertex tracks and their number
These inputs are re-normalised and transformed by tanh() - except joint and secondary vertex probabilities.
Tracks/vertices have to pass some minimal selection cuts.
![Page 4: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/4.jpg)
Page 4
NN Input Flavour Discriminating Variables
Inputs are sent to 3 neural networks (8 inputs each) according to the number of secondary vertices found in a given jet– 0 vertices:
R-, Rz- significance and momenta for 2 leading tracks
Joint Probability (R, Rz)
– 1 vertex and >1 vertices:Decay length, decay length significance, pt-corrected vertex mass,
Total momentum of non-primary vertex tracks and their number,
Joint Probability (R, Rz), Secondary vertex probability
This is not a dogma, inputs can be added/removed– Requires some coding.– Studies better done outside the package (I fancy FANN package for this purpose).
![Page 5: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/5.jpg)
Page 5
Input Variables – Additional Topics
Joint Probability Calculation– Estimated using fits to impact parameter distributions.– Might depend on detector geometry and sim/rec effects.
Ks, and conversion tagger– Part of the package, depends on detector geometry.
Cuts on tracks/vertices for NN Inputs– There is a number of parameters to tune up the package (see next slide).
![Page 6: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/6.jpg)
Page 6
LCFI Package Optimisation
Optimisation is not only a matter of Neural Net retraining. The package has plenty of parameters:– Track selection params– ZVRES params– Flavour Tag params– Vertex Charge params
![Page 7: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/7.jpg)
Page 7
Example 1SiD FastMCDi-jets @ 500GeVISR removed by Minv cut
b-jets (red)c-jets (green)
Light-jets (black)
R 1 R 2 Z 1
JP R JP Z M 1 M 2
DL S DL Pt CM RM
#t V #VSVP E
Z 2
![Page 8: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/8.jpg)
Page 8
Further Examples
I compared various samples (sorry for too many plots). Let’s start with the same setup but for 3 TeV
– It’s pretty much similar as far as input variables are concerned.
![Page 9: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/9.jpg)
Page 9
SiD FastMCDi-jets @ 3TeVISR removed by Minv cut
SiD FastMCDi-jets @ 500GeVISR removed by Minv cut
b-jets (red)c-jets (green)
Light-jets (black)
R 1 R 2 Z 1 Z 2
JP R JP Z M 1 M 2
DL S DL Pt CM RM
#t V #VSVP E
![Page 10: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/10.jpg)
Page 10
Further Examples
I compared various samples (sorry for too many plots). Let’s start with the same setup but for 3 TeV
– It’s pretty much similar as far as input variables are concerned.
ff 2-jet events @ 3 TeV
![Page 11: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/11.jpg)
Page 11
Di-jets @ 3TeVISR removed by Minv cut
ILD Full Sim/Recff @ 3TeVDST files area normalisedMinv cut
R 1 R 2 Z 1 Z 2
JP R JP Z M 1 M 2
DL S DL Pt MC RM
#t V #VSVP E
b-jets (red)c-jets (green)
Light-jets (black)
![Page 12: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/12.jpg)
Page 12
Further Examples
I compared various samples (sorry for too many plots). Let’s start with the same setup but for 3 TeV
– It’s pretty much similar as far as input variables are concerned.
ff 2-jet events @ 3 TeV
H0A0 4-jet events– First reconstructed with the SiD FastMC,– then with the full simulation and reconstruction.– Please, ignore c-jets.
![Page 13: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/13.jpg)
Page 13
Di-jets @ 3TeVISR removed by Minv cut
SiD FastMCH0A0 @ 3TeVno Minv cut4 jet eventsarea normalised
b-jets (red)c-jets (green)
Light-jets (black)
b-jets (red)c-jets (green)
Light-jets (black)
R 1 R 2 Z 1 Z 2
JP R JP Z M 1 M 2
DL S DL Pt MC RM
#t V #VSVP E
![Page 14: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/14.jpg)
Page 14
ILD Full Sim/RecH0A0 @ 3TeVDST files 224 – 231, 825-8404 jet eventsarea normalized
R 1 R 2 Z 1 Z 2
JP R JP Z M 1 M 2
DL S DL Pt MC RM
#t V #VSVP E
b-jets (red)c-jets (green)
Light-jets (black)
SiD FastMCH0A0 @ 3TeVno Minv cut4 jet eventsarea normalised
![Page 15: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/15.jpg)
Page 15
Discussion
SiD FastMC consistent for 500GeV and 3TeV.– And consistent to full SiD reconstruction @ 500GeV.
Then things get bit more complicated to compare– Different events, detectors, reconstruction, low statistics.– ff events comparable for b- and c-tag. Light jets probably polluted (?).– H0A0 events: b-events more or less OK, however:
• Differences between FastMC and full simulation reconstruction (e.g. Pt corrected mass secondary vertex reconstruction?).
Different input distribution compared to the reference one worse performance with default nets.
![Page 16: LCFI Package and Flavour Tag @ 3TeV](https://reader030.vdocuments.mx/reader030/viewer/2022032805/56813242550346895d98b2d4/html5/thumbnails/16.jpg)
Summary
LCFI package has a number of flavour tag sensitive variables, these can be revised/modified.
We’ve looked at a couple of samples using SiD FastMC as well as DST files from Marco (full simulation and reconstruction).
Future Plans:
b-tag will be studied more closely.
c- and uds- mistag efficiencies.
Optimisation of the LCFI package.