b-ID Status

Conveners

Herb retired from b-ID last month, after 2 years of hard work

Still helping out with b-ID significantly!

Management is trying to find a new b-ID convener...

CAFe interface

Now working stably :)

Extra features added lately:

taggability parameterizations are applied during tagging - Gordon

combined systematics of taggability+TRF uncertainties (BUG FIXED!!!)

BTagJetSelector, Permuter (with systematics)...

Documentation: https://plone4.fnal.gov/P1/D0Wiki/bid/Documentation/

p17 NN – v1.1 (Tim, Miruna, Stephen)

Preliminary certification note is now in CB review

Frank has asked that the review be completed as quickly as possible, hopefully by the end of the month

http://www-d0.fnal.gov/phys_id/bid/d0_private/certification/cert_p17/

Many analyses in the Higgs and Top groups are using p17 NN v1.1 tagging

Good data/MC agreement after tagging is being seen in many analyses

See the following talk from this morning's convener's meeting...

b-ID Status

Performance of p17 NN v1.1

Up to 1/3 the fake-rate for same b-efficiency

Smaller systematic uncertainties

Wider range of operating points

b-ID Status

TRF discrepancies (Jan Steggemann)

studied TRFs for gluon-splitting samples, like Wbb, Zbb

Observes a 5-10% overestimate of the TRF, compared to actual tagging in MC

Finds that it is due to lower b-quark momentum (as a fraction of the jet momentum) in these samples

Need further studies and a fix for this..
simply use direct tagging + scale factor for these samples?

5-10%, low pT

Z->bb - direct
production

Wbb - gluon
production

b-ID Status

Taggability

Timour finished the taggability parameterizer processor

Needs to be tested / improved

Ioana has released a fantastic D0Note (5240) on her taggability studies:

We are underestimating the taggability for high CPF jets at low pT by 5-10%

Add a systematic uncertainty to the low pT jet taggability of 5-10%?

We should correct for this instead!

SVT Optimization (Yvonne)

Random grid search of taggability and secondary-vertexing parameters

Fix old feature of re-using tracks on vertices

Revive the 2-pass vertexing algorithm

muon NN tagger for p17? (Hwidong)

Adds ~5% efficiency to b-ID / negligible extra fake rate

We need to focus on a schedule for bringing this to completion

current operating points

points from search

Taggability now done vs. PV_Z, pT, eta

b-ID Status

CVS package: nn_cert

Worked to turn certification macros from the p17 NN into a repeatable procedure

Steps to certification:

Use nn_cert framework package (based on d0root_example) to make “nn_ntuples” from b-ID, QCD, and emQCD data skims and all MC samples

In the future, these nn_ntuples could be made from CAF...

Merge samples using btag_info_macros

Train NN / run system 8 certification / make plots, using nn_cert_macros

Some documentation has been written (in nn_cert/doc)

p17 NN – v2.0 (Sarah Schlobohm + Who???)

Final JES, I am told there will be significant differences at low pT

nn_cert improvements:

Better parameterizations (PV_z)

Include new inclusive b samples in Beta error

Tau TRFs?

Light-quark data/MC scale factor?

Optimized SVT/taggability parameters

A “tight SVT” for comparison (also coming for v1.1) – from Justace/Pieter

New systematic: b->mu/b->incl. data/MC ratio?

b-ID Status

p20 – it's here!

Benoit has re-tuned JLIP resolution functions, extended track categories for Layer 0

Test MC samples are being produced

Z->bb,cc,qq at various luminosities (0,150,300 e30)

We need a volunteer to look at this MC and measure eff. / fake rates, try to optimize, compare to p17, study Layer 0, etc.

Basic p20 NN certification (Sarah + Who???)

What major additions are foreseen for p20?

whatever improvements planned for p17 that did not make p17, we'll try to get into p20 :)

train NN against charm as well as light?

train NN against g->cc/bb, as well as light?

We've made a lot of progress in the past ~year:

CAFe interface for tagging, taggability, selection, and systematics

A working NN tagger for p17 data, excellent performance, nearly certified

An automated CAFe taggability paramaterizer

nn_cert: a semi-automated NN certification package

Optimized SVT parameters, and algorithm improvements

Things still aren't perfect, but progress has been made understanding some issues:

Overestimated tag-rate at low-pT in gluon-splitting samples (5-10% effect)

Underestimated taggability at low pT for high CPF jets (5-10% effect)

Finite cone size for b-hadron matching in MC / system 8 (2% effect) ...

Lots still to do: ***

Fix the above problems...

Get the muon-NN working,
finish certifying SVT for p17

Basic certification of NN p17 v2.0 and make additional improvements:
(PV_Z, tau TRFs, new systematics, light-jet data/MC SF's, etc...)

Basic certification of taggers for p20
and make improvements: (charm-jet separation, g->bb rejection, etc...)

*** will probably get done
may get done with current personnel
probably won't get done without new people

b-ID Status : Conclusions

Andy Haas

2004-07-07T15:59:13