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Progress in Jet Lifetime b-tagging

Progress in Jet Lifetime b-tagging. positive IP if  < 90° negative IP if  > 90°. Daniel Bloch + Benoit Clément, D.Gelé, S.Greder, I. Ripp-Baudot (IReS Strasbourg). “b’’ axis. IP. track. . Primary Vertex (Ariel’s code).

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Progress in Jet Lifetime b-tagging

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  1. Progress in Jet Lifetime b-tagging positive IP if  < 90° negative IP if  > 90° Daniel Bloch + Benoit Clément, D.Gelé, S.Greder, I. Ripp-Baudot (IReS Strasbourg) “b’’ axis IP track  Primary Vertex (Ariel’s code) Then combine all positive (negative) IP in the same jet to compute a positive (negative) jet lifetime probability D. Bloch (IReS Strasbourg)

  2. Optimize the “b” axis estimate • Use the jet+muon axis if there is a muon inside the jet • Use the signed decay length between primary (PV) and secondary (SV) vertices if SVX are fitted inside the jet (using Ariel’s code) • Reject Kºs if it is a two-track SVX • Use the jet (+muon) axis if the decay length is too small (i.e. |L|/ < 5) For the SVX algorithm, use the following rule : 2D built-up 2ndary vertices using at least 2 tracks with  2 SMT hits and |IP|/ > 5 D. Bloch (IReS Strasbourg)

  3. Use jet axis by default Use jet + muon axis if muon inside jet Use PV-to-SVX axis if |L|/ > 5 jet+ Reject Kºs D. Bloch (IReS Strasbourg)

  4. jet+muon axis is a small effect using p13 (gtr+htf) TARC data rescaled to the same number of taggable jets SVX alone with jet+mu axis OLD JLIP(jet axis only) D. Bloch (IReS Strasbourg)

  5. Rejection of Kºs : nice signal, but also a small effect using 200,000 p13 jet trigger data Reject if 475<m(+-)<525 MeV D. Bloch (IReS Strasbourg)

  6. Improved jet lifetime in TARC data NEW JLIP+SVX SVX alone OLD JLIP D. Bloch (IReS Strasbourg)

  7. ptrel fits on muon+jet data better parametrisation D. Bloch (IReS Strasbourg)

  8. Jet lifetime performance in data NEW OLD full : central open : forward D. Bloch (IReS Strasbourg)

  9. BUT muons from pi/K decays look to have larger pTrel tails than ordinary tracks… ( Benoit Clément ) QCD (light) MC jet trigger data muon from pi/K muon any track any track D. Bloch (IReS Strasbourg)

  10. JLIP performance in MC NEW b OLD b NEW c OLD c D. Bloch (IReS Strasbourg)

  11. Summary • 10-15% improvement in jet lifetime IP b-tag if combined with secondary vertices • better parametrisation of ptrel distributions, but cross-checks going on • macros to be released soon D. Bloch (IReS Strasbourg)

  12. p14 MC requirements • 100 000 Z -> uu, dd, ss 100 000 Z -> bb 100 000 Z -> cc • 100 000 Z -> uu, dd, ss with at least one pi/K->mu 100 000 Z -> cc with at least one c->mu 100 000 Z -> bb with at least one b->mu or b->c->mu • 100 000 QCD pt>80 GeV 100 000 QCD pt>80 GeV with at least one c 100 000 QCD pt>80 GeV with at least one b will allow more detailed studies of tagging and mistag rates up to high pT’s, and to check the muon pTrel parametrisations D. Bloch (IReS Strasbourg)

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