A brief Update on secondary vertex tagged jets MC-based Efficiency/Purity studies 12/4/2019 Eugene Galyaev

Central region jets, |y| < 0.5 12/4/2019 Added variable bins: Central region jets, |y| < 0.5 12/4/2019 Eugene Galyaev

“Raw” X-section by trigger Central region jets, |y| < 0.5 12/4/2019 Eugene Galyaev

Work is being done on MC efficiencies Defined 5 cathegories: b-parent, b in the Jet No b-parent, but b in the Jet c-parent, c in the Jet No c-parent, but c in the Jet No parton showers This info will allow to estimate efficiencies/purities in MC 12/4/2019 Eugene Galyaev

What was done… Content study based on inclusive QCD MC Various mean Pt ranges were used, approximately 1.5M events total Central jets only | y | < 0.5 Have divided MC into 9 P regions: [0-40], [40-80], [80-120], [120-160], [160-240], [240-320], [320-400], [400-600], [600- ..] GeV Observed shapes for the tagging variable distributions for b, c, and udsg MC contents Template shapes shown to be universal at jet P > 40 GeV Results on the b-content extraction by fitting was overlaid with the MC – derived purity curve, no cut on Log(2DdLSig) Provides data-driven cross-check to the MC results Included the possibility to vary the Log(2DdLSig) cut to be able to see the effect on Efficiency/Purity results Will help to understand and optimize the cut 12/4/2019 Eugene Galyaev

Efficiency and Purity Sample plots for Efficiency and Purity vs. cut in Log(2-D Decay Length Significance) in a couple of Pt regions: [40-80] GeV [0-40] GeV 12/4/2019 Eugene Galyaev

Efficiency and Purity dependence on Pt (no cut applied): MC Efficiency, Purity vs. P (b-vtx, no cut) Efficiency and Purity dependence on Pt (no cut applied): b – vertex finding efficiency in MC is slowly decreasing with Pt b – content in data seems to be in disagreement with the MC at low Pt - The fitting procedure is inefficient at low Pt?… 12/4/2019 Eugene Galyaev

Check the fitting procedure (recent…) Try to fit the templates to the inclusive QCD MC Good “Simulation” Yield >>perfect<< fits EVERY TIME!!! Fitting is NICE with Monte Carlo! So the DATA must be different………. c2 = 0.75 At 100 GeV Pt bin ! 37% Vs. 34% MC ‘Truth’ purity 12/4/2019 Eugene Galyaev

MC Efficiency/Purity curves, b-vtx, 2DdLSig > 32 cut A cut: Decay Length Significance > 32 Cut was picked from 2D Decay length distribution shapes a while ago: Exists historically From this plot this may not be the best value? Let’s see corresponding Efficiency and Purity dependence on Pt!… cut position values Since Early 2VTX p13 studies… 12/4/2019 Eugene Galyaev

MC Efficiency, Purity vs. P, b-vtx, 2DdLSig > 32 cut Efficiency and Purity dependence on Pt (2DdLSig > 32): Efficiency @ 100 Gev Efficiency drop by ~30% Purity increase by the factor of x2 Purity @ 100 Gev 12/4/2019 Eugene Galyaev

MC Efficiency/Purity curves, b-vtx, 2DdLSig > 12 cut A new experimental cut: Decay Length Significance > 12 This point seem to have less efficiency loss with considerable gain in purity at the same time Let’s see Efficiency and Purity dependence on Pt for this cut value! cut position values cut position values 12/4/2019 Eugene Galyaev

MC Efficiency, Purity vs. P, b-vtx, 2DdLSig > 12 cut Efficiency @ 100 Gev Efficiency drop by ~7% It seems like this choice of cut would work better! Purity increase by the factor of x1.6 Purity @ 100 Gev 12/4/2019 Eugene Galyaev

Work in progress…! Status and plans… Need to think of some other cross-checks between MC and the data Overall fairly good results so far – this is just the first steps… Add a muon requirement? Suggestions welcome!!! Try to re-fit the low P data region Maybe make some special templates for that region? Come up with the ‘justified’ cut selection criteria Need to intelligently pick the Decay Length Significance cut value, based on all known information. Proceed with the 2VTX-tagged b-jet cross section results Figure out and apply all the efficiencies… Do the unsmearing… Work in progress…! 12/4/2019 Eugene Galyaev

Efficiency and Purity (continued) Efficiency and Purity vs. cut in Log(2-D Decay Length Significance) averaged per entire MC sample (all Pt) Corresponding Log(2-D Decay Length Significance) shapes 12/4/2019 Eugene Galyaev

MC Efficiency/Purity curves (b-vtx, no cut) No cut in Log(2DdLSig) applied… These curves reflect the Efficiency/Purity values for the possible cut position… Can be used to optimize the cut! 12/4/2019 Eugene Galyaev