Identification of heavy flavour jets with the CMS detector at 13 TeV
http://cms.cern.ch/cds/BTV-16-002
The comment may be found at this URL: http://cds.cern.ch/record/2280283
A. English/Style/Formatting (including figures)
B. Everything else (e.g. strategy, paper structure, emphasis, additions/subtractions, etc).
================================ Ksenia
Type A
o) L 281 “Only SVs with MSV6.5 GeV are considered.” Missing “>”.
o) Figure 13, left bottom x-axis label “P(dusg)” —> “P(udsg)”
o) Figure 20 caption “Efficiency for c jet identification versus the misidentification probability for light- flavour jets (left) or b jets for various c tagging algorithms applied to jets in tt events.” —> Efficiency for c jet identification versus the misidentification probability for b jets (left) or light- flavour jets (right) for various c tagging algorithms applied to jets in tt events.
o) Figure 25 It says pruned mass 50-200 GeV, while in text at L 806 it said to start at 70: “Jets are selected when they have a pruned mass between 70 and 200 GeV”.
o) L1586 “For convenience, the discriminator values are transformed from [− 1, 1 [ to [− 1, 1 [+ 2 ( N jets − 2 )” Misprinted brackets (also in Fig. 43 caption)
o) L1711 “pt” —> “p_{T}”
Type B
o) “These additional simulated events are then reweighted according to the observed number of pileup collisions or the observed PV multiplicity.”
How the “observed number of PU collisions” is defined? Maybe I just misread this sentence…
o) Figure 17, top left What causes the rapid decrease of b-jet tagging efficiency after pt~100? Maybe one could add a few words explaining the effect around L548?
================================ Margherita
Type B
The paper is too long and contains too many details. The chosen structure is more appropriate for an internal reference note than for a summary paper on jet identification in CMS.
English should be reviewed more accurately.
Many repetitions may be eliminated just rephrasing a bit some sentences.
Type A
Line 42 replace “beginning in 2015” with “in 2016”
Line 57: non-boosted
Line 173: trackS at their point of …
Lines 175-179: Not clear, rephrase
Line 198: angular distance between them DR = …
Line 195, 199 … matching generated jet → matched generated jet
Line 228: The category “fake” contains tracks that are more likely misreconstructed, …
Line 248: except for variables (remove when)
Line 281: “M_SV6.5GeV”→ something missing
Line 363: “obtained by integrating the resolution function R(s) from −∞ to the negative of the absolute track IP significance …
Line 365: remove “where R(S) is the resolution function
Line 385: the fact that the calibration of the resolution function is performed independently for data and simulation …
Line 412: a combined invariant mass at least 50 MeV away from the K0S mass are found(remove “that lies” and replace were → are).
Lines 413-415: Therefore, all variables related to the fitted vertex position cannot be calculated.
Fig. 11 caption: Ratio of the “E_T” of the summed … E_T of the jet; remove ] before pt
Lines 484-487 The lower right panel in Fig. 13 also shows the P(b) + P(bb) discriminator used to tag b jets in physics analyses. It has been checked that summing …
Line 498 A soft lepton in only present
Fig. 19-left: very difficult to distinguish light and c jet contributions
Lines 846-850: However, it is possible to obtain a rough estimate of the PV position along the beam line by projecting the position of the silicon pixel tracker hits associated with the jets along the jet direction on the beam line. The region along the beam line with the higher number of projected pixel hits is most likely to correspond to the position of the PV.
Fig. 26 replace “ on the z-axis” with “on the beam line”
Fig. 27 left plot with the double peak is really necessary? I would show only the plot on the right, modifying the text accordingly
Fig 28, x-axis label: Offline CVSv2 discriminator
Line 931: Figure 29 compares the HLT and offline b tagging performance using …
Line 938: add “,” after is lower
Line 939 remove “that is assigned”
Line 971:
Offline, the leading muon and electron are required to have pT > 25 GeV and be (remove “identified as”) isolated, as (remove “is”) expected for leptonic…
Line 981: Events are further considered if they contain at least four jets with pT > 25 GeV separated from
Fig. 32, caption: from [-1,1] (check the second parenthesis)
Line 1112: The reason for the smaller uncertainty for the c tagger compared to the b taggers is the different definition of the working points (remove”for the b and c taggers”). The working points for the c tagger have a much higher …
Line 1141: the reconstructed transverse mass of the lepton (remove and P_T_Miss), defined as
Line 1188: the scale factors are remeasured after varying the jet energies according to their uncertainty. The systematic …
Fig. 37: remove “The W+jets and Z+jets events are denoted by “V+jets”, and the multijet events as “QCD”.”
Line 1283: the eFfect
Fig. 38: “The lower panels show the same combined scale factor value with the result of a constant fit function superimposed…” Not true, the fit is not done with a constant function
Line 1397: “from the fit before AND after applying …”
Line 1404: The fraction of jets with a default JP discriminant value is maximum at very low jet pT (8%) and drops below 1%…”
Line 1437: S8 → System-8
Line 1460-1461 dominating → dominant
Line 1490 varying it BY +/-30%
Line 1526/Fig. 41 ”the thick error bar corresponds to the statistical error and the narrow one to the overall statistical and systematic uncertainty”. Thick error bars are not visible in the plots.
Line 1553/55/57: and THE largest
Line 1559: why the uncertainty was estimated varying the top mass by 3GeV?
Fig. 42 contributions from tW and “Other” not distinguishable
Line 1655: the uncertainty due to the factorization and renormalization scales are assessed as described in Section 8.3.2, except for the scale for FSR in the parton shower THAT is …
Line 1748: varied BY (not with) n%
Line 1750: Section 8.3.1
Line 1752: Section 8.3.2
Fig 48: Thick error bars are not visible in the plots.
Line 1826: In the first iteration no scale factor is applied, while for the next iteration the background is subtracted (remove while) using the scale factors obtained in the previous iteration. The iterative procedure stops (remove”once the scale factors obtained in the current iteration are stable with respect to the scale factors obtained in the previous iteration. This convergence is”) typically after three iterations. ….
Line 1913 remove “a” before the
Line 1917: remove “and uses jets from gluon splitting to bb.“
Line 1957-59: rephrase:” The measurement is compared to the corresponding AK4 jet scale factor and within the uncertainty both scale factors using jets with pT > 200 GeV”
Replace Softdrop subject → soft drop subjets
================================ Nadia sent mail with comments on August 20th