CADI:
https://cms.cern.ch/iCMS/analysisadmin/cadilines?line=HIG-20-008&tp=an&id=2332&ancode=HIG-20-008
Color Code
Color |
Meaning |
BLACK |
Question or comment from ARC/conveneers |
RED |
Authors know but not yet added/implemented |
GREEN |
Answer from Authors |
ORANGE |
Authors working on this item |
BLUE |
authors answered but might need iteration with ARC |
Comments for data-card
NP naming: in order for the NP to completely follow the HComb convention, it would be nice if you could add _hzz to the analysis-specific nuisances names
done
Lumi NP: you mention that for the lumi you are using a weighted average of the three years as NP. However, this is not taking into account the partial correlations among different years. Also, the value quoted by the Lumi POG for the full Run II uncertainty on the luminosity should be 1.8%, somewhat different than the 2.4% you are quoting. Please consider using the correct value of 1.8%, this should be fine as you are considering a single signal process inclusive on the three years. OTOH note that when using this 1.8% you would not be considering the partial correlations among years, but this should not have any substantial impact on the analysis results.
I changed to the recommended luminosity uncertainty of 1.8%.
Blinded limits: since you are using HybridNew to extract blinded limits, you should generate an asimov toy first (with GenerateOnly --saveToys) and use -D <file_with_toys.root>:toys/toy_asimov to have a blind limit, otherwise you are getting post- fit expected, which already uses data.
done
CMS_H_mean_e NP: In the ZJpsi->2e2mu and ZJpsi->4mu cards (so the separate ones) there are param lines in the datacards that are not associated with any params that actually exist in the input workspace. For example there is a parameter CMS_H_mean_e in the workspace, and a param line CMS_H_mean param 124.690 0.047 Please fix this and use consistent naming between datacard and workspace.
done
Background: Both in the AN and in the presentations given at HZZ/HIG PAG meetings you mention that this analysis uses "data-driven background". OTOH you also quote three MC samples used to model the background. Our understanding is that the background is not really data driven, but rather parametrized with an analytical expression using these MC samples. Can you please clarify on this?
The background is dominated by associated production which is sampled from the side-bands. In addition, possible peaking background is estimated from dedicated MC samples and is found to be negligible (far less than 1 event). These backgrounds are not included in the fit. Hence, we characterize the procedure as purely data driven.
Also, you have a NP associated to the background (CMS_bkg_frac param) only in the JJ4mu card. I think you should have NPs associated to the background in all your cards.
The parameters of the background shape functions are free to float. Therefore, they are not accounted for as NP – the inclusion of the background fraction which is floated in the JJ card was a mistake (double counting).
text2workspace: if you are using any particular model, please upload it to the repository. It would be nice, just for completeness, if you could also share the text2worskpace commands you use to generate the workspaces starting from the datacards, especially if they contain any particular option for the POIs ranges and/or re-definitions.
done
Data-card approval message
Thanks for uploading the datacards for review so early. After some iteration with the authors we're now happy with the cards so they are approved. If major changes to the structure are made between now and the pre-approval presentation, please do let us know so that we can double check. [ https://hypernews.cern.ch/HyperNews/CMS/get/HIG-20-008/3.html]
MUON POG approval message from Jonatan
Thank you for filling the muon documentation required for HIG-20-008[ https://twiki.cern.ch/twiki/bin/view/CMS/TWikiHIG-MUO][ https://twiki.cern.ch/twiki/bin/view/CMS/HIG20008muons]. I have reviewed it and I haven't found any outstanding issue, therefore you have the HIG-MUO green light.
JME approval message from Alexis
Thank you for completing the JME questionnaire. Given that you are using neither jets nor MET, we only have to wish you good luck with the rest of the analysis review! [ https://hypernews.cern.ch/HyperNews/CMS/get/HIG-20-008/5.html]
Comments From Giacomo
Abstract: I think the abstract is the only part needing a somewhat larger revision. The way It is written is a bit too convoluted imho. It would be better to rewrite it making the sentences more straightforward. For example the first sentence could read as “This paper presents the first measurement of the H->Z J/Psi decay. H->Z J/Psi candidate are studied in the four leptons final state exploiting the full LHC Run 2 dataset of 137fb-1. In addition, H and Z boson decays into pairs […] Different polarisation scenarios of the Z boson are studied.” etc.
⇒ We rewrote the abstract in the next version.
L35 (second paragraph). Is it possible to include a table with the available predictions for the SM? Or add it in a new column in table 3?
⇒ It would be nice to summarize all measured and predicted BF in a table - for measured done.
Majority of the Quarkonium channels do not have SM predictions:
1. No predictions for Higgs to Y(ns)Y(mS) (except Y(1S)(1S)) and Z boson to Y(nS)Y(mS) channels;
2. Feed-down quarkonium channels (H→ J\psi \psi(2S), H→ \psi(2S) \psi(2S)) have no SM calculations.
In the case of the H→ Y(1S)Y(1S) channel, SM theoretical prediction is not consistent:
Previous calculation using a phenomenological approach provides BF in order of 10^-5 [31]. But Latter, Ref.[35] assumes dominant contribution from indirect Higgs coupling, and provides BF in order of 10^-9 [35].
L35: I’m not sure it is a good idea to cite HL-LHC here, since this is a purely LHC paper. But this can be discussed with ARC and in CWR.
⇒ We removed HL-LHC sentence
L48: I should probably go through ref [29], but it is not clear to me how is it possible to have a BR>1 in any channel. Surely the maximum value should be 1-(whatever has been observed for other channel), isn’t it?
⇒ Ref.[29], page 4, last paragraph: 𝜎(pp→ H). BF(H->ZJ\psi) = 100 pb.
L51: Maybe I miscounted, but isn’t this the “second” class you are speaking of? Otherwise, mention explicitly which is the second when you introduce it.
⇒ L:22 A related class of such processes…….. ⇒ A second related class of such processes…...
L207: You select 4mu events as well, so this should be “event with at least 2 muons plus two leptons”
⇒ done
L210: does the 5 GeV cut applies both to Z and J/psi? If yes, “each dilepton resonance…”
⇒ done
L214-216: Invert the 2 sentences: put “A total of…” first, and “The range of…” second, so the range is already defined when you mention it. L214: you should specify which threshold you are referring to.
⇒ “The range of the four-muon invariant mass is chosen to exclude the region close to the threshold. A total of 164 (124) single candidate events are found in the 4μ(2e2μ) invariant mass between 112 and 142 GeV ” is changed to “ ⇒A total of 164 (124) single candidate events are found in the 4$\Pgm$ ($2\Pe2\Pgm$) invariant mass between 112 and 142~\GeV. The lower range of the four-muon invariant mass is chosen to exclude the region close to the threshold.”
L230: “before unblinding”
⇒ done
L232: I think at the end of the line it should be Y (without (1S))
⇒ done
L259: either here or in the systematics section you should mention you did the bias studies and the effect of other shapes was found to be negligible
⇒ L259: Added sentence ⇒ “A possible bias in the choice of the background parametrization is probed with alternative functional forms and found to be negligible.”
L293: Please note there is a new prescription for the treatment of the luminosity uncertainty https://hypernews.cern.ch/HyperNews/CMS/get/physics-announcements/6191.html
⇒ Lumi uncertainty is changed to 1.6 % from 1.8 %
(Data-cards are updated. The expected BF will be updated in the next version.)
It is not necessary for preapproval I think, but is nevertheless better if you start including it Section 8: It would be nice to quote how much you are improving wrt previous results (for those channel where we had a previous result).
⇒ We will quote improvements in the next version.
Table 3: Can you add 2 columns for the results under the alternative polarisation hypotheses? And maybe a third one with SM expectations?
⇒ we will add a column for the polarization hypothesis in table 3 in the next version.
Finally it would be nice to have a summary plot of the results, maybe something similar in style to this one [ https://cms-results.web.cern.ch/cms-results/public-results/publications/HIG-19-001/CMS-HIG-19-001_Figure_014.png]
but with BF instead of cross-sections
⇒ Some of our channels do not have SM predictions. Measured Upper limit in our channels are 3 (5) orders of magnitude smaller than the SM prediction in ZJ\psi (Quarkonium) channels. SM predictions for ZJ\psi (Quarkonium) channels are 10^-6(10^-9--10^-12). We prefer showing these result summaries in the table.
Comments From Maria, Nick and Jan
(*) General: It would be great if you can add a comparison of the expected results of this analysis and HIG-18-025, and point out any differences and updates since then.
⇒This concerns the channels H->JJ, H->YY, Z->JJ, Z->YY and we added a table in the next version of the AN (Table 19 and Text L 447 to L452).
L292: You give as source for the muon efficiencies the following link https://twiki.cern.ch/twiki/bin/viewauth/CMS/MuonReferenceEffs2017 - this is for 2017 only, so please update the information
⇒ For the 2016, 2017, and 2018 period the full list is given here: https://twiki.cern.ch/twiki/bin/view/CMS/MuonReferenceEffsRun2 which is included in the next version of the AN.
L329-331: What does it mean that "the event uncertainty is [...] less than unity"?
⇒ The resulting relative uncertainty is found to be less than one percent. ‘Unity’ is a typographical error.
L323-338: It does not become clear how you evaluate the momentum scale uncertainties given that the signal shape is obtained from a fit. Please clarify.
⇒ The change in the resonance mass was finally measured from the J/psi and Z di-lepton signals, in data and Monte Carlo. There we find, that the relative shift between the reconstructed MC signals and the signals in data when fit with the same parameterization is at about 0.2% (PDG values were generated). We conservatively assume that combining the signals leads to a 0.4% relative shift of the Higgs mass. Repeating the UL extraction with this shifted Higgs moves the UL by less than 1% in the 4mu (3% in the (Z->ee J->mumu) channel). We conservatively adopted the 1% in the 4mu, 3% in the 2e2mu channel.
Himal started out using the Rochester (electron) correction method and described this in the note. The scale factors are found to be one. Since we actually use the conservative estimates based on the control signals described above, we updated the text in the AN (L323 to L 333).
Figure 15: Do you have an explanation why the background fraction parameter has such asymmetric uncertainty and impact?
⇒ The impact plot is obtained with toy samples. The toy Monte Carlo demonstrates that this functional form, the combination of an exponential and a uniform function leads to an asymmetry in the fraction.
Figure 20: For the YY channel in the bottom right plot, the signal is far out in the tail, so the background from the fitted function must be negligible. Have you tested fit functions that have a larger tail than exponential + uniform? (I understand from section 7 that you tested different functions, but it is not clear if this led to any uncertainty or whether all tests were satisfactory)
⇒ Other parameterizations were exponential plus uniform and exponential plus exponential. In both cases we found that the extra contribution fits to zero fraction.
Comments From Pre Approval
Many thanks for the clear pre-approval talk yesterday at the Higgs PAG meeting. We have collected the few to-do items to follow up on. Since you have completed the list of pre-approval checks, once we are satisfied with the responses to these few items, we can move onto unblinding.
We think there should be further study of background functions that could provide alternative fits to assess the level to which the choice of background function could impact the result. During the pre-approval it was mentioned that other functions were tried but the fits were unstable. We think in some of the fits, something like a power-law function (a*x^{b}, with x as the mass and a, b are the free parameters) would work. At the very least it would be helpful to compare the nominal fit to at least one other and show the resulting background functions under the signal peak are similar (within the uncertainty on the fit).
We implemented the power law function with floating power (b) in the YY final state as discussed above. We obtain 95% CL upper limits with this new background pdf. We find at most a 2% change in the BF for the Higgs bosons (6% for the Z boson). In addition, the number of expected events for 3 sigma, 5 sigma significance are within one event with the previous estimate.
We find that the fit quality has deteriorated (the chisquare becomes worse above 75 GeV) and the change in the BF is within or close to the estimated systematic uncertainty due to the background parameterization.
For the fit on slide 12, it looks like there would be enough data to split into categories based on the resolution of the events. Could you try to see what would be the expected gain (if any) of splitting the events (just for this particular case where there are more events) into two regions based on the mass resolution (or say leading lepton eta which would make a good proxy for the resolution)?
The sample is about evenly split when requiring that the leading muon is either to be found in the barrel region (|eta| < 1.1 ) or in the forward region (|eta| >= 1.1 ). Maintaining the full background sample, the reduction of the upper limit for the barrel region sample was about 5%, while for the forward region sample the increase in the BF was about 12%. Hence, we do not expect to gain by splitting the event sample.
For slide 18 (just for the AN) can we have a version of the bottom plot with the 3 resonances split into different lines (with different colors) to see more clearly the different peaking contributions?
We now display the simulated samples in different colors: H→ Y(1S)Y(1S) in black , H→ Y(2S)Y(2S) in red and H→ Y(3S)Y(3S) in green.
Followup Comments From Nick
Many thanks for your responses. I have a couple of follow up questions,
1. For the test using a power-law, its good to see that the expected limit is not changing very much however, the significance from observing a fixed number of events (which is in the end what we would report) seems to change. What I was hoping to see was a direct comparison of the background estimate under the peak using the two functions and there are 2 ways to do it
a) plot the background functions that are fitted overlaid on top of each other all the way out to 140 GeV (so that they can be seen), with the uncertainty bands from the fit included (e.g using the RooFit method VisualizeError taking each fit result : https://root.cern/doc/v608/rf610__visualerror_8C_source.html
)
b) calculate the integral of each fitted background function in a suitable range under the signal peak (say 120->130 GeV) and their uncertainty.
In either of the above, what we want to see is that the difference between the background estimate under the peak is much smaller than the uncertainty.
The quality of the fit (chisquare) with the power law disqualifies this function. Hence, it was inappropriate by Himal to use it for further extraction of results. The distribution of events in the four-muon invariant mass decreases rapidly with an endpoint around 85-90 GeV, which makes the use of any function to extrapolate the behavior into the Higgs signal region questionable. The discussion about this happened during the review of the previous paper. Given that the lower sideband, say extending 20 GeV, is depopulated and the depopulated upper sideband in principle extends to infinity, the interpolation of the background into the Higgs signal region results in zero background events. The 95% CL upper limit signal yield for this zero-counting experiment is about 3. This is reproduced with the exponential function which was used as vehicle to apply the Higgs combiner tools.
In case there is indeed one event in the signal region after unblinding, there will be a completely different treatment of the background. In coordination with the statistics committee we formulated the publication strategy last time: “The proposal, agreed with the SC, in case of a single event under the Higgs peak, is therefore to publish the event without a significance; rather provide observables (4mu, 2mu invariant masses); possibly an event display.” We do not report any significance in the present paper draft.
2. For the splitting of the events in H -> ZJ -> 4mu, thanks for checking the individual sensitivities, but can you also just go ahead and produce the expected limit from the combination of the two categories (to be sure what the combined result would be compared to the single category scenario)
From the simultaneous evaluation of the expected 95% CL BF upper limit with the two sets categorized by |eta|, Himal yields: BF = 3.34 e-3. The single category result is: BF = 3.3 e-3. This is done with 1000 toys – the closeness is probably coincidence as the sample by sample fluctuations are more like 5% – but they are close.
Followup Comments From Nick
However, for the limit, I would still like to clarify my conceptual concern. Right now you have upper limits consistent with 3 events (which is what one expects if you see no events), snd since the background expectation is ~0 those 3 events can be converted into a branching ratio. However, you seem to have concluded that you expect 0 background events and then confirm it with the exponential - I think it would be even more convincing that you expect ~0 by trying with more than one function (doesn’t have to be a power-law, that was a suggestion based on what was discussed in the pre-approval), and show that either function would yield a prediction of 0 (or at least something close such that in either case, you’re back to ~0). The point being that with >1 function predicting ~0, the arbitrary choice of that function becomes irrelevant - I think the plot I asked for would directly show that (unless I’m missing why an exponential is really the physics driven function)
Sorry, I forgot to add that the discussion on the effect of different background parameterisations was so far only concerning the YY channel, but equally (probably more important) a similar concern about the background choice is there for the J/psi J/psi and Z J/psi channels..
Please find the background functions that are fitted overlaid on top of each other with the uncertainty bands from the fit included for the Z J/psi and J/psi J/psi final states in the attached slides. We used the RooFit method VisualizeError. Please find the calculated integral of each fitted background function in the range 120->130 GeV together with their uncertainty listed in the table on the last slide.
I separately evaluated H->YY using the exponential and the power law function. The integrals yield 0.00 +/- 0.00 and 0.03 +/- 0.03 events, respectively, with the caveat mentioned earlier, that the power law function has a much lower fit quality.
[ https://hypernews.cern.ch/HyperNews/CMS/get/AUX/2021/08/02/20:52:38-74320-Pre-ApprovalFollowUpComments.pdf
]
Followup Comments From Nick
Many thanks for these - the plots are exactly what I was looking to see. I think this answers my concern so we can give the go ahead to unblind.
Please get the un-blinded results [ https://hypernews.cern.ch/HyperNews/CMS/get/AUX/2021/08/09/20:06:59-73314-UnblingingOfHIG-20-008-Step3.pdf]
Pre-Approval Message From Maria, Nick and Jan
Thanks for providing the unblinded results (though we were expecting first to see the distributions before the observed limits, but don’t worry ). Everything looks ok to us so please go ahead and update the AN and paper draft with the unblinded plots/results and after that I think we can pre-approve.
Comments From ARC member Keith
general: how did you determine the selection cuts?
The selection cuts are determined using sideband data to estimate background and signal simulations to estimate the efficiency times acceptance. The cuts are optimized to maintain high signal efficiency times acceptance while keeping background to the level necessary to obtain the best expected upper limit.
5.1 I still can't quite tell what the final muon selection is. Is it one of the standard Muon POG approved IDs? Be clear as this will justify using standard POG derived scale factors and uncertainties.
The official soft muon ID is used in the analysis. Standard scale factors are available, and the treatment of the muons is confirmed by the muon POG.
5.1 You don't mention muon isolation. But you must use some isolation criteria, right? Again, if it is a POG derived version, make that clear.
The muon isolation is described in Sec. 5.4. I moved this text to Sec 5.1 in the next version of the AN.
5.2 Also here, is it a standard POG ID and isolation?
The same standard muon ID definition is used in all channels. We use a loose track isolation. ID and isolation criteria are approved by Muon POG.
5.2 What is the advantage of track-based isolation over particle flow-based isolation?
Our criteria including isolation are based on the muon track reconstruction. The isolation cut is designed to maintain a 99% efficiency as estimated from simulation.
5.4 muon pt>3 GeV seems very low to me for a Z->mu,mu selection. The single mu trigger requirements must already be quite a bit tighter than this, no?
The single muon trigger requires at least one of the muons from the Z boson to be higher than 27 GeV. From Fig:4(c) and (e), almost all the muons from the Z boson have pT greater than 10 GeV. On the other hand, the Jpsi Fig:4(d)(f) decay muons have very low pT. Hence, we choose 3 GeV.
5.4 You mention the electron isolation here, but it would be easier to follow if you put it up in Sec. 5.2.
The muon and electron isolation descriptions are moved now to Sec. 5.1 and 5.2, respectively.
Section 7 In equation (4) does "Uniform" just mean a constant?
yes.
In 7.1.2 and 7.1.3 it would be nice if you could give the actual expected background numbers (like you do in 7.1.1).
I have now provided the expected number of events in each case. In case of gg-->ZZ*-->4 mu and qq->ZZ*->4mu, we expect 0.04 and 0.4 events, respectively.
Fig. 14. What range in the 4 lepton mass is used for these fits? The plots would be a lot easier to evaluate if you should also the sideband used for the fit. Also the fit range should be specified somewhere in the event selection section (maybe I just missed it).
These plots are designed to visualize the possible bias due to the choice of the background function near the signal (see discussion in Twiki). The fit is applied to the full range. The description of the fit region is added to the AN.
Fig. 14. How are the uncertainties plotted? The quoted numerical change in the background predictions look smaller than the plotted bands.
The details of the method are discussed here: https://twiki.cern.ch/twiki/bin/view/Sandbox/HimalAcharyaSandbox#Followup_Comments_From_Nick_AN1
The background yield is obtained from the integration of the center curve. The uncertainties are the differences between the integration of the curves that bound the bands and the center curve.
Sec. 7.3 line 280 seems to say "Fit 2" is used for the quarkonium channel. I think "Fit 2" means an exponential plus a constant. But back in Eq. 5 I thought it was just an exponential.
Exponential + Uniform is used for Jpsi Jpsi channels. Exponential only function is used for YY channels. I updated the text to state this clearly.
Sec. 10 -I'm confused about what is being fit. Is there one big simultaneous fit to the 4mu and 2mu+2e mass shapes? Or is each fit simultaneously? And within 4mu, is it one fit separately in the Higgs mass range and another in the Z range, or a combined fit to all simultaneously?
The 4mu and 2e2mu four-muon invariant mass spectra in the ZJ/psi channel are fitted simultaneously using the Higgs combiner tool (RooFit). The model allows for a common slope for the background as found from the individual fits. The signal shapes are parameterized and fit individually. In the 4 mu quarkonium final states the Higgs and Z boson upper limits are obtained independently.
-For whatever number of fits is being done, make clear what the floating parameters are and what the fixed parameters are.
Sec 10 (L 425) I added :“The signal parameters are fixed and the background parameters are floated in the maximum likelihood fits. The uncertainty associated with each signal parameter is incorporated as a nuisance parameter in the upper limit calculation.”
-For the background-only fit, are you still blinding the signal mass window, or is it now fitting the whole range?
For this exercise it was agreed to use the Asimov dataset created from unblinded data (made background in a combiner as -t -1 --expectSignal=0), feeding the combiner without inspecting the sample.
-Lines 438-444. You use all of the Upsilon resonances, which seems good. But when Y(2S) or Y(3S) feeds down to Y(1S)->mu,mu, the 4mu mass must be off from the Higgs mass. How do you handle the feeddown in the fit? With separate line shapes for each?
For the Z->YY channels we obtained the combined signal shape from the simulation of all the possible transitions, adding them with the ratios obtained from PDG, while assuming that the YY coupling to Z is the same for all Y(nS) pair states. The contribution from the indirect feed-down channels Y-> Y(1S) X is small compared to the direct decay channels Y(3s)->mumu, Y(2S)->mumu and results in a modest increase in the width. The change in the upper limit is found to be small (at the level of the systematics due to the uncertainty in the width). The details are given in Sec. A 28 (page 68). Since there is no background contribution above 75 GeV, the Higgs boson is not affected by this.
-For each fit, please also give the fitted signal yields. This will allow us to compare the final upper limits with the results of the fit. I'm guessing you are statistical limited (and the systematics aren't so important), but it's hard to tell from how this is presented currently.
I have added observed signal yields in the table. In addition, I attached the slide “FinalUnblindedUpperLimitCalcHIG-20-008.pdf”, which shows details of the calculation.
-Show the data mu+mu- distributions and the e+e- distributions. Are these shapes as expected? Do the fits agree with the MC? Are there any signs of peaking backgrounds beyond those discussed already?
The Figure 3 shows the di-lepton invariant mass distributions. In each case, the signal is modeled from simulation and fits the data together with a smooth background function.
-Table 16. In the first row with number there are some values in the parenthesis. What are those?
They are the next significant digit. We removed this.
-Table 18. Why is the Z->J/psi,J/psi result worse than expected from scaling the 2016 result. Is there some background that is worse in the 2017-2018 data?
The change is less than 1 sigma consistent with an upward fluctuation.
-Table 17 gives the expected significances for various scenarios. Did you do a test where you artificially inject such a signal into MC backgrounds and check that your fitting procedure would recover the signal as expected?
Yes. Fit diagnostics for 0 and 1 signals are done and verified that we get the same signal as we injected. This is one of the exercises for the data-card approval.
Comments From ARC member Jonatan
- Abstract. Why it is important to remark that you are "using online event filters"?
removed this statement
- Abstract. I don't fully understand the word "decay" in the sentence "Longitudinal polarization is expected for the Z boson and assumed for the decay mesons".
Shortened the statement: Different polarization scenarios for Z and quarkonium resonances are considered.
- Line 12. decay into --> Higgs decay into
done
- Line 12. I think CMS recommends {\rm \bar{c}c}.
done
- Lines 17, 19, 20, 23. I would remove the spaces in the different decays.
done
- Line 20. You don't need to specify again that the vector meson is V, as it has been done in line 17.
done
- Line 23. represent --> represents
done
- The Figure 1 caption is incomplete.
The caption reads now: Sample Feynman diagrams depicting direct (left) and indirect quark coupling contributions to the $\PH \to \cPZ \rm{Q}$ decay, where $\rm{Q}$ represents a quarkonium resonance. The diagrams represent Higgs boson decays into quarkonium pairs when replacing the bottom section with the upper half in each.
- Line 53. How about representing the corresponding Feynman diagrams? It would be more clear.
We also add text in the caption addressing this. We would be prepared to add more diagrams - at this point we assumed that can save the space as the diagrams can be simply derived?
- Line 66. What is Z_a?
This is a typo as it should refer to the pair decay: H -> Z_d Z_d
- Lines 68, 75, 78, 81. Paper --> paper
done
- Line 72. You have written twice the BR of H -> Z J/psi.
typo before → one BR of H->ZJ/psi is changed to ZPsi(2S)
- Line 81. (p p) --> (pp)
done
- Line 83. In the Abstract you have 137/fb and here the number is 133/fb.
Quarkonium pair trigger started later in 2017 and is missing in 2017 B, which makes this only 133 /fb.
- Line 109. It might be necessary to write what X_0 stands for.
radiation lengths - we use here standard text which assumes the common … interleaved with lead corresponding to a total of three radiation lengths …
- Line 110. Particles should be written in non-italic form, therefore you should write ${\rm Z \to ee}$.
done
- Line 116. In this sentence the MET doesn't take into account electrons or muons. Is this correct?
Yes. The sentence describes the standard Run-2 primary vertex calculation.
- Line 130. ZJ/psi channel --> the ZJ/psi channel
done
- Line 135. probability of greater --> probability greater
done
- Lines 138-139. As you have already required an invariant mass for the dimuon system, I would remove the requirement of pt > 0 GeV for 2016. In fact this is not a requirement.
done
- Line 165. In this Paper --> In this paper
done
- Table 1. I would explicitly add "Acceptance relative change [%]" (or something like that) in Table 1.
Use your proposal - done
- Line 214. selectrion --> selection
done
- Line 215. shonw --> shown
done
- Line 229. with each pT > 4 GeV --> with pT > 4 GeV each
done
- Overall, a table with the different selections would be very helpful. Maybe also another table with the yields.
Selection criteria are described in the text and final yields are presented with the 4-lepton invariant mass distributions. The intermediate yields do not contribute to the calculation of upper limits BF at 95% C.L. These are our arguments not to include such table and save space.
- Line 252. invariant mass distribution --> invariant mass distributions
done
- Line 257. Which alternative functional forms have been tried?
exponential only, power law, double exponential, low order (2) Chebyshev polynomials
- Line 331. this Paper --> this paper
done
Follow Up Comments From ARC member Keith
I still don't see why track-based isolation would be better that PF isolation.
Both, PF and track-based isolation for muons are available. For both, studies for Run-2 are published and the scale factors are established. The agreement between simulation and data is found with scale factors close to 100% and systematic uncertainties of less than 0.5% for both methods. In this as in the previous analysis we chose track-based isolation, approved by the muon-pog.
I'm sorry, but I still don't understand what the "full range" of the fit is here. Where in the AN is it described?
In each channel, the fits are performed within the ranges as chosen for the final results. These visualization plots were requested to focus on the regions near the signal to demonstrate the level of difference under the signal. The ‘full ranges’ are described where applied to the different channels. We will collect the information in a table here.
All of the different fits need to be spelled out clearly in the AN. Let me see if I understand it. For Z+J/Psi, you simultaneously fit the 4mu mass and the 2e+2mu mass. Those shapes are both fit with an exponential + a constant. You float a single value for the exponential and apply it to both backgrounds? What about the constant part? Is it common between the 4mu and 2m2e as well? What would really be the most helpful is a table with all of the floating and fixed parameters for each fit.
Then you have limits for both Z+J/Psi and Z+Psi(2S). Do you do two different versions of the 4mu and 2mu2e shapes, one to get the Z+J/Psi limit and one to get the Z+Psi(2S) result? Or you have a single signal shape that includes both of them in the appropriate ratio? Again, I think a table with all of the fit parameters would help me a lot.
The above example is for Z+J/Psi, but similar information is needed for the J/Psi+J/Psi and Upsilon+Upsilon fits as well.
We are going to implement the description to address this.
OK. So is the signal line shape in Fig. 21 bottom right including all of the Upsilon(nS) states then?
Yes
I guess you mean AN table 16, right? I don't really understand the "observed yield" column. For example for the H -> YY case you observe 2.86 events? From the plot in Fig. 21 bottom right it looks like your fitted yield should be very close to zero. Also include uncertainties on the fitted yields.
Observed yield corresponds to the 95% CL upper limit. The corresponding BF is the observed BF. In case of H->YY with no signal and marginal background the yield is close to the zero-counting value.
-Table 17 gives the expected significances for various scenarios. Did you do a test where you artificially inject such a signal into MC backgrounds and check that your fitting procedure would recover the signal as expected? >
> Ans: Yes. Fit diagnostics for 0 and 1 signals are done and verified that we get the same signal as we injected. This is one of the exercises for the data-card approval.
That study should go in the AN for the next version.
We will add the information in the next version of the AN.
Comments on AN From ARC member Nuno
general:
+ selection
it was not clear, incl. from the AN, whether a specific criteria,
- e. quantitative figure of merit, was used to decide on the selection; I trust this will have been discussed extensively in previous review steps leading to unblinding. this element being always central for a search, it would be appropriate to try to motivate the rationale for the selection cuts, in addition to listing them.
We will describe this in new version of the AN. Please see the answer to Keith on that, too. We also propose to add the description in the paper.
I noted this addition in paper v6 (wrt v3) "Further selection criteria are applied to the different four-lepton final states to achieve the lowest expected upper limit at 95% CL. This optimization was performed with data with the direct decay signal regions removed [64]." It is nice to see the reference to blinding technique; indeed the main point here would be ensure the reader our selection is determined in an unbiuased fashion. But is the optimization really done with signal (sideband) only, not MC?? could some more info (or reference!) on method used to quantify lowest 'expected upper limit at 95%CL' be added perhaps.
We added details the following:
Further selection criteria are applied to the different four-lepton final states to achieve the lowest expected upper limit at
95\% \CL~\cite{junk,read,combiner}. This optimization was performed with data with the direct decay signal
regions removed~\cite{blinding} and replaced by simulated events, and with the simulated signal shape.
+ combination of the different data taking years
this does not seem to be mentioned in the paper all results report to the (somehow) ‘merged' dataset paper should clarify how the 'combination' is achieved this is relevant because of course the datasets have different features (resolutions, backgrounds, calibrations, triggers, etc), which the affect the fitting and the efficiency correction parts of the analysis
The combination of datasets 2016, 2017 and 2018 is described now in the AN Section 11.2
suitable to mention in paper, too?
We do not consider mentioning it for this letter.
from the appendix of the AN, sections 18 and 19, I understand systematic changes on the fit model are estimated in sec.19 these systematics seem to be missing however in the systematics table
This uncertainty is part of the signal model uncertainty.
I also understand that some MC ensamble is constructed merging the 3 years (sec.18)
how can such a merging be justified as most suitable choice; i.e. couldn’t the three years be included in a simultaneous procedure, employing corresponding parameters (in data fit and mc efficiency) per year
was the closure of the adopted averaging procedure confirmed?
The samples are not merged. Shapes are determined for each year separately.
ok, for fitting; but I understood they were merged for efficiency calculation purposes (?)
The efficiencies are combined numerically. The change in the UL outcome is
found to be small when obtained for the three years individually combined in the calculation.
The difference is included in the efficiency systematic uncertainty (AN 19.)
+ likelihood description
this seems to be missing, in both paper and AN modelling of separate channels and components is described but the actual fit that is used finally in the analysis is not e.g. it is unclear if it is a fit at a time or all at once e.g. if direct and feed-drown channels are treated separately
We clarified in Section 8
no fit related systematic appear listed in Table 2 or section 6 what does “signal modelling" in l.228 correspond to in the table?
All the parameter uncertainties of the signal models are included in the upper limit estimate as nuisance parameters.
is the fit stability and closure verified, e.g. with toy MC
a 1D fit to the 4-lepton invariant mass is adopted in the analysis couldn’t e.g. inclusion of dilepton mass add more complete characterization of the data how are the plots in Fig.3 of the AN used in the analysis?
Yes, fit stability and closure were verified and certified. The dimuon signals are selected by mass interval, only. The choices are supported by the Fig.3. No peaking background is expected.
great, thanks; could you for convenience specify relevant section(s) in the AN
This is AN Sec. 8, but also the exchange with the statistics committee to follow the standard approval process:
see the discussion above on the fit and data card procedures followed here:
https://twiki.cern.ch/twiki/bin/viewauth/CMS/HiggsWG/HiggsPAGPreapprovalChecks
+ observable
what’s measured is presumable the product cross-section x BF this could be clarified in the paper as well as how BF final results are arrived at
Eqn. 6 in the AN describes sigma x BF = ... . The final results are obtained by dividing by the quoted Higgs (Z) production cross section.
+ parameter fixing vs constrainig
various parameters are extracted from simulation and fixed in the fit to the data couldn’t constraining rather than fixing be more suitable e.g. it would automatically account for associated systematics
Only signal parameters are fixed.
+ data vs MC
MC simulation is used, in both fitting and efficiency components were data-vs-MC comparisons performed, e.g. using calibration samples were thus derived corrections applied to the MC in the nominal setting and leftover discrepancies propagated as systematic errors
Yes.
great, thanks; could you for convenience specify relevant section(s) in the AN
In AN-19-232 we refer to the previous analysis HIG-18-025 (related note AN-18-106 (Sec 6) and
for muon T&P for quarkonium channels also therein to AN-18-201).
+ psi(2S)
excited charmonium and bottomonium states appears treated slightly different in the analysis also the choice was made not to search for the psi2(S) using the same exclusive decay (mumu) but rather via the inclusive decay (Jpsi X)
was the search in the exclusive mode extended to the psi2s dimuon mass region (eg as a check?)
does increased BF compensate inherent loss of resolution and dependence on simulation when adopting the inclusive approach in AN section 12 I realise this is briefly discussed; I’m curious whether the estimated factor of ~2 favouring the inclusive approach is significant (i.e. whether its uncertainty is not large)
I wonder if some justification could be at any rate added to the paper draft
B(ps(2S)i→J/psi) x B(Jpsi → 2 mu) is 3.7 % and psi(2S)-> 2 mu = 0.8 %. Given the acceptance times efficiency is comparable, and we use the optimum signal from the exclusive decay, the factor is 2.2.
Comments on Paper From ARC member Nuno
(line numbers refer to paper version 3)
83 given 3 data taking years are listed, luminosity per year could suit here?
We propose to use total luminosity as in other CMS letter publications.
130 how is the "Z boson specific” trigger specific/dedicated for the analysis, can this be reinforced with additional info other that than the pt threshold
We removed 'specific' - it is not warranted, as these are widely used triggers.
Table 1, move caption to top of table, as standardly done, and for self consistency w/ other figure
Done
217 “as to fit to a common vertex with a probability”, as stated reader may wonder how this probability was estimated
Changed to: ... a common vertex with a probability of greater than 0.5%, as determined by a Kalman vertex fit.
255 “exponential plus a uniform function” can a uniform (constant?) function for the background be physically motivated?
It fit the data in the given range.
263 "mass resolution” as it is not mentioned I presume the per-event resolution is not employed in the analysis, here you may mean the standard deviation parameter of the Gaussian functions and corresponding parameters of the CB functions
We more specifically address the parameters, here: the standard deviation in the Voigtian function.
264 “fixed in the fit to the data”, wouldn't constraining be more suitable here how are associated systematics estimated are the signal shapes fixed/constrained from simulation or are relative normalisations free to float — could the choice be motivated, and in any case be made more clear in the text
see above.
270 on feed-down signals. feed down fractions are taken from simulation. are these all well known, resulting in negligible systematics? it is not clear how fit to feed down signals is done i.e. what shape parameters are free or ow constrained nor how feedddown contribution is considered in the fits to extract the direct components
They are taken from the PDG; uncertainties are small and are included as nuisance parameters.
272 “For the fits to the feed-down channels”, are these really different fits? surely the direct channels could not be discarded, right?
Feed down channels fit separately with the same background as in the direct channels. With no signal, there is no correlation expected and found.
275 “No significant correlations between the different signal contributions are found.” clarify which contributions are being referred here
Signals from the feed-down and direct channels.
Table 2 Items in session do not correspond exactly to listing in the table? reword last item, limited sample size
done. In the table the "lepton efficiency" is changed to “lepton Identification”. The “Muon Isolation” is added in the table.
actually, I no longer see the systemartics table in v6 ... (I assume this was dropped following separate review requests?)
Yes, to adjust for the letter.
290 here some text is missing (!), introducing the listing that follows
It is a latex formatting error (nothing is missing).
I see the connection between text a listing is still missing in v6. Suggest to replace full stop with colon in line 283.
done
295 “the method used to measure the efficiency”, which is it? There is no section in the paper describing how the efficiency is measure In its absence it is inferred this is done from MC (Which would render unclear what was the method and the source of its uncertainty ) What is missing then is the description of the procedure employed to correct the MC with measurements from data, and describe associated systematics Presumably, different components of the efficiency were estimated/calibrated with different methods?
Efficiency is obtained from MC simulation and the T&P method is used to obtain scale factors and uncertainty estimates.
thanks for having added info to the paper, now specifying the method in item #ii of the systematics listing
299 same comment for electron, as above for muon
Efficiency is obtained from MC simulation and the T&P method is used to obtain scale factors and uncertainty estimates.
while this has now been specified for the muons; for the electrons, the statement remains "It arises from the method used for the efficiency measurement"; if it is indeed similar as for the muons, try to reword/drop statement about "the method" that may remain unspecified.
We shorten the sentence to refer to [71].
302 “fit efficiency”, what is it?
It is the percentage of events surviving the 4 lepton vertex fit criterion when applied last.
so it is not so much an efficieny of a fit, as it is the efficiency of a selection criteria based on a fit quality ... not a big deal but siggest to simply refine accordingly
We replaced it with 'criterion'
304 need to specify how energy scales and resolutions were calibrated
Differences in the lepton resolution and momentum scale in data and simulation were estimated from J/psi and Z dilepton signals and extrapolated to the four-lepton signals. The systematic uncertainty is the relative change of the upper limit when varying the signal mass mean and width by these differences. This text is added.
thanks, more clear in paper now
325 “coupling strength of the bosons to any Y(nS) pairing is assumed to be the same"
done. Italic (nS) is changed to normal.
Table 3 caption “will be updated after unblinding”, confirm whether this was done
removed (will be updated after unblinding). The numbers are final.
// type A
46, 47 branching fraction
done
81 and elsewhere, ensure consistent use of symbol “pp” i.e. use tdr/latex macro
used in all text {\Pp\Pp}
214 selection
The selection → selection
217 case of the jpsi
done
222 in the jpsi
done
229 each with
done
Fig 4 caption: plots show, observed -> existing
done. we keep observed.
note that (i) 'observed limit' may sound self-contradictory, and (ii) not clear whether used limits are 'existing' ones or obtained here
... the observed UL BF at 95% CL as obtained in this analysis ...
234 and the azimuthal
done
236, 238 use consistent symbols, i.e. \newcommand
space is deleted in YY
238 distributions
done
246 space missing
done
289 Tab -> Table
done
291 uncertainty … is
done
296 uncertainties … are
done
332 in association with -> and
done
335 ", are used"
done
342 Y consider all -> stands for the
done
462 CMS Collaboration
done
465 Higgs
done
491 fix symbols in title
done
492 drop page range
done
505 ATLAS Collaboration
done
506 fix symbols, names in title
done
527 Higgs
done
536 fix reference, incl. collaboration name, symbols, remove repeated symbols etc
done
543 revise reference, missing author filed, doi seems not openly available etc
Fixed reference.
594 fix particle symbol
done
611 revise reference
%GREEN % done
613 check authorship, CMS
done
Comments on AN From ARC member Hwi dong
Thank you very much for excellent analysis. It looks very nice and study rare decay of Higgs boson widely, extending from the previous analysis.
I have following 1st set of comments as below with my major concern. It might be overlapped with other ARC members’ comments which I didn’t have a chance to follow up yet. Please point out your answers delivered if my comment and question are same and we can discuss further details in upcoming ARC-author meeting soon.
1. Target journal - Do you target a letter style journal (ex. PRL or PLB)? In my opinion, overall description written in the paper draft is not so much friendly for readers, and therefore I think it’s less comprehensive or minimized to learn something. For example, I think event selections are quite important but the description of event selection (how to decide the working point and optimize the performance in each channel) is only delivering the facts (what you did). If you target to PRL (we should discuss whether it’s feasible), then of course it’s fine. But if not, I think JHEP style is more suitable for your study. I think readers will learn a lot if you share the details how to optimize and motivation of the selection cuts etc.
After discussion, we decided to target PLB.
2. Trigger strategy and description - you describe the trigger selections in LL129-139. But as your analysis contains several channel and therefore your trigger strategy is quite different w.r.t. the channels, it is always better to provide a table for the summary of pt, eta, and other requirement w.r.t. such online selection. I have same comment for the event selection parts. It’s quite unclear in the text of the paper draft. - According to AN section 3.2, you use HLT_IsoMu27, HLT_Ele27_xxx for the channel with H->ZJ/psi (Z->ee or mumu), and the others are based on BPH trigger. It looks reasonable approach but it’s a bit strange w.r.t. your offline event selection. I will comment more in the event selection issue - AN table 5, 6, you counted the yield with the order of preselection => trigger etc. It looks strange to me why you count the preselection (it’s offline lepton based) => trigger. Certainly trigger is online selection and it should affect all aspects of your samples you start this analysis. It’s looks strange order. Moreover, preselection contains dilepton vertex cut etc. which is very dangerous order in the selection strategy. - How did you get the reco+id, iso and trigger efficiency for muon and electron? First of all, the description is not well available in either paper or AN. And if you applied the efficiencies (and SFs) and systematic uncertainties provided by muon POG, did you report and discuss details in muon POG and its contact in HIG group? I think your application on the muons particularly looks a bit unusual, I think it’s quite important step.
We do not include such table as letter publications usually point out the important features, but not in such detail. The selection criteria and steps are common, particularly for quarkonium analyses, and with respect to the signal very open. In our final states the order preselection/trigger was checked and does not matter. The lepton efficiencies and uncertainties were discussed with the analysis object groups and the analysis group.
3. Offline event selection - The most difficult part to understand. I think the section 4 should be reorganized and improved significantly. As mentioned above, if you target the letter and deliver only facts you used, at least you need a table to summarize the requirement, cut value, etc. for each channel. - If your selection is quite standard in BPH (I am not working in the group unfortunately), then please include some references that I can also follow up the standard treatment in similar BPH.
We add text to describe the selection strategy. We checked the order of the criteria. All the signal selection criteria are very open to maintain a high efficiency.
Comments on Paper From ARC member Hwi dong
L184: pt > 3 GeV, but at least in ZJ/psi channel you used IsoMu27. So one muon should be greater than 27 GeV in offline. In general, most of muon POG analyses, at least 1 GeV is added for offline muon pt due to the difference of the resolution performance in trigger. Moreover, 3 GeV is quite low for the accuracy of muon reconstruction. For instance, the GLB muon has turn-on effect around 6-7 GeV.
Iso Mu 27 trigger requires one isolated muon to have pT greater than 27 GeV. Soft muons have been studied from pT=2 GeV on. The trigger muon is the leading muon which is safely above 27 GeV according to simulation.
LL195-196: you mention only the BB and EE cases, but didn’t you accept BE case?
We did. The sentence though is publication board standard description.
L204: same question as muons. EGM POG usually used +3 GeV in offline pt of electrons compared to the trigger threshold. It will be more significant problem because electrons’ accuracy is worse than muons. What is fake rate of electrons in such low pt region?
As all of our electrons are high pT electrons from Z boson decays we do not have that problem (see Fig. 4).
L205: what about the ECAL gap? Is it not applied?
It is included in simulation and corrections.
L207: how did you treat the electron mis-charge identification? The mis-charge id of muon is negligible up to 1 TeV, so it’s not a problem but electron is larger, moreover you are accepting very low electrons as well, so it might be problematic.
The electron pT range is 10 - 100 GeV.
LL208-215: I understand the motivation of common vertex cuts to suppress fake and combinatorial backgrounds, but I don’t see any optimization discussion for the cut values. Are they optimized and so how did you do? The details (plots, procedure, test etc.) should be included in the documents, at least AN.
We follow the overall optimization strategy to obtain the lowest UL at 95% CL.
L209: why do you need the dilepton pt cut 5 GeV (and L211)? Before applying the cut, how did you decide the pairs? Most of channels are based on 4 muons and you have several choices of the combination. How did you select the best pairs? Then what is the order of the additional dilepton cuts? Did you select pairs first then apply the dilepton cuts or vice versa? Is there any dependence on the order of the selections?
We first apply very loose selection criteria defined as preselection in the AN. We first select di-leptons by mass. We find the 5 GeV cut in our optimization for the best expected UL. After the charge requirement pairing +- +- combinatorics is strongly suppressed. There is no dependence in the order of the selection in the optimization cut.
- Figure 2: you bin size is 3 GeV. Though statistics are not so big, I think it should be 2GeV or lower because of the dilepton (and four lepton) mass resolution around Higgs mass. As you see the signal distribution, your data points are just 1-2 bins to denote them. If you have 20 bins per plot for example, it might look better to see resonance structure (statistics are not so poor to do, I think).
The actual fit is an un-binned ML fit. The plots serve to demonstrate the background distribution.
- Figure 2: maybe stupid question but why the peak of H->Zpsi(2S) (green distribution) is lower than 125 GeV
Psi(2S) is measured from the daughter J/psi in the decay Psi(2S)->J/Psi X where the X is not detected. It is dominated by X->pi pi.
- If you estimate backgrounds with data distribution by the fitting, is it not helpful to relax your background suppression on the event selection? It is related to the optimization of all event selections.
yes, we have the same strategy, i.e.relax selection criteria.
L218: why 0.5%?
The dimuon vertexing probability becomes uniformly distributed after 0.5%.
L218: 3.5 GeV pt cut of J/psi candidate but according to table 3 in AN, the pt cut is not applied in 2016 triggers. Has it been applied in 2016 as well?
Yes.
L218: same question above, how did you select the J/psi candidate pairs with which order?
same order as defined for Z J/psi
L221: dimuon mass resolution should be expressed with % (same as dielectron case above)
done
L224: 5% vtx cut additionally for 4 muons, how much impact after apply the common dilepton vtx cuts?
The 4 mu vtx cut relatively reduces the background 2 times more than signal.
Figure 3: same question, why some signals’s peaks are lower than 125 GeV?
same as above
L231: The dimuon invariant masses are overlapped. How many events are overlapped between two plots in figure 4? Why do you need to separate them in the plots?
We are testing two different di-lepton mass ranges with two different models (in the Y(1)Y(1) case we do not make assumptions about the Higgs decays). The plots demonstrate these separate exercise.
LL233-234: same questions for cut values, why they need and the justification of the cut values
We will add optimization strategy in the AN.
I have more questions on the event selections but I can ask more if I am still not clear with your answers for above questions.
Sure
4. Systematic uncertainties - ii and iv contains four muon (lepton) vertex fit. It should be more clarified.
We explain now how we obtain 4 mu vertexing in the AN.
- vi: is it the effect from Parton Distribution Function choice? How did you estimate it?
We added reference and text.
Comments on Paper From ARC Chair Keith
Thanks for the updated documentation. Below you can find a first pass through the paper for editorial comments. In general, I found it to be very nicely written. I also think it would make sense to assign a Language Editor at this point. We will try to get back to you as soon as possible with any final physics questions.
Title -You should probably mention the Z decays, too
Here is a new proposed title: Search for Higgs boson decays into $\cPZ \JPsi$ and Higgs and Z boson decays into $\JPsi$ or $\PgU$ meson pairs at CMS
Abstract -Mention CMS somewhere
Included it in the first sentence
-line 2 drop "decays"
done
-line 6-7 I think you can drop the whole sentence "Different polarization scenarios..." just to shorten the abstract
done
General: all plots should have "Preliminary" removed.
done
Introduction -line 8 "the SM" => "SM"
done
-lines 12, 18 you define "(CL)" twice
Removed from line 18
-line 17 "... have been searched for" make clear by which experiment(s)
Added “have been searched for at LHC”
-line 19 "... expected values in the SM" better to add in the theory reference with these predictions already here
Sentence line 16 refers to the theory. In line 19 the references [19-21] quoted in the previous sentence also evaluate these deviations from the SM with the corresponding theory references.
-Fig. 1 caption "indirect quark" => "indirect (middle, right) quark"
done
-line 45 "... experimentally at the LHC" add in by which experiment
added"… studied by the ATLAS collaboration ..."
-line 69 or so. I think it would help make clear what you are actually searching for to explicitly list out all of the final states around this point.
We merged the subsequent two paragraphs.
Simulated samples -line 142. "in the four-muon invariant mass" you also use the MC for the 2mu+2e invariant mass, right?
replaced by four-lepton
-line 169 I don't think you've defined "acceptance" yet here. You might want to just move this whole table down to when you are talking about systematics.
Moved table behind systematics.
- Also
- Changes are given to 2 digits only (30.2 -> 30)
-Table 1. "Transversal" => "Transverse" and I also think "Uniform" => "Unpolarized" is better to be consistent with the language used in the text
done
Event reconstruction -line 209 "with data in the direct" => "with data with the direct"
done
-line 213. you first mention the vertex fit probability here. Down in line 221 you mention that this is "determined by Kalman vertex fit probability" Move up the description of how you get the vertex fit probability to the first mention in line 213.
done
-line 217. Not clear what "threshold" is meant here.
added “.. close to the Z J/psi threshold..”
-line 233 "A Y pair" => "An Y pair"
done
-line 233 Not clear (to me at least) what "Y" means here as distinct from "Y(1S)" I would normally think "Y" alone would mean all of the Y states, but then the mass window for "Y" couldn't be different from "Y(1S)" so I'm confused.
Here, Y refers generically to all Upsilon states. But we went throughout the paper to correct inconsistent use (and formatting) of Y(nS)Y(mS) and Y(1S)Y(1S) occurrences.
-line 244-245. Need to mention the electron efficiency scale factors as well, I think.
done
-line 251-252. 28 and % get split across the lines.
done
Signal extraction -line 256-258 I thought the background fits were now done across the whole mass window including the signal region.
New sentence: The background shapes in the four-lepton invariant mass distributions are obtained from data.
-line 259 "uniform" => "constant"
done
-line 262 you use "direct channel" quite a bit, but I don't think it is ever explicitly defined. There can also be confusion with the way "direct" is used in Fig. 1 so some care is needed.
we define direct signal as ”... a combination of the same functions as used for the Higgs directly decaying into ground state mesons (direct signal).”
-line 269 "line" => "lines"
done
-line 275 and 353 "Psi(2s) -> J/Psi" I think would be better with a "+ X" or similar added.
L275 : changed to “...involving the inclusive transition from psi(2S) to J/\psi….” L353 : changed to “ ...result of an inclusive Psi(2S) to J/\psi transition….”
-line 274-285. Say explicitly that separate fits are performed to the 4 lepton mass distributions for the different signal hypotheses.
We adopt the sentence. “Separate fits are performed to the four-lepton mass distributions for the different signal hypotheses.”
Systematic uncertainties -In point ii I think you need to mention the electrons as well.
done
-line 317 "1.73" => "1.7"
done
-line 319 I think those numbers are in "%" right?
done
Results -line 327 and 345 "Higgs (Z)" => "Higgs or Z"
done
-after line 339. Add some comparison between your limits and those expected from the SM and/or BSM possibilities.
We add a statement such as: The observed upper limit in branching fractions agree with the expected limits and are 826 times in the case of H → ZJ/ψ [18] or higher than the SM predictions for these rare channels. With the increase in luminosity at the high luminosity LHC and the combination of final states for the channel H → ZJ/ψ, the observed branching fraction could reach the SM predicted value within an order of magnitude. In the H → Υ ( nS ) Υ ( mS ) channel, the observed upper limit in branching fraction is found to be a factor 5.8 higher than the value from earlier SM predictions [31], which could be reached with the high luminosity LHC data.
-Table 2. A few lines have leftover "(X)" values. I think those should be removed.
done
-Table 2. The J/Psi,J/Psi and Y(nS)Y(mS) lines have rather asymmetric expected ULs of 4.6+2.0-0.6 and 3.6+0.1-0.3. Do you understand the asymmetry? And why it would have different sign for the two channels?
The background is qualitatively very different in these channels. It is very small in the YY channels.
Comments From Language Editor Paul
Title : Ask pen names being used
done
Abstract : For the first time decays...>>For the first time, decays....
done
Abstract: Integrated luminosity of about 137 fb-1 >> Integrated luminosity of 137 fb-1
done
Abstract: While an observation >>An observation
done
Abstract: the standard model, no significant excess.... >> standard model, and no significant excess
done
Abstract: Upper limit at 95% CL >>Upper limit at the 95% CL
done
Abstract: Put some numbers in the abstract?
%GREENE% done
L5: boson are so far consistent >> boson are, so far, consistent
L:18 at LHC>>at the LHC
done
L39: fermions [11]. An example is a version of >> fermions [11], for example, a version of
done
L40: Yukawa couplings are possible.... >>Yukawa couplings are also possible
done