(r4) CMS-BPH-10-002-001 < Main

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---+ Report number CMS-BPH-10-002-001 Version 1
---++ Title: Prompt and non-prompt J-psi cross sections in pp collisions at sqrt(s) = 7 TeV

---+++ Deadline for comments 26 Oct 2010; CIT comments in cdsweb: Piotr Traczyk

This is the first measurement of the J-psi cross section at 7 TeV. A preliminary result was presented at ICHEP, in the paper the statistics has been increased with respect to the conference, using the same analysis method. This improved measurement will be presented for approval during the Physics Days, next week. The paper is intended for publication in the European Physical Journal C.<br /><br /> [[Report number CMS-BPH-10-002-001 Version 1 Title Prompt and non-prompt J-psi cross sections in pp collisions at sqrt(s) = 7 TeV Submitter roberto.tenchini@cern.ch Date of document 14 Oct 2010 Deadline for comments 26 Oct 2010 Note This is the first measurement of the J-psi cross section at 7 TeV. A preliminary result was presented at ICHEP, in the paper the statistics has been increased with respect to the conference, using the same analysis method. This improved measurement will be presented for approval during the Physics Days, next week. The paper is intended for publication in the European Physical Journal C.

[[http://cdsweb.cern.ch/record/1299853?ln=en][http://cdsweb.cern.ch/record/1299853?ln=en]]
---+++ 
---+++ Comments
---+++++ Add your name and comments

---+++ Marat
There are some problems with the PDF: there are lines with
no numbers, e.g. on pp. 3 and 5.

Page 3, between lines 99 and 100:
How exactly "the dependence of the peak shapes" on muon
kinematics was studied, and how big is the associated systematics ?

Lines 229-232: What was the motivation for Crystal Ball and
Crystal Ball+Gaussian for the signal, was the dependence on the
background  parameterization studied at all ? Only a choice of a
second order polynomial is mentioned for the background part.
We know that the yield estimation can vary a lot in our pi0
studies. Therefore, this should be explained in more detail.
As we can see in Table 3, the Fit function is a quite siginificant
source of systematic error.

Section 6.1, from the beginning: the method used for separating
prompt and non-prompt decays appears to be confusing. As far
as I know, Chris had some questions about it, so I let him comment.


---+++ Dorian

(i) physics/content/clarity

- p 3, Table 1. These numbers are so small, do they affect anything?<br />- p 3-4. I am not sure why we switch from pseudo-rapidity to rapidity. Maybe this is logical, I have no experience with this type of analysis.<br />- line 202-203. Seems strange that the correction is applied then the whole of it is taken as systematic uncertainty.<br />- line 222-223. Does the fine-grained binning help to determine better center of mass, or what is otherwise its advantage?<br />- p 11, Figure 3. Is there need for any discussion of the similarity of the pT dependence in the different rapidity ranges?<br />- p 15. Table 7. Why are all systematic errors symmetric?<br />- line 349, conclusions. 'reasonable agreement between the data and the theory curves'. It depends on what the criterium is, but I would have said that none of the theoretical curves describes the measured cross sections.

(ii) editorial

- line 3 and elsewhere in the text. "J/Psi's" should not be used for the plural since it can be confused with the possessive form. Simply J/Psis would be better.<br />- line 100-101. Use ~ between 'fit' and reference 27 such that it is not broken in a new line.<br />- p 4, Figure 1. Labels too small, especially the rapidity ranges.<br />- line 144. '; for' -&gt; '. For'<br />- line 176-177. Repetition of the word 'also' within the sentence. Remove the first occurrence at the beginning of the sentence<br />- line 225. 2*s: 'bremstrahlung' -&gt; 'Bremsstrahlung' or 'bremsstrahlung'<br />- line 241. remove comma after 'section'.<br />- p 10, Table 4, caption, 1st line. Remove comma after 'bin'<br />- p 10, Table 4, caption, 4th line. 'Only for' -&gt; 'For'<br />- p 13, Figure 4. write the pT ranges inside the plots to make clear the difference between left and right plot. add y-labels to the plots below with the pull. add a key in the legend to explain that the points are the data.<br />- line 293, remove comma after 'modules'<br />- line 326. CEM is a model and a theory? I would have left just model and removed the word 'theory'.<br />- p 16, Table 8, caption, line 3. 'Only for' -&gt; 'For'

- in some places the 'T' in pT is not roman. please do a global search of 'p_' and fix this

---+++++ Artur:

<div id="_mcePaste">Based on: http://cdsweb.cern.ch/record/1299853/files/BPH-10-002-paper-v3.pdf</div> <div id="_mcePaste">1) l14: "historical discrepancy": please rephrase, sounds funny.</div> <div id="_mcePaste">2) l51: remove rapidity coverage of muon detector: already descried on line 38</div> <div id="_mcePaste">3) l56-57: while interesting piece of information, I don't see how relevant it is that there were 1.6 collisions per crossing.</div> <div id="_mcePaste">4) l58: "good quality data" is not immediately clear, would suggest to replace with something like "Tracker, the Muon and the luminosity measurement detectors were fully operational".</div> <div id="_mcePaste">5) l61: "without any further processing" sounds unclear as to what processing you are referring to. Add a statement about HLT passthrough.</div> <div id="_mcePaste">6) line 67: remove "also".</div> <div id="_mcePaste">7) l68-74: as a non-expert, it is not clear to me if the MC generators listed here have all the improvements listed on lines 15-19. It would be nice to clarify.</div> <div id="_mcePaste">8) l84: define "central" and "forward" in terms of (pseudo)rapidity.</div> <div id="_mcePaste">9) l91: would recommend changing "cuts are applied&hellip;" to e.g.: "To reduce backgrounds from fake muons &hellip;, muon tracks are required to pass the following requirements".</div> <div id="_mcePaste">10) l92: I guess it is *at least two* tracks in the pixel layer, not exactly two?</div> <div id="_mcePaste">11) l101: Which mass distributions were used in the fit? I imagine the inclusion of J/Psi into this fit could bias the cross-section measurement? Please clarify how the correction is made, and why/how it does not cause a bias.</div> <div id="_mcePaste">12) l144-147: not clear the choice of polarization for non-prompt. Could you please clarify a bit why usage of babar measurement is directly transferable here, and how the comparison of that with EvtGen is a proper evaluation of systematic? What are the settings used in EvtGen?</div> <div id="_mcePaste">13) l150, 175 and 181: What values do you assign to these uncertainties?</div> <div id="_mcePaste">14) l153: You need to rephrase this sentence: different implies a comparison with something, while there is none here. Would suggest dropping the first sentence, and rephrase the second sentence a little bit.</div> <div id="_mcePaste">15) l161: can you motivate the choice of 20%? Maybe a reference?</div> <div id="_mcePaste">16) l185: I guess it needs to be "eff_off_track is the muon identification <strong>efficiency</strong>".</div>

<div id="_mcePaste">17) l190: "mapped" sounds strange, you have "parameterized" the efficiency.</div> <div id="_mcePaste">18) l195: "The efficiency for the "-&gt;"The efficiency of the *requirement* for the&hellip;"</div> <div id="_mcePaste">19) l199: a bias on which distribution? Eta, Pt? If this is a feature of the method, how come it is not present in MC, allowing you to study it? Can you have derived the corrections from data?</div> <div id="_mcePaste">20) l229-232: how are these systematic uncertainties used in the analysis? Do they enter the cross-section measurement? please clarify in text.</div> <div id="_mcePaste">21) l330-339: can you give at least a qualitative interpretation of the differences observed in different MC models, e.g. Pythia give a significantly different prediction for the prompt J/Psi's, while for non-prompt it is not so different (at least at high Pt). What could be causing this?</div>

-- Main.smaria - 2010-10-17
Topic revision: r4 - 2010-10-25 - ptraczyk
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