-- RuiXiao -

Lambda_C Analysis

Useful Links


  • Compare lambdaC/D0 ratio in pp and PbPb collisions to study the roles of coalescence production. .


  • Rui Xiao, Jian Sun, Hao Qiu, Jing Wang, Wei Xie

Analysis note link:



freezing document:

upload the newest verison of AN (pdf file), and upload paper (through CADI->switch edit mode, add, but this is from svn, so the version in svn should be the newest version), then send an email.

paper command:

The link of the cadi is: http://cms.cern.ch/iCMS/analysisadmin/cadilines?line=HIN-18-009

When we have a cadi entry, we should send an email to George to request a svn area for paper.

For upload AN into CADI: first go to http://cms.cern.ch/iCMS/jsp/iCMS.jsp?mode=single&block=publications click on Action on Analysis note then upload pdf files.

svn co -N svn+ssh://svn.cern.ch/reps/tdr2 HIN-18-009
cd HIN-18-009
svn update utils
svn update -N papers
svn update papers/HIN-18-009
eval `./papers/tdr runtime -csh` # for bash. use -sh for bash.
cd papers/HIN-18-009/trunk
tdr --style=paper b HIN-18-009

#You can commit your changes with
svn commit -m "commit message"
#New files will first need to be added with
svn add NewFileNames
#before they can be committed.


The URL of the svn web browser for our documents is https://svnweb.cern.ch/cern/wsvn/tdr2/?. Your AN is under notes.

Instructions for retrieving the template version and building it are now available on the wiki at https://twiki.cern.ch/twiki/bin/view/CMS/Internal/TdrProcessing. There are additional hints in the template document itself, which is available formatted as https://svnweb.cern.ch/cern/wsvn/tdr2/papers/XXX-08-000/trunk/XXX-08-000_temp.pdf. Please note the use of our standard definitions for particle names and commonly used HEP terms as shown in the appendices. BibTeX hints are in both the tex and bib files. A more thorough treatment of many CMS document production tasks may be found at https://svnweb.cern.ch/cern/wsvn/tdr2/utils/trunk/general/notes_for_authors.pdf. The general CMS style guide is currently located at https://twiki.cern.ch/twiki/bin/view/CMS/Internal/PubGuidelines, and the publications wiki page is https://twiki.cern.ch/twiki/bin/viewauth/CMS/Internal/Publications.

We strongly suggest running tdr with the “—preview” flag before uploading. It will provide diagnostics on many common reference problems.

In particular:

> svn co -N svn+ssh://svn.cern.ch/reps/tdr2 myDir # where myDir is a placeholder for a name of your choice

> cd myDir

> svn update utils

> svn update -N notes

> svn update notes/AN-17-307

> eval `./notes/tdr runtime -csh` # for tcsh. use -sh for bash.

> cd notes/AN-17-307/trunk

# (edit the template, then to build the document)

> tdr --style=an b AN-17-307

You can commit your changes with

> svn commit –m "commit message"

New files will first need to be added with

> svn add NewFileNames

before they can be committed.

Please note that svn needs to know what to do with various file types, and that this info is contained in the .subversion/config file in your home directory. (This file is created by your first invocation of svn.) We recommend that you make sure that the auto-props section contains the following as a minimum:


*.pdf = svn:mime-type=application/pdf

*.png = svn:mime-type=image/png

*.jpg = svn:mime-type=image/jpeg

*.tex = svn:eol-style=native

*.eps = svn:mime-type=application/postscript

Setting file types you don't wish to have uploaded can be done globally with, e.g.,


global-ignores = *.o *.bak *~

Filenames should not contain any of the following characters: /\?%*:|"<> plus space. The dot (.) when used as anything but a filetype extension can also can cause problems. The usual reserved filenames for the varying OSs should also be avoided, e.g., CON, AUX, COMn, LPTn, PRN, NUL, with any extension and any combination of upper/lower case.


How to request an official MC:
  • fill the form https://twiki.cern.ch/twiki/bin/view/CMS/Run2015HIHFMCRequest#D_meson_new_request_Mar_2017
  • follow this thread about testing the setup for MC request: https://hypernews.cern.ch/HyperNews/CMS/get/hi-general/4206/1.html It is to include your .dec file for the lambdaC decay channel in fragment file, so that it is not necessary to add the .dec file in CMSSW
  • In the above step need to check whether CMSSW_X_X_X/GeneratorInterface/EvtGenInterface/plugins/EvtGen/EvtGenInterface.cc have the user_decay_embedded block. If not, need to add the user_decay_embedded. The link is here: The back-port was done by Matt in this PR
    <a href="https://secure-web.cisco.com/11CvdcfRtsi-DaHPw_f7y_mtywBVeZl-abuqhCcBfZTa_-l-lfpRA0VTBWuBx8zfKuOGkqR1f2-knedswy9BL68Z3XWeeltnuh7Hw8G3fE9jdoLmN-G4ksw3B7MUC_IEhaKos_itNKTtsLvgVVq5lSPSBkFdtLeckwIYv97LKqf64u8rHdaiSvPLjWQ9TBZjYxuo25iSLBLnpGZ2yLQII31iC3UrCWWmn2J-MNDjf0WstJE7n0wd2Yfu-ZsTKWVazWRsMr36YnegkQBxqX0xxeBJcHRPDzOlCZrOncfETbl92x-vhRlVNZZ-zSWsu8LauxpcKq67yx7T8NrFbWoogdO9pbvVUsFaDwkVergf2JY94Sj5VcYwGqM_iBEnqt3kx/https%3A%2F%2Fgithub.com%2Fcms-sw%2Fcmssw%2Fpull%2F20080" rel="noopener noreferrer" target="_blank">https://secure-web.cisco.com/11CvdcfRtsi-DaHPw_f7y_mtywBVeZl-abuqhCcBfZTa_-l-lfpRA0VTBWuBx8zfKuOGkqR1f2-knedswy9BL68Z3XWeeltnuh7Hw8G3fE9jdoLmN-G4ksw3B7MUC_IEhaKos_itNKTtsLvgVVq5lSPSBkFdtLeckwIYv97LKqf64u8rHdaiSvPLjWQ9TBZjYxuo25iSLBLnpGZ2yLQII31iC3UrCWWmn2J-MNDjf0WstJE7n0wd2Yfu-ZsTKWVazWRsMr36YnegkQBxqX0xxeBJcHRPDzOlCZrOncfETbl92x-vhRlVNZZ-zSWsu8LauxpcKq67yx7T8NrFbWoogdO9pbvVUsFaDwkVergf2JY94Sj5VcYwGqM_iBEnqt3kx/https%3A%2F%2Fgithub.com%2Fcms-sw%2Fcmssw%2Fpull%2F20080</a>
  • Send an email to George and Ta-Wei.



Slides for today: 0319_presentation_new.pdf


Slides for today: 0212-update.pdf


Slides for today: 0122-updates.pdf


Slides for today: 01162018.pdf


Slides for today: 0108_presentation.pdf

To do:

for pp 5-6 add Dalpha plots and for pp 4-5 add Dchi2cl plots.


Slides for today: 1211_lambda_C.pdf


slides for today * In the meantime, trying to find signals from other centrality in PbPb collisions including tracker-only data.



  • have already fixed the bugs in both PbPb and pp data
To do:
  • signal exaction.
  • when the number of pending jobs ~ 1000, begin to submit MB3.
  • TMVA--track pt. need to produce tuple with daughter pt first.



  • Just a reminder in the future: for PbPb 8-10, due to we do not have enough statistic, we do not fit this pt range untill we have the official MC.
  • Try to repair data due to my previous bug.




Slides for today: 1016.pdf


Slides for today: 1009presentation.pdf

To do:

  • the missing pp sample should be submitted.
  • PbPb centrality 0-100% for MB2,3 should be resubmitted.
  • After we done the PbPb production, have a look for pt<8GeV.
  • After pp production is done, make the mass plot from data and over the MC signal with the same cut on it.
  • signal exaction.
  • remake the MC request tables.


Slides for today: gruop_meeting_18.pdf


Sildes for today: lambdaC--purdue_0927correted_one.pdf


Slides for today: 0918presentation.pptx

To do: release the mass window but keep the other cuts to see the match and mismatch ratio.

To check the shape of mismatch( which is asymmetry now).

Have a look at the signal below 10 Gev for PbPb and not only the centrality range 30-100%.


Slides for today: new_group_meeting.pptx


Slides for today: presentation14.pptx


Slides for today: presentation_13.pptx


Slides for today: group_meeting12.pptx

To do list: lambdaC_ToDoList.pdf


Slides for today: groupmeeting11.pptx


Slides for today: Presentation_10.pptx


Slides for today: status_of_preparing_MC_request.pdf


1)For the pp data: resubmit two more times to see whether the interior error of crab could be solved or not. Otherwise need to contact.

2)For preparing MC request:

1/ need to plot pthat vs LambdaC pt to find the biggest pthat for pt>10 GeV.

2/ need to get all the information for these 8 channels.

3) need to tell George Stephen that we need to add new channels to official CMSSW before Jian leave for shift.


I roughly checked the gen level Lambda_C mass (got from Pythia) and the reconstructed mass that was got from its daughters.



After the group meeting, I have tried the old lambda channel with the same cuts that Rice did. However, I still could not see the signal. lambdaC_old_channel__using_rice_cuts.pdf


Slides for today: Presentation_9__group_meeting.pdf

Besides the to do list on the slides, there is also one thing that needs to be done:

Calculate the error for the number of the lambdaC.


Slides for today: presentation8_group_meeting.pdf

To do list for the future:

1) compare the plots with and without PV refit with the same two cuts, and do fit to compare the number of lambdaC.

2)after the pp tracking is done, compare the plots with pp tracking and with PV refit. (They should be similar.)

3) study significance of measurement, then tell professor the meaning of significance.

4)modify the decay table, where I have to add one channel and also change the branch ratio to the new values.(talk to Jian to discuss the details about this and the private test).

5)MC request.

6)Talk to Jing about TMVA.

7)efficiency and acceptance.

8)cross section.


Slides for today: Presentation_7__group_meeting.pdf

After discuss: The problems that presented in slides have been solved:

1) Already found the particle ID for delta++ and lambda(1520)

2)The sum of all branch ratios of four channels is bigger than the branch ratio of the whole that is listed in the particle physics booklet and the reason is that one need to take into account the branching ratio of K*0(892)->k-pi+ and lambda(1520)->pK-. The details can be found in the slides here.

The clebsch-Gordon Coefficient: http://pdg.lbl.gov/2002/clebrpp.pdf

To do:

1) apply pp tracking to exam that I have applied PV refit previously.

2)QA to make sure that I have applied PV refit.

3)produce the plots which are without PV refit again to make sure that there is no bug in the codes.

4)If everything is correct, reapply the cuts.


Slides for today: Presentation_6__group_meeting.pdf

Conclusion: The channel that we are using now should be given up and we should move to a new channel.


The slide for today is Presentation_5__group_meeting.pdf

we use the lambda_C decay to lambda and pion decay channels.

To do:

1. change lambda decay length significance cut to >7 and > 10 and compare with decay length significance >5.

2. reapply the mass window for lambda [1.11,1.12].

3. add the following into ntuple.

a) lambda decay length signnificance.

b) lambda mass

c) lambda_C decay length significance

d) lambda_C alpha angle

4. If this channel won't work, then change to proton, kaon and pion channel, then the following things need to be done:

a) confirming lambda_C peak obseved before, using pp vertexing for data with heavy-ion tracking.

b) confirming lambda_C peaking pp tracking.

c) check lambda_C peak in other cenralities, i.e. 0-30%

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf 0108_presentation.pdf r1 manage 750.3 K 2018-01-09 - 02:32 RuiXiao  
PDFpdf 01162018.pdf r1 manage 431.8 K 2018-01-23 - 23:05 RuiXiao  
PDFpdf 0122-updates.pdf r1 manage 590.1 K 2018-01-23 - 23:03 RuiXiao  
PDFpdf 0212-update.pdf r1 manage 1071.4 K 2018-02-12 - 18:22 RuiXiao  
PDFpdf 0319_presentation.pdf r1 manage 103.6 K 2018-03-19 - 16:08 RuiXiao  
Unknown file formatpptx 0319_presentation.pptx r1 manage 324.0 K 2018-03-19 - 16:06 RuiXiao  
PDFpdf 0319_presentation_new.pdf r1 manage 102.8 K 2018-03-19 - 16:12 RuiXiao  
Unknown file formatpptx 0918presentation.pptx r1 manage 657.6 K 2017-09-18 - 23:21 RuiXiao  
PDFpdf 1009presentation.pdf r1 manage 1166.5 K 2017-10-11 - 05:20 RuiXiao  
PDFpdf 1016.pdf r1 manage 1412.9 K 2017-10-19 - 02:26 RuiXiao  
PDFpdf 1023newproduction.pdf r1 manage 172.9 K 2017-10-24 - 17:09 RuiXiao  
PDFpdf 1211_lambda_C.pdf r1 manage 1719.7 K 2017-12-11 - 22:44 RuiXiao  
PDFpdf 20171120-1120presentation.pdf r1 manage 981.3 K 2017-11-22 - 16:42 WeiXie  
PDFpdf AN-17-307_0219.pdf r1 manage 3872.5 K 2018-02-19 - 23:33 RuiXiao  
PDFpdf AN-17-307_temp.pdf r2 r1 manage 3872.5 K 2018-02-19 - 23:31 RuiXiao  
PDFpdf AN-17-307_temp_0219_new.pdf r1 manage 3872.3 K 2018-02-20 - 00:37 RuiXiao  
Unknown file formatpptx Presentation_10.pptx r1 manage 35.2 K 2017-08-15 - 05:03 RuiXiao  
PDFpdf Presentation_2__group_meeting.pdf r1 manage 2216.4 K 2017-05-02 - 04:52 RuiXiao updates
PDFpdf Presentation_3__group_meeting.pdf r1 manage 532.2 K 2017-05-02 - 04:52 RuiXiao updates
PDFpdf Presentation_4__group_meeting.pdf r1 manage 380.6 K 2017-05-02 - 04:52 RuiXiao updates
PDFpdf Presentation_5__group_meeting.pdf r1 manage 232.0 K 2017-06-14 - 05:47 RuiXiao  
PDFpdf Presentation_6__group_meeting.pdf r1 manage 414.1 K 2017-06-14 - 05:48 RuiXiao  
PDFpdf Presentation_7__group_meeting.pdf r1 manage 357.8 K 2017-06-14 - 05:44 RuiXiao  
PDFpdf Presentation_9__group_meeting.pdf r1 manage 386.3 K 2017-07-05 - 18:17 RuiXiao  
PNGpng _2018-02-26_10.16.48.png r1 manage 192.3 K 2018-02-26 - 16:27 RuiXiao  
Unknown file formatpptx group_meeting12.pptx r1 manage 35.3 K 2017-08-22 - 21:55 RuiXiao  
Unknown file formatpptx groupmeeting11.pptx r1 manage 258.3 K 2017-08-22 - 21:54 RuiXiao  
PDFpdf gruop_meeting_18.pdf r1 manage 1270.7 K 2017-10-11 - 05:18 RuiXiao  
PDFpdf lambdaC--purdue_0927correted_one.pdf r1 manage 1250.5 K 2017-09-28 - 04:55 RuiXiao  
PDFpdf lambdaC2pkpiBranchingRatio.pdf r1 manage 346.8 K 2017-06-14 - 21:59 WeiXie  
PDFpdf lambdaC_1018.pdf r1 manage 1581.8 K 2017-10-19 - 02:28 RuiXiao  
PDFpdf lambdaC_ToDoList.pdf r1 manage 242.7 K 2017-08-22 - 21:57 RuiXiao  
PDFpdf lambdaC_old_channel__using_rice_cuts.pdf r1 manage 353.5 K 2017-07-24 - 23:06 RuiXiao  
Unknown file formatpptx new_group_meeting.pptx r1 manage 414.0 K 2017-09-18 - 23:17 RuiXiao  
Unknown file formatpptx presentation14.pptx r1 manage 102.7 K 2017-09-18 - 23:14 RuiXiao  
PDFpdf presentation8_group_meeting.pdf r1 manage 374.3 K 2017-06-27 - 17:45 RuiXiao  
Unknown file formatpptx presentation_13.pptx r1 manage 38.8 K 2017-09-18 - 23:13 RuiXiao  
PDFpdf roughly_check_gen_level.pdf r1 manage 272.1 K 2017-08-01 - 17:44 RuiXiao  
PDFpdf status_of_preparing_MC_request.pdf r1 manage 153.4 K 2017-08-01 - 17:45 RuiXiao  
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