1.5 Where to get help

Complete: 4
Detailed Review status


This WorkBook chapter describes many of the help, information and documentation sources available for CERN and CMS users.

There is a very good resource here regarding getting good support from software experts.


Main web pages

For new users, even the main web pages for CERN/CMS can be hard to find. Some useful links are:

User support and Help Main CMS homepage CERN IT Computing Service Desk CMS Reference Manual CERN main users page CERN document server (very useful) CMS Computing and Physics Technical Design Reports CERN Search Page CERN users office (important for new users) CMS public info CMS twiki CERN public page Offline Software Guide CMS Conference server (CINCO)

Email and CMS Talk

For a distributed community such as CMS, email is the primary means of communication.


MMM (My Mail and More) is the CERN mail service. To access MMM mail, you will need a CERN NICE account (CERN SSO) for accessing Windows computing services, and will need to contact the CMS administration to obtain a MMM account. Most offsite users have their CERN email forwarded to their primary email account at their home institution, but that is NOT always setup by default. You may miss important emails about events/workshops you have registered for as well as grid certificate renewals if you do not ensure your @cern.ch email is not forwarded.

CERN mailing lists

A number of mailing lists exist in CERN to provide a discussion facility for people working on similar projects. The CERN mailing lists are defined in e-groups. To login you'll need a CERN NICE username and password (CERN SSO). Once logged in, you can search for a group and you can show the groups you are on.

Once you are subscribed, you can send an receive emails sent to groupname@cern.ch where groupname is the name of the e-group you are subscribed to. Some of the e-groups archive the mails sent to the group. This feature can be configured by the group owner.

CMS Talk

CMS Talk is a collection of discussion groups and is the primary discussion tool in CMS. Login with your CMS CERN SSO. Anyone with a CMS account (i.e. cms-web-access member) can access the CMS Talk website.

CMS Talk User Guide CMS Talk Frequently Asked Questions (FAQ) CMS Talk Feedback Instructions on how to get support for CRAB on CMS Talk

General guidelines

  • Do not cross-post on several forums, this will not work
  • Observe usual etiquette and civility to other CMS Talk users
  • Try to select the most appropriate forum to post your enquiry/announcement to, when uncertain, use the Computing Tools group
  • Quote only relevant parts of the previous email/s, and include the name of the poster of the quoted text. Remember that users can browse all of the previous postings to the forum via the web interface, so it is unnecessary and wastes space to quote huge portions of a conversation.

CMS-wide announcements

The announcements for all CMS physicists are sent to the cms-physics e-group that all CMS Physics members are automatically subscribed to. About CERN e-groups.

All CMS members using CRAB will find the Computing Tools CMS Talk group useful, this has both announcements and support.

CMS Computing and Software User Support

The general User Support page gives a brief introduction to the CMS Computing and Software User Support and a collection of useful links.

Fireworks Event Display Support

From the main WorkBookFireworks twiki, there is a page with dedicated WorkBookFireworksHowToFix information. Alternately, you can search or email the visualization CMS Talk.

Contact Online with Savannah

Users can submit questions through the CMSSW Savannah page. You do not need to login to savannah in order to submit questions, but it is recommended as when you login (which requires registration), notifications of the follow-ups will be e-mailed to you. Choose the category corresponding to your question. If you are not logged in in savannah, you will need to type your e-mail address. Choose the release you are using, and specify the severity (you can also leave this field unchanged). (If you are logged in, you see the Status and Assigned to fields which you should leave unchanged.) Type the short summary which describes your problem in the Summary field, and describe your problem in the Original submission field. Remember to specify
  • on which machine you are running
  • what configuration file you are using
  • which data you are trying to access
If needed, you can attach files (output, config files etc) by clicking on the Browse button under Attached files. When completed, submit the question by clicking on the Submit button. Note that if you are not logged in, you may get a warning on the top of the page that your mail is being checked by spam filters.The notification goes to the support staff and to the conveners of the task corresponding to the category chosen. You will get an e-mail on submission with a link to your question in savannah, and you will get an e-mail notification on each update. Do not reply to these mails for further communication, but always follow the given link and write your reply in the Post a comment field. -->

Grid/CRAB Help at CMS

See the SWGuide CRAB guide for getting support

The Grid Analysis Job Diagnosis Template guides you through steps which will allow you to identify the problems you experience with your grid analysis jobs and instructs how to report the problems.


CERN IT department provides support to CMS related problems with CERN facilities (e.g. lxplus, batch jobs, staging files), send mail to cms.support@cernNOSPAMPLEASE.ch . Alternatively, you can contact the CERN Service Desk service-desk@cernNOSPAMPLEASE.ch which will direct your question to the appropriate service and provide a ticket with which you can follow your request.


At FNAL, you can contact LPC Computing Support.

Grid Help through GGUS

Grid-based problems can be handled by GGUS (Global Grid User Support). Do not send application (CMSSW, CRAB) problems to GGUS.


Much useful information can be found by browsing through the presentations given at previous meetings, many of which are stored at CERN through the agenda system. It is also often possible for users to attend CERN-based meetings through Zoom.

Conference/Meeting Agendas

The CERN Indico tool stores notices of forthcoming meetings, as well as archiving presentations from past meetings. Following the links, you should select "experiments", and follow that link to "CMS". From there are links to CMS-specific meetings (links conferences, workshops, etc are also present on the main agenda page).

Note that the 'CMS meetings' category containing the CMS agendas in indico is now protected. It is only accessible to CMS members (and CMS Emeritus) who are registered in the CMS database and who login indico with their NICE login (CERN SSO) in the ZH group (ZH=CMS group).

Presentations archived on the agenda system can provide a very useful start for learning about a new task or analysis topic.


Zoom meetings are typically booked through indico. CERN CMS users are all able to make a CERN Zoom account. CERN Frequently Asked Questions about Zoom including how to login and create Zoom account CERN documentation on Zoom

Telephone conferences

Telephone conferences at CERN can be booked by sending Standard.Telephone@cernNOSPAMPLEASE.ch an e-mail with the following information:

Name of the meeting (you should tell the participants the same): 
 Number of participants: X max.

Tell the participants to call +41 22 767 7000 and ask to join the meeting.

CMS Notes and other Scientific Documents

There are several kinds of CMS Scientific Documents, some publicly available and others internal to CMS. The internal documents are structured in three areas: Analysis Notes, Detector Notes, and Internal Notes. The public documents, besides the Journal Publications and the Theses prepared by CMS students, exist in three flavours: the CMS Notes, the Conference Reports, and the Physics Analysis Summaries. A detailed listing, together with some relevant information to each of the several cases (and useful links), is available in the CMS Scientific Publications web page, which also contains instructions concerning Submitting a document to the CMS approval process. The submission procedure depends on whether the document concerns physics or technical results.

The same page provides other useful information related to CMS Scientific Publications, including direct links to the procedure for the approval of physics analyses, guidelines concerning the style of the CMS physics publications, etc.


The task of the CMS Conference Committee is to promote and to facilitate the presentation of results of CMS to the broad international public. This includes conferences, workshops, symposiums and the like. Presentations at international laboratories are treated as conference talks (as of October 23, 2015, this includes seminars at CERN and the Fermilab "Wine and Cheese" seminar series).

Cms INformation on COnferences (CINCO)

CINCO web pages are provided to CMS members to deal with the handling of conferences and presentations (talks and posters). The list of all CMS conferences is maintained on a central web site. Each conference has a custom-made conference web page that in turn lists presentations and selected speakers. The process of selecting speakers is handled through these web pages by nominating speakers for individual presentations. The web pages provide an archive for past presentations as well as the system to prepare future conferences, examine and approve presentations and select speakers.


All the news regarding CMS conferences are posted at the Conference Announcement on CMS Talk.

Contacting the Conference Committee

The members of the committee can be contacted using the generic e-mail address cms-conf@cernNOSPAMPLEASE.ch. Feel free to contact any or all of the committee members with any inquiries related to conferences with CMS presentations. Remember to re-edit the e-mail address to remove the Twiki spam protection

Title and Abstract

Any presentation (talk or poster) at a conference has to be first created in CINCO, with title, abstract and appropriate flags for approval by the concerned conveners. It is very important that each presentation has a well prepared abstract. The person entering the presentation into CINCO should describe what shall be presented in an abstract. For abstracts with contents related to POGs and PAGs a list of references is required. They can be added following the Update Bibliography link from the Presentations menu after the presentation has been defined. Abstracts can be prepared in advance by the physics groups or sub-detector committees.


Each presentation in CINCO should list bibliography with references to PAS or other publicly available CMS notes.

Approval of Abstracts

Before abstracts are submitted to the conferences, they must be approved by the relevant convener. The CMS Conference Committee or the prospective speakers should seek the approval of the conveners. Depending on the conference, abstracts are submitted centrally by the CCC, or the selected speaker is asked to submit. In the second case, the speaker will receive instructions from the CCC to do so.

Speaker Selection

Potential speakers may volunteer (self nominate) or be nominated by someone else. Nominations are usually for a specific presentation at a given conference. Follow step-by-step instructions for the collaborators. It is very important to add one or a few sentences of recommendation to the nomination, with good reasons explaining why the nominee is best suited to give the presentation.

Starting in February 2009, Institute Representatives, Group Leaders and in fact anyone in CMS is allowed to identify (or recommend) good speakers for future talks without specifying a particular talk. Detailed instructions on how to provide information to the committee are here.

Step-by-step procedure of arranging a talk

The Conference Committee coordinates the CMS presentations by communicating with the conference organizers and the interested CMS members. The committee is continually improving the policies and practices. The Conference Committee Help pages contain updated step-by-step instructions for the collaborators.

Invited talks

Talks are only considered as “invited talks” if the following facts apply:

  • the invitation is personal
  • the talk has the typical characteristics of an invited talk, i.e. the talk should be an overview or review. The only exception to this rule is talks at national meetings and restricted groups discussing special topics.
When receiving an invitation for a talk please add the talk to CINCO and inform the conference committee without delay. If the talk is eligible for an invited talk you will immediately be acknowledged as the speaker.

See also the guidelines for invited talks: https://cms-docdb.cern.ch/cgi-bin/DocDB/RetrieveFile?docid=3043&filename=Guidelines%20for%20Talks.pdf

Student talks at national meetings and schools

The rules for student presentations at national meetings and schools, especially concerning the presentation of unapproved physics results, is defined here: https://twiki.cern.ch/twiki/bin/viewauth/CMS/PhysicsApprovals#Student_presentations_of_unappro

Presentation file upload

A week before the conference, the draft presentation file shall be uploaded by the speaker to CINCO, for screening by the collaboration and approval. If the Bibliography (see above) is missing, incomplete, or inaccurate, please update it at this time. The appropriate conveners will get automatic mail from CINCO after upload, provided the appropriate category flags are set for the presentation.

Conference Proceedings

Conference proceedings need to be approved by the CMS Publications Committee. To start the approval process the authors need to upload the final version of the proceedings pdf file through a dedicated web page in CINCO.

  1. Navigate to the CINCO web page corresponding to your talk or poster
  2. Make sure that the title and abstract match exactly the title and abstract of the proceedings
  3. Select Submit Conference Proceedings option from the Presentations menu.
  4. Make sure that all the options are properly adjusted and submit the document to the Icms system.
After you submit the pdf file it will be reviewed by a referee. Expect about 2 weeks for the review process to be completed if the paper contains new material from CMS only and about 3 weeks if it also contains new material from another experiment, e.g. ATLAS. The updates to the document need to be handled through the Icms system ( Collaboration tab, bottom left corner, iCMS publications link).

Only after you receive a go-ahead from the Publications committee you can submit the proceedings to the conference organizers. Make sure you start the approval process early enough so that you do not miss the deadline for submission to the conference organizers. After final sign-off by the PubCom chair (or deputy chair), the conference report is assigned a number and is published on CDS. Only then can it be submitted to the conference organizers.

When writing conference proceedings, please adhere to the following guidelines:

  1. A conference report is published under the responsibility of the author and not of CMS as a whole, so the refereeing process is lighter than for a standard CMS paper.
  2. A CMS subeditor will be assigned to review the paper. When approved by the subeditor, the PubCom chair (or deputy chair) performs a few final checks and, in the case of joint ATLAS-CMS conference reports, submits the draft to the ATLAS PubCom for approval. Any further communication with ATLAS is handled by the PubCom chair (or deputy chair).
  3. To facilitate the review process, the draft should have line numbers. These should be removed when producing the final version to be published on CDS.
  4. The paper should be signed as 'XY on behalf of the CMS Collaboration' (or the ATLAS and CMS Collaborations, in that order).
  5. The report should include a reference to the CMS detector paper, "CMS Collaboration, The CMS experiment at the CERN LHC, JINST 3 (2008) S08004, doi:10.1088/1748-0221/3/08/S08004", for reports with ATLAS, LHCb and/or Alice list also to the corresponding references "ATLAS Collaboration, The ATLAS Experiment at the CERN LHC, JINST 3 (2008) S08003, doi: 10.1088/1748-0221/3/08/S08003", and corresponding references S08005 and/or S08002 for LHCb and Alice.
  6. In references to papers by collaborations like CMS, the individual author list should be replaced by "CMS Collaboration".
  7. Reference to PAS, PUB/CONF notes, or TDR should include a CDS URL.
  8. Text, figures, and tables should be consistent with approved CMS results and cite the correct reference. Each figure caption should explicitly cite the document from which the figure is taken.
  9. Conference reports are a historical snapshot of results as they were presented at the time of the conference. Thus the plots and results cited in the conference report should reflect what was actually shown at the conference. If, however, more recent results become available before the report is published, it is recommended to mention this fact briefly in the text or a footnote, with a proper reference to the new results.
  10. For CO notes with ATLAS, please add on page 1 the following copyright statement in a footnote: "Copyright 2022 CERN for the benefit of the ATLAS and CMS Collaborations. Reproduction of this article or parts of it is allowed as specified in the CC-BY-4.0 license"

If you have any questions please contact the chair and deputy of the Publications committee by sending an email message to cms-pubcomm-coordinators@cernNOSPAMPLEASE.ch

Please notice: Students' talks at national conferences sometimes include material which has not yet been approved by CMS. It is not allowed to include such material in proceedings.

There is more information about the CMS Publications Committee at Publications

Conference Committee Internal Procedures

The Conference Committee is working on optimizing its internal procedures. We are in process of documenting on how we do things.



The CERN website can be rather difficult to navigate through - though if you know the keywords you are interested in, and can find it, the CERN search engine is useful:

Links to the search options are all on the CERN Users pages, though they can be tricky to find.

You can search the CERN Document Server for papers, photos, meetings, presentations, etc, on:

And the people database to find information such as the phone number, building number or email address of a colleague.

To find where a particular building is in CERN, use the building search:

Analysis Documentation

The CMSSW software documentation consists of three main components:

  • the WorkBook which is this document
  • the CMSSW Software Guide (described below)
  • the CMSSW Reference Manual (described below)

The CMS Offline Software Guide

The CMS Offline Software Guide contains a more detailed description of the CMS software, detailing the use of the various software packages and containing instructions to carry out tasks, e.g. physics analyses, which are beyond the scope of the WorkBook. The SWGuide is rapidly evolving to be the online storehouse for all offline software documentation for CMS.

Reference Manual

The CMSSW Reference Manual provides an introduction to different domains (data, functional and detector views) and should contain a brief description of contents and purpose of each package.

The Reference Manual is generated using Doxygen which is a documentation system for programming languages including C++ (the language of choice for CMS programme), Java, Python among others. It is an easy-to-use tool which can be used to generate online documentation (html), as well as a text manual (latex source), from a set of documented source files.

For a set of interrelated packages with various classes, the documentation includes dependence diagrams showing inter-class relationships, and provides hyperlinked listings of functions, data members, class headers, etc. Since the documentation is generated directly from the source files, it is easy to keep the documentation up to date - the only caveat being the requirement to provide useful documentation in the code!

While generally Doxygen simply documents the source code and illuminates the various relationships within the code, it can be used to generate a reference manual which complements, but does not replace documentation like the CMS WorkBook which contains introductory material and step-by-step tutorials for new users.

CVS Web Browser

The CVS Web Browser allows you to browse the code. You can choose a specifc CMSSW version and tag from a pull-down menu from the bottom of the page on any page containing link to files (and not just directories). If you do not select anything, the most recent "head" version is shown.

CMSSW Software Cross-Reference (LXR)

The CMSSW Software Cross-Reference is a cross referenced display of the CMS source code. With the LXR tool (LXR stands for "Linux Cross Reference") it is possible to search through the entire CMS source text; or to search for files whose name matches a pattern; or to search for the definitions of particular functions, variables etc.

Sample Use Case

Let's learn a little about the code provided for finding isolated tau tags.

If you want to select events with an identified isolated (i.e. not in a particle jet) tau lepton tag, you need to find the classes and functions which have been provided for you in CMSSW.

To find the code in the CMSSW CVS repository, go to CMSSW Software Cross-Reference (LXR), and use the search facility to find IsolatedTauTag. From the list of results, click on the header file /CMSSW/src/DataFormats/BTauReco/interface/IsolatedTauTagInfo.h to find out what its private data members are:

001 #ifndef DataFormats_BTauReco_IsolatedTauTagInfo_h
002 #define DataFormats_BTauReco_IsolatedTauTagInfo_h
003 //
004 // \class IsolatedTauTagInfo
005 // \short Extended object for the Tau Isolation algorithm.
006 // contains the result and the methods used in the ConeIsolation Algorithm,
007 // to create the object to be made persistent on RECO
008 //
009 // \author: Simone Gennai, based on ORCA class by S. Gennai and F. Moortgat
010 //
012 #include "DataFormats/BTauReco/interface/RefMacros.h"
013 #include "DataFormats/Math/interface/Vector3D.h"
014 #include "DataFormats/BTauReco/interface/JTATagInfo.h"
015 #include "DataFormats/JetReco/interface/JetTracksAssociation.h"
017 namespace reco { 
019   class IsolatedTauTagInfo : public JTATagInfo {
061   private:
062     TrackRefVector selectedTracks_;
063   };
065   DECLARE_EDM_REFS( IsolatedTauTagInfo )
067 }
069 #endif // DataFormats_BTauReco_IsolatedTauTagInfo_h

From line 19 we see that IsolatedTauTagInfo inherits from the class JTATagInfo. Click on JTATagInfo, and select its header file to learn, among other things, that JTA stands for Jet Tracks Association.

Further information

Other Documents

There are many sources of documentation about for CMS users. The CERN Document Server enables a search through much of the printed and online CERN media. Further information can be obtained from the sources including General Offline home page.

CERN/CMS Images and Plots

There are over 10,000 images of CERN and its associated experiments on the CERN photo server (see link below). For talks and presentations, a more specialised selection of photos is provided (see link below).

CERN Press Office Multimedia Gallery

Figures from CMS Physics Analysis summaries can be found in a CERN Document server (CDS) collection. Similar collection for all CMS journal publications and their figures is being prepared (September 2009).

CMS plots and images from the Technical Design Report (TDR) times can be found in http://cmsdoc.cern.ch/cms/cpt/tdr/index.html -- under each TDR there is a "Figure gallery".

Other useful help links

Review status

Reviewer/Editor and Date (copy from screen) Comments
MargueriteTonjes - 18 Jan 2023 Hypernews to CMS Talk, Vidyo to Zoom, remove a lot of other outdated material - not yet complete
StefanoBelforte - 2020-11-26 update HyperNews info
MargueriteTonjes - 4 April 2018 overhaul, removing EVO links
XuanChen - 16 Jul 2014 replaced the link of “How-To organize a videoconference at CERN”
AndriusJuodagalvis - 17-Sep-2010 A note on EVO CMS community
JennyWilliams - 09 Oct 2007 redid LXR example to use current code
JennyWilliams - 26 Sep 2007 updated info on SWGuide
KatiLassilaPerini - 26 Jun 2007 Updates on EVO
CMSUserSupport - 20 Nov 2006 (Kati Lassila-Perini) Updated the User Support part)

I went through chapter 1 section 4 .(email from morelos to Kati).

The information is relevant and clear.

This section has several links out of date, they require little direct work.

In several email addresses, it will help to add the warning "(remove SPAMNOT)".

I would suggest to update the link at " here "

I would suggest to update the link at " CERN IT Computing Helpdesk "

I would suggest to update the link at "Offline Software Guide "

I would suggest to update the link at " LPC "

I would suggest to update the link at "http://it-multimedia.web.cern.ch/it-multimedia/collaborative/howto.html"

I would suggest to update the link at "http://it-multimedia.web.cern.ch/it-multimedia/collaborative/recommendations.html"

I would suggest to update the link at "Information on CERN sites "

I would suggest to update the link at "CERN Press Office Multimedia Gallery"

I would suggest to update the link at "CERN Users Office FAQ"

Updated the straightforward links that A.Morelos suggested.

Responsible: SudhirMalik
Last reviewed by: KatiLassilaPerini - 27 Jan 2011

Topic attachments
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GIFgif SiPix-root-browser.gif r1 manage 18.1 K 2006-06-08 - 18:10 UnknownUser <nop>SiPixelClusterCollection, ROOT Events browser
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