2005 - LHC Olympics

Home Research Classes


This web page is now out of date. I'll improve it soon. Most importantly, the LHC Olympics link has moved a little bit (those darn theorists; can't keep a URL stable!).

Basic Links

ROOT Files And Source Code

blackbox1.root - Downloaded .dat from the LHC Web site 6/1/2005 (basic plots)
LHCOlympics ROOT Code (gzipped/tared) 5/29/2005.

Known Issues:

  • The missing ET is never close to zero - resolved: that is the proper thing, according to Steve.

Steve has provided a .dat file (text file) that contains 2 fb-1 of data. I've converted it to a root file that can be read by the ROOT program (version 4.03.00 or better is required!!!!). The file contains about 73K events. To use the ROOT files do the following (on Windows or on Linux):

  1. Make sure ROOT is properly setup on your system. You should be able to type "root" at the command line and you should be able to type "gcc" (on Linux) or "cl" (on Windows) and have the C++ compiler run.
  2. Download and untar/unzip this source code archive. Make sure the path you unpack it to has no spaces in it. This contains the source code for the conversion and some sample code to run over the root file.
  3. Download the blackbox1 root file. Save it in the directory you unpacked above.
  4. In a shell cd to the unpacked directory and type "root rootlogon.C blackbox1.root". ROOT should start and compile several small C++ files. You'll get some messages but should not get errors (this will happen only after you change the files that it is compiling, so the next time you start root you won't see these messages). You don't need the rootlogon.C file if you are on Windows; for reasons I don't understand it doesn't seem to do it on my root version on Linux (it may on yours -- try it without and see how it fails).
  5. Start a TBrowser ("TBrowser b1") and explore the file. Jets, MET, etc. should all be there.

There is a simple macro that generates met, eta, phi, etc., plots for all objects. This is what I used to verify the root conversion process. Use the following command to run through all the events and produce an output file of simple plots:

root -l -q basicPlots.C+

The output file will be basicPlots.root (there is a copy in the zip file so you can see what I get when I run it).

I've got another macro that we use at DZERO a lot that turns a .root file into a html file (plots, etc., turned into gif/ps files). Running this is a bit more messy since you have to pass arguments on the command line:

root -q -l make_all_plot_html.C(\"basicPlots.root\",\"plots\") [Windows]

root -q -l 'make_all_plot_html.C("basicPlots.root","plots")' [Linux]

It will produce a subdirectory, which will contain an html file that holds all the plots (this html file is generated for the blackbox1 file).

Doing an analysis should just be a matter of modifying basicPlots.C. I really have tried to keep Gordon code out of it (no iterators, no for_each loops -- Toby will hate the lack of those).