Data sets

This section explains the different data sets that can be processed using BOSS. There are essentially three types of data files of relevance here:

• Raw data
  These are data files containing raw recorded data from either real measurements in BESIII or from Monte Carlo simulations.
  Extension: rtraw or raw, see here for how to convert them into each other.
• Reconstructed data
  Raw files are too large to be handled in an analysis: the recorded data first has to be converted to tracks data. The output of this reconstruction step is a DST file.
  Extension: dst.
• Output from the initial event selection
  In the analysis step, you analyze the events contained in the DST files. The output of that analysis is stored to a TTree in a ROOT file.
  Extension: root

Locations on the IHEP Server

Inventories of the latest file locations are found on the Offline Software pages (requires login):

• Raw data
• Reconstructed data

In general, all data files are located on the BESIII file system (besfs5) folders on the IHEP Server. There are a few different folders, because the files have been distributed to different servers.

• besfs5: contains user files only
• besfs2: a symbolic link that points to /besfs3/offline/data/besfs2. Contains inclusive Monte Carlo samples.
• besfs3: file system that contains files of the runs before 2018
• bes3fs: a newer file system that contains for instance 2018 data

Within these folders, the data files are located under offline/data (e.g. /besfs3/offline/data) and then the BOSS version with which these files have been created.

Warning

Make sure you do not confuse the numbers when navigating these paths.

Querying for data sets

On lxlogin

You can find all information about the data sets through MySQL on lxlogin. To open the database, type:

mysql --user=guest --password=guestpass -h bes3db2.ihep.ac.cn offlinedb

Now it’s a matter of searching through the database through MySQL query commands. Some examples (in this case to find the exact energies of the data set):

• show tables;
• select * from MeasuredEcms where sample = "4360";
• select * from MeasuredEcms2 limit 20;

For a reference of MySQL queries, see here.

Note that there are a few BOSS packages that allow you to fetch data from the MySQL database from the C++ code. The main one is DatabaseSvc. For fetching exact beam energy values, use MeasuredEcmsSvc.

Web interface

Alternatively, you can have a look at this page for an overview of run numbers et cetera.