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Data sets

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):

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 lxslc#

You can find all information about the data sets through MySQL on lxslc. 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
http://bes3db.ihep.ac.cn/online/webserver/runinfo/runparams.php
for an overview of run numbers et cetera.

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