CMS luminosity information, for 2012 CMS open data

Description

Updated on December 1st 2022. This record contains outdated luminosity information, please use the detailed luminosity information instead.

CMS measures the luminosity with different luminometers (luminosity detectors) and algorithms. The luminosity values presented here correspond to an early version of those obtained with the Hadron Forward calorimeter's Zero Counting algorithm (hfoc). However, as of 2020, an upgraded and more detailed version of the luminosity information is available (and recommended).

The integrated luminosity for validated runs and luminosity sections of the 2012 public data (RunB and RunC) is available in the tables 2012RunBlumi.txt and 2012RunClumi.txt. (The integrated luminosity for validated runs and luminosity sections of all 2012 p-p data taking is available in 2012lumi.txt.)

In your estimate for the integrated luminosity, check for which runs the trigger you have selected is active and sum the values for those runs. The uncertainty in the luminosity measurement of 2012 data should be considered as 2.6% (reference CMS PAS LUM-13-001).

If you are using prescaled triggers, you can find the trigger prescale factors as shown in the trigger example. The change of prescales (run, lumi section, index of prescales) is recorded in prescale2012.txt.

For luminosity calculation, a detailed list of luminosity by lumi section is provided in 2012lumibyls.csv for the list of validated runs and lumi sections.

Note that if there are orphan lumi sections listed at the bottom of the lumi files as in json but not in results, they can be safely ignored. These lumi sections have no events as they correspond to the very end of runs for which the stable beam flag was not disabled yet during acquisition.

Additional information on how to extract luminosity values using the brilcalc tool can be found in the luminosity calculation guide.

Related datasets

An upgraded (recommended) version of this luminosity description is available:

CMS detailed luminosity information, for 2012 CMS open data