Particle name and class

In addition to the loops described above, it is possible to access particles by their name. In many cases, this method is faster and the code is easier to read than the standard loops described in 7.1. Two quantities must be specified:

• The particle name (example: `E+' or `GAMMA'); see 15.1.
• The object (= track = particle) class which distinguishes between reconstructed tracks, the Monte-Carlo truth, and any Lorentz frame derived from one of them:
  • Class KRECO: Reconstructed objects read from the event input file and everything derived from them except Lorentz boosted objects.
  • Class KMONTE: Monte-Carlo truth.
  • Each Lorentz frame is considered as its own class (see 9.6). These classes are denoted by the number of the object which defines the Lorentz rest frame.

KRECO and KMONTE are available everywhere as integer Fortran parameters. Their actual values are -1 and -2, respectively. Positive integers denote Lorentz frames. Integers less than -2 can be used to create your own particle classes (see KVSAVC in 9.2.12).

The particle name of MC particles is specified in the MC particle table (see 15.1). Reconstructed objects have the names `CHARGED', `ECAL', `HCAL', `CALOBJ', `EFLW', 'NEOB', and 'GAMP' for charged tracks, ECAL objects, HCAL objects, unspecified ( e.g., composite) calorimeter objects, energy flow objects, neutral calorimeter objects, and GAMPEC photons, respectively. The functions KVSAVE, KVSAVC, and KIDSAV (see 9.2.11) can be used to create new tracks with a name. A list of standard particle names is given in App. F. New particle names can be introduced by using them in ALPHA subroutine calls or by specifying them on data cards (see 15.4.2).