Boost the track ITK into the rest frame of IREST and store the result in IBOOST.
The sample of all tracks boosted into the rest frame of any track IREST constitutes its own track class which is denoted by the track number IREST, and which can be accessed directly as described in 7.4. Another way to access boosted tracks is to use KSAME (see 7.6), which makes it possible to jump from a given track to the same track in other Lorentz frames.
A track can be boosted into its own rest frame. The result is a vector with the initial direction and a momentum very close to 0.
KTLOR does not boost a track into a given frame twice. It returns, instead, the number of the already boosted track. This rule is only valid as long as you leave the mass and the particle name unchanged.
If a composite track is to be boosted, all daughters, granddaughters, etc. (but NOT mothers, etc!) of the track are boosted at the same time. The mother-daughter and daughter-mother relationships among the boosted tracks are established. If these relationships are not needed, use KTLOR1 or QTCLAS described below.
The track to be boosted (ITK) and the track which defines the rest frame (IREST) may belong to different track classes. No check is done that the boost makes sense. Note, however, an important restriction: If more than one track is boosted into a frame, all of them must come from the same class. This restriction prevents putting reconstructed tracks and MC truth into the same track class; see example in 9.6.3.
A maximum of six Lorentz frames can be used simultaneously. Frames which are not used any more can be dropped by CALL QVDROP (' `, IREST) (see 9.2.6) to reduce the number of frames in use, and to release the space occupied by the boosted tracks.