In particle physics, the tracking is the act of measuring the direction and magnitude of charged particlesmomenta. The particles entering a tracker (the device used for tracking), release part of their energy in the device: the tracker has to be finely segmented in order to be able to reconstruct with good precision where the particle passed. Since the tracking is usually made in a region where a magnetic field is present, it is possible to reconstruct part of the helix made by the particle inside the tracker (that is called track), and from the track parameters, and by knowing the mass of the particle under study (which is known by the use of particle identification), it is possible to reconstruct the actual direction and magnitude of the particle momenta. From these information the tracking of charged particles can be used to reconstruct secondary decays, this can be done for B-tagging (in experiments like CDF or at LHC) or to fully reconstruct events (like in BaBar and Belle).
Tracking, one of the first freefall skills learned by a novice skydiver, is the technique of assuming a body position that allows the skydiver to move horizontally while freefalling.
Although there are many variations of the basic body position it essentially involves the skydiver moving out of the traditional face to earth arched position, straightening the legs, bringing the arms to the sides and de-arching, using the body to cup the air as a means of providing greater lift. There is, however, debate over what exactly constitutes the most efficient tracking position (providing the best glide ratio) especially concerning how far (if at all) the skydiver's legs should be spread. Some variations of the tracking position work well for some individuals and not so well for others. Also, when a skydiver gains experience, his or her preferred body position often changes.
It is claimed that good trackers can cover nearly as much ground as the distance they fall, approaching a glide ratio of 1:1. It is known that the fall rate of a skydiver in an efficient track is significantly lower than that of one falling in a traditional face-to-earth position; the former reaching speeds as low as 90mph, the latter averaging around the 120mph mark.