TrackTrajectory

A trajectory represents the orbit followed by a (charged) particle through the experiment. This trajectory has a validity range which specifies where the results can be reliably interpreted (i.e. if a trajectory is extrapolated beyond the bounds of the experiment, there is no guarantee that the results, or the quoted covariances are correct). A trajectory can be represented by a collection of states, each of which parameterize the 'local' orbit of the (charged) particle. These states basically represent straight line segments, including a covariance matrix. To achieve a 'global' representation of the trajectory, a set of states parameterized as a function of an 'external' parameter is used. Given the geometry of the experiment, this parameter is choosen to be the position projected onto the nominal beamaxis, i.e. the z coordinate in the canonical LHCb reference frame.

At this point, there is no seperate class which represents a trajectory. For a discussion on this subject, please go here.

-- GerhardRaven - 03 Apr 2005