class HKickMassFit: public TObject

_HADES_CLASS_DESCRIPTION

 HKickMassFit

   This class makes both particle identification and a inverse
kinematics momentum fit.

   There is a table of masses for known particles defined in the class.
When a user calls fitMomentum giving a mass and a velocity, that mass is
compared to each of the masses in the table.

   If the mass given by the user is compatible with one and only one of the
masses in the table then the corresponding Id is assigned to the particle,
as a second step the momentum of this particlei, determined from its real mass
(the one in the table) and the given velocity, is calculated.

   To check if a mass is compatible with one of those in the table the
following criterium is used

    (mass - mass_table) / error_in_mass  <  tolerance

   Where tolerance is a parameter of the class with the default value of 3.

   The table of masses consists of two static arrays: fMassTable and
fPidTable. The first table is an array of known masses plus one last element
which always equals -1 and signals the end of the table.

   Each of the entries in the fMassTable array corresponds to two entries in
fPidTable which are the two types of particles with that mass: first is
positive charged and second is negative charged.