2 4 76                  Table of beams
             This table consists of four fields:

1. "Name" for an identifier of the beam. It may contain up to 6 characters.
   The first character must be a letter, others may be either letters or 
   digits; CompHEP identifiers are sensitive to the case of characters. 
   But any two identifiers must be different after rewriting them in low 
   case. There are reserved names, which cannot be used here: 
  "i" is used for imaginary unit;
  "Sqrt2" is used for sqrt(2)
  "p1","p2","p3",.. are used for particle momenta. 
  "m1","m2","m3",.. are reserved for Lorentz indexes of particles.
   G5 is used for the gamma-five Dirac matrix;
   
2. "Mass" for numerical value of the beam mass in GeV units;

3. "Content" is a list of particles in the beam. All names must coincide
    with particle names in the model, which you use. Otherwise, this beam 
    will not available for the model.
    
4. "Structure functions" is a name of a structure functions which are used 
   for the beam. This name has to coincide with a name from the structure
   function table. Also one can use beams without structure functions,
   for the beams you can enter either OFF in the field, or leave this 
   field empty.
