MSHELL _ _ _ _ _ _ _ _ _ _ _ _ command

The mshell command puts particles on the mass shell in high-energy physics calculations.

syntax:

mshell<vector-var>{,<vector-var>}*

<vector-var> must have had a mass attached to it by a mass declaration.

examples:

vector v1,v2; 

mass v1=m,v2=q; 

mshell v1; 

v1.v1; 

   2
  M  


v2.v2; 

  V2.V2 


mshell v2; 

v1.v1*v2.v2; 

   2  2
  M *Q

Even though a mass is attached to a vector variable representing a particle, the replacement does not take place until the mshell declaration is given for that vector variable.