double precision PI
      double precision ECHARGE, CLSP0, RE, MC2EV, MC, MC2 
      double complex IM 
      parameter ( PI= 3.14159265358979323846d0  )
      parameter ( IM = ( 0.0d0, 1.0d0 ) )
      parameter ( ECHARGE = 1.602177d-19, CLSP0 = 299792458.0d0 )
      parameter ( RE = 2.817938d-15,  MC2EV = 511003.4d0 )
      parameter ( MC = 2.730969732d-22,  MC2 = 8.187241286d-14 )
c