# Elektron Positron Paarvernichtung und Z-Resonanz:
> with(plots):
> Q_u:=2/3;

                              Q_u := 2/3

> v:=-1/2+2*0.223;

                          v := -.0540000000

> a:=1/2;

                               a := 1/2

> v_u:=1/2-2*2/3*0.223;

                          v_u := .2026666667

> v_u := .2026666667;

                          v_u := .2026666667

> a_u:=1/2;

                              a_u := 1/2

> M_Z:=91.182;

                            M_Z := 91.182

> M_F:=37.281;

                            M_F := 37.281

> s:=W^2;

                                     2
                               s := W

> B:=M_Z^2/4/M_F^2;

                           B := 1.495488681

> Gamma:=2.495;

                            Gamma := 2.495

> f_BW:=1/((s-M_Z^2)^2+M_Z^2*Gamma^2);

                                      1
              f_BW := ---------------------------------
                        2               2
                      (W  - 8314.157124)  + 51755.83595

> plot(f_BW,W=80..100);

> G1:=Q_u^2-2*Q_u*v*v_u*B*s*(s-M_Z^2)*f_BW+(v^2+a^2)*(v_u^2+a_u^2)*B^2*s
> ^2*f_BW;

                                  2   2
                                 W  (W  - 8314.157124)
  G1 := 4/9 + .02182217084 ---------------------------------
                             2               2
                           (W  - 8314.157124)  + 51755.83595

                                       4
                                      W
         + .1646439011 ---------------------------------
                         2               2
                       (W  - 8314.157124)  + 51755.83595

> plot(G1,W=85..100);

> c_Ld:=-1/2+1/3*0.223;

                         c_Ld := -.4256666667

> c_Rd:=1/3*0.223;

                         c_Rd := .07433333333

> v_d:=-1/2+2*1/3*0.223;

                         v_d := -.3513333333

> a_d:=1/2;

                              a_d := 1/2

# Formel 7.40 wird fuer 2 u-artige und 3 d-artige Quarks (u,d,c,s,b)
# ausgewertet:
> sig:=4*Pi/137.05^2*B^2*s*f_BW*(v^2+a^2)*(2*v_u^2+2*a_u^2+3*v_d^2+3*a_d
> ^2);

                                               2
                                           Pi W
       sig := .0002050782390 ---------------------------------
                               2               2
                             (W  - 8314.157124)  + 51755.83595

# Der Faktor 398400 gibt den Wirkungsquerschnitt in nanobarn:
> plot(398400*sig,W=85..95);

>