1000 Solved Problems in Modern Physics

592 10 Particle Physics – II

(b)R∼

c

mc^2

=

197 MeV−fm

100 × 103 MeV

= 2 × 10 −^3 fm

10.96 MW^2 =

4 πα

8sin^2 θW

·

√

2

(c)^3

GF

=

(4π)

8sin^228. 170

·

√

2

128

×

1

1. 166 × 10 −^5

= 6 , 670

MWc^2 = 81 .67 GeV

the experimental value being 81 GeV

MW/MZ=cosθW→MZ=MW/cosθW

MZ= 81. 67 /cos 28. 170

= 92 .64 GeV

the experimental value being 94 GeV.

10.3.7 FeynmanDiagrams ................................

10.97 (i) Weak interaction

Fig. 10.15(i)τ+decay
τ+→μ++νμ+ντ

(ii) Strong interaction

Fig. 10.15(ii)Ω−production
inK−interaction
K−+p→Ω−+K++K^0

(iii)

Fig. 10.15(iii)Decay ofD^0
D^0 →K++π−

10.98 (i)l=νe