367
B. Natural Units
where a millibarn, mb, is defined to be
2
10
−31
Note that a ‘typical’ hadronic cross section corresponds to an area of about
1 mb =
m .
λ
2
π where
λ
2 = 1/M
2
Electromagnetic cross sections are an order of magnitude smaller: specifically
for lowest order e
+ e → μ
+ μ
−
86.8
σ ≈
nb
(B.18)
s
π
where s is in (GeV)
2 (see problem 8.18(d) in chapter 8).
π
= 20 mb.
B. Natural Units
where a millibarn, mb, is defined to be
2
10
−31
Note that a ‘typical’ hadronic cross section corresponds to an area of about
1 mb =
m .
λ
2
π where
λ
2 = 1/M
2
Electromagnetic cross sections are an order of magnitude smaller: specifically
for lowest order e
+ e → μ
+ μ
−
86.8
σ ≈
nb
(B.18)
s
π
where s is in (GeV)
2 (see problem 8.18(d) in chapter 8).
π
= 20 mb.