1000 Solved Problems in Modern Physics

(Tina Meador) #1
10.3 Solutions 589

|Ks〉=

1


2

(∣

∣K^0


+



∣K^0

〉)

|KL〉=

1


2

(∣

∣K^0 〉−



∣K^0

〉)

ψ(t)=

1

2

e−imsc

(^2) t/[
e−t/^2 τs


(∣

∣K^0


+



∣K^0

〉)

+eiΔmc

(^2) t/(∣∣
K^0






∣K^0

〉)]

=

1

2

e−imsc

(^2) t/[∣∣
K^0


〉(

e−t/^2 τs+eiΔmc

(^2) t/)


+



∣K^0

〉(

e−t/^2 τs−eiΔmc

(^2) t/)]
The intensity of the component is obtained by taking the absolute square of
the coefficient of




∣K^0


I

(∣∣

K^0

〉)

=

1

4

[

e−t/τs+ 1 + 2 e−t/^2 τscos

(

Δmc^2 t/

)]

Similarly,

I



∣(K^0

〉)

=

1

4

[

e−t/τs+ 1 − 2 e−t/^2 τscos

(

Δmc^2 t/

)]

10.92 Refering to Problem 10.91, theKLstate can be written as


|KL〉=

1


2

(∣

∣K^0





∣K^0

〉)

(1)

WhenKLenters the absorber, strong interactions would occur withK^0 (S=
+1) and



∣K^0


(S=−1) components of the beam of the originalK^0 beam
intensity, 50% has disappeared byKS-decay. The remainingKLcomponent
consists of 50%K^0. Upon traversing the material the existence ofK^0 with
S =−1 is revealed by the production of hyperons in a typical reaction,
K^0 +p→Λ+π+
WhileK^0 components can undergo elastic and charge-exchange scattering
only, theK^0 component can in addition participate in absorption processes
resulting in the hyperon production. The emergent beam from the slab will
then have theK^0 amplitude f


∣K^0 〉andK (^0) amplitude f




∣K^0


with f <
f <1. The composition of the emergent beam from the slab is given by
modifying (1).

1

2

(

f


∣K^0


−f


∣∣K 0

〉)

=

(

f+f

)

2


2

(∣

∣K^0





∣K^0

〉)

+

(

f−f

)

2


2

(∣

∣K^0


+



∣K^0

〉)

=

1

2

(

f+f

)

|KL〉+

1

2

(

f−f

)

|KS〉
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