Mathematical Principles of Theoretical Physics

(Rick Simeone) #1

4.5. STRONG INTERACTION POTENTIALS 221


whereδ(r)is the Dirac delta function,θμj is a constant tensor, inversely proportional to the
volume of the particle. Hence


ρkSμjλijkθiμ=Sμjθjμδ(r),

whereS
j
μ∼S


j
μ(^0 )takes the following average value

(4.5.14) S


j
μ=

1


|Bρw|


Bρw

Sμjdv.

Hereρwis the radius of aw∗-weakton. Later, we shall see that


S


j
μ∼

1


r
asr→ 0.

Hence we deduce from (4.5.14) that


S
j
μ=ξ

j
μρ
− 1
w (ξ

j
μ is a constant tensor).

Thus, (4.5.13) becomes


(4.5.15) ∂μQμ=−
κ
ρw


δ(r) (ρwis the radius of aw∗-weakton),

whereκis a parameter given by


(4.5.16) κ=


2 gs
hc ̄
ξμjθ
μ
j,

andκis inversely proportional to the volume ofw∗-weakton.
Therefore, equation (4.5.12) is rewritten as


(4.5.17) −∆φs+k^20 φs=−
gsκ
ρw


δ(r),

whose solution is given by


(4.5.18) φs=−
gsκ
ρw


1


r

e−k^0 r.

Step 2. Solution of (4.5.11).The quantitygsQ=−gsQ 0 is the strong charge density of a
w∗-weakton, and without loss of generality, we assume that


(4.5.19) Q=β δ(r),


andβ>0 is a constant, inversely proportional to the volume of thew∗-weakton. Hence
(4.5.11) can be rewritten as


(4.5.20) −∆Φs=gsβ δ(r)+


gsA
ρw

1


r

e−k^0 r,
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