content_image/308553.jpg content_image/308560.jpg content_image/308559.jpg content_image/308558.jpg
Using the result (2.35), setting d = 4 + 2 ϵ and working in the MS renormalization scheme, 

<img src='content_image/308553.jpg'>

Because the $_{4}$F$_{3}$ hypergeometric function has one common upper and lower index, it reduces to a $_{3}$F$_{2}$ hypergeometric function. Using the series representation of the hypergeometric function, the result can be written as 

<img src='content_image/308560.jpg'>

Noting that the factor multiplying the sum is O ( ϵ $^{0}$), we only need to expand the sum to this order. Also, note that the for n ≥ 2 we may safely set ϵ = 0 in the sum, so we can extract the n = 0 and n = 1 terms. Doing so, we have 

<img src='content_image/308559.jpg'>

Letting k = n − 2 and using the properties of the Gamma function, the sum can be expressed as a hypergeometric function 

<img src='content_image/308558.jpg'>

