content_image/299681.jpg content_image/299680.jpg content_image/299679.jpg content_image/299678.jpg content_image/299677.jpg content_image/299676.jpg content_image/299675.jpg
we can write 

<img src='content_image/299681.jpg'>

Now, consider the integral 

<img src='content_image/299680.jpg'>

To evaluate this integral we will use the following identity [110, 118] 

<img src='content_image/299679.jpg'>

The integration variable α is called an alpha parameter and serves a similar purpose to the Feynman parameters introduced earlier. The resulting k$_{1}$ and k$_{2}$ loop integrals can be evaluated using the integral [118] 

<img src='content_image/299678.jpg'>

Doing this, the result is 

<img src='content_image/299677.jpg'>

The functions D ( α ) and Q ( α , a$_{1}$ , a$_{2}$ ) are 

<img src='content_image/299676.jpg'>

<img src='content_image/299675.jpg'>

