When ever something, you write down, evaluates to Sqrt[Pi]
it comes from an integral over a full circle squared. Since you have Gamma functions, there is always a
Sqrt[Pi] =Gamma[1/2]
around.
Best example`
(Integrate[Exp[-x^2],{x,-Infinity, Infinity}])^2 == Pi
This can be demonstrated by the fact, that the product of two integrals equals the Integral of the product with two different variables
Integrate[Exp[-x^2-y^2] , {x,-oo,oo}, {y,-oo,oo}] ==
Integrate[Exp[-r^2] r {r, 0, oo}] 2 Pi == Integrate[Exp[-u] ,{u, 0, oo}] Pi
If you find an identity for Pi or sqrt Pi, its an identiy in the integers. where the transcendent is as factor, mostly stemming from integrals over circles in the complex plane.