U⁡(a,z)=ⅇ-14⁢z2⁢z-a-122⁢π⁢ⅈ⁢Γ⁡(12+a)⁢∫-ⅈ⁢∞ⅈ⁢∞Γ⁡(t)⁢Γ⁡(12+a-2⁢t)⁢2t⁢z2⁢t⁢ⅆ⁡t,