Fullsimplify not working perfectly


Here I am using the below code for a simplification.

DB = \[Sigma]*\[Sigma]*\[Phi]*\[Phi]     BB = Sqrt[DB] // FullSimplify // PowerExpand     g = 1/DB         \[Alpha]I = a\[Phi]     \[Alpha] = \[Alpha]I - 0.5*BB*D[BB, \[Phi]]     \[Alpha]s = \[Alpha] - ((1/2)*BB*D[BB, \[Phi]])     UG = 0.375 \[Sigma]^2     Phi = UG - ((1/2)*(g*\[Alpha]s*\[Alpha]s)) // FullSimplify //        PowerExpand 

But I am getting a result without cancelling the common term $ $ \phi $ $ Below is what I am getting. But I need to cancel the common terms. Here $ $ a, \sigma $ $ are constants. $ $ \phi$ $ is a variable

Result I got:

res