4.4 “End of Inflation” Mechanism 65 non-Gaussianity parameter f$_{NL}$ is obtained as [51] where the prime denotes the derivative with respect to ψ . By substituting N$_{TI}$ from Eq. (4.58) or Eq. (4.62) into Eq. (4.69) we obtain where A = 5 6 for Γ$_{ϕ}$ ≳ H$_{TI}$ (Eq. (4.58)) or A = 5 16 for Γ$_{ϕ}$ ≪ H$_{TI}$ (Eq. (4.62)). Then, from our mass definition m , Eq. (4.3), we obtain The non-Gaussianity parameter g$_{NL}$ is obtained as [51] By substituting N$_{TI}$ from Eq. (4.58) or Eq. (4.62) into Eq. (4.72) we obtain g$_{NL}$ ≃ B ( 2 − 3 mm ′′ m ′ 2 + m $^{2}$m ′′′ m ′ 3 ) (4.73) g$_{NL}$ = 25 54 N ′′′ N ′ 3 (4.72) f$_{NL}$ ≃ A [ 1 + 2 α − 1 α ( m 2 $_{0}$M 2 α − 2 P 2 h $^{2}$ψ2 α − 1 )] (4.71) f$_{NL}$ = 5 6 N ′′ N ′ 2 (4.69) f$_{NL}$ ≃ A ( 1 − mm ′′ m ′ 2 ) (4.70)