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A recent measurement of $^4$He photodisintegration reactions,$^4$He($\gamma$,$p$)$^3$H and $^4$He($\gamma$,$n$)$^3$He with laser-Comptonphotons shows smaller cross sections than those estimated by other previousexperiments at $E_\gamma \lesssim 30$ MeV. We study big-bang nucleosynthesiswith the radiative particle decay using the new photodisintegration crosssections of $^4$He as well as previous data. The sensitivity of the yields ofall light elements D, T, $^3$He, $^4$He, $^6$Li, $^7$Li and $^7$Be to the crosssections is investigated. The change of the cross sections has an influence onthe non-thermal yields of D, $^3$He and $^4$He. On the other hand, thenon-thermal $^6$Li production is not sensitive to the change of the crosssections at this low energy, since the non-thermal secondary synthesis of$^6$Li needs energetic photons of $E_\gamma \gtrsim 50$ MeV. The non-thermalnucleosynthesis triggered by the radiative particle decay is one of candidatesof the production mechanism of $^6$Li observed in metal-poor halo stars(MPHSs). In the parameter region of the radiative particle lifetime and theemitted photon energy which satisfies the $^6$Li production above the abundancelevel observed in MPHSs, the change of the photodisintegration cross sectionsat $E_\gamma \lesssim 30$ MeV as measured in the recent experiment leads to$\sim 10$% reduction of resulting $^3$He abundance, whereas the $^6$Liabundance does not change for this change of the cross sections of$^4$He($\gamma$,$p$)$^3$H and $^4$He($\gamma$,$n$)$^3$He. The $^6$Li abundance,however, could show a sizable change and therefore the future precisemeasurement of the cross sections at high energy $E_\gamma \gtrsim$ 50 MeV ishighly required.

New Constraints on Radiative Decay of Long-Lived Particles in Big Bang Nucleosynthesis with New $^4$He Photodisintegration Data