Charge Independence in (γ, n) and (γ, t) Reactions

The comparison of ($\gamma , n$) and ($\gamma , t$) reactions on light nuclei with $A=4n+3\mathrm{}$ will give information on charge symmetry versus charge independence for nuclear forces. If isotopic spin is a good quantum number (charge independence), more individual levels should appear in ($\gamma , n$) reactions than in ($\gamma , t$); those peculiar to ($\gamma , n$) have $T=\frac{3}{2}$, the others have $T=\frac{1}{2}$. The one presently measured case of ${\mathrm{Li}}^7$ favors charge independence.