Measurement of the α-particle monopole transition form factor challenges theory: a low-energy puzzle for nuclear forces?

S. Kegel, P. Achenbach, S. Bacca +30

We perform a systematic study of the $\alpha$-particle excitation from its ground state $0_1^{+}$ to the $0_2^{+}$ resonance. The so-called monopole transition form factor is investigated v…