Measurement of the Radiative-Decay Probability of the Hoyle State

The radiative-decay probability of the Hoyle state is actually controversial because new data which contradicts the currently adopted value has been recently reported. In this work, we performed the new reliable measurement of the radiative-decay probability of the Hoyle state. We successfully obtained 40 triplecoincidence events of scattered α particles, recoil 12C, and emitted γ rays for the first time. Further analysis will determine the radiative-decay probability, and puzzle over the radiative-decay probability.