Experimental search for the radiative capture reaction d + d → 4He + γ from the ddμ muonic molecule state J = 1

A search for the muon catalyzed fusion reaction d + d → 4He + γ in the ddμ muonic molecule was performed using the experimental installation TRITON with BGO detectors for γ quanta. The high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect γ quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the ddμ state J=1 was obtained at a level ηγ ≤ 8·10-7 per fusion