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 -> He-4 + gamma in the dd mu muonic molecule was performed using the experimental installation TRITON with BGO detectors for gamma-quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect gamma-quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the dd mu state J = 1 was obtained at the level of eta(gamma) <= 8 x 10(-7) per fusion.