Missing-mass spectroscopy of the ${}^{12}\mathrm{C}(p,d)$ reaction near the ${\eta }^{\mathrm{\prime }}$-meson production threshold

Excitation-energy spectra of ${}^{11}$C nuclei near the ${\eta }^{\mathrm{\prime }}$-meson production threshold have been measured by missing-mass spectroscopy using the ${}^{12}$C($p$,$d$) reaction. A carbon target has been irradiated with a 2.5 GeV proton beam supplied by the synchrotron SIS-18 at GSI to produce ${\eta }^{\mathrm{\prime }}$ meson bound states in ${}^{11}$C nuclei. Deuterons emitted at $0^{\circ }$ in the reaction have been momentum-analyzed by the fragment separator (FRS) used as a high-resolution spectrometer. No distinct structure due to the formation of ${\eta }^{\mathrm{\prime }}$-mesic states is observed although a high statistical sensitivity is achieved in the experimental spectra. Upper limits on the formation cross sections of ${\eta }^{\mathrm{\prime }}$-mesic states are determined, and thereby a constraint imposed on the ${\eta }^{\mathrm{\prime }}$-nucleus interaction is discussed.