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arXiv · 1712.06257

Possible $η' d$ bound state and its $s$-channel formation in the $γd \to ηd$ reaction

Takayasu Sekihara·Hiroyuki Fujioka·Takatsugu Ishikawa
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Abstract

We theoretically investigate a possibility of an $η^{\prime} d$ bound state and its formation in the $γd \to ηd$ reaction. First, in the fixed center approximation to the Faddeev equations we obtain an $η^{\prime} d$ bound state with a binding energy of 25 MeV and width of 19 MeV, where we take the $η^{\prime} N$ interaction with a coupling to the $ηN$ channel from the linear $σ$ model. Then, in order to investigate the feasibility from an experimental point of view, we calculate the cross section of the $γd \to ηd$ reaction at the photon energy in the laboratory frame around 1.2 GeV. As a result, we find a clear peak structure with the strength $\sim$ 0.2 nb/sr, corresponding to a signal of the $η^{\prime} d$ bound state in case of backward $η$ emission. This structure will be prominent because a background contribution coming from single-step $η$ emission off a bound nucleon is highly suppressed. In addition, the signal can be seen even in case of forward $η$ emission as a bump or dip, depending on the relative phase between the bound-state formation and the single-step background.

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Takayasu Sekihara, Hiroyuki Fujioka, Takatsugu Ishikawa. 2018-04-22. Possible $η' d$ bound state and its $s$-channel formation in the $γd \to ηd$ reaction. https://doi.org/10.1103/physrevc.97.045202

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