bindings found in [@oset02c]: E\_= -9.71 [MeV]{}, && \_= 35.0 [MeV for\^[12]{}\_[ ]{}C]{}, E\_= -12.57 [MeV]{}, && \_= 33.4 [MeV for\^[24]{}\_[ ]{}Mg]{}. \[eq:EB-Oset\]

Bindings with equally large widths arise also in calculations [@jido02; @nagahiro05; @jido08] that use a chiral doublet model and treat $\eta A$ and $S_{11}(1535)A$ attraction as a result of partial restoration of chiral symmetry in the dense nuclear matter leading to reduction of the $S_{11}(1535){-}N$ mass gap. It is clear that experimental data on energies and widths of $\eta$-mesic nuclei are needed to test these and many other models and calculations.

Signature for eta-mesic nuclei produced in photoreactions {#signature-for-eta-mesic-nuclei-produced-in-photoreactions .unnumbered}
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A mechanism of $\eta$-mesic nuclei formation and decay in the photoreaction + A N’ + \_[ ]{}(A-1)N’ + + N + (A-2) \[reac:piN\] is shown in Fig. \[diagrams-piN\]a. A fast nucleon $N'$ ejected forward at the first stage of the reaction, i.e. in the subprocess + N’ N’ + \_[slow]{}, \[reac:eta\] escapes the nucleus, whereas a slow $\eta$ is captured by remaining $A-1$ nucleons to a bound state. At $E_\gamma \sim 800{-}900$ MeV, a minimal momentum transfer to $\eta$ in the reaction (\[reac:eta\]) is not large (less than $70~{\rm MeV}/c$). That is why the total cross 