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Abstract.A search for resonant absorbtion of 14.4 keV solar axions by 57 Fe target was performed. The Si(Li) detector placed inside the low-background setup was used to detect the γ-quanta appearing in the deexcitation of 14.4 keV nuclear level: A + 57 Fe → 57 Fe * → 57 Fe + γ. The new upper limit for the hadronic axion mass have been obtained: mA ≤ 151 eV (90% C.L.) (S=0.5, z=0.56).

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The search for resonant absorption of the Primakoff solar axions by 169 Tm nuclei have been performed. Such an absorption should lead to the excitation of low-lying nuclear energy level: A+ 169 Tm → 169 Tm * → 169 Tm +γ (8.41 keV). The Si(Li) detector and 169 Tm target placed inside the low-background setup were used for that purpose. As a result, a new restriction on the axion-photon coupling and axion mass was obtained: g Aγ (GeV −1 ) · m A (eV ) ≤ 1.36 · 10 −5 (90% c.l.). In model of hadronic axion this restriction corresponds to the upper limit on axion mass -m A ≤ 191 eV for 90% c.l.

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A search for resonant absorption of 14.4 keV solar axions by a 57 Fe target was performed. The Si(Li) detector placed inside the low-background setup was used to detect the γ -quanta appearing in the deexcitation of the 14.4 keV nuclear level: A + 57 Fe → 57 Fe * → 57 Fe + γ . The new upper limit for the hadronic axion mass has been obtained of m A ≤ 159 eV (95% c.l.) (S = 0.5, z = 0.56).

In considering spherically symmetric three-dimensional systems, inverse methods are applied to the nuclear bound-state problem. While retaining only the self-interactions of the (occupied)bound-state levels, an analytical solution is obtained for the potential. The simplest possible approximation to it corresponding to a single fictitious bound state is used to evaluate (root mean square) radii. Combining this formula with the well-known A ' dependence of the nuclear radii, a new formula is obtained containing the collective binding energy effect and the one of the saturation of nuclear forces. For absolute and relative radii (of isotopes of Sn, Xe, Nd, Dy, Yb, Os, Hg, Pb, and Pu), the results compare favorably with experiment. In spite of the crude approximations made, this approach yields the typical curvature of the plot of the experimental relative radii as a function of the mass number. The extreme simplicity of the formula recommends its use for global discussions or predictions. Yet, for a correct description of the finer details it is necessary to account explicitly for shell effects and deformations.

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