A. V. Derbin

Constraints on the axion-electron coupling constant for solar axions appearing owing to bremsstrahlung and the compton process

The axio-electric effect in silicon atoms is sought for solar axions appearing owing to bremsstrahlung and the Compton process. Axions are detected using a Si(Li) detector placed in a low-background setup. As a result, a model-independent constraint on the axion-electron coupling constant |gAe| ≤ 2.2× 10 −10 has been obtained, which leads to the bounds mA ≤ 7.9 eV and mA ≤ 1.4 keV for the mass of the axion in the DFSZ and KSVZ models, respectively (90% C.L.).The axio-electric effect in silicon atoms is sought for solar axions appearing owing to bremsstrahlung and the Compton process. Axions are detected using a Si(Li) detector placed in a low-background setup. As a result, a model-independent constraint on the axion-electron coupling constant |gAe| ≤ 2.2 × 10−10 has been obtained, which leads to the bounds mA ≤ 7.9 eV and mA ≤ 1.4 eV (at 90% C.L.) for the mass of the axion in the DFSZ and KSVZ models, respectively.

Search for solar axions emitted in an M1 transition in 7Li* nuclei

The resonance absorption of solar axions by 7Li nuclei, which is accompanied by the excitation of the first nuclear level of lithium a + 7Li → 7Li* → 7Li + γ, is sought. To this end, the energy spectrum has been measured by an HPGe detector that is surrounded by a LiOH layer. A new upper limit ma ≤ 16 keV (at 90% C.L.) has been determined for the mass of the hadron axion.

Search for axions emitted in nuclear magnetic transitions

Searches for invisible axions emitted in the electromagnetic transitions of isomeric nuclei are continued. It is found experimentally that the probability of axion emission in an M1 transition in 125mTe is less than 8.5×10−6 (90% C.L.).

Measurement of the 45Ca β spectrum in search of deviations from the theoretical shape

The 45Ca β spectrum has been measured with a Si(Li) detector. New limits on the mixing parameter (|UeH|2≤0.005) for a neutrino with mass in the interval 75–100 keV are obtained. The possibility of a monochromatic peak appearing at the end of the β spectrum is analyzed.