Search of x-ray solar activity correlations with ⁵⁵Fe, ⁶⁰Co nucleus decay rates

Several experimental groups observed temporary modulations of some nuclei strong and weak decay constants, which are of the order of 10⁻³ and with periods of one year, solar day, i.e. 24 hours and some others. In our experiments the decay rates were measured for ⁵⁵Fe e-capture and ⁶⁰Co β-decay during 2012–2020. Altogether, six decay rate dips of the order 10⁻² – 10⁻³ and with duration from 40 to 208 hours were found, they deviate essentially from exponential decay rate fit. It is shown that their occurrence correlate with x-ray solar flares with significant reliability. Besides, two long term deviations of ⁵⁵Fe decay rate of 62 and 41 days were observed in 2017–2018, it's argued that they are related to the change of 11 year solar cycle stages.