Nuclear fusion reactions play a key role in astrophysics, governing the energy production and evolution of stars, particularly in the final stages of their life cycle. Besides, these reactions critically influence the abundance and distribution of chemical elements throughout the Universe.

Experimental data have revealed a pronounced suppression of fusion cross sections at extremely low energies – a phenomenon that appears to be systematic across different nuclear systems. This suppression significantly affects the predicted astrophysical S-factors and, consequently, the calculated astrophysical reaction rates. However, no unified theoretical framework has yet been established to explain this low-energy fusion behavior.

In this talk, an attempt is made to interpret the observed fusion hindrance phenomenon within the framework of the extended quantum diffusion model. New estimates for the temperature dependence of the reaction rates are provided, offering a deeper insight into fusion processes under stellar environment.