Electro-Weak Transitions in A=2,3 Nuclei in Pionless Effective Field Theory

In this thesis, which is in the field of few-body systems, I am studying low-energy electro-weak interactions in light nuclear systems whose number of nucleons, $A$, is smaller than 4 ({\it i.e.,} $d$, ${}^3$H, ${}^3$He), where the main purpose of this work is to calculate the proton-proton ($pp$) fusion rate.