ABSTRACT
In the Standard Model strong and weak interactions are described and, as a consequence, there is a decrease in the coupling constant with increasing energy, the so-called asymptotic freedom. It is convenient to explore another extension of the Standard Model, which is given by supersymmetry. The minimal supersymmetric Standard Model is a model containing the minimal extension of the field contents of the Standard Model as well as minimal extensions of interactions. Neutrino masses are set to zero in the Standard Model. Therefore, any evidence of a non-vanishing neutrino mass would indicate physics ‘beyond the Standard Model’. Neutrino masses can be created in the Standard Model by extending the particle content of the theory. An independent possibility introducing neutrino masses in the Standard Model would be adding non-renormalizable operators. There is only one 5-dimensional operator (called Weinberg operator). Higher dimensional operators have an even higher suppression so they are normally ignored.
