STUDY OF THE ISOSPIN SYMMETRY IN 80ZR

In Nature, symmetries help us to describe a complex physical system in a simple way and to understand better its behavior. Indeed, symmetries are strongly related to conservation laws which, in quantum mechanics, translate into good quantum number to describe the system. At the same time, the possible breaking of a symmetry opens the gates for new and unexpected scenarios. In nuclear physics many symmetries were identified. One of these is the isospin symmetry, which plays a key role in nuclear structure and nuclear reaction. The isospin symmetry was introduced by Heisenberg in 1932 to describe the experimental evidence of the charge independence of the nuclear interaction: neutrons and protons are considered as two different states of the same particle, the nucleon. In the atomic nuclei, the presence of the Coulomb interaction between protons breaks this symmetry and induces a mixing between states with different isospin. In this situation it is impossible to assign to a nuclear state a unique value of isospin. This phenomenon is called isospin mixing. The knowledge of the isospin mixing is a fundamental quantity needed both to explain the properties of the Isobaric Analogue State and for its connection with the test of the unitarity of the Cabibbo-Kobayashi-Maskawa matrix. In this Thesis, we report a new study addressing the problem of the isospin mixing in the nucleus 80Zr, using the Giant Dipole Resonance -decay.