Contributions to $Z^0$ decays from a X17 extension of the Standard Model

The present work proposes a Born-Infeld contribution to the $U(1{)}_{B-L}$ extension of the Standard Model, where it is introduced associated to the X17 neutral boson. The decay width of the $Z^0$ decay into 3$X$ and 3$\gamma$ processes are computed, based on NA64 and ATLAS experiments data.