A $U(1)_{B-L}$-extension of the Standard Model from Noncommutative Geometry.

We derive a $U(1)_{B-L}$-extension of the Standard Model from a generalized Connes-Lott model with algebra ${\mathbb C}\oplus{\mathbb C}\oplus {\mathbb H}\oplus M_3({\mathbb C})$. This generalization includes the Lorentzian signature, the presence of a real structure, and a weakening of the order $1$ condition. In addition to the SM fields, the model contains a $Z_{B-L}'$ boson and a complex scalar field $\sigma$ which spontaneously breaks the new symmetry. This model is the smallest one which contains the SM fields and is compatible with both the Connes-Lott theory and the algebraic background framework.