Black holes with primary hair

General Relativity black holes are described by mass, angular momentum and electric/magnetic charge. They are said to have no hair in the sense that they are uniquely defined by these charges as measured from a far away observer and not by other details. These characteristics are thought to persist in modified theories of gravity by so called no hair theorems.

We will see how one can bifurcate the no hair paradigm and construct explicit black hole solutions that admit additional independent charges in theories modifying general relativity. These black holes have additional properties that make them quite different from their GR solutions.

We will give two different classes of theories with two different explicit examples and their properties. One originates from DHOST theories with scalar primary hair and one from vector tensor with Proca primary hair. The latter admits a cosmological constant as a free integration constant.