Plasmas of geometrically thick , black hole ( BH ) accretion flows in active galactic nuclei ( AGNs ) are generally collisionless for protons , and involve magnetic field turbulence .
Under such conditions a fraction of protons can be accelerated stochastically and create relativistic neutrons via nuclear collisions .
These neutrons can freely escape from the accretion flow and decay into protons in dilute polar region above the rotating BH to form relativistic jets .
We calculate geometric efficiencies of the neutron energy and mass injections into the polar region , and show that this process can deposit luminosity as high as L _ { j } \sim 2 \times 10 ^ { -3 } \dot { M } c ^ { 2 } and mass loading \dot { M } _ { j } \sim 6 \times 10 ^ { -4 } \dot { M } for the case of the BH mass M \sim 10 ^ { 8 } M _ { \odot } , where \dot { M } is mass accretion rate .
The terminal Lorentz factors of the jets are \Gamma \sim 3 , and they may explain the AGN jets having low luminosities .
For higher luminosity jets , which can be produced by additional energy inputs such as Poynting flux , the neutron decay still can be a dominant mass loading process , leading to e.g. , \Gamma \sim 50 for L _ { j, { tot } } \sim 3 \times 10 ^ { -2 } \dot { M } c ^ { 2 } .