  Using a hybrid (viscous hydrodynamics + hadronic cascade) framework, we model
the bulk dynamical evolution of relativistic heavy-ion collisions at
Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) collision
energies, including the effects from non-zero net baryon current and its
dissipative diffusion. This framework is in full (3+1)D, which allows us to
study the non-trivial longitudinal structure and dynamics of the collision
systems, for example baryon stopping and transport, as well as longitudinal
fluctuations. For the first time, the quantitative effect of net-baryon
diffusion on hadronic observables is addressed. Finally, we propose a dynamical
initialization scheme to study the importance of the pre-equilibrium stage at
the RHIC BES energies.
