  Properties of the nuclear equation of state (EoS) can be probed by measuring
the dynamical properties of nucleus-nucleus collisions. In this study, we
present the directed flow ($v_1$), elliptic flow ($v_2$) and stopping (VarXZ)
measured in fixed target Sn + Sn collisions at 270 AMeV with the S$\pi$RIT Time
Projection Chamber. We perform Bayesian analyses in which EoS parameters are
varied simultaneously within the Improved Quantum Molecular Dynamics-Skyrme
(ImQMD-Sky) transport code to obtain a multivariate correlated constraint. The
varied parameters include symmetry energy, $S_0$, and slope of the symmetry
energy, $L$, at saturation density, isoscalar effective mass, $m_{s}^*/m_{N}$,
isovector effective mass, $m_{v}^{*}/m_{N}$ and the in-medium cross-section
enhancement factor $\eta$. We find that the flow and VarXZ observables are
sensitive to the splitting of proton and neutron effective masses and the
in-medium cross-section. Comparisons of ImQMD-Sky predictions to the S$\pi$RIT
data suggest a narrow range of preferred values for $m_{s}^*/m_{N}$,
$m_{v}^{*}/m_{N}$ and $\eta$.
