  In the present work we study collapse process of a homogeneous and isotropic
fluid in Brans-Dicke ({BD}) theory with non-vanishing spacetime torsion. In
this theory, torsion can be generated by the {BD} scalar field as well as the
intrinsic angular momentum (spin) of matter. Assuming the matter content of the
collapsing body to be a Weyssenhoff fluid, which is a generalization of perfect
fluid in general relativity ({GR}) in order to include the spin effects, we
find that in BD theory with torsion, the existence of spin effects could avoid
the spacetime singularity that forms in the original version of this theory
(Scheel et al. in Phys Rev D 51:4208, 1995, Scheel et al. in Phys Rev D
51:4236, 1995). Numerical simulations of collapse model show that the spacetime
singularity is replaced by a non-singular bounce, the spacetime event at which
the collapse process halts at a minimum radius and then turns into an expanding
phase. Moreover, the model parameters can be set so that the apparent horizon
will never meet the boundary of the collapsing body so that the bounce event
can be detectable by external observers in the Universe.
