Low-redshift constraints on homogeneous and isotropic universes with
  torsion
  One of the possible extensions of Einstein's General Theory of Relativity
consists in allowing for the presence of spacetime torsion. The form of the
underlying torsion tensor can be chosen such that the homogeneity and isotropy
of Friedmann-Lemaitre-Robertson-Walker universes is preserved, and it has been
recently suggested that such universes may undergo accelerating phases. We use
recent low-redshift data, coming from Type Ia Supernova and Hubble parameter
measurements, to phenomenologically constrain this class of models under the
so-called steady-state torsion assumption of a constant fractional contribution
of torsion to the volume expansion. We start by considering models without a
cosmological constant (where torsion itself would be expected to yield the
current acceleration of the universe) finding, in agreement with other recent
works, that these are strongly disfavoured by the data. We then treat these
models as one-parameter extensions of $\Lambda$CDM, constraining the relative
contribution of torsion to the level of a few percent in appropriate units.
Finally, we briefly discuss how these constraints may be improved by
forthcoming low-redshift data and check the robustness of our results by
studying an alternative to the steady-state torsion parametrization.
