The nature of dark matter remains a mystery, although enormous efforts have
been made to search for dark matter candidate particles. Scalar field dark
matter is one of the most prominent options that is being explored by the
various precision experiments, such as gravitational-wave detectors, atomic
clocks and gravity experiments. We describe a direct search for scalar field
dark matter using the short-range gravity experiments, in which we investigate
the possible influences of scalar field dark matter as a function of its mass.
By analyzing the torque signals in the torsion pendulum experiments of the
HUST-18 and HUST-20, we set new constraints on the large mass regions of scalar
field dark matter parameter space. Based on the maximum reach analysis (MRA)
method, the constraints on the photon coupling parameter Λγ​ and
electron coupling parameter Λe​ improve on limits from
previous direct searches in interferometer experiments by more than four orders
of magnitude. Further combining the HUST-18 and HUST-20 experiments, we also
present the exclusion limits that are not dependent on MRA approximation. This
work paves the way for dark-matter search in future HUST experiments, and the
projected constraints can be competitive with those limits produced by the MRA
method.Comment: 13 pages, 5 fiure