  Understanding star formation rates (SFR) is a central goal of modern
star-formation models, which mainly involve gravity, turbulence and, in some
cases, magnetic fields (B-fields). However, a connection between B-fields and
SFR has never been observed. Here, a comparison between the surveys of SFR and
a study of cloud-field alignment - which revealed a bimodal (parallel or
perpendicular) alignment - shows consistently lower SFR per solar mass for
clouds almost perpendicular to the B-fields. This is evidence of B-fields being
a primary regulator of SFR. The perpendicular alignment possesses a
significantly higher magnetic flux than the parallel alignment and thus a
stronger support of the gas against self-gravity. This results in overall lower
masses of the fragmented components, which are in agreement with the lower SFR.
