  We study spin- and mass-imbalanced mixtures of spin-$\tfrac{1}{2}$ fermions
interacting via an attractive contact potential in one spatial dimension.
Specifically, we address the influence of unequal particle masses on the pair
formation by means of the complex Langevin method. By computing the
pair-correlation function and the associated pair-momentum distribution we find
that inhomogeneous pairing is present for all studied spin polarizations and
mass imbalances. To further characterize the pairing behavior, we analyze the
density-density correlations in momentum space, the so-called shot noise, which
is experimentally accessible through time-of-flight imaging. At finite spin
polarization, the latter is known to show distinct maxima at momentum
configurations associated with the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)
instability. Besides those maxima, we find that additional features emerge in
the noise correlations when mass imbalance is increased, revealing the
stability of FFLO-type correlations against mass imbalance and furnishing an
experimentally accessible signature to probe this type of pairing.
