  The D0 Collaboration has recently seen a resonant-like peak in the $B_s\pi$
invariant mass spectrum, claimed to be a new state called $X(5568)$. Using a
$B_s\pi$--$B\bar{K}$ coupled channel analysis, implementing unitarity, and with
the interaction derived from Heavy Meson Chiral Perturbation Theory, we are
able to reproduce the reported spectrum, with a pole that can be associated to
the claimed $X(5568)$ state, and with mass and width in agreement with the ones
reported in the experimental analysis. However, if the $T$-matrix
regularization is performed by means of a momentum cutoff, the value for the
latter needed to reproduce the spectrum is $\Lambda = 2.80 \pm 0.04\
\text{GeV}$, much larger than a "natural" value $\Lambda \simeq 1\ \text{GeV}$.
In view of this, it is difficult to interpret the nature of this new state.
This state would not qualify as a resonance dynamically generated by the
unitarity loops. Assuming the observed peak to correspond to a physical state,
we make predictions for partners in the $D$, $D^\ast$, and $B^\ast$ sectors.
Their observation (or lack thereof) would shed light into this issue.
