  We discuss a novel effective-field-theory-based approach for extracting
two-body scattering information from finite volume energies, serving as an
alternative to L\"uscher's method. By explicitly incorporating one-pion
exchange, we overcome the challenging left-hand cut problem in L\"uscher's
method and can handle finite volume energy levels both below and above the
left-hand cut. Applied to the lattice data for $DD^*$ scattering at a pion mass
of 280 MeV, as an illustrative example, our results reveal the significant
impact of the one-pion exchange on P-wave and S-wave phase shifts. The pole
position of the $T_{cc}(3875)^+$ state, extracted from the finite-volume energy
levels at this pion mass while taking into account left-hand cut effects, range
corrections and partial-wave mixing, is consistent with a near-threshold
resonance. This study demonstrates, for the first time, that two-body
scattering information can be reliably extracted from lattice spectra including
the left-hand cut.
