  We present a new method for constraining the mass transfer evolution of low
mass X-ray binaries (LMXBs) - a reverse population synthesis technique. This is
done using the detailed 1D stellar evolution code MESA (Modules for Experiments
in Stellar Astrophysics) to evolve a high-resolution grid of binary systems
spanning a comprehensive range of initial donor masses and orbital periods. We
use the recently developed Convection And Rotation Boosted (CARB) magnetic
braking scheme. The CARB magnetic braking scheme is the only magnetic braking
prescription capable of reproducing an entire sample of well studied persistent
LMXBs -- those with their mass ratios, periods and mass transfer rates that
have been observationally determined. Using the reverse population synthesis
technique, where we follow any simulated system that successfully reproduces an
observed LMXB backwards, we have constrained possible progenitors for each
observed well-studied persistent LMXB. We also determined that the minimum
number of LMXB formations in the Milky Way is 1500 per Gyr if we exclude Cyg
X-2. For Cyg X-2, the most likely formation rate is 9000 LMXB per Gyr. The
technique we describe can be applied to any observed LMXB with well-constrained
mass ratios, period and mass transfer rate. With the upcoming GAIA DR3
containing information on binary systems, this technique can be applied to the
data release to search for progenitors of observed persistent LMXBs.
