  Several analyses have shown that LCDM-based models cannot jointly describe
the clustering (GC) and galaxy-galaxy lensing (GGL) of galaxies in the SDSS-III
BOSS survey, which is commonly known as the 'lensing-is-low problem'. In this
work, we show that an extension of Subhalo Abundance Matching, dubbed SHAMe,
successfully solves this problem. First, we show that this model accurately
reproduces the GC and GGL of a mock galaxy sample in the TNG300 hydrodynamic
simulation with analogous properties to BOSS galaxies. Then, we switch our
attention to observed BOSS galaxies at z=0.31-0.43, and we attempt to reproduce
their GC and GGL by evaluating SHAMe on two different simulations: one adopting
best-fitting cosmological parameters from Planck and the other from weak
gravitational lensing surveys (Low S8), where the amplitude of matter
fluctuations is lower for the latter. We find excellent agreement between SHAMe
predictions and observations for both cosmologies, indicating that the
lensing-is-low problem originates from approximations in previous theoretical
descriptions of the data. The main difference between SHAMe results in these
cosmologies is the level of galaxy assembly bias, which is approximately 20 and
10% for Planck and Low S8, respectively. These results highlight the dangers of
employing oversimplified models to analyse current large-scale structure
datasets, and the need for realistic yet flexible descriptions of the
galaxy-halo connection.
