Assembly bias in quadratic bias parameters of dark matter halos from
  forward modeling
  We use the forward modeling approach to galaxy clustering combined with the
likelihood from the effective-field theory of large-scale structure to measure
assembly bias, i.e. the dependence of halo bias on properties beyond the total
mass, in the linear ($b_1$) and second order bias parameters ($b_2$ and
$b_{K^2}$) of dark matter halos in $N$-body simulations. This is the first time
that assembly bias in the tidal bias parameter $b_{K^2}$ is measured. We focus
on three standard halo properties: the concentration $c$, spin $\lambda$, and
sphericity $s$, for which we find an assembly bias signal in $b_{K^2}$ that is
opposite to that in $b_1$. Specifically, at fixed mass, halos that get more
(less) positively biased in $b_1$, get less (more) negatively biased in
$b_{K^2}$. We also investigate the impact of assembly bias on the $b_2(b_1)$
and $b_{K^2}(b_1)$ relations, and find that while the $b_2(b_1)$ relation stays
roughly unchanged, assembly bias strongly impacts the $b_{K^2}(b_1)$ relation.
This impact likely extends also to the corresponding relation for galaxies,
which motivates future studies to design better priors on $b_{K^2}(b_1)$ for
use in cosmological constraints from galaxy clustering data.
