  In this work, we want to exploit the magnification bias of the SMGs using two
different foreground samples, quasi-stellar objects (QSOs) and galaxies. Our
aim is to study and compare their mass density profiles and estimate their
masses and concentrations. The background SMG sample consists of objects
observed by \textit{Herschel} with 1.2<z<4.0. The foreground samples are QSOs
and massive galaxies with spectroscopic redshifts between 0.2 and 1.0. The
cross-correlation measurements are estimated with the Davis-Peebles estimator
by stacking the SMG-QSO and SMG-galaxy pairs for the two analysed cases,
respectively. This approach allows us to study the mass density profile from
$\sim2$ to $\sim250$ arcsec. Moreover, the analysis is carried out by combining
two of the most common theoretical mass density profiles in order to fit the
cross-correlation measurements. The measurements are correctly fitted after
splitting the available angular scales into an inner and an outer part using
independent mass density profiles for each region. For the QSOs, we obtain
masses and concentrations of $\log_{10}(M/M_{\odot})=13.51\pm0.04;
C=6.85\pm0.34$ for the inner part and $\log_{10}(M/M_{\odot})=13.44\pm0.17;
C=0.36\pm0.18$ for outer parts. For the galaxy sample are
$\log_{10}(M/M_{\odot})=13.32\pm0.08; C=8.23\pm0.77$ and
$\log_{10}(M/M_{\odot})=12.78\pm0.21; C=1.21\pm1.01$ for the inner and outer
parts, respectively. In both samples, the inner part has an excess in the mass
density profile and much higher concentration with respect to the outer part.
We obtain similar values for the central mass with both samples, in agreement
with those of galaxy clusters results. However, the estimated masses for the
outer region and the concentrations of the inner region both vary with lens
sample. This could be related to the probability of galactic interactions
and/or the different evolutionary stages.
