  The structure of the three-boson bound state in Minkowski space is studied
for a model with contact interaction. The Faddeev-Bethe-Salpeter equation is
solved both in Minkowski and Euclidean spaces. The results are in fair
agreement for comparable quantities, like the transverse amplitude obtained
when the longitudinal constituent momenta of the light-front valence wave
function are integrated out. The Minkowski space solution is obtained
numerically by using a recently proposed method based on the direct integration
over the singularities of the propagators and interaction kernel of the
four-dimensional integral equation. The complex singular structure of the
Faddeev components of the Bethe-Salpeter vertex function for space and
time-like momenta in an example of a Borromean system is investigated in
detail. Furthermore, the transverse amplitude is studied as a mean to access
the double-parton transverse momentum distribution. Following that, we show
that the two-body short-range correlation contained in the valence wave
function is evidenced when the pair has a large relative momentum in a
back-to-back configuration, where one of the Faddeev components of the
Bethe-Salpeter amplitude dominates over the others. In this situation a
power-law behavior is derived and confirmed numerically.

High Energy Physics - Phenomenology