  The contact formalism, a useful tool for analyzing short-range correlations,
is generalized here for systems with coupled channels, such as in nuclear
physics. The relevant asymptotic form is presented and contact matrices are
defined. Generally, for the case of two coupled channels, two two-body
functions are included in the asymptotic form, resulting a 2 x 2 contact
matrix. Nevertheless, it is shown that if the coupling terms of the potential
are very weak or very strong, only a single two-body function is needed,
resulting a single contact. This universal result is directly relevant to
nuclear systems, and provides a theoretical explanation for the fact that
proton-neutron short-range correlations can be described using the single
bound-state deuteron wave function. It is achieved by applying an appropriate
boundary condition on the two-body functions. This boundary condition can be
interpreted as a mean field potential imposed on the correlated pair due to the
residual system.
