  The confinement mechanism proposed earlier by the author is employed for to
compute the decay constants $f_P$ corresponding to leptonic decays $P\to
l^\pm+\nu_l$, $l=\mu, e$, where $P$ stands for any meson from $\pi^\pm$,
$K^\pm$. For this aim the weak axial form factor of $P$-meson is
nonperturbatively calculated. The study entails estimates for parameters of the
confining SU(3)-gluonic field in charged pions and kaons. The corresponding
estimates of the gluon concentrations, electric and magnetic colour field
strengths are also adduced for the mentioned field at the scales of the mesons
under consideration. Further the obtained results are applied to the problem of
chiral symmetry breaking in quantum chromodynamics (QCD). It is shown that in
chirally symmetric world masses of pions and kaons are fully determined by the
confining SU(3)-gluonic field among (massless) $u$, $d$ and $s$ quarks and not
equal to zero. Accordingly chiral symmetry is sufficiently rough approximate
one holding true only when neglecting the mentioned SU(3)-gluonic field between
quarks and no additional mechanism of the spontaneous chiral symmetry breaking
connected to the so-called Goldstone bosons is required. Finally, a possible
relation of the results obtained with a phenomenological string-like picture of
confinement is discussed too.
