  We consider the prompt photon production in pp collisions using, within the
framework of perturbative QCD, a non-Gaussian distribution for the transverse
momentum distribution of the partons inside the proton. Our description adopts
the widely used in the literature factorization of the partonic momentum
distribution into longitudinal and transverse components. It is argued that the
non-Gaussian distribution of the intrinsic transverse momenta of the partons is
dictated by the asymptotic freedom as well as the 3D confinement of the partons
in the proton. To make this association more transparent we use the MIT bag
model, which plainly incorporates both properties (asymptotic freedom,
confinement), in order to determine in a simplified way the partonic transverse
momentum distribution. A large set of data from six different experiments have
been fitted with this simple description using as a single free parameter the
mean partonic transverse momentum <kT>. Surprisingly enough, a perfect fit of
the experimental data turns out to require <kT> values which are compatible
with Heisenberg's uncertainty relation for the proton and decrease almost
smoothly as a function of the scaled variable z=pT/\sqrt{s}, where pT is the
transverse momentum of the final photon and \sqrt{s} is the beam energy in the
center of mass frame. Our analysis indicates that asymptotic freedom and 3D
confinement may influence significantly the form of the partonic transverse
momentum distribution leaving an imprint on the pp\to{\gamma}+X cross section.
