  We report first time measurements of the beta-neutrino angular correlation
based on the kinetic energy shift of protons emitted in parallel or
anti-parallel directions with respect to the positron in the beta decay of
$^{32}$Ar. This proof of principle experiment provided simultaneous
measurements for the superallowed 0$^+$~$\rightarrow$~0$^+$ transition followed
by a 3356~keV proton emission and for a Gamow-Teller transition followed by a
2123~keV proton emission. The results, respectively ${\tilde
a_{\beta\nu}}=1.01(3)_{(stat)}(2)_{(syst)}$ and ${\tilde
a_{\beta\nu}}=-0.22(9)_{(stat)}(2)_{(syst)}$, are found in agreement with the
Standard Model. A careful analysis of the data shows that future measurements
can reach a precision level of 10$^{-3}$ for both pure Fermi and pure
Gamow-Teller decay channels, providing new constraints on both scalar and
tensor weak interactions.

Nuclear Experiment