  Phase-sensitive measurements on a composite ring made of a superconductor of
interest connected by a known singlet $s$-wave superconductor can unambiguously
determine its pairing symmetry. In composite rings with epitaxial
$\beta-$Bi$_2$Pd and $s$-wave Nb, we have observed half-integer quantum flux
when Nb is connected to the opposite crystalline ends of $\beta-$Bi$_2$Pd and
integer-quantum flux when Nb is connected to the same crystalline ends of
$\beta-$Bi$_2$Pd. These findings provide unequivocal evidence of odd-parity
pairing state of the triplet superconductor $\beta-$Bi$_2$Pd.
