  Using inelastic cotunneling spectroscopy, we observe a 55{\mu}eV zero field
splitting in the spin triplet manifold of Ge hut wire quantum dots. The
degeneracy of the heavy hole triplet state is lifted since the interplay of
strong spin orbit coupling and strong confinement leads to a preferred
direction of the heavy-hole pseudospin. The reported effect should be
observable in a broad class of strongly confined hole quantum-dot systems and
needs to be considered when operating hole spin qubits.
