dependence on the angle $\phi$ between the outgoing proton transverse momenta, $\vec p_{3\perp}$ and $\vec p_{4\perp}$, is different for the natural ($0^+$) and unnatural ($0^-$) parity states of $h$. The comparison with Fig. \[fig:4\] shows that absorptive effects have significantly distorted the $\phi$ distributions and, in fact, have increased the difference between the $0^+$ and $0^-$ distributions. Thus this distribution provides a unique possibility to distinguish between $0^+$ and $0^-$ bosons, which, in the case of [*inclusive*]{} production[^9], is extremely difficult.

We have seen that the amplitude for the production of unnatural parity ($P=(-1)^{J+1}$) states contains a factor $(\vec p_{3\perp}\times\vec p_{4\perp})\cdot\vec n_0$. Thus the cross section vanishes as $p_{3\perp}$ or $p_{4\perp}\to0$ and vanishes as $\sin^2\phi$ as $\phi\to0$ or $\pi$. These properties may be used to suppress the cross section for natural parity ($P=(-1)^J$) production in comparison to that of unnatural parity states. In particular, selecting events with $p_{3\perp},p_{4\perp}>0.4~\GeV$ and $20^\circ < \phi < 120^\circ$ suppresses the $0^+$ yield by about a factor of 10, while only decreasing the $0^-$ cross section by a factor of 2.3. The relative $0^-$ enhancement may be important as the cross section for the central exclusive production of an $A(0^-)$ boson is quite small, and 