  We calculate the diphoton distribution in the decay of arbitrary spin-0 and
spin-2 bosons produced from gluon fusion, taking into account the fact that
gluons inside an unpolarized proton are generally linearly polarized. The gluon
polarization brings about a difference in the transverse momentum distribution
of positive and negative parity states. At the same time, it causes the
azimuthal distribution of the photon pair to be non-isotropic for several
spin-2 coupling hypotheses, allowing one to distinguish these from the
isotropic scalar and pseudoscalar distributions.
