Conservation ofs-Channel Helicity inρ0Photoproduction

An analysis was made of the decay angular distribution of rho mesons produced via $\gamma p\to p{\rho }^0$ by linearly polarized photons at 2.8 and 4.7 GeV. The reaction proceeds almost completely through natural-parity exchange, the contribution from unnatural-parity exchange for momentum transfers $\mathrm{}\left|t\right|<1\mathrm{}$ Ge${\mathrm{V}}^2$ being (3.1±2.2)% at 2.8 GeV and (-1.1±1.9)% at 4.7 GeV. The behavior of the density-matrix elements shows that the rho-production mechanism conserves $s$-channel c.m. system helicity for $\mathrm{}\left|t\right|<0.4\mathrm{}$ Ge${\mathrm{V}}^2$.