phi photo-production from Li, C, Al, and Cu nuclei at Egamma=1.5 - 2.4 GeV

Abstract

The photo-production of $\ddot{I}•$ mesons from Li, C, Al, and Cu at forward angles has been measured at $E_{g}amma$=1.5--2.4 GeV. The number of events for incoherent phi photo-production is found to have a target mass number dependence of $A^{0.72\pm 0.07}$ in the kinematical region of $|t|\le 0.6$ ${\mathrm{GeV}}^2/c^2$. The total cross section of the $\ddot{I}•$-nucleon interaction, $\ddot{I}{ƒ}_{\ddot{I}•N}$, has been estimated as $35_{-11}^{+17}$ mb using the $A$-dependence of the $\ddot{I}•$ photo-production yield and a Glauber-type multiple scattering theory. This value is much larger than $\ddot{I}{ƒ}_{\ddot{I}•N}$ in free space, suggesting that the $\ddot{I}•$ properties might change in the nuclear medium.

12 pages 4 figures, submitted to Phys. Lett. B