Measurement of the incoherent $\gamma d \to \phi p n$ photoproduction near threshold

TL;DR

This study measures differential cross sections and decay asymmetries of phi-meson photoproduction from deuterons near threshold, revealing significant nuclear effects that challenge current models of phi-N interactions.

Contribution

It provides new experimental data on phi-meson photoproduction from deuterons at forward angles, highlighting the need to refine theoretical understanding of phi-N interactions within nuclei.

Findings

Large suppression in nuclear transparency ratio for deuteron

Inconsistency with isospin asymmetry explanations

Implication for refining phi-N interaction models

Abstract

We report measurements of differential cross sections and decay asymmetries of incoherent $\phi$-meson photoproduction from the deuteron at forward angles using linearly polarized photons at \Eg=1.5-2.4 GeV. The nuclear transparency ratio for the deuteron shows a large suppression, and is consistent with the A-dependence of the ratio observed in a previous measurement with nuclear targets. The reduction for the deuteron cannot be adequately explained in term of isospin asymmetry. The present results suggest the need of refining our understanding of the $\phi$-N interaction within a nucleus.