Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles

TL;DR

This paper develops analytical formulas within Glauber theory to accurately describe incoherent pseudoscalar meson photoproduction off nuclei at forward angles, accounting for absorption and Pauli suppression, aiding precise extraction of decay widths.

Contribution

It provides new analytical expressions for incoherent meson photoproduction cross sections, including nuclear effects, based on Glauber multiple scattering theory, enhancing theoretical modeling accuracy.

Findings

Calculated incoherent cross sections for 16O and 12C nuclei.

Compared different approaches to estimate their impact.

Provided formulas accounting for meson absorption and Pauli suppression.

Abstract

Recent advances in the photon tagging facilities together with the novel, high resolution fast calorimetry made possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. The most updated description of general processes, including the nuclear coherent amplitude, is done in our previous paper. In this work, based on the framework of Glauber multiple scattering theory, we obtain analytical expressions for the incoherent cross section of the photoproduction of pseudoscalar mesons off nuclei accounting for the mesons absorption in nuclei and Pauli suppression at forward production angles. As illustrations of the obtained formulas, we calculate the incoherent cross section for photoproduction from a closed shell nucleus, 16^O, and from an unclosed shell nucleus, 12^C. These calculations allow one to compare different approaches and estimate their impact on the incoherent cross section of the processes under consideration.