Preliminary Cross Section Measurements of the γn→π^-p Reaction in Deuterium from 6 to 11 GeV

Exclusive pion photoproduction is a fundamental process to study the strong interaction by providing valuable information on nuclear resonances and the transition from nucleon-meson to quark-gluon degrees of freedom. The constituent counting rule was proposed as a signature of such transition and predicts the differential cross section at a fixed c.m. angle θ_c.m. scales as dσ/dt∝s^-7 for pion photoproduction. Previous measurements of the γn→π^-p reaction in deuterium at Hall A and B of Jefferson Lab confirmed the global scaling behavior and a broad enhancement before its onset, however, only at certain θ_c.m. due to the limited photon energies. The SRC-CT experiment (E12-19-003) uses the GlueX detector at Hall D of Jefferson Lab with the upgraded beam energy and different nuclear targets (D, He-4, C-12). Though mostly focused on the study of short-range correlations (SRC) and color transparency (CT), it still offers a great opportunity to study the pion photoproduction at higher energies. In this talk, we will present some preliminary results of the cross section measurements of the γn→π^-p reaction in deuterium from 6 to 11 GeV. Apart from investigating the global scaling behavior, we will also study its possible substructure, shown as an oscillatory behavior around the predicted scaling value.