Measurement of the Differential Cross Section for the Reactionγn→π−pfrom Deuterium

We report a measurement of the differential cross section for the $$\gamma n \to \pi^- p$$ process from the CLAS detector at Jefferson Lab in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles ($$\theta_{c.m.}$$) between 50$$^\circ$$ and 115$$^\circ$$. We confirm a previous indication of a broad enhancement around a c.m. energy ($$\sqrt{s}$$) of 2.2 GeV at $$\theta_{c.m.}=90^\circ$$ in the scaled differential cross section, $$s^7 {\frac{d\sigma}{dt}}$$. Our data show the angular dependence of this enhancement as the scaling region is approached in the kinematic region from 70$$^\circ$$ to 105$$^\circ$$.