We report a measurement of the differential cross section for the γn→π−p process from the CLAS detector at Jefferson Laboratory in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (θc.m.) between 50° and 115°. We confirm a previous indication of a broad enhancement around a c.m. energy (s√) of 2.1 GeV at θc.m.=90° in the scaled differential cross section s7dσdt and a rapid falloff in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of this enhancement as the suggested scaling region is approached for θc.m. from 70° to 105°.
Physical Review Letters
Chen, W. and Biselli, Angela, "Measurement of the Differential Cross Section for the Reaction γn→π−p from Deuterium," (2009). Physics Faculty Publications. 50.
W. Chen et al., "Measurement of the Differential Cross Section for the Reaction γn→π−p from Deuterium," Physical Review Letters 103.1 (2009) DOI: 10.1103/PhysRevLett.103.012301