Photoproduction of charged pions on deuterium in the first resonance region

Neutron helicity amplitudes

“…Listed are the observable, the number of events, and the χ 2 /N data in two fits. Two separate entries are given for the γn → π − p differential cross section as measured in bubble chamber [28,29] and counter [30][31][32][33][34][35][36] experiments. The χ 2 old shows the quality of the description of γn data in 2013 [11], the χ 2 new represents the new description.…”

Helicity amplitudes for photoexcitation of nucleon resonances off neutrons

“…The data used for the determination of the γn couplings of the N * states are listed in Table 1. In addition to the new JLab data on γn → pπ − [35,36] a large number of further data on this reaction [37,38,39,40,41,42] has been included in the fit.…”

“…1. Differential cross section for γn → π − p. Data: red filled stars are from [36], black open circles are from [37], red open squares are from [38], green open triangles are from [39], blue filled circles are from [40], pink filled squares are from [41], black filled triangles are from [42]. [58], red filled circles are from [59].…”

“…Fig. 1 shows differential cross sections for γd → pπ − (p) from JLab [36] and earlier measurements [37,38,39,40,41,42]. The data on recoil polarization P and target asymmetry T are shown in Fig.…”

Quasifree pion photoproduction on the deuteron in the Δ region

“…2 we show the total cross sections for pion photoproduction on the deuteron which can be compared to the free nucleon case in the upper part. In the case of π − production on the neutron we compare our results with data from the inverse reaction π − n → pγ [12,13] and with data extracted from experiments on the deuteron [14,15]. For the pion production operator of Sect.…”