Incoherent pion photoproduction on the deuteron in the first resonance region

Abstract

Incoherent pion photoproduction on the deuteron is studied in the first resonance region. The unpolarized cross section, the beam asymmetry, and the vector and tensor target asymmetries are calculated in the framework of a diagrammatic approach. Pole diagrams and one-loop diagrams with N N scattering in the final state are taken into account. An elementary operator for pion photoproduction on the nucleon is taken in various on-shell forms and calculated using the SAID and MAID multipole analyses. Model dependence of the obtained results is discussed in some detail. A comparison with predictions of other works is given. Although a reasonable description of many available experimental data on the unpolarized total and differential cross sections and photon asymmetry has been achieved, in some cases a significant disagreement between the theory and experiment has been found. Invoking known information on the reactions γd → π 0 d and γd → np we predict the total photoabsorption cross section for deuterium. We find that our values strongly overestimate experimental data in the vicinity of the ∆ peak.

Incoherent pion production in neutrino-deuteron interactions

“…We first establish our calculation procedures by showing that the available data of incoherent pion photo-production reaction on the deuteron can be described reasonably well. Our results are fairly consistent with those from the earlier works [32][33][34][35][36] on this reaction, as will be discussed later. Thus the developed calculation procedures can be used reliably to investigate the πNN final state interaction effects on the cross sections of neutrino-induced single pion production reactions on deuteron.…”

“…The importance of the np final-state interactions is demonstrated, in agreement with the results of Ref. [32][33][34][35][36].…”

“…5 we see that the π 0 np re-scattering effects bring the differential cross sections of γ + d → π 0 + n + p calculated from keeping only the impulse term (dashed curves) to values (solid curves) which are in reasonable agreement with the data. Similar comparisons for the total cross sections and differential cross sections for γ + d → π − + p + p are shown in Fig.6 and Fig.7 [32][33][34][35][36]. It perhaps can be understood qualitatively from the properties of the initial deuteron wave function and the final NN wave functions.…”

“…Our calculations for this reaction are similar to that of Refs. [32][33][34][35][36], while there are differences between different approaches in the formulation and the input to the calculations.…”

Helicity dependence and contribution to the Gerasimov-Drell-Hearn sum rule of theγ→d→→πNNreaction channels

“…[1][2][3][4] where also references to earlier research can be found. This interest is partly due to the new generation of high-intensity and high duty-cycle electron accelerators, such as MAMI at Mainz and ELSA at Bonn (Germany), JLab at Newport News (USA), and MAX-Lab at Lund (Sweden) as well as laser backscattering facilities such as GRAAL at Grenoble (France) and LEGS at Brookhaven (USA)-for an experimental overview see Refs.…”