Forward-angle charged-pion electroproduction in the deuteron

Abstract

A direct experimental determination has been made of the ratio of the forward-angle positive-pion electroproduction cross section for a proton bound in the deuteron with that of a free proton for invariant masses of 1160 and 1232 MeV. A significant quenching of the reaction in the deuteron is observed. PACS numbers: 25.30.Fj, 13.60.Le, 25.10.+S

Incoherent single pion electroproduction on the deuteron with polarization effects

“…We will begin the comparison with an earlier calculation by Loucks et al [7] who have studied the influence of FSI for the kinematics of the Saclay experiment [5] using a simple pion production model. In particular, they found a strong dependence of the semi-exclusive cross section on the deuteron orientation by considering the idealized case of an intial deuteron state being prepared in a state with definite spin projection m 0 d on the momentum transfer.…”

“…Now we turn to a comparison of our results with experimental data and with the calculations of Hafidi and Lee [8] and Levchuk et al [9] in Fig. 14. The left panel shows the semi-exclusive differential cross section for pion emission in forward direction for the kinematics of the Saclay data [5] while the right panel shows the one for the kinematics of the Jefferson Lab data [6].…”

“…However, at lower missing mass our calculation as well as the one of Levchuk et al exhibit the sharp and very pronounced 1 S 0 -peak right at threshold which is absent in the calculation of Hafidi and Lee and also not seen in the data. It remains a puzzle why this pronounced peak, which is seen in deuteron electrodisintegration near threshold [21] as well as in pion photoproduction [22], is absent in the data of [5].…”

“…For example, it would be interesting to see whether some kinematic regions exist where πN -rescattering becomes more important. Indeed, several studies of the role of FSI and medium effects have already been undertaken in the past, both experimentally [4,5,6] as well as theoretically [7,8,9].…”

“…Brown et al [4] was designed to study the isoscalar-isovector interference of the elementary amplitude and the role of nuclear corrections by measuring on the one hand the ratio of π − to π + production on the deuteron and on the other hand the ratio of π + production on the deuteron to the one on hydrogen. The forward-angle production of charged pions on the deuteron was measured by R. Gilman et al [5] in order to investigate possible influences of the spectator nucleon on the elementary production amplitude. For the cross section ratio of π + production on the deuteron to the one on the proton they found a significant deviation from unity.…”