Experimental study of the A ( e , e ′ π + ) reaction on H 1 , H 2 , C 12 , Al 27 , Cu 63 , and Au 197

• Published in: Physical review. C, Nuclear physics Nuclear physics, 2010-05, Vol.81 (5), Article 055209
• Main Authors: Qian, X., Horn, T., Clasie, B., Arrington, J., Asaturyan, R., Benmokhtar, F., Boeglin, W., Bosted, P., Bruell, A., Christy, M. E., Chudakov, E., Dalton, M. M., Daniel, A., Day, D., Dutta, D., El Fassi, L., Ent, R., Fenker, H. C., Ferrer, J., Fomin, N., Gao, H., Garrow, K., Gaskell, D., Gray, C., Huber, G. M., Jones, M. K., Kalantarians, N., Keppel, C. E., Kramer, K., Li, Y., Liang, Y., Lung, A. F., Malace, S., Markowitz, P., Matsumura, A., Meekins, D. G., Mertens, T., Miyoshi, T., Mkrtchyan, H., Monson, R., Navasardyan, T., Niculescu, G., Niculescu, I., Okayasu, Y., Opper, A. K., Perdrisat, C., Punjabi, V., Rauf, A. W., Rodriquez, V. M., Rohe, D., Seely, J., Segbefia, E., Smith, G. R., Sumihama, M., Tadevosyan, V., Tang, L., Villano, A., Vulcan, W. F., Wesselmann, F. R., Wood, S. A., Yuan, L., Zheng, X.
• Format: Article
• Language: English
• Subjects: ATOMIC AND MOLECULAR PHYSICS; CEBAF ACCELERATOR; CROSS SECTIONS; DATA; DIFFERENTIAL CROSS SECTIONS; ENERGY; FOUR MOMENTUM TRANSFER; FUNCTIONS; MASS; OPACITY; ORDERS; PARTICLE ACCELERATORS; PIONS; REACTION KINETICS; TARGETS
• ISSN: 0556-2813; 1089-490X
• DOI: 10.1103/PhysRevC.81.055209

Cross sections for the p($e,e'\pi^{+}$)n process on $^1$H, $^2$H, $^{12}$C, $^{27}$Al, $^{63}$Cu and $^{197}$Au targets were measured at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in order to extract the nuclear transparencies. Data were taken for four-momentum transfers ranging from $Q^2$=1.1 to 4.8 GeV$^2$ for a fixed center of mass energy of $W$=2.14 GeV. The ratio of $\sigma_L$ and $\sigma_T$ was extracted from the measured cross sections for $^1$H, $^2$H, $^{12}$C and $^{63}$Cu targets at $Q^2$ = 2.15 and 4.0 GeV$^2$ allowing for additional studies of the reaction mechanism. The experimental setup and the analysis of the data are described in detail including systematic studies needed to obtain the results. The results for the nuclear transparency and the differential cross sections as a function of the pion momentum at the different values of $Q^2$ are presented. Global features of the data are discussed and the data are compared with the results of model calculations for the p($e,e'\pi^{+}$)n reaction from nuclear targets.