Self energies of the pion and the Delta isobar from the ³He(e,e 'pi⁺)³H reaction

Kohl, M. et al. (2002) Self energies of the pion and the Delta isobar from the ³He(e,e 'pi⁺)³H reaction. Physics Letters B, 530(1-4), 67 -73. (doi: 10.1016/S0370-2693(02)01345-X)

Abstract

In a kinematically complete experiment at the Mainz microtron MAMI, pion angular distributions of the He-3(e,e'pi(+))H-3 reaction have been measured in the excitation region of the Delta resonance to determine the longitudinal (L), transverse (T), and the LT interference part of the differential cross section. The data are described only after introducing self- energy modifications of the pion and Delta-isobar propagators. Using Chiral Perturbation Theory (ChPT) to extrapolate the pion self energy as inferred from the measurement on the mass shell, we deduce a reduction of the pi(+) mass of Deltam(pi+) = (- 1.7(-2.1)(+1.7)) MeV/c(2) in the neutron-rich nuclear medium at a density of rho = (0.057(-0.057)(+0.085)) fm(-3). Our data are consistent with the Delta self energy determined from measurements of pi(0) photoproduction from He-4 and heavier nuclei.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: UNSPECIFIED
• Authors: Kohl, M., Bartsch, P., Baumann, D., Bermuth, J., Bohm, R., Bohinc, K., Derber, S., Ding, M., Distler, M.O., Ewald, I., Friedrich, J., Friedrich, J.M., Jennewein, P., Kahrau, M., Kamalov, S.S., Kozlov, A., Krygier, K.W., Kuss, M., Liesenfeld, A., Merkel, H., Merle, P., Muller, U., Neuhausen, R., Pospischil, T., Potokar, M., Rangacharyulu, C., Richter, A., Rohe, D., Rosner, G., Schmieden, H., Sschrider, G., Seimetz, M., Sirca, S., Suda, T., Tiator, L., Urban, M., Wagner, A., Walcher, T., Wambach, J., Weis, M., and Wirzba, A.
• Subjects: Q Science > QC Physics
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Physics Letters B
• Publisher: Elsevier BV
• ISSN: 0370-2693
• ISSN (Online): 1873-2445