Author/Editor		Kohl, M; Kuss, M; Rangacharyulu, C; Richter, A; Schrieder, G; Suda, T; Bohinc, K; Širca, S
Title		Medium effects in pion electroproduction off 3He
Type		članek
Source		Nucl Phys A
Vol. and No.		Letnik A684
Publication year		2001
Volume		str. C454-6
Language		eng
Abstract		The differential coincident pion electroproduction cross section in the 3He(e,e'pi+)3H reaction has been measured with the high resolution three-spectrometer facility at the Mainz Microtron MAMI. Two kinds of measurements were performed: For fixed four-momentum transfers Qz 0.045 (0.1) (GeV/c)2 with the pions detected in parallel kinematics, the incident energy was varied between 555 and 855 MeV in order to enable a separation of the longitudinal and transverse structure functions. In the second case the pion emission angle with respect to the momentum transfer direction was varied over a large range at fixed incident energy E0 = 855 MeV and fixed four-momentum transfers Q2 = 0.045 (0.1) (GeV/c)2. From the angular distributions the LT interference term can be extracted. The experimental data are compared to model calculations assuming standard Born amplitudes, including delta and higher resonance terms and accounting for the final state interaction of the outgoing pion. The effects of medium modifications of the delta and of the pion are dicussed.
Descriptors		NUCLEAR PHYSICS HELIUM MESONS ISOTOPES