Induced Polarization in 4He($$e,e'\vec{p}$$)3H
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
The transferred polarization in the 4He(~e, e0~p )3H reaction at Q2 values of 0.4, 0.5, 1.0, 1.6, and 2.6 GeV2 have been measured to study possible medium modifications of the proton form factors. The measured ratio of polarization-transfer coefficients was described by the inclusion of in-medium proton form factors. This interpretation was recently challenged by a calculation by Schiavilla et al including, particularly, a spin-dependent charge exchange in the final-state interaction (FSI). The induced polarization of the recoiling proton in this reaction is a measure of FSI. Precise data on these are key to shed more light on this controversy. Even more, a precise knowledge of the induced polarization will allow improvement of the FSI treatment by providing additional experimental constraints to existing theoretical calculations. In our follow-up experiment E03-104 at JLab high statistics data were taken at a Q2 of 0.8 GeV2 and 1.3 GeV2 on 1H and 4He targets. The extraction of the small induced polarization is complicated by the possible presence of instrumental asymmetries in the focal-plane polarimeter. The induced polarization in the elastic 1H(e, e0~p) reaction is (in one-photon approximation) zero and provides crucial information about these false asymmetries. Our preliminary results indicate an induced polarization of about ?0.03 and seem to be in reasonable agreement with the RDWIA calculation of Udias et al.
- Research Organization:
- Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1964108
- Report Number(s):
- JLAB-PHY-07-961; DOE/OR/23177-5914
- Country of Publication:
- United States
- Language:
- English
Similar Records
Polarization Transfer in 4He($\vec{e},e'\vec{p}$)3H
Polarization Transfer in 4He(e-vector,e[prime]p-vector)3H