TY - JOUR
T1 - Measurements of the induced polarization in the quasi-elastic A(e,e′p→) process in non-coplanar kinematics
AU - Paul, S. J.
AU - Kolar, T.
AU - Brecelj, T.
AU - Achenbach, P.
AU - Arenhövel, H.
AU - Ashkenazi, A.
AU - Beričič, J.
AU - Böhm, R.
AU - Bosnar, D.
AU - Cline, E.
AU - Cohen, E. O.
AU - Debenjak, L.
AU - Distler, M. O.
AU - Esser, A.
AU - Friščić, I.
AU - Gilman, R.
AU - Giusti, C.
AU - Heilig, M.
AU - Hoek, M.
AU - Izraeli, D.
AU - Kegel, S.
AU - Klag, P.
AU - Kohl, Y.
AU - Korover, I.
AU - Lichtenstadt, J.
AU - Mardor, I.
AU - Merkel, H.
AU - Middleton, D. G.
AU - Mihovilovič, M.
AU - Müller, J.
AU - Müller, U.
AU - Olivenboim, M.
AU - Piasetzky, E.
AU - Pochodzalla, J.
AU - Ron, G.
AU - Schlimme, B. S.
AU - Schoth, M.
AU - Schulz, F.
AU - Sfienti, C.
AU - Širca, S.
AU - Spreckels, R.
AU - Štajner, S.
AU - Strauch, S.
AU - Thiel, M.
AU - Tyukin, A.
AU - Weber, A.
AU - Yaron, I.
N1 - Publisher Copyright: © 2020 The Author(s)
PY - 2020/12/10
Y1 - 2020/12/10
N2 - We report measurements of the induced polarization P→ of protons knocked out from 2H and 12C via the A(e,e′p→) reaction. We have studied the dependence of P→ on two kinematic variables: the missing momentum pmiss and the “off-coplanarity” angle ϕpq between the scattering and reaction planes. For the full 360° range in ϕpq, both the normal (Py) and, for the first time, the transverse (Px) components of the induced polarization were measured with respect to the coordinate system associated with the scattering plane. Px vanishes in coplanar kinematics, however in non-coplanar kinematics, it is on the same scale as Py. We find that the dependence on ϕpq is sine-like for Px and cosine-like for Py. For carbon, the magnitude of the induced polarization is especially large when protons are knocked out from the p3/2 shell at very small pmiss. For the deuteron, the induced polarization is near zero at small |pmiss|, and its magnitude increases with |pmiss|. For both nuclei such behavior is reproduced qualitatively by theoretical results, driven largely by the spin-orbit part of the final-state interactions. However, for both nuclei, sizeable discrepancies exist between experiment and theory.
AB - We report measurements of the induced polarization P→ of protons knocked out from 2H and 12C via the A(e,e′p→) reaction. We have studied the dependence of P→ on two kinematic variables: the missing momentum pmiss and the “off-coplanarity” angle ϕpq between the scattering and reaction planes. For the full 360° range in ϕpq, both the normal (Py) and, for the first time, the transverse (Px) components of the induced polarization were measured with respect to the coordinate system associated with the scattering plane. Px vanishes in coplanar kinematics, however in non-coplanar kinematics, it is on the same scale as Py. We find that the dependence on ϕpq is sine-like for Px and cosine-like for Py. For carbon, the magnitude of the induced polarization is especially large when protons are knocked out from the p3/2 shell at very small pmiss. For the deuteron, the induced polarization is near zero at small |pmiss|, and its magnitude increases with |pmiss|. For both nuclei such behavior is reproduced qualitatively by theoretical results, driven largely by the spin-orbit part of the final-state interactions. However, for both nuclei, sizeable discrepancies exist between experiment and theory.
UR - http://www.scopus.com/inward/record.url?scp=85097156092&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.physletb.2020.135984
DO - https://doi.org/10.1016/j.physletb.2020.135984
M3 - Article
SN - 0370-2693
VL - 811
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
M1 - 135984
ER -