Measurement of polarization transfer in the quasi-elastic ${}^{40}\mathrm{Ca}(\vec{e},e^{\prime }\vec{p})$ process

Abstract

Polarization transfer to a bound proton in polarized electron knock-out reactions, $\mathrm{A}(\vec{e},e^{\prime }\vec{p})$, is a powerful tool to look for in-medium modification of the bound proton. It requires comparison to calculations which consider the many-body effects accompanying the quasi-free process. We report here measured components $P_x^{\prime }$, $P_z^{\prime }$, and their ratio $P_x^{\prime }/P_z^{\prime }$, of polarization transfer to protons bound in ${}^{40}\mathrm{Ca}$, which is described well by the shell model and for which reliable calculations are available. While the calculations capture the essence of the data, our statistical precision allows us to observe deviations which cannot be explained by simple scaling, including by varying the proton electromagnetic form factor ratio $G_E/G_M$. We further explore the deviations of the ratio of the polarization transfer components from that of a free proton, $(P_x^{\prime }/P_z^{\prime }{)}_{\mathrm{A}}/(P_x^{\prime }/P_z^{\prime }{)}_{\mathrm{H}}$, and its dependence on the bound-proton virtuality.

References in corpus (20)

• A New Parameterization for the Lagrangian Density of Relativistic Mean Field Theory
• The electric and magnetic form factors of the proton
• Polarization Transfer in the ^4He(\vec e,e'\vec p)^3H Reaction up to Q^2 = 2.6 (GeV/c)^2
• Polarization transfer in the ${}^4$He$(\vec{e},e^{\prime }{\vec{p}}^3$H reaction
• Polarization Transfer in the 4He(e,e'p)3H Reaction at Q^2 = 0.8 and 1.3 (GeV/c)^2
• In-medium electron-nucleon scattering
• Electromagnetic form factors of the bound nucleon
• General Survey of Polarization Observables in Deuteron Electrodisintegration
• On the dependence of the wave function of a bound nucleon on its momentum and the EMC effect
• Polarization transfer in ${}^4$He$(\vec{e},e^{\prime }\vec{p})$${}^3$H: is the ratio $G_{Ep}/G_{Mp}$ modified in medium ?
• Polarization transfer in the d(epol,e' ppol)n reaction up to Q^2=1.61 (GeV/c)^2
• The focal plane proton-polarimeter for the 3-spectrometer setup at MAMI
• Measurement of polarization-transfer to bound protons in carbon and its virtuality dependence
• Components of polarization-transfer to a bound proton in a deuteron measured by quasi-elastic electron scattering
• Polarization transfer to bound protons measured by quasi-elastic electron scattering on ${}^{12}$C
• Comparison of recoil polarization in the ${}^{12}\mathrm{C}(\vec{e},e^{\prime }\vec{p})$ process for protons extracted from $s$ and $p$ shell
• Nuclear Density Dependence of In-Medium Polarization
• Quasi-elastic polarization-transfer measurements on the deuteron in anti-parallel kinematics
• The influence of Fermi motion on the comparison of the polarization transfer to a proton in elastic $\vec{e}p$ and quasi-elastic $\vec{e}A$ scattering
• Polarization observables for elastic electron scattering off a moving nucleon

Cited by in corpus (2)

• Electroweak form factors of baryons in dense nuclear matter
• Octet baryon electroweak form factors in dense nuclear matter