Download or read book Polarization Transfer in the Reaction 4He vec v E vec p 3H in the Quasielastic Scattering Region written by and published by . This book was released on 2002 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been a longstanding issue concerning possible nucleon modifications in a (dense) nuclear medium. Polarization transfer data for exclusive quasielastic electron scattering are a sensitive to the ratio of the electric and magnetic nucleon form factors in the medium. Although proper interpretation of the results requires accounting for such effects as final state interactions and meson exchange currents, their effect on polarization transfer is predicted to be small. Studies of model dependencies, e.g., the off-shell current operator and spinor distortions, have been done. Final results of a measurement of polarization transfer in the 4He($\vec{v}$, e'$\vec{p}$)3H reaction will be discussed. The experiments were carried out at MAMI, Mainz at a Q2 of 0.4 GeV2 and at the Thomas Jefferson Lab, Newport News, Virginia at the Q2 values 0.5, 1.0, 1.6 and 2.6 GeV2. Measured values of the transferred and induced polarization are compared with various theoretical calculations. The experiment showed a difference between the fully relativistic model with may indicate medium modifications of the form factor.
Download or read book Polarization Transfer in the Reaction 44He e E p 3H in the Quasi elastic Scattering Region written by Sonja Dieterich and published by . This book was released on 2002 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polarization Transfer in the 4He e2 e p2 3H Reaction at Q2 written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, proton recoil polarization was measured in the quasielastic 4He(e→,e'p→)3H reaction at Q2 = 0.8 (GeV/c)2 and 1.3 (GeV/c)2 with unprecedented precision. The polarization-transfer coefficients are found to differ from those of the 1H(e→,e'p→) reaction, contradicting a relativistic distorted-wave approximation, and favoring either the inclusion of medium-modified proton form factors predicted by the quark-meson coupling model or a spin-dependent charge-exchange final-state interaction. For the first time, the polarization-transfer ratio is studied as a function of the virtuality of the proton.
Download or read book Polarization Transfer in the 4He rvec E E rvec P 3H Reaction written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarization transfer in the 4He ({rvec e}, e'{rvec p})3H reaction was measured at Q2 of 0.4 GeV2 at MAMI, Mainz, and at Q2 of 0.5, 1.0, 1.6 and 2.6 GeV2 at the Thomas Jefferson National Accelerator Facility (Jefferson Lab), Newport News. The ratio of transverse to longitudinal polarization components of the ejected proton was compared with the same ratio for 1He({rvec e}, e'{rvec p}). Results at lower Q2 are consistent with a recent relativistic calculation including a predicted medium modification of the proton form factor based on a quark-meson coupling model.
Download or read book Polarization Transfer Measurements of the Quasielastic Region on 3He with the right Arrow Above p right Arrow Above n Reaction at 200 MeV written by Georgios Savopulos and published by . This book was released on 1998 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polarization Transfer in the 4He e u2192 e p u2192 3H Reaction at Q2 written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, proton recoil polarization was measured in the quasielastic 4He(e→,e'p→)3H reaction at Q2 = 0.8 (GeV/c)2 and 1.3 (GeV/c)2 with unprecedented precision. The polarization-transfer coefficients are found to differ from those of the 1H(e→,e'p→) reaction, contradicting a relativistic distorted-wave approximation, and favoring either the inclusion of medium-modified proton form factors predicted by the quark-meson coupling model or a spin-dependent charge-exchange final-state interaction. For the first time, the polarization-transfer ratio is studied as a function of the virtuality of the proton.
Download or read book Polarization Transfer in 4He e vector E prime p vector 3H written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarization transfer in quasi-elastic nucleon knockout is sensitive to the properties of the nucleon in the nuclear medium, including possible modification of the nucleon form factor and/or spinor. In our recently completed experiment E03-104 at Jefferson Lab we measured the proton recoil polarization in the 4He(e-vector, e[prime]p-vector)3H reaction at a Q2 of 0.8 (GeV/c)2 and 1.3 (GeV/c)2 with unprecedented precision. These data complement earlier data between 0.4 and 2.6 (GeV/c)2 from both Mainz and Jefferson Lab, in which the measured ratio of polarization-transfer coefficients differs from a fully relativistic DWIA calculation. Preliminary results hint at a possible unexpected Q2 dependence in the polarization transfer coefficient ratio. Final analysis will help constrain FSI models.
Download or read book Polarization Transfer in The sup 4 He rvec E E prime rvec P sup 3 H Reaction written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarization transfer in the[sup 4]He([rvec E], E[prime][rvec P])[sup 3]H reaction was measured in Jefferson Lab experiment 93-049. The ratio of the polarization transfer coefficients, (P[prime][sub x]/P[prime][sub z])[sub He], is on average significantly reduced as compared to the same ratio in elastic ep scattering. This is so far unaccounted for by relativistic DWIA calculations, and favors the inclusion of a predicted medium modification of the proton form factor.
Download or read book Polarization Transfer in the 4He rvec E E rvec P 3H Reaction written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarization transfer in the 4He({rvec E}, E′{rvec P})3H reaction was measured in Jefferson Lab experiment 93-049. The ratio of the polarization transfer coefficients, (P′x/P′{sub z}){sub He}, is on average significantly reduced as compared to the same ratio in elastic ep scattering. This is so far unaccounted for by relativistic DWIA calculations, and favors the inclusion of a predicted medium modification of the proton form factor.
Download or read book Polarization Transfer in 4He e E p 3H written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarization observables in the 4He({rvec e}, e(prime) {rvec p})3H reaction are calculated using accurate three- and four-nucleon bound-state wave functions, a realistic model for the nuclear electromagnetic current operator, and a treatment of final-state-interactions with an optical potential model constrained by p 3H elastic and charge-exchange cross section data. In contrast to earlier studies, no significant discrepancies are found between theory and experiment both for the ratio of transverse to longitudinal polarization transfers and for the induced polarization, when free-nucleon electromagnetic form factors are used in the current operator. The present results challenge the current interpretation of the experimental data in terms of medium-modified form factors.
Download or read book Search for Effects Beyond the Born Approximation in Polarization Transfer Observables in vec e p Elastic Scattering written by and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, $G_{E}/G_{M}$, obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange (TPEX) contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic $H(\vec{e}, e'\vec{p})$ reaction for three different beam energies at a fixed squared momentum transfer $Q^2 = 2.5$ GeV$^2$, spanning a wide range of the virtual photon polarization parameter, $\epsilon$. From these measured polarization observables, we have obtained separately the ratio $R$, which equals $\mu_p G_{E}/G_{M}$ in the Born approximation, and the longitudinal polarization transfer component $P_\ell$, with statistical and systematic uncertainties of $\Delta R \approx \pm 0.01 \mbox{(stat)} \pm 0.013 \mbox{(syst)}$ and $\Delta P_\ell/P^{Born}_{\ell} \approx \pm 0.006 \mbox{(stat)}\pm 0.01 \mbox{(syst)}$. The ratio $R$ is found to be independent of $\epsilon$ at the 1.5% level, while the $\epsilon$ dependence of $P_\ell$ shows an enhancement of $(2.3 \pm 0.6) %$ relative to the Born approximation at large $\epsilon$.
Download or read book Polarization Transfer in the He 4 polarized e E prime Polarized p H 3 Reaction Up to Q2 written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the proton recoil polarization in the 4He(polarized-e, e-prime, p)3H reaction at Q2 = 0.5, 1.0, 1.6, and 2.6 (GeV/c)2. The measured ratio of polarization transfer coefficients differs from a fully relativistic calculation, favoring the inclusion of a predicted medium modification of the proton form factors based on a quark-meson coupling model. In contrast, the measured induced polarizations agree reasonably well with the fully relativistic calculation indicating that the treatment of final-state interactions is under control.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 2001 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Double Polarized Asymmetries in Quasi elastic Processes 3 vec He vec e E D and 3 vec He vec e E P written by and published by . This book was released on 2012 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is dedicated to a study of a spin-isospin structure of the polarized 3He. First, an introduction to the spin structure of 3He is given, followed by a brief overview of past experiments. The main focus of the thesis is the E05-102 experiment at Jefferson Lab, in which the reactions ${}^3\vec{He}(\vec{e}, e' d)$ and ${}^3\vec{He}(\vec{e}, e' p)$ in the quasi-elastic region were studied. The purpose of this experiment was to better understand the effects of the S'- and D-state contributions to the 3He ground-state wave-functions by a precise measurement of beam-target asymmetries Ax and Az in the range of recoil momenta from 0 to about 300 MeV/c. The experimental equipment utilized in these measurements is described, with special attention devoted to the calibration of the hadron spectrometer, BigBite. Results on the measured asymmetries are presented, together with first attempts at their comparison to the state-of-the art Faddeev calculations. The remaining open problems and challenges for future work are also discussed.
Download or read book Polarization Transfer Measurements of D e E p Reaction in the Dip Region at Q2 0 31 GeV2 c2 written by Kyungseon Joo and published by . This book was released on 1997 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to the Theory of Thermal Neutron Scattering written by G. L. Squires and published by Cambridge University Press. This book was released on 2012-03-29 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: A long-awaited reprint of the book that has established itself as the classic textbook on neutron scattering. It will be an invaluable introductory text for students taking courses on neutron scattering, as well as for researchers and those who would like to deepen their knowledge on the subject through self-study.
Download or read book Solid Surfaces Interfaces and Thin Films written by Hans Lüth and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book emphasises both experimental and theoretical aspects of surface, interface and thin film physics. Compa- red to the earlier editions, which bore the title "Surfaces and Interfaces of Solid Materials", the book now places more emphasis on thin films, including also their superconducting and ferromagnetic properties. The present 4th edition thus presents techniques of preparing well-defined solid surfaces and interfaces, fundamental aspects of adsorption and layer growth, as well as basic models for the descripti- on of structural, vibronic and electronic properties of sur- faces, interfaces and thin films. Because of their importan- ce for modern information technology, significant attention is paid to the electronic properties of semiconductor inter- faces and heterostructures. Collective phenomena , such as superconductivity and ferromagnetism, also feature promi- nently. Experimental sections covering essential measurement and preparation techniques are presented in separate panels.
