Download or read book Neutron Electric Form Factor Up to Q sup 2 written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ratio of the electric to the magnetic form factor of the neutron, g /equiv G{sub En}/G{sub Mn}, was measured via recoil polarimetry (R.G. Arnold, C.E. Carlson, F. Gross, Phys. Rev. C 23, 363 (1981)) from the quasielastic 2H (/mathop(e)/limitse' /mathop(n)/limits) 1H reaction at three values of Q2 (viz, 0.45, 1.15, and 1.47 (GeV/c)2) in Hall C of the Thomas Jefferson National Accelerator Facility. The data reveal that GEn continues to follow the Galster parameterization up to Q2 = 1.15 (GeV/c)2 and rises above the Galster parameterization at Q2 = 1.47 (GeV/c)2.
Download or read book Measurement of the Neutron Electric Form Factor at Q sup 2 0 8 GeV c sup 2 written by Derek Glazier and published by . This book was released on 2003 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutron Charge Form Factor at Large Q sup 2 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutron charge form factor G{sub En}(q) is determined from an analysis of the deuteron quadrupole form factor F{sub C2}(q) data. Recent calculations, based on a variety of different model interactions and currents, indicate that the contributions associated with the uncertain two-body operators of shorter range are relatively small for F{sub C2}(q), even at large momentum transfer q. Hence, G{sub En}(q) can be extracted from F{sub C2}(q) at large q2 without undue systematic uncertainties from theory.
Download or read book Electric Form Factor of the Neutron written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent polarization-based precision measurements of the nucleons' elastic electric form factors have led to surprising results. The measurement of the ratio of the proton's electromagnetic form factors, $\mu_p G_E^p/G_M^p$, was found to drop nearly linearly with $Q^2$ out to at least $5 \mathrm{GeV}^2$, inconsistent with the older Rosenbluth-type experiments. A recent measurement of $G_E^n$, the neutron's electric form-factor saw $G_E^n$ does not fall off as quickly as commonly expected up to $Q^2 \approx 1.5 \mathrm{GeV}^2$. Extending this study, a precision measurement of $G_E^n$ up to $Q^2=3.5 \mathrm{GeV}^2$ was completed in Hall A at Jefferson Lab. The ratio $G_E^n/G_M^n$ was measured through the beam-target asymmetry $A_\perp$ of electrons quasi-elastically scattered off polarized neutrons in the reaction ${}^{3}\overrightarrow{He}(\overrightarrow{e}, e' n)$. The experiment took full advantage of the electron beam, recent target developments, as well as two detectors new to Jefferson Lab. The measurement used the accelerator's 100\% duty-cycle high-polarization (typically 84\%) electron beam and a new, hybrid optically-pumped polarized ${}^{3}\overrightarrow{He}$ target which achieved in-beam polarizations in excess of 50\%. A medium acceptance (80msr) open-geometry magnetic spectrometer (BigBite) detected the scattered electron, while a geometrically matched neutron detector observed the struck neutron. Preliminary results from this measurement will be discussed and compared to modern calculations of $G_E^n$.
Download or read book Measurements of the Electric Form Factor of the Neutron at Q2 written by and published by . This book was released on 2003 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precise measurements of the electric form factor of the neutron, Gn E, over a wide range of the square of the four-momentum transfer, Q2, are important for understanding nucleon and nuclear electromagnetic structure. In the non-relativistic limit, the electric and magnetic form factors are related to the charge and magnetization distribution inside a nucleon, respectively. The measured values of the form factors also serve as an important test for nucleon models. Among the four nucleon form factors, the electric form factor of the neutron, Gn E, is the most difficult one to measure and therefore has been very poorly known especially in the region Q2 > 1 (GeV/c)2 due to the lack of a free neutron target and the small value of Gn E. The Jefferson Laboratory E93-038 collaboration measured the ratio of the electric to magnetic form factor of the neutron, g = Gn E/Gn M, at three acceptance-averaged Q2 values of 0.45, 1.13 and 1.45 (GeV/c)2 using the quasi-elastic 2H(ẽ, e0ñ)1H reaction. In our experiment, an electron was scattered quasielastically from a neutron in a liquid-deuterium target, and the electron was detected in an electron spectrometer in coincidence with the neutron which was detected in a neutron polarimeter. The polarimeter was used to analyze the polarization of the recoil neutrons by measuring the np elastic scattering asymmetry. The experiment was performed in Hall-C at Thomas Jefferson National Accelerator Facility during the period from September 2000 to April 2001. The value of g was determined from the measured ratio of the sideways and longitudinal components of the neutron polarization vector. The values for Gn E were computed from our measured values of g = Gn E/Gn M using the Gn M values obtained from a fit to the world data. The E93-038 collaboration reported the first measurements of Gn E using polarization techniques at Q2 greater than 1 (GeV/c)2. Furthermore, our measurements of Gn E at the two higher Q2 values of 1.13 and 1.45 (GeV/c)2 are more precise than prior measurements at lower Q2. In this dissertation, the data analyses and our results for g and Gn E at Q2=0.45 (GeV/c)2 and Q2=1.13 (GeV/c)2 are given. Our high-accuracy data are included with the 'world' data for Gn E to form an improved data set that was fit with an empirical function to give a simple parameterization of Gn E as a function of Q2. In addition, the data for the ratio Gn E/Gn M are compared to theoretical models of the nucleon. We found that no theoretical model predicts both proton and neutron form factor data.
Download or read book Measurements of the Electric Form Factor of the Neutron at Q2 written by Shigeyuki Tajima and published by . This book was released on 2003 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Neutron Electric Form Factor to Q2 written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The nucleon elastic electromagnetic form factors are fundamental quantities needed for an understanding of nucleon and nuclear electromagnetic structure. The evolution of the Sachs electric and magnetic form factors with Q2, the square of the four-momentum transfer, is related to the distribution of charge and magnetization within the nucleon. High precision measurements of the nucleon form factors are essential for stringent tests of our current theoretical understanding of confinement within the nucleon. Measurements of the neutron form factors, in particular, those of the neutron electric form factor, have been notoriously difficult due to the lack of a free neutron target and the vanishing integral charge of the neutron. Indeed, a precise measurement of the neutron electric form factor has eluded experimentalists for decades; however, with the advent of high duty-factor polarized electron beam facilities, experiments employing polarization degrees of freedom have finally yielded the first precise measurements of this fundamental quantity. Following a general overview of the experimental and theoretical status of the nucleon form factors, a detailed description of an experiment designed to extract the neutron electric form factor from measurements of the neutron's recoil polarization in quasielastic 2H(e, e')1H scattering is presented. The experiment described here employed the Thomas Jefferson National Accelerator Facility's longitudinally polarized electron beam, a magnetic spectrometer for detection of the scattered electron, and a neutron polarimeter designed specifically for this experiment. Measurements were conducted at three Q2 values of 0.45, 1.13, and 1.45 (GeV/c)2, and the final results extracted from an analysis of the data acquired in this experiment are reported and compared with recent theoretical predictions for the nucleon form factors.
Download or read book Measurements of the Electric Form Factor of the Neutron Up to Q2 written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The electric form factor of the neutron was determined from studies of the reaction \rea{} in quasi-elastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the $Q^2$-range over which it is known, we find \GEn{}$ = 0.0225 \pm 0.0017 (stat) \pm 0.0024 (syst)$, $0.0200 \pm 0.0023 \pm 0.0018$, and $0.0142 \pm 0.0019 \pm 0.0013$ for $Q^2$ = 1.72, 2.48, and 3.41~\gevsq, respectively.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutron Form Factors from Elastic Electron Deuteron Scattering Ration Experiments at Very Low Momentum Transfer written by Raymond William Berard and published by . This book was released on 1973 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the ratio of the elastic electron-deuteron scattering cross section to the elastic electron-proton scattering cross section were made for low momentum transfers. Augmented by the work of Topping these data span a range of (q sup 2) from 0.05 (fm sup -2) to 0.50 (fm sup -2). From these, the electric form factor of the neutron, (G sub E sub n), was extracted using three Lomon-Feshbach wave functions for the deuteron, (LF1, LF5, and LF15). Values of the slope of (G sub E sub n) versus q2 were measured to be 0.0218 plus or minus 0.0022 for LF1, 0.0220 plus or minus 0.0022 for LF5, and 0.0185 plus or minus 0.0022 for LF15. Although the data seems to prefer model LF15, all were found to be in agreement with the thermal neutron-electron slope of 0.0193 plus or minus 0.0004. (Modified author abstract).
Download or read book Neutron Form Factors from Elastic Electron deuteron Scattering Ratio Experiments at Very Low Momentum Transfers written by Raymond William Berard and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the ratio of the elastic electron-deuteron scattering cross section to the elastic electron-proton scattering cross section were made for low momentum transfers. Augmented by the work of Topping these data span a range of (q sup 2) from 0.05 (fm sup -2) to 0.50 (fm sup -2). From these, the electric form factor of the neutron, (G sub E sub n), was extracted using three Lomon-Feshbach wave functions for the deuteron, (LF1, LF5, and LF15). Values of the slope of (G sub E sub n) versus q2 were measured to be 0.0218 plus or minus 0.0022 for LF1, 0.0220 plus or minus 0.0022 for LF5, and 0.0185 plus or minus 0.0022 for LF15. Although the data seems to prefer model LF15, all were found to be in agreement with the thermal neutron-electron slope of 0.0193 plus or minus 0.0004.
Download or read book A Measurement of the Neutron Electric Form Factor in Dvec evec E n p Quasielastic Scattering at Q2 written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The form factors of the neutron give information on fundamental properties of the nucleons and provide a critical testing ground for models based on QCD. In late 1998, Jefferson Lab (JLAB) experiment E93-026 measured the spin-dependent part of the exclusive (e, e'n) scattering cross section from a polarized deuterated ammonia (15ND3) target at a four momentum transfer squared of Q2 = 0.5 (GeV/c)2. A longitudinally polarized electron beam was scattered from the polarized target and the quasi-elastically scattered electron was detected in coincidence with the knocked-out neutron. The data have been analyzed in terms of the spin-correlation parameter, or the electron-deuteron vector asymmetry (A{sub ed}{sup V}), of (e, e'n) to determine the neutron electric form factor G{sub E}(superscript n). The result is consistent with data from existing experiments and shows a good agreement with the Galster parameterization of G{sub E}(superscript n) within experimental uncertainty.
Download or read book The Neutron Electric Form Factor to Q2 written by Bradley Robert Plaster and published by . This book was released on 2004 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Following a general overview of the experimental and theoretical status of the nucleon form factors, a detailed description of an experiment designed to extract the neutron electric form factor from measurements of the neutron's recoil polarization in quasielastic 2H(e, e')1H scattering is presented. The experiment described here employed the Thomas Jefferson National Accelerator Facility's longitudinally polarized electron beam, a magnetic spectrometer for detection of the scattered electron, and a neutron polarimeter designed specifically for this experiment. Measurements were conducted at three Q2 values of 0.45, 1.13, and 1.45 (GeV/c)2, and the final results extracted from an analysis of the data acquired in this experiment are reported and compared with recent theoretical predictions for the nucleon form factors.
Download or read book Journal de la campagne de 1760 written by and published by . This book was released on 1761 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sup 3 He Pol Rvec E E Prime X and the Neutron Electromagnetic Form Factors written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent data for the spin-dependent A[sub T], and A[sub TL], asymmetries in[sup 3]He[pol]([rvec e], e[prime]) quasielastic scattering are reviewed. The neutron electric and magnetic form factors are extracted from the data using a plane wave impulse approximation (PWIA) model, and the model uncertainties are estimated. The extracted G[sub M][sup n] is in agreement with the dipole prediction as well as with other recent experiments. No meaningful result for G[sub E][sup n] is obtained due to large uncertainties and possible final-state interaction effects. At higher Q[sup 2], the determination of G[sub E][sup n] in[sup 3]He[pol]([rvec e], e[prime]) does appear feasible based on the plane wave impulse approximation (PWIA) predictions.
Download or read book Measuring G sup N sub E at High Momentum Transfers written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiment E02-013 at Thomas Jefferson National Accelerator Facility will extend the measured range of the neutron electric form factor G[sup n][sub E] to Q[sup 2]=3.4 (GeV/c)[sup 2] through a measurement of the cross section asymmetry in the reaction[sup 3][rvec H]e([rvec e], e'n). Recent theoretical investigations, motivated by the results on the ratio of the proton electric and magnetic form factor, predict higher values of G[sup n][sub E] compared to older predictions. The experiment utilizes a polarized[sup 3]He target and the polarized CEBAF electron beam. Scattered electrons will be detected in the BigBite spectrometer, recoiling neutrons in an array of scintillators. The experimental and theoretical developments needed to perform the measurement and the extract G[sup n][sub E] from[sup 3]He will be described. Concepts of extending the measurement of G[sup n][sub E] to even higher momentum transfers will be discussed.
