Download or read book Measurements of the Electric Form Factor of the Neutron at JLab Via Recoil Polarimetry in the Reaction written by J. M. Finn and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Preliminary results are reported for measurements of the ratio of the electric form factor to the magnetic form factor of the neutron, GEn/GMn, obtained via recoil polarimetry from the quasielastic 2H(e, e?n) 1H reaction at Q2 values of 0.45, 1.13, and 1.45 (GeV/c)2. The measurements, conducted in Hall C of the Thomas Jefferson National Accelerator Facility, together with other recent polarization measurements, are the result of a decade long effort to establish a firm experimental database for the important, but elusive, electric form factor of the neutron.
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 The Electric Form Factor of the Neutron at Q2 written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Jefferson Laboratory E93-038 collaboration measured the ratio of the electric form factor to the magnetic form factor of the neutron, g = Gne/Gnm, via recoil polarimetry from the quasielastic 2H(e, en)1 H reaction at q2 = 0.45, 1.17 and 1.47 (GeV/c)2 in Hall C of the Thomas Jefferson National Accelerator Facility. A polarimeter designed specifically for E93-038 was used to measure the up-down scattering asymmetry from the transverse component of the recoil neutron's polarization vector, and a dipole magnet located in front of the polarimeter was used to precess the polarization vector in the scattering plane through an angle of x. Sequential measurements of the scattering asymmetry with the polarization vector precessed through angles x = 0s and x = ±90s for Q2 = 1.47 (GeV/c)2 were made during January 2001 and through angles x = ±40s for Q2 = 1.17 (GeV/c)2 during April 2001 and will be reported on in this dissertation. This ratio method removes the need to know the analyzing power.
Download or read book Measurement of the Neutron Electric Form Factor Via Recoil Polarimetry written by and published by . This book was released on 2003 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of the Neutron s Electric Form Factor G E n Via Doubly Polarized Quasi elastic Scattering at Jefferson Lab written by Frank Wesselmann and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We determined the electric form factor of the neutron GEn via the reaction d(e, e?n)p using a longitudinally polarized electron beam and a frozen, polarized 15ND3 target at Jefferson Lab. The knocked out neutrons were detected in a segmented plastic scintillator in coincidence with the quasi-elastically scattered electrons which were tracked in Hall C's High Momentum Spectrometer. To extract GEn, we compared the experimental beam-target asymmetry with theoretical calculations based on different GEn models. We report the results of the fall 2001 run at Q2=0.5 and 1.0 (GeV/c)2.
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 The Neutron Electric Form Factor to Q2 written by and published by . This book was released on 2004 with total page 541 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 Neutron Electric to Magnetic Form factor Ratio G En written by and published by . This book was released on 2006 with total page 25205 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report values for the neutron electric to magnetic form factor ratio, G{sub En}/G{sub Mn}, deduced from measurements of the neutron's recoil polarization in the quasielastic 2H({rvec e}, e(prime){rvec n}) 1H reaction, at three Q2 values of 0.45, 1.13, and 1.45 (GeV/c)2. The data at Q2 = 1.13 and 1.45 (GeV/c)2 are the first direct experimental measurements of GEn employing polarization degrees of freedom in the Q2> 1 (GeV/c)2 region and stand as the most precise determinations of GEn for all values of Q2.
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 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 Measurement of the Neutron Electric Form Factor at Q2 written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nucleon form factors allow a sensitive test for models of the nucleon. Recent experiments utilising polarisation observables have resulted, for the first time, in a model-independent determination of the neutron electric form factor GnE. This method employed an 80% longitudinally polarised, high intensity (10 uA) electon beam (883 MeV) that was quasi-elastically scattered off a liquid deuterium target in the reaction D (e, en)p. A neutron polarimeter was designed and installed to measure the ratio of transverse-to-longitudinal polarisation using neutron scattering asymmetries. This ratio allowed a determination of the neutron elastic form factor, GnE, free of the previous large systematic uncertainties associated with the deuterium wave function. The experiment took place in the A1 experimental hall at MAMI taking advantage of a high resolution magnetic spectrometer. A detailed investigation was carried out into the performance of the neutron polarimeter.
Download or read book A Measurement of the Neutron Electric Form Factor at Very Large Momentum Transfer Using Polaried Electrions Scattering from a Polarized Helium 3 Target written by and published by . This book was released on 2010 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. Of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q2 and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized 3 He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Polarized electrons were scattered off this target, and both the scattered electron and neutron were detected. Gn E was measured to be 0.0242 ± 0.0020(stat) ± 0.0061(sys) and 0.0247 ± 0.0029(stat) ± 0.0031(sys) at Q2 = 1.7 and 2.5 GeV2 , respectively.
Download or read book Measurements of the Electric Form Factor of the Neutron at Q2 written by Seamus Patrick Riordan and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book SPIN 2002 written by Yousef I. Makdisi and published by American Institute of Physics. This book was released on 2003-09-04 with total page 1198 pages. Available in PDF, EPUB and Kindle. Book excerpt: The SPIN 2002 Proceedings describe the recent advances in the field of spin physics. The topics cover research in high energy and nuclear physics and the study of the nuclear spin structure. The symposium also covers advances in polarized proton and electron acceleration and storage as well as polarized ion sources and targets. The first measurement of spin physics observables in pp collisions at center of mass energy of 200 Gev was announced at this symposium.
Download or read book Measurement of the Electric Form Factor of the Neutron at 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 electric form factor of the neutron was determined from measurements of the d ((almost equal to)e, e n) p reaction for quasielastic kinematics. Polarized electrons were scattered o a polarized deuterated ammonia (15ND3) target in which the deuteron polarization was perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle detector. We find Gn E = 0.0526 ± 0.0033(stat) ± 0.0026(sys) and 0.0454 ± 0.0054 ± 0.0037 at Q2 = 0.5 and 1.0 (GeV/c)2, respectively.
