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 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 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 Measurement of the Neutron Electric Form Factor GEn in Quasielastic Scattering written by and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have measured the electric form factor of the neutron, GEn, at two momentum transfers (Q2= 0.5 and Q2= 1.0 GeV/c2) through quasielastic scattering in Jefferson Lab's Hall C. Longitudinally polarized electrons scattered from polarized deuterated ammonia and GEn was extracted from the beam-target asymmetry AVed which, in quasielastic kinematics, is particularly sensitive to GEn and insensitive to MEC and FSI.

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 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 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 Vibronic Interactions Jahn Teller Effect in Crystals and Molecules written by Michael D. Kaplan and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based mostly on the reports presented at the XVth International lahn-Teller Symposium on Vibronic Interactions in Crystals and Molecules and NATO Advanced Research Workshop Colossal Magnetoresistance and Vibronic Interactions that took place at Boston on August 16-22 of the year 2000. This is the first time the Symposium took place in the USA where recently the giant splash of the attention to the 1 ahn-Teller effect occurred. This tremendous interest to the field all over the world is reflected not only in the numerous publications in many American and European 10urnals, but of the leading scientists from additionally in the Symposium's participation the well known Universities, National Laboratories and industrial companies, which was the largest in the history of the Symposium. The renaissance of the 1ahn-Teller physics is closely related to the three fundamental discoveries in science. The most significant among them is the discovery of high-Tc superconductivity by K. -A. Muller and G. Bednorz, for whom the "1ahn-Teller idea" was the motivation in their search. The result of this search is well known - a wide spectrum of the 1ahn-Teller ion based materials with Tc between 24K and 135K were found. The second discovery is the existence of a new polymorph of carbon - the C60. The microscopic analysis of all physical, chemical and biological properties of the buckyballs is based on 1ahn-Teller type of interactions. The third is colossal magnetoresistance.