Download or read book Measurement of the Parity Violating Asymmetry in Deep Inelastic Scattering at JLab 6 GeV written by and published by . This book was released on 2013 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: The parity-violating asymmetry in deep inelastic scattering (PVDIS) offers us a useful tool to study the weak neutral couplings and the hadronic structure of the nucleon, and provides high precision tests on the Standard Model. During the 6 GeV PVDIS experiment at the Thomas Jefferson National Accelerator Facility, the parity-violating asymmetries A{sub PV} of a polarized electron beam scattering off an unpolarized deuteron target in the deep inelastic scattering region were precisely measured at two Q2 values of 1.1 and 1.9 (GeV/c)2. The asymmetry at Q2=1.9 (GeV/c)2 can be used to extract the weak coupling combination 2C2u - C2d, assuming the higher twist effect is small. The extracted result from this measurement is in good agreement with the Standard Model prediction, and improves the precision by a factor of five over previous data. In addition, combining the asymmetries at both Q2 values provides us extra knowledge on the higher twist effects. The parity violation asymmetries in the resonance region were also measured during this experiment. These results are the first APV data in the resonance region beyond the [Delta] (1232). They provide evidence that the quark hadron duality works for APV at the (10-15)% level, and set constraints on nucleon resonance models that are commonly used for background calculations to other parity-violating electron scattering measurements.
Download or read book Parity Violation Inelastic Scattering Experiments at 6 GeV and 12 GeV Jefferson Lab written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the measurement of parity-violating asymmetries in the deep inelastic scattering and nucleon resonance regions using inclusive scattering of longitudinally polarized electrons from an unpolarized deuterium target. The effective weak couplings C$_{2q}$ are accessible through the deep-inelastic scattering measurements. Here we report a measurement of the parity-violating asymmetry, which yields a determination of 2C$_{2u}$ - C$_{2d}$ with an improved precision of a factor of five relative to the previous result. This result indicates evidence with 95% confidence that the 2C$_{2u}$ - C$_{2d}$ is non-zero. This experiment also provides the first parity-violation data covering the whole resonance region, which provide constraints on nucleon resonance models. Finally, the program to extend these measurements at Jefferson Lab in the 12 GeV era using the Solenoidal Large Intensity Device was also discussed.
Download or read book Parity Violation in Deep Inelastic Scattering at JLab 6 GeV written by Xiaochao Zheng and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The parity-violating asymmetry in e-$^2$H deep inelastic scattering (DIS) can be used to extract the weak neutral-current coupling constants $C_{2q}$. A measurement of this asymmetry at two $Q^2$ values is planned at Jefferson Lab. Results from this experiment will provide a value of $2C_{2u}-C_{2d}$ to a precision of $\pm 0.03$, a factor of eight improvement over our current knowledge. If all hadronic effects can be understood, this results will provide information on possible extensions of the Standard Model, complementary to other experiments dedicated to new physics searches. Presented here are the physics motivation, experimental setup, potential hadronic effects and their implications, and the future of PV DIS at Jefferson Lab.
Download or read book Recovery Act Measurement of Parity Violation in Deep Inelastic Scattering and Studies of the Nucleon Spin Structure at JLab 6 and 11 GeV written by and published by . This book was released on 2016 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The program proposed contains two ingredients which aim to address aspects of two of the three research frontiers of nuclear science as identified in the 2007 NSAC Long Range Plan. The first topic, a test of the current Standard Model, is an ongoing project focusing on measurements of the parity-violating asymmetry in ~e-2H deep inelastic scattering (PVDIS). The PVDIS measurement is complementary to other completed or ongoing low- to medium-energy tests of the Standard Model. As the first, exploratory step, an experiment using a 6 GeV electron beam will be carried out from October to December 2009 at the Thomas Jefferson National Accelerator Facility (JLab). Meanwhile, a program using the upgraded JLab 11 GeV beam is being planned. The PVDIS program as a whole will provide the first precision data on the axial quark neutral-weak coupling constants. This will either put the current Standard Model to a test that has never been done before, or reveal information on where to look for New Physics beyond the current Standard Model. The PVDIS program will also provide results on hadronic physics effects such as charge symmetry violation. The second part of the proposed program uses spin observables to address the research frontier concerning QCD and structure of the nucleon. An experiment using the JLab 6 GeV beam in 2001 showed that, contrary to predictions from perturbative quantum chromodynamics (pQCD), while the valence up quark's spin is parallel to the nucleon's spin, the valence down quark's spin is not. In order to test the limit of QCD in describing the nucleon spin structure to a region beyond the 6 GeV kinematics, this measurement will be extended to a more energetic, "deeper" valence quark region using the upgraded JLab 11 GeV beam with a polarized 3He target. Although the two topics of the proposed program appear to focus on different physics, for the upgraded JLab 11 GeV beam, both will utilize a new, yet-to-be-built large acceptance spectrometer, called "SoLID". Once built, SoLID can be used for other topics such as using PVDIS on a proton target to measure the valence quark distributions, using PVDIS on a polarized target to measure new electro-weak interference structure functions of the nucleon, and semi-inclusive deep inelastic scattering experiments. SoLID will greatly enhance the exploration potential of JLab. The proposed program will first focus on completion of the 6 GeV PVDIS experiment, its data analysis and publishing physics results. This 6 GeV experiment will explore whether precision PVDIS measurements are feasible, will set limits on the hadronic physics effects, and will improve our knowledge on the quark neutral weak couplings, optimally by a factor of six. Starting early 2010, efforts will be spent on preparation for the 11 GeV program, focusing on simulations of SoLID, optimization and construction of the SoLID detector package, and studies of the polarized 3He target and its improvements. Funding support for the whole program is requested here.
Download or read book Parity Violating Deep Inelastic Electron Scattering from the Deuteron at 6 GeV written by and published by . This book was released on 2013 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment that measured the parity violating (PV) asymmetry Ad in e-2H deep inelastic scattering (DIS) at Q2 ~ 1.10 and 1.90 (GeV/c)2 and xB ~ 0.3 was completed in experimental Hall A at the Thomas Jefferson National Accelerator Facility. The asymmetry can be used to extract the neutral weak coupling combination (2C2u-C2d), providing a factor of five to six improvement over the current world data. To achieve this precision, asymmetries of the 10-4 level needed to be measured at event rates up to 500 kHz with high electron detection efficiency and high pion background rejection capability. A specialized scaler-based counting data acquisition system (DAQ) with hardware-based particle identification was successfully implemented. The statistical quality of the asymmetry measurement agreed with the Gaussian distribution to over five orders of magnitudes and the experimental goal of 3-4% statistical uncertainty was achieved. The design and performance of the new DAQ system is presented with the preliminary asymmetry results given in the end.
Download or read book Parity Violation at 8 12 GeV at Jlab written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments on parity violation in electron scattering measure the asymmetry A = [sigma][sub R] - [sigma][sub L]/[sigma][sub R] + [sigma][sub L] where [sigma][sub R(L)] is the cross section for Right(Left) handed longitudinally polarized electrons. This asymmetry arises, in first order, from the interference between photon and Z-boson exchange amplitudes. Experiments make two basic uses of the Z-boson as a probe in electron-quark or electron-nucleon scattering. Historically the first usage was to test the electroweak theory in regions of kinematics where the hadronic structure is sufficiently understood. They discuss the application of higher energies at Jefferson Lab to repeat the SLAC e-D deep inelastic parity violation experiment [1] at a level of precision [approx] 0.5% in sin[sup 2][theta][sub W] which would be a useful constrain on extensions of the Standard Model [2]. The second, more recent usage of the Z-boson probe is to assume the Standard Model is correct at about the 1% level and use this as a unique method to address fundamental issues of nucleon structure, such as: (1) are the strange quarks an important component of the nucleon [3]; (2) In deep inelastic scattering, are the high momentum quarks u or d quarks? To address the first question, they discuss the feasibility of extending the HAPPEX experiment to higher Q[sup 2]. For the second question, they discuss a possible measurement of the ratio of valence quarks d/u in the proton using deep inelastic parity violation.
Download or read book From Parity Violation to Hadronic Structure and more written by K. de Jager and published by Springer Science & Business Media. This book was released on 2008-06-21 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the proceedings of the third international workshop on From Parity Violation to Hadronic Structure and More. The many applications of parity violation are way beyond the scope of what Lee and Yang could have imagined fifty years after their proposal. For the physics topics discussed during this workshop, the application of parity violation has become a standard work horse allowing for the extraction of many physics topics in different experiments.
Download or read book Parity Violation in Ep Scattering at Jlab written by Paul Souder and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We review the program of parity violation in the scattering of polarized electrons at JLab. Results are presented from recent experiments measuring the weak form factors, which in turn measure the contribution of strange quarks to the elastic form factors. In addition, we discuss the physics of parity violation in deep inelastic scattering, which will become possible with the upgrade of the JLab energy to 12 GeV.
Download or read book Measurements of the Strangeness Content of the Proton Through Parity Violating Electron Scattering at JLAB written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Scaler based Data Acquisition System for Measuring Parity Violation Asymmetry in Deep Inelastic Scattering written by Kai Pan (S.M.) and published by . This book was released on 2013 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment that measured the parity violating (PV) asymmetry Ad in e- 2H deep inelastic scattering (DIS) at Q2 ~ 1.10 and 1.90 (GeV/c) 2 and XB ~ 0.3 was completed in experimental Hall A at the Thomas Jefferson National Accelerator Facility. The asymmetry can be used to extract the neutral weak coupling combination (2C2u-C2d), providing a factor of five to six improvement over the current world data. To achieve this precision, asymmetries of the 10- level needed to be measured at event rates up to 500 kHz with high electron detection efficiency and high pion background rejection capability. A specialized scaler-based counting data acquisition system (DAQ) with hardware-based particle identification was successfully implemented. The overall pion contamination in the electron sample was controlled to approximately 2 x 10-4 or lower with an electron efficiency above 91% throughout the experiment. The DAQ deadtime contributed an approximately 0.2% uncertainty to the final asymmetries. The statistical quality of the asymmetry measurement agreed with the Gaussian distribution to over five orders of magnitudes and the experimental goal of 3-4% statistical uncertainty was achieved. The results presented here demonstrate that this type of scaler-based DAQ is able to perform accurate measurements of small asymmetries at the 1ppm level. The design of the DAQ system is presented including the analysis of PID performance, deadtime effect and the capability of measuring small asymmetries.
Download or read book Measurement of Parity violating Asymmetry in Electron deuteron Inelastic Scattering written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The parity-violating asymmetries between a longitudinally-polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were published earlier, but are presented here in more detail.
Download or read book Parity Violation in Elastic Electron Scattering written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of Experiment E04-115 (the G0 backward angle measurement) at Jefferson Lab is to investigate the contributions of strange quarks to the fundamental properties of the nucleon. The experiment measures parity-violating asymmetries in elastic electron scattering off hydrogen and quasielastic electron scattering off deuterium at backward angles at Q2 = 0.631 (GeV/c)2 and Q2 = 0.232 (GeV/c)2. The backward angle measurement represents the second phase of the G0 experiment. The first phase, Experiment E00-006 (the G0 forward angle experiment), measured parity-violating asymmetries in elastic electron scattering off hydrogen at forward angles over a Q2 range of 0.1-1.0 (GeV/c)2. The experiments used a polarized electron beam and unpolarized hydrogen and deuterium liquid targets. From these measurements, along with the electromagnetic form factors, one can extract the contribution of the strange quark to the proton's charge and magnetization distributions. This thesis represents a fi.
Download or read book Physics Division Annual Report written by Argonne National Laboratory. Physics Division and published by . This book was released on 2004 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parity violating DIS at 12 GeV written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of the 12-GeV upgrade at JLab will present an excellent opportunity to study parity violation in deep inelastic scattering at high values of x. The physics issues in this domain include charge symmetry violation, quark-quark correlations in the nucleon, and tests of the Standard Model. This program will require a high-luminosity detector with high acceptance for scattering angles up to about 35°. A possible design for a solenoidal spectrometer that meets this requirement is suggested.
Download or read book From Parity Violation to Hadronic Structure and more written by Serge Kox and published by Springer Science & Business Media. This book was released on 2007-06-07 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost 50 years after the proposal of Lee and Young in 1956 to test the hypothesis of parity violation in weak interactions and the subsequent experimental verification of parity violation by C. S. Wu, parity violation has today become a useful property of weak interactions. This is due to the fact that the focus nowadays has changed: parity violation in weak interactions is no more a topic of investigation but is used as a tool in many different fields ranging from nuclear physics to the search for the hidden extra dimensions requested by string theory. For our first workshop which took place June 5-8, 2002, at the Institut fiir Ke- physik of the Johannes Gutenberg-Universitat Mainz, we concentrated on the in vestigation of the strangeness contribution in the nucleon. This book contains the refereed and selected papers of the second workshop "From Parity Violation to Hadron Structure and more (Part II)", which took place June 8-11, in the Labo- toire de Physique Subatomique et de Cosmologie, in Grenoble. These papers appear in EPJAdirect, the electronic-only part of EPJA, and they are accessible without restrictions. They will also appear in printed form and can be ordered through Springer. The excellent presentations show the dramatic and steady progress in the accuracy of measured parity violating asymmetries over the last few years.
Download or read book Parity Violation In Electron Scattering Proceedings Of The Workshop written by E J Beise and published by World Scientific. This book was released on 1990-08-23 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings cover the recent progress and future directions of parity violation in electron scattering. Both experimental and theoretical issues are discussed, such as those of hadronic structure, radiative corrections, and tests of the standard model. There are three sessions, the first of which serves as a general overview of theory and experiment. The second session deals with the technical aspects of making a measurement of the parity violating asymmetry in electron scattering, including not only detector design but polarized electron beams and beam polarimeters.. The remaining session covers the corrections to lowest order parity violating cross sections.
Download or read book Measurement of the Parity Violating Asymmetries in Electron Deuteron Scattering in the Nucleon Resonance Region written by and published by . This book was released on 2013 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on parity-violating asymmetries in the nucleon resonance region measured using 5 - 6 GeV longitudinally polarized electrons scattering off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the [Delta](1232), and provide a verification of quark-hadron duality in the nucleon electroweak [gamma] Z interference structure functions at the (10-15)% level. The results are of particular interest to models relevant for calculating the [gamma] Z box-diagram corrections to elastic parity-violating electron scattering measurements.
