Download or read book Two Photon Exchange Radiative Correction to Electron proton Elastic Scattering written by Jaseer Ahmed and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Measurement of the Two photon Exchange Effect in Elastic Electron proton Scattering with OLYMPUS written by Rebecca Lynn Russell and published by . This book was released on 2016 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Elastic electron-proton scattering has long been the tool of choice for the study of the proton form factors, GE(Q 2 ) and GM(Q2 ), which describe the electric and magnetic distributions of the proton as a function of momentum transfer. Recent experiments, measuring the form factors from polarization observables in polarized elastic electron-proton scattering, have found values of the ratio GE(Q2 )/GM(Q2) at high Q2 that contradict the results from unpolarized measurements. A proposed explanation for this discrepancy is the unaccounted two-photon exchange radiative correction, which could affect the unpolarized measurements. As this effect is currently not possible to calculate in a model-independent way, the OLYMPUS experiment was designed to make a direct measurement of it by measuring the elastic positron-proton to electron-proton scattering cross section ratio. The experiment was run in 2012 at DESY using the BLAST spectrometer and the DORIS positron and electron beams at 2 GeV incident on a gaseous hydrogen target. To analyze the data, a careful reconstruction of the scattering events, detailed simulation of the experimental setup, and full radiative corrections to the measured cross sections were performed. Preliminary results for the experiment show a statistically significant two-photon exchange effect, increasing over the measurement range of 0.6 GeV2

Download or read book Two Photon Exchange in Electron proton Scattering written by Gary Kalman Greenhut and published by . This book was released on 1968 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two Photon Exchange Correction to Parity Violating Elastic Electron Proton Scattering written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Higher-order QED effects play an important role in precision measurements of nucleon elastic form factors in electron scattering. Here we introduce a two-photon exchange QED correction to the parity-violating polarization asymmetry of elastic electron-proton scattering. We calculate this correction in the parton model using the formalism of generalized parton distributions, and demonstrate that it can reach several per cent in certain kinematics, becoming comparable in size with existing experimental measurements of strange-quark effects in the proton neutral weak current.

Download or read book Elastic and Inelastic Electron proton Scattering written by Ernest Albert Allton and published by . This book was released on 1973 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two Photon Exchange Effects in Elastic Electron Proton Scattering written by and published by . This book was released on 2013 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two methods, Rosenbluth separation and polarization transfer, can be used to extract the proton form factor ratio [mu]p GEp/GMp, but they do not yield the same results. It is thought that the disagreement is due to two photon exchange corrections to the differential cross sections. High precision proton Rosenbluth extractions were carried out at 102 kinematics points spanning 16 values of momentum transfer Q2, from 0.40 to 5.76 GeV2. Reduced cross sections were found to 1.1% or better for Q2 less than 3 GeV2 increasing to 4% at 5.76 GeV2 The form factor ratios were determined to 1:5-3% for Q2

Download or read book Positron proton Scattering written by Andrew Arnold Browman and published by . This book was released on 1964 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of two-photon exchange in elastic electron-proton scattering was investigated by measuring the ratio of positron-proton to electron-proton scattering. Four momentum transfers as large as 0.756 (BeV/c) to the 2nd power (19.5 F to the -2nd power) were used. The data indicate that two-photon effects are 4.0 = 1.5% larger than those predicted by the radiative corrections at the highest momentum transfers attained in these experiments. The two-photon corrections predicted, using a static charge distribution, fit the data well at lower momentum transfers and forward angles but appear to be small at higher momentum transfers and backward angles. (Author).

Download or read book Two photon Exchange in Elastic and Inelastic Electron proton Scattering written by W. Melnitchouk and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present an explicit quantum field theoretical calculation of two-photon exchange contribution to elastic electron-proton scattering and to Delta resonance production in electron-proton collisions.

Download or read book The Contribution of Two photon Exchange in Elastic Lepton proton Scattering written by Colton David Graham O'Connor and published by . This book was released on 2017 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the electric-to-magnetic ratio of the proton's elastic form factors, GE/GM, have recently been shown to diverge at high momentum transfer, Q2, based on which of two experimental methods is employed. Reanalysis of all results might be able to bring them into agreement if some previously neglected correction were introduced whose magnitude increases with Q2. In the high-energy community, two-photon exchange has become the favored candidate for such a correction. But theoretical models disagree on the size and form of a two-photon exchange correction term entering into elastic lepton-proton scattering and existent empirical data is not sufficiently precise to settle the matter. OLYMPUS is one of several new experiments designed to evaluate R2[gamma], the ratio of the elastic cross sections for positron-proton and electron-proton scattering, whose difference from unity provides a direct measure of the amplitude of the two-photon exchange matrix elements. In this dissertation, OLYMPUS is considered from its motivation, construction, and operation to its analysis, along with the associated Monte Carlo simulation. Special attention is given to the symmetric Møller/Bhabha detector system, which is not described in full elsewhere. The results achieved by the OLYMPUS collaboration, reported herein, achieve unprecedented precision over a wide kinematic range and make a significant contribution to the understanding of two-photon exchange.

Download or read book Two photon Exchange Contribution to Elastic Electron proton Scattering Measurements at the VEPP 3 Storage Ring written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book TWO PHOTON EXCHANGE IN ELECTRON PROTON ELASTIC SCATTERING written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent theoretical developments in the studies of two-photon exchange effects in elastic electron-proton scattering are reviewed. Two-photon exchange mechanism is considered a likely source of discrepancy between polarized and unpolarized experimental measurements of the proton electric form factor at momentum transfers of several GeV$^2$. This mechanism predicts measurable effects that are currently studied experimentally.

Download or read book Two photon Exchange and Elastic Electron proton Scattering written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-photon exchange contributions to elastic electron-proton scattering cross sections are evaluated in a simple hadronic model including the finite size of the proton. The corrections are found to be small, but with a strong angular dependence at fixed Q2. This is significant for the Rosenbluth technique for determining the ratio of electric and magnetic form factors of the proton, and partly reconciles the apparent discrepancy with the results of the polarization transfer technique.

Download or read book An Upper Bound on the Two Photon Exchange Amplitude for Electron Proton Elastic Scattering written by Robert Clarence Perisho and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct Measurements of Two Photon Exchange on Lepton proton Elastic Scattering Using Simultaneous Electron positron Beams in CLAS written by Dasuni Kalhari Adikaram and published by . This book was released on 2014 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Precision Measurement of the E p e p Elastic Scattering Cross Section Ratio at the OLYMPUS Experiment written by Brian Scott Henderson and published by . This book was released on 2016 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the ratio of the proton elastic form factors ([mu]pGe/Gm) using Rosenbluth separation and those using polarization-based techniques show a strong discrepancy, which has persisted both in modern experimental results and in re-analyses of previous data. The most widely accepted hypothesis to explain this discrepancy is the treatment of the contributions from hard two-photon exchange (TPE) to elastic electron-proton scattering in the radiative corrections applied to the Rosenbluth separation measurements. Calculations of the hard TPE contribution are highly model dependent, but the effect may be measured experimentally with a precise determination of the ratio of the positron-proton and electron-proton elastic scattering cross sections. The OLYMPUS experiment collected approximately 4 fb-1 of e+p and e-p scattering data at the DORIS storage ring at DESY in 2012, with the goal of measuring the elastic [sigma]e+p/[sigma]e-p ratio over the kinematic range (0.4

Download or read book Two photon Exchange Corrections in Elastic Lepton proton Scattering written by Oleksandr Tomalak and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Delta Resonance Contribution to Two photon Exchange in Electron proton Scattering written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We calculate the effects on the elastic electron-proton scattering cross section of the two-photon exchange contribution with an intermediate [Delta] resonance. The [Delta] two-photon exchange contribution is found to be smaller in magnitude than the previously evaluated nucleon contribution, with an opposite sign at backward scattering angles. The sum of the nucleon and [Delta] two-photon exchange corrections has the angular dependence compatible with both the polarization transfer and the Rosenbluth methods of measuring the nucleon electromagnetic form factors.