Download or read book Induced Final State Proton Polarization in Neutral Pion Electroproduction Near the delta 1232 Resonance at Q2 written by Glen Andrew Warren and published by . This book was released on 1997 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutral Pion Electroproduction in the Delta Resonance Region written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The electroproduction of baryon resonances at high Q2 is examined. Analysis focuses on the Delta(1232) resonance via exclusive pseudoscalar meson production of À0 particles. Differential cross sections are extracted for exclusive À0 electroproduction. In the central invariant mass (W) region the cross sections are used to extract resonant multipole amplitudes. In particular, the ratio of the electric quadrupole to magnetic dipole amplitudes (E2/M1) will be discussed for the Delta(1232) resonance. The transition to pQCD is discussed in terms of E2/M1 and other multipoles. The helicity amplitude A3/2 can be used as a baryon helicity conservation meter in this context and will be discussed. The fast shrinking of the resonant contribution in the Delta region is observed at this high momentum transfer. Apart from the observables related to pQCD scaling, the transition form factor GM is extracted along with the scalar to magnetic dipole ratio C2/M1.
Download or read book Induced Proton Polarization for Pi0 Electroproduction at Q2 written by and published by . This book was released on 1998 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the induced proton polarization P{sub n} in [pi]° electroproduction on the proton around the [Delta] resonance. The measurement was made at a central invariant mass and a squared four-momentum transfer of W = 1231 MeV and Q2 = 0.126 GeV2/c2, respectively. We measured a large induced polarization, P{sub n} = -0.397 ± 0.055 ± 0.009. The data suggest that the scalar background is larger than expected from a recent effective Hamiltonian model.
Download or read book Recoil Polarization Measurements for Neutral Pion Electroproduction at Q 2 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q2 = 1.0 (GeV/c)2 in 10 bins of W across the Delta resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near 1.232 GeV, but variations among models is large for response functions governed by imaginary parts and for both increases rapidly with W. We performed a nearly model-independent multipole analysis that adjusts complex multipoles with high partial waves constrained by baseline models. Parabolic fits to the W dependence of the multipole analysis around the Delta mass gives values for SMR = ( -6.61 +/- 0.18)% and EMR = ( -2.87 +/- 0.19)% that are distinctly larger than those from Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+) = (+7.1 +/- 0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe. Finally, using a unitary isobar model (UIM), we find that excitation of the Roper resonance is dominantly longitudinal with S1/2 = (0.05 +/- 0.01) GeV{sup ( -1/2)} at Q2=1. The ReS0+ and ReE0+ multipoles favor pseudovector coupling over pseudoscalar coupling or a recently proposed mixed-coupling scheme, but the UIM does not reproduce the imaginary parts of 0+ multipoles well.
Download or read book Neutral Pion Electroproduction in the Resonance Region written by and published by . This book was released on 2007 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: The electroproduction of baryon resonances at high Q2 is examined. Analysis focuses on the ?(1232) resonance via exclusive pseudoscalar meson production of ?0 particles. Differential cross sections are extracted for exclusive ?0 electroproduction. In the central invariant mass (W) region the cross sections are used to extract resonant multipole amplitudes. In particular, the ratio of the electric quadrupole to magnetic dipole amplitudes (E2/M1) will be discussed for the ?(1232) resonance. The transition to pQCD is discussed in terms of E2/M1 and other multipoles. The helicity amplitude A3/2 can be used as a baryon helicity conservation meter in this context and will be discussed. The fast shrinking of the resonant contribution in the ? region is observed at this high momentum transfer. Apart from the observables related to pQCD scaling, the transition form factor G$*\atop{M}$ is extracted along with the scalar to magnetic dipole ratio C2/M1.
Download or read book Measurement of Polarization Observables in the Electro Excitation of the Proton to Its First Excited State written by and published by . This book was released on 2003 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports results from the Thomas Jefferson National Accelerator Facility (Jefferson Lab) Hall A experiment E91-011, which measured double-polarization observables in the pion electroproduction reaction from the proton. Specifically, the experiment measured the recoil proton polarization, polarized response functions, and cross section for the p$\vec{e}$, e' $\vec{p}$ [pi]° reaction at a center-of-mass energy centered at W = 1232 MeV--the peak of the [Delta](1232) resonance--and at a four-momentum transfer squared of Q2 = 1.0 GeV2/c2. Both the recoil proton polarization and polarized response function results will be presented in this thesis.
Download or read book Neutral Pion Electroproduction in the Delta Resonance Region written by Anthony Nicholas Villano and published by ProQuest. This book was released on 2007 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probing Proton Structure Through Single Polarisation Observables of Compton Scattering and Pion Photoproduction Within the Delta 1232 Region written by Cristina Collicott 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 Low Momentum Transfer Measurements of Pion Electroproduction and Virtual Compton Scattering at the Delta Resonance written by and published by . This book was released on 2016 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-spherical components of the nucleon wave function are measured through p(e, e'p)[pi]0 experiment at the [Delta]+(1232) resonance for Q2 = 0.04, 0.09, and 0.13 (GeV=c)2 utilizing the Jefferson National Accelerator Facility (JLab) pulsed beam and Hall A spectrometers. The new data extend the measurements of the Coulomb quadrupole amplitude to the lowest momentum transfer ever reached. The results disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations that include pion cloud effects, chiral effective field theory and lattice calculations. The reported measurements indicate that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements. The Coulomb to magnetic multipole ratio (CMR) and generalized polarizability (GP) of the nucleon are also measured through virtual Compton scattering (VCS) for Q2 = 0.2(GeV=c)2 utilizing the Mainz Microtron (MAMI) continuous beam and A1 spectrometers. This data represents the first low Q2 GP measurement at the [Delta]+(1232) resonance. The GP measurement explores a region where previous data and theoretical calculations disagree. The CMR measurement will be the first VCS extraction to compare with world data generated through pion electroproduction. The Dispersion Relation (DR) model used for the VCS extraction provides a new theoretical framework for the data signal and backgrounds that is largely independent from the pion electroproduction models. The independence of the DR from the traditional models provides a strong crosscheck on the ability of the models to isolate the data signal.
Download or read book Recoil Polarization for Neutral Pion Electroproduction Near the Delta Resonance written by and published by . This book was released on 2003 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proton Induced Inclusive Pion Production from Light Nuclei in the Region of the delta 1 2 3 2 Resonance written by Garth Murray Huber and published by . This book was released on 1987 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Near threshold Proton induced Neutral Pion Production from Deuterium written by Mark Anthony Pickar and published by . This book was released on 1982 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Virtual Compton Scattering and Neutral Pion Electro production from the Proton in the Nucleon Resonance Region written by Luminita Todor and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The experiment (E93-050) at Jefferson Lab measured the ep {yields} ep{gamma} and ep {yields} ep{pi}{sup 0} cross sections in the nucleon resonance region, from the threshold to W = 1.9 GeV at Q{sup 2} = 1 GeV{sup 2} for backward emission of the {gamma} or {pi}{sup 0}.
Download or read book Regensen written by and published by . This book was released on 1908 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exclusive Single Pion Electroproduction Off the Proton in the High lying Resonances at Q2 5 GeV2 from CLAS written by and published by . This book was released on 2014 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The differential cross sections and structure functions for the exclusive electroproduction process ep --> e'n pi+ were measured in the range of the invariantmass for the np+ system 1.6 GeV lte W lte 2.0 GeV, and the photon virtuality 1.8 GeV2 lte Q2 lte 4.0 GeV2 using CLAS at Jefferson Lab. For the first time, these kinematics are probed in the exclusive p+ production from the protons with nearly full coverage in the azimuthal and polar angles of the np+ center-of-mass system. In this analysis, approximately 39,000 differential cross-section data points in terms of W, Q2, cosq theta* _ pi, and phi*_p-, were obtained. The preliminary differential cross section and structure function analyses are carried out, which allow us to extract the helicity amplitudes in high-lying resonances.
Download or read book Virtual Compton Scattering and Neutral Pion Electro production from the Proton in the Nucleon Resonance Region written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The experiment (E93-050) at Jefferson Lab measured the ep [yields] ep[gamma] and ep [yields] ep[pi][sup 0] cross sections in the nucleon resonance region, from the threshold to W = 1.9 GeV at Q[sup 2] = 1 GeV[sup 2] for backward emission of the [gamma] or [pi][sup 0].
Download or read book Recoil Polarization for Delta Excitation in Pion Electroproduction written by and published by . This book was released on 2005 with total page 102001 pages. Available in PDF, EPUB and Kindle. Book excerpt: We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W=1.23 GeV at Q2=1.0 (GeV/c)2, obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re(S1+/M1+)=-(6.84+/-0.15)% and Re(E1+/M1+)=-(2.91+/-0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and sp truncation.
