NEW RESULTS FROM THE BATES LARGE ACCEPTANCE SPECTROMETER TOROID (BLAST)

2009 ◽  
Vol 18 (02) ◽  
pp. 209-219
Author(s):  
◽  
HAIYAN GAO
Keyword(s):  
Form Factor ◽  
Form Factors ◽  
Magnetic Form Factor ◽  
The Novel ◽  
Hydrogen Deuterium ◽  
Nucleon Form Factors ◽  
Gas Targets ◽  
Large Acceptance ◽  
First Time ◽  
Deuterium Gas

An experiment using the novel technique of scattering a longitudinally polarized electron beam from polarized internal hydrogen/deuterium gas targets was carried out in the South Hall Ring at the MIT-Bates Accelerator Center. The scattered particles were detected by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The proton electric to magnetic form factor ratio, [Formula: see text] at Q 2 = 0.1 - 0.65 ( GeV/c )2 has been determined from the experiment by measuring the spin-dependent ep elastic scattering asymmetry in the two symmetric sectors of the BLAST simultaneously for the first time. The neutron electric form factor [Formula: see text] in the same Q2 range has been extracted by measuring the spin-dependent asymmetry from the [Formula: see text] process with a vector polarized deuterium target. These results on the nucleon form factors from the BLAST experiment are presented.

THE BLAST EXPERIMENT: POLARIZED ELECTRON SCATTERING FROM HYDROGEN AND DEUTERIUM

2009 ◽  
Vol 24 (11n13) ◽  
pp. 875-880
Author(s):  
◽  
R. ALARCON
Keyword(s):  
Form Factor ◽  
Electron Scattering ◽  
Form Factors ◽  
Proton Form Factor ◽  
Beam Source ◽  
Polarized Electrons ◽  
Deuterium Target ◽  
Factor Ratio ◽  
Nucleon Form Factors ◽  
Large Acceptance

At the MIT-Bates Linear Accelerator Center, the nucleon form factors have been measured by scattering polarized electrons from vector-polarized hydrogen and deuterium. The experiment used the longitudinally polarized electron beam stored in the MIT-Bates South Hall Ring along with an isotopically pure, highly vector-polarized internal atomic hydrogen and deuterium target provided by an atomic beam source. The measurements were carried out with the symmetric Bates Large Acceptance Spectrometer Toroid (BLAST). Results are presented for the proton form factor ratio, [Formula: see text], and for the charge form factor of the neutron, [Formula: see text]. Both results are more precise than previous data in the corresponding Q2 ranges.

A Study of Spin and Orbital Magnetic Form Factors of CeRh3B2 by X-Ray Magnetic Diffraction

2011 ◽  
Vol 497 ◽  
pp. 3-7 ◽  
Author(s):  
Masahisa Ito ◽  
Ryota Nagayasu ◽  
Tatsuki Tadenuma ◽  
Kosuke Suzuki ◽  
Ayako Sato ◽  
...  
Keyword(s):  
Form Factor ◽  
Form Factors ◽  
Real Space ◽  
Dipole Approximation ◽  
Magnetic Form Factor ◽  
Rare Earth Compound ◽  
X Ray ◽  
Curve Fitting Analysis ◽  
Magnetic Form Factors ◽  
First Time

An experimental method of X-ray magnetic diffraction was applied to the ferromagnetic rare-earth compound CeRh3B2, and its spin and orbital magnetic form factors were measured independently for the first time. Our curve-fitting analysis shows that the orbital magnetic form factor is reproduced by the calculated atomic-model form factor of Ce-4f electrons under the dipole approximation. The comparison of the sum of form factors and the total magnetic form factor measured by the polarized neutron diffraction reveals anisotropic distribution of the magnetic moment in real space.

Magnetic Scattering: General Properties

2020 ◽  
pp. 185-212
Author(s):  
Andrew T. Boothroyd
Keyword(s):  
Form Factor ◽  
Partial Response ◽  
Response Function ◽  
Absorptive Part ◽  
Form Factors ◽  
Dipole Approximation ◽  
Magnetic Form Factor ◽  
Magnetic Scattering ◽  
Response Functions ◽  
Fluctuation Dissipation

The basic theory of magnetic scattering is presented. A response function for magnetic scattering is defined, and expressed in terms partial response functions. The relation between the partial response functions and the correlation function for components of the magnetization is obtained, and the dynamical part of the partial reponse functions is linked via the fluctuation-dissipation theorem to the absorptive part of the generalized susceptibility. It is shown how the dipole approximation can be used to simply the magnetic scattering operator for localized electrons, and the magnetic form factor is introduced. Examples of the use of the dipole magnetic form factor, as well as more general anisotropic magnetic form factors, are given. A comparison with the X-ray atomic form factor is given. Various sum rules for the magnetic response function and generalized susceptibility are obtained.

scholarly journals Sensitivity of elastic electron scattering off the 3He to the nucleon form factors

2019 ◽  
Vol 204 ◽  
pp. 05009 ◽  
Author(s):  
Serge Bondarenko ◽  
Valery Burov ◽  
Sergey Yurev
Keyword(s):  
Experimental Data ◽  
Electron Scattering ◽  
Impulse Approximation ◽  
Form Factors ◽  
Magnetic Form Factor ◽  
Elastic Electron ◽  
Elastic Electron Scattering ◽  
Relativistic Generalization ◽  
Nucleon System ◽  
Nucleon Form Factors

Elastic electron-3He scattering is studied in the relativistic impulse approximation. The amplitudes for the three-nucleon system – 3He – are obtained by solving the relativistic generalization of the Faddeev equation. The charge and magnetic form factor are calculated and compared with the experimental data for the momentum transfer squared up to 100 fm-2. The influence of the various nucleon form factors is investigated.

scholarly journals Pauli Radius of the Proton

2021 ◽  
Vol 38 (12) ◽  
pp. 121401
Author(s):  
Zhu-Fang Cui ◽  
Daniele Binosi ◽  
Craig D. Roberts ◽  
Sebastian M. Schmidt
Keyword(s):  
Form Factor ◽  
Form Factors ◽  
Magnetic Form Factor ◽  
Proton Scattering ◽  
Statistical Sampling ◽  
Function Form ◽  
The Difference ◽  
Factor Data ◽  
Form Factor Data ◽  
Prime 2

Using a procedure based on interpolation via continued fractions supplemented by statistical sampling, we analyze proton magnetic form factor data obtained via electron+proton scattering on Q 2 ∈ [0.027, 0.55] GeV2 with the goal of determining the proton magnetic radius. The approach avoids assumptions about the function form used for data interpolation and ensuing extrapolation onto Q 2 ≃ 0 for extraction of the form factor slope. In this way, we find r M = 0.817(27) fm. Regarding the difference between proton electric and magnetic radii calculated in this way, extant data are seen to be compatible with the possibility that the slopes of the proton Dirac and Pauli form factors, F 1,2(Q 2), are not truly independent observables; to wit, the difference F ′ 1 ( 0 ) − F ′ 2 ( 0 ) / κ p = [ 1 + κ p ] / [ 4 m p 2 ] , viz., the proton Foldy term.

scholarly journals The electromagnetic form factors of Λ hyperon in e+e−→Λ̄Λ

2018 ◽  
Vol 33 (22) ◽  
pp. 1850133 ◽  
Author(s):  
Yongliang Yang ◽  
Zhun Lu
Keyword(s):  
Form Factor ◽  
Cross Sections ◽  
Form Factors ◽  
Magnetic Form Factor ◽  
Electromagnetic Form Factors ◽  
Threshold Region ◽  
Double Spin ◽  
Electron Positron Annihilation ◽  
Effective Form ◽  
Two Parameters

We study the electromagnetic form factors of [Formula: see text] hyperon in the time-like region using the experimental data in the exclusive production of [Formula: see text] pair in electron–positron annihilation. We present a pQCD inspired parametrization of [Formula: see text] and [Formula: see text] with only two parameters, and we consider a suppression mechanism of the electric form factor [Formula: see text] compared to the magnetic form factor [Formula: see text]. The parameters are determined through fitting our parametrization to the data of the effective form factor [Formula: see text] from the DM2, BaBar and BESIII Collaborations in the reaction [Formula: see text]. We use the parametrizations for [Formula: see text] and [Formula: see text] to calculate the Born cross-sections as well as the ratio [Formula: see text]. Except the threshold region, our parametrization can describe the known behavior of the existing data of effective form factor, Born cross-section and the ratio [Formula: see text] from the BaBar, DM2 and BESIII Collaborations. We also predict the double spin polarization observables [Formula: see text], [Formula: see text] and [Formula: see text] in [Formula: see text] which could provide more information on the size of the lambda EMFFs as well as their phase angles.

scholarly journals The $$ \overline{B} $$ → π form factors from QCD and their impact on |Vub|

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Domagoj Leljak ◽  
Blaženka Melić ◽  
Danny van Dyk
Keyword(s):  
Form Factor ◽  
Lattice Qcd ◽  
Sum Rules ◽  
Semileptonic Decay ◽  
Form Factors ◽  
Scalar Form Factor ◽  
Small Momentum Transfer ◽  
Scalar Form ◽  
Sum Rule ◽  
First Time

Abstract We revisit light-cone sum rules with pion distribution amplitudes to determine the full set of local $$ \overline{B} $$ B ¯ → π form factors. To this end, we determine all duality threshold parameters from a Bayesian fit for the first time. Our results, obtained at small momentum transfer q2, are extrapolated to large q2 where they agree with precise lattice QCD results. We find that a modification to the commonly used BCL parametrization is crucial to interpolate the scalar form factor between the two q2 regions. We provide numerical results for the form factor parameters — including their covariance — based on simultaneous fit of all three form factors to both the sum rule and lattice QCD results. Our predictions for the form factors agree well with measurements of the q2 spectrum of the semileptonic decay $$ {\overline{B}}^0\to {\pi}^{+}{\mathrm{\ell}}^{-}{\overline{\nu}}_{\mathrm{\ell}} $$ B ¯ 0 → π + ℓ − ν ¯ ℓ . From the world average of the latter we obtain |Vub| = (3.77 ± 0.15) · 10−3, which is in agreement with the most recent inclusive determination at the 1 σ level.

scholarly journals U(1) symmetry resolved entanglement in free 1+1 dimensional field theories via form factor bootstrap

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Dávid X. Horváth ◽  
Luca Capizzi ◽  
Pasquale Calabrese
Keyword(s):  
Form Factor ◽  
Branch Point ◽  
Complete Solution ◽  
Form Factors ◽  
Vacuum Expectation ◽  
Field Theories ◽  
The Novel ◽  
Bootstrap Approach ◽  
Twist Fields

Abstract We generalise the form factor bootstrap approach to integrable field theories with U(1) symmetry to derive matrix elements of composite branch-point twist fields associated with symmetry resolved entanglement entropies. The bootstrap equations are solved for the free massive Dirac and complex boson theories, which are the simplest theories with U(1) symmetry. We present the exact and complete solution for the bootstrap, including vacuum expectation values and form factors involving any type and arbitrarily number of particles. The non-trivial solutions are carefully cross-checked by performing various limits and by the application of the ∆-theorem. An alternative and compact determination of the novel form factors is also presented. Based on the form factors of the U(1) composite branch-point twist fields, we re-derive earlier results showing entanglement equipartition for an interval in the ground state of the two models.

scholarly journals Nucleon form factors in the nuclear medium

2018 ◽  
Vol 33 (02) ◽  
pp. 1850016
Author(s):  
Chanyong Park ◽  
Jung Hun Lee
Keyword(s):  
Form Factor ◽  
Free Parameter ◽  
Anomalous Dimension ◽  
Form Factors ◽  
Nucleon Form Factor ◽  
Nuclear Medium ◽  
Nucleon Form Factors ◽  
Ads Geometry

By using the AdS/CFT correspondence, we investigate various form factors between nucleons and mesons in a nuclear medium. In order to describe a nuclear medium holographically, we take into account the thermal charged AdS geometry with an appropriate IR cutoff. After introducing an anomalous dimension as a free parameter, we investigate how the nucleon’s mass is affected by the change of the anomalous dimension. Moreover, we study how the form factors of nucleons rely on the properties of the nuclear medium. We show that in a nuclear medium with different numbers of proton and neutron, the degenerated nucleon form factor in the vacuum is split into four different values depending on the isospin charges of nucleon and meson.

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