scholarly journals ANNIHILATION POLES FOR FORM FACTORS IN THE XXZ MODEL

1994 ◽  
Vol 09 (12) ◽  
pp. 2087-2102 ◽  
Author(s):  
S. PAKULIAK
Keyword(s):  
Form Factor ◽  
Linear Combination ◽  
Form Factors ◽  
Vertex Operators ◽  
Xxz Model ◽  
Particle Form

The annihilation poles for the form factors in the XXZ model are studied using vertex operators introduced in Ref. 1. An annihilation pole is the property of form factors according to which the residue of the 2n-particle form factor in such a pole can be expressed through linear combination of the (2n−2)-particle form factors. To prove this property we use the bosonization of the vertex operators in the XXZ model which was invented in Ref. 2.

scholarly journals An Operator Product Expansion for Form Factors II. Born level

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Amit Sever ◽  
Alexander G. Tumanov ◽  
Matthias Wilhelm
Keyword(s):  
Form Factor ◽  
Operator Product Expansion ◽  
Wilson Loop ◽  
Form Factors ◽  
Building Blocks ◽  
Operator Product ◽  
Yang Mills ◽  
Singlet States ◽  
Particle Form ◽  
Elementary Building

Abstract Form factors in planar $$ \mathcal{N} $$ N = 4 Super-Yang-Mills theory admit a type of non-perturbative operator product expansion (OPE), as we have recently shown in [1]. This expansion is based on a decomposition of the dual periodic Wilson loop into elementary building blocks: the known pentagon transitions and a new object that we call form factor transition, which encodes the information about the local operator. In this paper, we compute the two-particle form factor transitions for the chiral part of the stress-tensor supermultiplet at Born level; they yield the leading contribution to the OPE. To achieve this, we explicitly construct the Gubser-Klebanov-Polyakov two-particle singlet states. The resulting transitions are then used to test the OPE against known perturbative data and to make higher-loop predictions.

The influence of the nuclear and atomic form factors on the muon bremsstrahlung cross section

1968 ◽  
Vol 46 (10) ◽  
pp. S377-S380 ◽  
Author(s):  
A. A. Petrukhin ◽  
V. V. Shestakov
Keyword(s):  
Form Factor ◽  
Cross Section ◽  
Born Approximation ◽  
Form Factors ◽  
Experimental Results ◽  
Simple Analytical Expression ◽  
Nuclear Form Factor ◽  
The Cross ◽  
Atomic Electrons ◽  
Bremsstrahlung Process

The cross section for the muon bremsstrahlung process is calculated as a function of the nuclear form factor in the Born approximation following the Bethe and Heitler theory. The influence of the nuclear form factor is greater than that taken by Christy and Kusaka. The simple analytical expression for the effect of the screening of the atomic electrons is found. The influence of a decrease in the cross section upon the interpretation of some experimental results is estimated.

Helm model interpretation of 16O form factors: application to pion photoproduction and muon capture

1980 ◽  
Vol 58 (1) ◽  
pp. 48-62 ◽  
Author(s):  
R. D. Graves ◽  
B. A. Lamers ◽  
Anton Nagl ◽  
H. Überall ◽  
V. Devanathan ◽  
...  
Keyword(s):  
Form Factor ◽  
Electron Scattering ◽  
Form Factors ◽  
Muon Capture ◽  
Physical Parameters ◽  
Medium Energy ◽  
Model Interpretation ◽  
Charged Pions ◽  
Transition Densities ◽  
Energy Processes

The available experimental data for the form factors of the T = 1 levels in 16O, obtained from electron scattering at low (Darmstadt), medium (Tohoku), and high momentum transfer (Stanford), are interpreted by the generalized Helm model. This phenomenological model reduces the form factor description of each level to the listing of a few physical parameters, i.e., the radius and smearing width of the transition densities of charge (current) and magnetization, and their corresponding strength constants. Its parameters having been determined by the form factor fits, the model may then be used to predict the results of other medium energy processes; this is done here for the photoproduction of charged pions and for muon capture in16O.

scholarly journals Form Factor of Eucalyptus Saligna Species in a Commercial Forest Plantation

2021 ◽  
Author(s):  
N. Lara ◽  
M. Guallpa ◽  
F. Acosta ◽  
Á. Barahona
Keyword(s):  
Form Factor ◽  
Graphical Method ◽  
Form Factors ◽  
Coefficient Of Determination ◽  
Forest Plantation ◽  
Eucalyptus Saligna ◽  
Palabras Clave ◽  
Para Determinar ◽  
Commercial Forest ◽  
Volume Equations

The present investigation proposes to determine the form factor of the species Eucalyptus saligna in a commercial forest plantation of the Tambillo bajo sector, of the Colta canton, Chimborazo province. For this purpose, 100 individual specimens with straight shafts and without bifurcations were taken as a sample, and each individual’s commercial and total height, diameter at breast height, and diameters along the stem were measured, to determine the real volume of the wood using the Smalian and Newton formulas, the graphical method, and with a form factor of 0.70. Based on the measured data, a comparative analysis of the calculation of real volume by the method used was performed; the results obtained showed significant differences between calculation methods. In addition, five potential volume equations that presented the highest adjusted coefficient of determination and the lowest mean square error were selected. To verify the commercial volume calculated with the estimated form factors against the volume equations, the commercial volume was recalculated based on the form factors and equations found. The calculation of the commercial volume by the Smalian formula is taken as the exact value, and the other methods are taken as approximated values. Keywords: dasometry, form factor, forest plantation, volumen equations, commercial volume. Resumen La presente investigación propone: determinar el factor de forma de la especie Eucalyptus saligna en una plantación forestal comercial; para lo cual se toma como muestra 100 individuos con fustes rectos y sin bifurcaciones, a cada individuo se midió la altura comercial y total, diámetro a la altura del pecho y diámetros a lo largo del fuste, para determinar el volumen real de madera utilizando la fórmula de Smalian, Newton, método gráfico y con un factor de forma de 0,70. En base a los datos medidos, se realiza un análisis comparativo del cálculo de volumen real por método empleado, los resultados obtenidos mostraron diferencias significativas entre métodos de cálculo empleados. Además, se seleccionó 5 ecuaciones de volumen potenciales los cuales presentaron mayor coeficiente de determinación ajustado y menor error cuadrático medio. Para la verificación del volumen comercial calculado con los factores de forma estimados frente a las ecuaciones de volumen se vuelve a calcular el volumen comercial a partir de los factores de forma y ecuaciones encontrados, se toma como valor exacto el cálculo de volumen comercial por la fórmula de Smalian y como valor de aproximación los demás métodos. Palabras clave: dasometría, ecuaciones de volumen, factor de forma, plantación forestal, volumen comercial.

scholarly journals Numerically stable form factor of any polygon and polyhedron

2021 ◽  
Vol 54 (2) ◽  
pp. 580-587
Author(s):  
Joachim Wuttke
Keyword(s):  
Form Factor ◽  
Small Angle ◽  
Form Factors ◽  
Small Angle Scattering ◽  
Important Application ◽  
Divergence Theorem ◽  
Series Expansions ◽  
Stable Form ◽  
Application Domain ◽  
Angle Scattering

Coordinate-free expressions for the form factors of arbitrary polygons and polyhedra are derived using the divergence theorem and Stokes's theorem. Apparent singularities, all removable, are discussed in detail. Cancellation near the singularities causes a loss of precision that can be avoided by using series expansions. An important application domain is small-angle scattering by nanocrystals.

The contribution of valence quarks in the nucleon GE and GM

2019 ◽  
Vol 34 (27) ◽  
pp. 1950148
Author(s):  
Negin Sattary Nikkhoo ◽  
Mohammad Reza Shojaei
Keyword(s):  
Experimental Data ◽  
Angular Momentum ◽  
Form Factor ◽  
Total Angular Momentum ◽  
Form Factors ◽  
Distribution Functions ◽  
The Other ◽  
Parton Distribution Functions ◽  
Nucleon Electromagnetic Form Factor ◽  
Elastic Form

The goal of this paper is to extract the flavor decomposition of nucleon electromagnetic form factor using the modified Gaussian and extended Regge ansatzes in the GPDs. We consider the CJ15 and JR09 parton distribution functions for both of these ansatzes in calculating the nucleon elastic form factors. Our results are compared with experimental data in the range [Formula: see text] 4-momentum transfers. Also, we calculate the total angular momentum carried by quarks, the gravitational form factors, and the transverse gravitational density for quarks of the nucleon. In the end, our results are compared with the other studies.

Heterogeneous sensing in a multifunctional soft sensor for human-robot interfaces

2020 ◽  
Vol 5 (49) ◽  
pp. eabc6878 ◽  
Author(s):  
Taekyoung Kim ◽  
Sudong Lee ◽  
Taehwa Hong ◽  
Gyowook Shin ◽  
Taehwan Kim ◽  
...  
Keyword(s):  
Form Factor ◽  
Form Factors ◽  
Soft Sensor ◽  
Compact Form ◽  
Original Form ◽  
Entire Body ◽  
Soft Sensors ◽  
Input Stimulus ◽  
Human Robot Interfaces ◽  
Deformation Modes

Soft sensors have been playing a crucial role in detecting different types of physical stimuli to part or the entire body of a robot, analogous to mechanoreceptors or proprioceptors in biology. Most of the currently available soft sensors with compact form factors can detect only a single deformation mode at a time due to the limitation in combining multiple sensing mechanisms in a limited space. However, realizing multiple modalities in a soft sensor without increasing its original form factor is beneficial, because even a single input stimulus to a robot may induce a combination of multiple modes of deformation. Here, we report a multifunctional soft sensor capable of decoupling combined deformation modes of stretching, bending, and compression, as well as detecting individual deformation modes, in a compact form factor. The key enabling design feature of the proposed sensor is a combination of heterogeneous sensing mechanisms: optical, microfluidic, and piezoresistive sensing. We characterize the performance on both detection and decoupling of deformation modes, by implementing both a simple algorithm of threshold evaluation and a machine learning technique based on an artificial neural network. The proposed soft sensor is able to estimate eight different deformation modes with accuracies higher than 95%. We lastly demonstrate the potential of the proposed sensor as a method of human-robot interfaces with several application examples highlighting its multifunctionality.

scholarly journals Measurement of hadronic form factors at BESIII

2018 ◽  
Vol 172 ◽  
pp. 03002
Author(s):  
Haiming HU
Keyword(s):  
Form Factor ◽  
Cross Section ◽  
Center Of Mass ◽  
Polar Angle ◽  
Form Factors ◽  
Pion Form Factor ◽  
Angle Distribution ◽  
Data Set ◽  
Center Of Mass Energy ◽  
The Cross

The measurements of hadronic form factors of three modes using the data samples collected with the BESIII detector at BEPCII collider are presented. The cross section of e+e- → p p̅ at 12 energies from 2232.4 to 3671.0 MeV are measured, the electromagnetic form factor is deduced, and the ratio |GE/GM| is extracted by fitting the polar angle distribution. The preliminary results about the form factors of e+e- → ∧c+ ⊼c- will also be described. The cross section of e+e- → π+ π-between effective center-of-mass energy 600 and 900 MeV is measured by the ISR return method using the data set with the integrated luminosity of 2.93 fb-1 taken at ψ(3773) peak, the pion form factor is extracted.

scholarly journals Pseudoscalar pole contribution to the hadronic light-by-light piece of aμ

2018 ◽  
Vol 192 ◽  
pp. 00027
Author(s):  
Adolfo Guevara ◽  
Pablo Roig ◽  
Juan José Sanz Cillero
Keyword(s):  
Form Factor ◽  
Chiral Symmetry ◽  
Chiral Symmetry Breaking ◽  
Form Factors ◽  
Effective Field ◽  
Pole Contribution ◽  
Symmetry Relations ◽  
The Impact ◽  
Best Fit ◽  
Momentum Region

We have studied the P → γ⋆ γ⋆ form factor in Resonance Chiral Theory, with P = π0; η, η', to compute the contribution of the pseudoscalar pole to the hadronic light-by-light piece of the anomalous magnetic moment of the muon. In this work we allow the leading U(3) chiral symmetry breaking terms, obtaining the most general expression for the form factor of order O(m2P). The parameters of the Effective Field Theory are obtained by means of short distance constraints on the form factor and matching with the expected behavior from QCD. Those parameters that cannot be fixed in this way are fitted to experimental determinations of the form factor within the spacelike momentum region of the virtual photon. Chiral symmetry relations among the transition form factors for π0, η and η' allow for a simultaneous fit to experimental data for the three mesons. This shows an inconsistency between the BaBar π0 data and the rest of the experimental inputs. Thus, we find a total pseudoscalar pole contribution of aP,HLbLη = (8:47 ± 0:16) · 10-10 for our best fit (neglecting the BaBar π0 data). Also, a preliminary rough estimate of the impact of NLO in 1=NC corrections and higher vector multiplets (asym) enlarges the uncertainty up to aP,HLbLη = (8:47 ± 0:16stat ± 0:09NC +0:5 -0:0asym).

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