THE ETA-MESON PHOTOPRODUCTION ON PROTON

2011 ◽  
Vol 26 (03n04) ◽  
pp. 645-646
Author(s):  
JAN DONOVAL ◽  
PETR BYDŽOVSKÝ
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Cross Sections ◽  
Form Factors ◽  
Coupling Constants ◽  
Tree Level ◽  
Recent Experimental Data ◽  
Model Coupling ◽  
Eta Meson ◽  
Meson Photoproduction

We have performed the tree-level calculations of the eta meson photoproduction on proton for photon laboratory energies between 714 and 1500 MeV. The resonances N (1535), N (1710), N (1650), N (1440) and N (1520) were assumed. The form factors were introduced in the hadron vertices to involve the structure of hadrons. The influence of various form factor recipes was investigated. In order to keep gauge invariance, the appropriate contact term was introduced. The parameters of our model (coupling constants, cutoffs) were fitted to recent experimental data of the cross sections and some polarization observables.

A combination of hadronic form factors for modeling the kaon photoproduction process γp → K+Λ

2015 ◽  
Vol 24 (02) ◽  
pp. 1550008 ◽  
Author(s):  
L. Syukurilla ◽  
T. Mart
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Differential Cross Section ◽  
Cross Section ◽  
Form Factors ◽  
Coupling Constants ◽  
Dipole Form Factor ◽  
Photoproduction Process ◽  
Different Types ◽  
Dipole Form

We have phenomenologically investigated the kaon photoproduction process γp → K+Λ by combining different types of hadronic form factors (HFFs) inside a covariant isobar model. We obtained the best model with the smallest χ2/N by using the dipole form factor in the Born terms and a combination of the dipole, Gaussian, as well as generalized dipole form factors in the hadronic vertices of the nucleon, kaon and hyperon resonances. By utilizing this model we found that the experimental data used in the analysis are internally consistent, whereas the behavior of differential cross-section at forward angles is not significantly affected by the variation of hadronic coupling constants (CCs) and form factor cutoffs in the model.

New analysis of the low-energy π±p differential cross-sections of the CHAOS Collaboration

2015 ◽  
Vol 24 (07) ◽  
pp. 1550050 ◽  
Author(s):  
E. Matsinos ◽  
G. Rasche
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Differential Cross ◽  
Form Factors ◽  
Partial Wave Analysis ◽  
Meson Mass ◽  
Data Sets ◽  
Differential Cross Sections ◽  
Pion Nucleon ◽  
Meson Factory

In a previous paper, we reported the results of a partial-wave analysis (PWA) of the pion–nucleon (πN) differential cross-sections (DCSs) of the CHAOS Collaboration and came to the conclusion that the angular distribution of their π+p data sets is incompatible with the rest of the modern (meson factory) database. The present work, re-addressing this issue, has been instigated by a number of recent improvements in our analysis, namely regarding the inclusion of the theoretical uncertainties when investigating the reproduction of experimental data sets on the basis of a given "theoretical" solution, modifications in the parametrization of the form factors of the proton and of the pion entering the electromagnetic part of the πN amplitude, and the inclusion of the effects of the variation of the σ-meson mass when fitting the ETH model of the πN interaction to the experimental data. The new analysis of the CHAOS DCSs confirms our earlier conclusions and casts doubt on the value for the πN Σ term, which Stahov, Clement and Wagner have extracted from these data.

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.

B − L extension of the Standard Model based on Σ(18) symmetry for fermion mass and mixing

2020 ◽  
Vol 35 (27) ◽  
pp. 2050223
Author(s):  
V. V. Vien
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Neutrino Mass ◽  
Tree Level ◽  
Fermion Mass ◽  
Recent Experimental Data ◽  
Type I ◽  
Quark Masses ◽  
The Standard Model ◽  
Experimental Values

In this work, we suggest a renormalizable [Formula: see text] extension of the Standard Model with [Formula: see text] symmetry in which the observed fermion mass and mixing pattern is consistent with the experimental values given in Ref. 1 at the tree-level. The neutrino mass ordering and the tiny neutrino masses are induced by the type-I seesaw mechanism. The effective neutrino mass parameters are predicted to be [Formula: see text], [Formula: see text] for NO and [Formula: see text], [Formula: see text] for IO which are well consistent with the recent experimental data. The quark masses are in good agreement while the quark mixing matrix has a little difference with the experimental data taken from Ref. 1 and the Cabibbo angle [Formula: see text] is related to the model parameter [Formula: see text] by the formula [Formula: see text].

Constraints on the ωπ form factor from analyticity and unitarity

2016 ◽  
Vol 31 (14n15) ◽  
pp. 1630020 ◽  
Author(s):  
B. Ananthanarayan ◽  
Irinel Caprini ◽  
Bastian Kubis
Keyword(s):  
Experimental Data ◽  
Form Factor ◽  
Information Needs ◽  
Theoretical Calculations ◽  
Form Factors ◽  
Experimental Information ◽  
Upper And Lower Bounds ◽  
Strong Interactions ◽  
Operator Product ◽  
Using Data

Form factors are important low-energy quantities and an accurate knowledge of these sheds light on the strong interactions. A variety of methods based on general principles have been developed to use information known in different energy regimes to constrain them in regions where experimental information needs to be tested precisely. Here we review our recent work on the electromagnetic [Formula: see text] form factor in a model-independent framework known as the method of unitarity bounds, partly motivated by the discrepancies noted recently between the theoretical calculations of the form factor based on dispersion relations and certain experimental data measured from the decay [Formula: see text]. We have applied a modified dispersive formalism, which uses as input the discontinuity of the [Formula: see text] form factor calculated by unitarity below the [Formula: see text] threshold and an integral constraint on the square of its modulus above this threshold. The latter constraint was obtained by exploiting unitarity and the positivity of the spectral function of a QCD correlator, computed on the spacelike axis by operator product expansion and perturbative QCD. An alternative constraint is obtained by using data available at higher energies for evaluating an integral of the modulus squared with a suitable weight function. From these conditions we derived upper and lower bounds on the modulus of the [Formula: see text] form factor in the region below the [Formula: see text] threshold. The results confirm the existence of a disagreement between dispersion theory and experimental data on the [Formula: see text] form factor around 0.6 GeV, including those from NA60 published in 2016.

scholarly journals PSI TO N NBAR m

2011 ◽  
Vol 02 ◽  
pp. 193-197 ◽  
Author(s):  
T. BARNES
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Experimental Measurement ◽  
Meson Exchange ◽  
Recent Experimental Data ◽  
Final States ◽  
Pole Model ◽  
Charmonium Production ◽  
Input Information ◽  
Production Processes

In this invited talk I discuss two recent applications of charmonium (Ψ) decays to [Formula: see text] final states, where N is a nucleon and m is a light meson. There are several motivations for studying these decays: 1) They are useful for the study of N* spectroscopy; 2) they can be used to estimate cross sections for the associated charmonium production processes [Formula: see text], which PANDA plans to exploit in searches for charmonium hybrid exotics; and 3) they may allow the direct experimental measurement of NNm (meson-nucleon) strong couplings, which provide crucial input information for meson exchange models of the NN force. The latter two topics are considered in this talk, which will also compare results from a simple hadron pole model of these decays to recent experimental data.

MATTER-DENSITY DISTRIBUTION IN DEUTERON AND DIFFRACTION DEUTERON-NUCLEUS INTERACTION

2005 ◽  
Vol 14 (07) ◽  
pp. 1073-1085 ◽  
Author(s):  
YU. A. BEREZHNOY ◽  
V. YU. KORDA ◽  
A. G. GAKH
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Asymptotic Behavior ◽  
Cross Section ◽  
Cross Sections ◽  
Deuteron Wave Function ◽  
Form Factors ◽  
Matter Density ◽  
Nucleus Interaction ◽  
Nucleus Scattering

We obtained a nonrelativistic deuteron wave function that accounts for the D-state and has correct asymptotic behavior. This was achieved on the basis of the experimentally measured charge and quadrupole deuteron form factors. The differential cross section of the elastic deuteron-nucleus scattering has been calculated by using this wave function. These predictions agree with the experimental data at the energy of 110 MeV. The integrated cross sections of the various processes involving the deuteron-nucleus interactions were also calculated.

scholarly journals Critical behavior of cross sections at LHC

2016 ◽  
Vol 31 (19) ◽  
pp. 1650107 ◽  
Author(s):  
I. M. Dremin
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Critical Behavior ◽  
High Energy ◽  
New Physics ◽  
Recent Experimental Data ◽  
Unitarity Condition ◽  
Total Cross Sections ◽  
Principal Change

Recent experimental data on elastic scattering of high energy protons show that the critical regime has been reached at LHC energies. The approach to criticality is demonstrated by increase of the ratio of elastic to total cross sections from ISR to LHC energies. At LHC it reaches the value which can result in principal change of the character of proton interactions. The treatment of new physics of hollowed toroid-like hadrons requires usage of another branch of the unitarity condition. Its further fate is speculated and interpreted with the help of the unitarity condition in combination with present experimental data. The gedanken experiments to distinguish between different possibilities are proposed.

Form Factor Perturbation Theory

2020 ◽  
pp. 863-881
Author(s):  
Giuseppe Mussardo
Keyword(s):  
Perturbation Theory ◽  
Form Factor ◽  
Mass Spectrum ◽  
Cross Sections ◽  
Form Factors ◽  
Field Theories ◽  
Conformal Field Theories ◽  
Conformal Field ◽  
Sine Gordon Model ◽  
First Order Perturbation

Chapter 22 introduces a perturbative technique based on the form factors to study non-integrable models. These models often include stumbling blocks like decays and production scattering processes, confinement phenomena and nucleation of false vacua, resonance peaks in the cross sections, etc. All these physical aspects are usually accompanied by a great mathematical complexity. However, the perturbative technique permits the computation of the corrections to the mass spectrum, the vacuum energy, the scattering amplitudes and so on. This chapter discusses in depth multiple deformations of the conformal field theories, form factor perturbation theory, first-order perturbation theory, non-locality and confinement of the excitations and the multi-frequency Sine–Gordon model.

scholarly journals Developing local volume tables for three important tree species in Nawalparasi and Kapilvastu districts

2018 ◽  
pp. 84-91 ◽  
Author(s):  
H. L. Shrestha ◽  
M. R. Kafle ◽  
K. Khanal ◽  
R. A. Mandal ◽  
K. Khanal
Keyword(s):  
Form Factor ◽  
Cross Sections ◽  
Tree Species ◽  
Form Factors ◽  
Smooth Curve ◽  
Stem Volume ◽  
Destructive Sampling ◽  
Timber Volume ◽  
Local Volume ◽  
Standing Trees

The local volume tables of specific species are very important to estimate the timber volume of standing trees but precise site-specific volume tables are lacking for three important tree species, namely Dalbergia sissoo, Shorea robusta and Terminalia alata. Therefore, this study was carried out to develop local volume tables and determine the form factors of these species using destructive and non-destructive methods. Kapilvastu and Nawalparasi districts were selected for this study. Altogether, 188 vigorous trees were selected for measurement, out of which 156 (52 trees for each species) were from destructive sampling and 32 were standing trees. The data of destructive sampling trees of three species were used in developing the models for under bark timber volume up to 10 and 20 cm top diameters. Thirty two data (12 for S. robusta, 10 for T. alata and for D. sissoo each) of standing trees were used to validate the models of three species. A number of cross sections were made and actual volumes of stem, butt log, other sections and top portion were calculated using cylindrical, Newton’s, Smalian’s and cone formulae, respectively. The cylindrical volume was estimated based on diameter at breast height. The form factor was determined from the ratio of actual and cylindrical volumes. The diameter and height relationship was made and, based on this; the smooth curve was drawn to develop the local volume tables. The results showed that estimated form factor of 10 cm and 20 cm top diameter of selected species varied from 0.50 to 0.69. In addition, local volume tables are developed for stem volume based on diameter under bark. Banko JanakariA Journal of Forestry Information for Nepal Special Issue No. 4, 2018, Page: 84-91 

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