scholarly journals CHIRAL QUARK MODEL (χQM) AND THE NUCLEON SPIN

2004 ◽  
Vol 19 (29) ◽  
pp. 5027-5041 ◽  
Author(s):  
HARLEEN DAHIYA ◽  
MANMOHAN GUPTA
Keyword(s):  
Angular Momentum ◽  
Magnetic Moments ◽  
Distribution Functions ◽  
Gluon Polarization ◽  
Spin Distribution ◽  
Polarization Functions ◽  
Singlet Component ◽  
Configuration Mixing ◽  
The Right ◽  
E866 Data

Using χ QM with configuration mixing, the contribution of the gluon polarization to the flavor singlet component of the total spin has been calculated phenomenologically through the relation [Formula: see text] as defined in the Adler–Bardeen scheme, where ΔΣ on the right-hand side is Q2 independent. For evaluation the contribution of gluon polarization [Formula: see text], ΔΣ is found in the χ QM by fixing the latest E866 data pertaining to [Formula: see text] asymmetry and the spin polarization functions whereas ΔΣ(Q2) is taken to be 0.30±0.06 and αs=0.287±0.020, both at Q2=5 GeV 2. The contribution of gluon polarization Δg' comes out to be 0.33 which leads to an almost perfect fit for spin distribution functions in the χ QM . When its implications for magnetic moments are investigated, we find perfect fit for many of the magnetic moments. If an attempt is made to explain the angular momentum sum rule for proton by using the above value of Δg', one finds the contribution of gluon angular momentum to be as important as that of the [Formula: see text] pairs.

scholarly journals CHIRAL CONSTITUENT QUARK MODEL AND THE COUPLING STRENGTH OF η′

2006 ◽  
Vol 21 (21) ◽  
pp. 4255-4267 ◽  
Author(s):  
HARLEEN DAHIYA ◽  
MANMOHAN GUPTA ◽  
J. M. S. RANA
Keyword(s):  
Spin Polarization ◽  
Coupling Strength ◽  
Magnetic Moments ◽  
Goldstone Boson ◽  
Quark Distribution ◽  
Constituent Quark Model ◽  
Distribution Functions ◽  
Difficult Case ◽  
Polarization Functions ◽  
Best Fit

Using the latest data pertaining to [Formula: see text] asymmetry and the spin polarization functions, detailed implications of the possible values of the coupling strength of the singlet Goldstone boson η′ have been investigated in the χCQM with configuration mixing. Using Δu, Δ3, [Formula: see text] and [Formula: see text], the possible ranges of the coupling parameters a, α2a, β2a and ζ2a, representing respectively the probabilities of fluctuations to pions, K, η and η′, are shown to be 0.10 ≲ a ≲ 0.14, 0.2 ≲ α ≲ 0.5, 0.2 ≲ β ≲ 0.7 and 0.10 ≲|ζ|≲ 0.70. To further constrain the coupling strength of η′, detailed fits have been obtained for spin polarization functions, quark distribution functions and baryon octet magnetic moments corresponding to the following sets of parameters: a = 0.1, α = 0.4, β = 0.7, |ζ| = 0.65 (Case I); a = 0.1, α = 0.4, β = 0.6, |ζ| = 0.70 (Case II); a = 0.14, α = 0.4, β = 0.2, ζ = 0 (Case III) and a = 0.13, α = β = 0.45, |ζ| = 0.10 (Case IV). Case I represents the calculations where a is fixed to be 0.1, in accordance with earlier calculations, whereas other parameters are treated free and the Case IV represents our best fit. The fits clearly establish that a small nonzero value of the coupling of η′ is preferred over the higher values of η′ as well as when ζ = 0, the latter implying the absence of η′ from the dynamics of χCQM. Our best fit achieves an overall excellent fit to the data, in particular the fit for Δu, Δd, Δ8 as well as the magnetic moments μn, μΣ-, μΣ+ and μΞ- is almost perfect, the μΞ- being a difficult case for most of the similar calculations.

scholarly journals QUARK ORBITAL ANGULAR MOMENTUM IN THE BARYON

2001 ◽  
Vol 16 (22) ◽  
pp. 3673-3697 ◽  
Author(s):  
XIAOTONG SONG
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Orbital Motion ◽  
Magnetic Moments ◽  
Sum Rule ◽  
Quark Spin ◽  
Quark Flavor ◽  
Quark Orbital Angular Momentum ◽  
Quark Flavors ◽  
Partition Factor

Analytical and numerical results, for the orbital and spin content carried by different quark flavors in the baryons, are given in the chiral quark model with symmetry breaking. The reduction of the quark spin, due to the spin dilution in the chiral splitting processes, is transferred into the orbital motion of quarks and antiquarks. The orbital angular momentum for each quark flavor in the proton as a function of the partition factor κ and the chiral splitting probability a is shown. The cancellation between the spin and orbital contributions in the spin sum rule and in the baryon magnetic moments is discussed.

Orbital angular momentum-driven anomalous Hall effect

2021 ◽  
Author(s):  
Oliver Dowinton ◽  
Mohammad Bahramy
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Transition Metal Oxides ◽  
Magnetic State ◽  
Magnetic Moments ◽  
Anomalous Hall Effect ◽  
Ferromagnetic State ◽  
Periodic Systems ◽  
Spin States ◽  
Berry Curvature

Abstract Orbital angular momentum (OAM) plays a central role in regulating the magnetic state of electrons in non-periodic systems such as atoms and molecules. In solids, on the other hand, OAM is usually quenched by the crystal field, and thus, has a negligible effect on magnetisation. Accordingly, it is generally neglected in discussions around band topology such as Berry curvature (BC) and intrinsic anomalous Hall conductivity (AHC). Here, we present a theoretical framework demonstrating that crystalline OAM can be directionally unquenched in transition metal oxides via energetic proximity of the conducting d electrons to the local magnetic moments. We show that this leads to `composite' Fermi-pockets with topologically non-trivial OAM textures. This enables a giant Berry curvature with an intrinsic non-monotonic AHC, even in collinearly-ordered spin states. We use this model to explain the origin of the giant AHC observed in the forced-ferromagnetic state of EuTiO3 and propose it as a prototype for OAM driven AHC.

scholarly journals Equilibrium Spin Distribution From Detailed Balance

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Ziyue Wang ◽  
Xingyu Guo ◽  
Pengfei Zhuang
Keyword(s):  
Spin Polarization ◽  
Transport Theory ◽  
Axial Vector ◽  
Detailed Balance ◽  
Kinetic Equations ◽  
Distribution Functions ◽  
Spin Distribution ◽  
Balance Principle ◽  
Quark Level ◽  
Vector Distribution

AbstractAs the core ingredient for spin polarization, the equilibrium spin distribution function that eliminates the collision terms is derived from the detailed balance principle. The kinetic theory for interacting fermionic systems is applied to the Nambu–Jona-Lasinio model at quark level. Under the semi-classical expansion with respect to $$\hbar $$ ħ , the kinetic equations for the vector and axial-vector distribution functions are obtained with collision terms. For an initially unpolarized system, spin polarization can be generated at the first order of $$\hbar $$ ħ from the coupling between the vector and axial-vector charges. Different from the classical transport theory, the collision terms in a quantum theory vanish only in global equilibrium with Killing condition.

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.

scholarly journals The Quaternionic Commutator Bracket and Its Implications

Symmetry ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 513 ◽  
Author(s):  
Arbab Arbab ◽  
Mudhahir Al Ajmi
Keyword(s):  
Wave Function ◽  
Electromagnetic Field ◽  
Angular Momentum ◽  
Charged Particle ◽  
Magnetic Fields ◽  
Interaction Energy ◽  
Internal Structure ◽  
Magnetic Moments ◽  
Electric And Magnetic Fields ◽  
Aharonov Bohm

A quaternionic commutator bracket for position and momentum shows that the quaternionic wave function, viz. ψ ˜ = ( i c ψ 0 , ψ → ) , represents a state of a particle with orbital angular momentum, L = 3 ℏ , resulting from the internal structure of the particle. This angular momentum can be attributed to spin of the particle. The vector ψ → , points in an opposite direction of L → . When a charged particle is placed in an electromagnetic field, the interaction energy reveals that the magnetic moments interact with the electric and magnetic fields giving rise to terms similar to Aharonov–Bohm and Aharonov–Casher effects.

Relativistic dynamics of a spinning magnetic particle

1942 ◽  
Vol 38 (1) ◽  
pp. 40-60 ◽  
Author(s):  
Myron Mathisson
Keyword(s):  
Angular Momentum ◽  
Magnetic Particle ◽  
Magnetic Moments ◽  
Equations Of Motion ◽  
Energy Tensor ◽  
Centre Of Mass ◽  
Electric Moment ◽  
Electric And Magnetic Moments ◽  
Second Moments ◽  
External Forces

The author's general variational method is applied to the case of a particle for which second moments are important but third and higher moments are negligible. Equations of motion are obtained for the angular momentum and for the centre of mass, equations (12·35) and (12·41), with arbitrary external forces X.The angular forces are then calculated for a charged particle with electric and magnetic moments moving in a general electromagnetic field, on the assumption that the effect of a certain part of the energy tensor, Tiii of (15·17), is negligible. This leads to the equations of angular motion, (17·13), from which it is inferred that, in order that the magnitude of the angular momentum may be integrable, the angular momentum, electric and magnetic moments must all be parallel in a frame of reference in which the particle is instantaneously at rest.The linear forces are then calculated for the case of no electric moment, leading to the equations for linear motion (18·10). From these it is inferred that, in order that the mass may be integrable, the ratio of the magnetic moment to the angular momentum must be constant.

Sign in / Sign up

Export Citation Format

Share Document