scholarly journals Valence quark spin distribution functions

1999 ◽  
Vol 59 (3) ◽  
Author(s):  
Nathan Isgur
Keyword(s):  
Valence Quark ◽  
Distribution Functions ◽  
Spin Distribution ◽  
Quark Spin

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 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.

scholarly journals Valence-quark distribution functions in the kaon and pion

2016 ◽  
Vol 93 (7) ◽  
Author(s):  
Chen Chen ◽  
Lei Chang ◽  
Craig D. Roberts ◽  
Shaolong Wan ◽  
Hong-Shi Zong
Keyword(s):  
Valence Quark ◽  
Quark Distribution ◽  
Distribution Functions

Quark spin distribution and quark-antiquark annihilation in single-spin hadron-hadron collisions

1993 ◽  
Vol 70 (12) ◽  
pp. 1751-1754 ◽  
Author(s):  
C. Boros ◽  
Liang Zuo-tang ◽  
Meng Ta-chung
Keyword(s):  
Spin Distribution ◽  
Single Spin ◽  
Quark Spin

scholarly journals Contact interaction analysis of pion GTMDs

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Jin-Li Zhang ◽  
Zhu-Fang Cui ◽  
Jia-Lun Ping ◽  
Craig D. Roberts
Keyword(s):  
Form Factor ◽  
Contact Interaction ◽  
Wigner Distribution ◽  
Interaction Analysis ◽  
Valence Quark ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Distribution Form ◽  
Negative Support

AbstractA contact interaction is used to calculate an array of pion twist-two, -three and -four generalised transverse light-front momentum dependent parton distribution functions (GTMDs). Despite the interaction’s simplicity, many of the results are physically relevant, amongst them a statement that GTMD size and shape are largely prescribed by the scale of emergent hadronic mass. Moreover, proceeding from GTMDs to generalised parton distributions, it is found that the pion’s mass distribution form factor is harder than its electromagnetic form factor, which is harder than the gravitational pressure distribution form factor; the pressure in the neighbourhood of the pion’s core is commensurate with that at the centre of a neutron star; the shear pressure is maximal when confinement forces become dominant within the pion; and the spatial distribution of transversely polarised quarks within the pion is asymmetric. Regarding transverse momentum dependent distribution functions, their magnitude and domain of material support decrease with increasing twist. The simplest Wigner distribution associated with the pion’s twist-two dressed-quark GTMD is sharply peaked on the kinematic domain associated with valence-quark dominance; has a domain of negative support; and broadens as the transverse position variable increases in magnitude.

scholarly journals An analysis of parton distribution functions of the pion and the kaon with the maximum entropy input

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Chengdong Han ◽  
Gang Xie ◽  
Rong Wang ◽  
Xurong Chen
Keyword(s):  
Parton Distribution ◽  
Valence Quark ◽  
Quark Distribution ◽  
Parton Model ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Theoretical Predictions ◽  
Gluon Distributions ◽  
Qcd Analysis ◽  
Mass Dependent

AbstractWe present pion and kaon parton distribution functions from a global QCD analysis of the experimental data within the framework of dynamical parton model. We use the DGLAP equations with parton–parton recombination corrections and the valence input of uniform distribution which maximizes the information entropy. At our input scale $$Q_0^2$$ Q 0 2 , there are no sea quark and gluon distributions. All the sea quarks and gluons of the pion and the kaon are completely generated from the parton splitting processes. The mass-dependent parton splitting kernel is applied for the strange quark distribution in the kaon. The obtained valence quark and sea quark distributions at high $$Q^{2}$$ Q 2 ($$Q^2>5$$ Q 2 > 5 GeV$$^2$$ 2 ) are compatible with the existed experimental measurements. Furthermore, the asymptotic behaviours of parton distribution functions at small and large x have been studied for both the pion and the kaon. Lastly, the first three moments of parton distributions at high $$Q^{2}$$ Q 2 scale are calculated, which are consistent with other theoretical predictions.

EXTRACTING GLUON FRAGMENTATION FUNCTIONS IN HADRON-HADRON COLLISIONS

1989 ◽  
Vol 04 (06) ◽  
pp. 1485-1491
Author(s):  
DONGSHENG DU ◽  
YUZHEN GE ◽  
MA LUO
Keyword(s):  
Valence Quark ◽  
Quark Distribution ◽  
Structure Functions ◽  
Distribution Functions ◽  
Pp Collisions ◽  
Fragmentation Functions ◽  
Gluon Fragmentation ◽  
Better Than

Two methods for extracting gluon fragmentation functions in π±p, [Formula: see text] and pp collisions are proposed. The only inputs are valence-quark distribution functions which we know much better than other structure functions and fragmentation functions. So better extraction of gluon fragmentation functions can be obtained.

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