Related papers: Quark Orbital Motion in the Nucleon
The conversion of nuclear matter to quark matter in the core of a rotating neutron star alters its moment of inertia. Hence the epoch over which conversion takes place will be signaled in the spin-down "signal_prl.tex" 581 lines, 22203…
The leading chiral contributions to the quark and gluon components of the proton spin are calculated using heavy-baryon chiral perturbation theory. Similar calculations are done for the moments of the generalized parton distributions…
Determination of the orbital angular momentum of the proton is a difficult but important part of understanding fundamental structure. Insight can be gained from suitable models of the gluon asymmetry applied to the Jz = 1/2 sum rule. We…
The implications of Chiral Quark Model with SU(3) and axial U(1) symmetry breakings as well as configuration mixing generated by one gluon exchange forces ($\chi$QM$_{gcm}$) are discussed in context of proton flavor and spin structure as…
The fundamental program in high energy spin physics focuses on the spin structure of the nucleon. The gluon and orbital angular momentum components of the nucleon spin are virtually unknown. The J_z=1/2 sum rule involves the integrated…
We study the covariant version of the quark-parton model, in which the general rules of the angular momentum composition are accurately taken into account. We demonstrate how these rules affect the relativistic interplay between the quark…
Proton spin is investigated in chiral effective field theory through an examination of the singlet axial charge, $a_0$, and the two non-singlet axial charges, $a_3$ and $a_8$. Finite-range regularization is considered as it provides an…
Definitions of orbital angular momentum based on Wigner distributions are used as a framework to discuss the connection between the Ji definition of the quark orbital angular momentum and that of Jaffe and Manohar. We find that the…
We analyse the baryon magnetic moments in a model that relates them to the parton spins $\Delta u$, $\Delta d$, $\Delta s$, and includes a contribution from orbital angular momentum. The specific assumption is the existence of a 3-quark…
We estimate in the QCD sum rule approach the amount of the nucleon spin carried by the gluon angular momentum: the sum of the gluon spin and orbital angular momenta. The result indicates that gluons contribute at least one half of the…
The quark model description of the hyperon nucleon forces, especially the antisymmetric spin-orbit forces, is studied from the spin-flavor SU(6) and the flavor SU(3) symmetry point of view. It is pointed out that the quark exchange…
Light-baryon resonances (with u,d, and s quarks in the SU(3) classification) fall on Regge trajectories. When their squared masses are plotted against the intrinsic orbital angular momenta {\rm L}, $\Delta^*$'s with even and odd parity can…
It is argued that the constituent quarks are expected to show a non-- trivial spin and flavor structure, due to the anomalous breaking of the chiral symmetry in the U(1) sector. CERN--TH.7079/93\\
We present results on the spin and quark content of the nucleon using $N_f=2$ twisted mass clover-improved fermion simulations with a pion mass close to its physical value. We use recently developed methods to obtain accurate results for…
Quark rotation asymmetry is proposed in calculating baryon magnetic moments. After taking into account interactions enforced on constituent quarks, assumed to be linear and Coulomb potentials, respectively, and the quark rotation asymmetry,…
We treat the baryon as a composite system made out of a \lq\lq core" of three quarks (as in the standard quark model) surrounded by a \lq\lq sea" (of gluons and $q\bar{q}$-pairs) which is specified by its total quantum numbers like flavor,…
The lowest two Mellin moments of hadronic Generalized Parton Distributions are explored within a model that allows investigation of the inter-related quark and gluon contributions. For light quarks their dynamical connection is strong due…
Based on a sumrule for the nucleon spin we expand quark and gluon orbital angular momentum operators and derive an evolution matrix for higher moments of the corresponding distributions. In combination with the spin-dependent DGLAP-matrix…
We derive the consequences of the Myhrer-Thomas explanation of the proton spin problem for the distribution of orbital angular momentum on the valence and sea quarks. After QCD evolution these results are found to be in very good agreement…
An alternate method is described to extract the quark contribution to the spin of the nucleon directly from the first moment of the deuteron structure function, $g^d_1$. It is obtained without recourse to the use of input on the nucleon…