Related papers: Proton spin content from skyrmions
Earlier work reported on the existence of a term within a generalized skyrmion approach that yields appreciable spin content for the proton. Unfortunately there is no accessible experiment that can fix the coefficient of this term directly;…
The fraction of the nucleon spin that is carried by the quarks, $\Delta \Sigma$, is computed in lattice QCD with dynamical staggered fermions. We obtain the value $\Delta \Sigma = 0.18 \pm 0.02$.
We apply a model for SU(3) breaking to the analysis of the spin contents of the nucleon from the the latest data on first moments of the spin dependent structure functions and include higher order QCD corrections. The results show that the…
The part of the proton spin $\Sigma$ carried by $u, d, s$ quarks is calculated in the framework of the QCD sum rules in the external fields. The operators up to dimension 9 are accounted. An important contribution comes from the operator of…
The part of the proton spin $\Sigma$ carried by $u, d, s$ quarks is calculated in the framework of the QCD sum rules in the external fields. The operators up to dimension 9 are accounted. An important contribution comes from the operator of…
In this letter, we have taken a particular Lagrangian, which was introduced to resolve U(1) problem, as an effective QCD Lagrangian, and have derived a formula of the quark content of the nucleon spin. The difference between quark content…
We investigate the hyperon semileptonic decays and the quark spin content of the proton $\Delta \Sigma$ taking into account flavor SU(3) symmetry breaking. Symmetry breaking is implemented with the help of the chiral quark-soliton model in…
Proton spin problem is given a new perspective with the proposition that spin is a topological invariant represented by a de Rham 3-period. The idea is developed generalizing Finkelstein-Rubinstein theory for Skyrmions/kinks to topological…
Within the skyrmion approach for the nucleon-nucleon force, difficulties have been experienced in obtaining an isoscalar attractive spin-orbit potential, in parallel to the problems of finding attraction in the isoscalar central potential.…
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…
There are several different experimental indications, such as the strangeness contribution to the magnetic moment of the proton, sigma_{\pi N} term, strange spin polarization, ratio of strange and non strange quark flavor distributions…
Using the known experimental data for the hyperon semileptonic decay constants, we calculate integrated quark densities $\Delta q_\Lambda$ and $% \Delta \Sigma_\Lambda$ for the hyperon $\Lambda$ with flavor SU(3) symmetry breaking taken…
The object of this brief review is to reconcile different points of view on how the spin of proton is made up from its constituents. On the basis of naive quark model with flavour symmetry such as isospin or SU(3) one finds a static…
We report the progress on the lattice QCD calculation of the glue spin contribution to proton spin. This calculation is carried out with valence overlap fermion on 2+1 flavor DWF gauge configurations at two lattice spacings with the…
The Auxiliary Field Diffusion Monte Carlo method is applied to compute the spin susceptibility and the compressibility of neutron matter at zero temperature. Results are given for realistic interactions which include both a two-body…
Considerable progress has been made in our knowledge of the spin distribution within the proton. The recently measured limits on polarized gluons in the proton suggest polarized gluons contribute very modestly to the proton spin. We will…
The recent measurements of lepton nucleon scattering with polarised neutron and deuteron targets are analysed together with the previous polarised proton data in a mutually consistent way. The detailed $x$-dependence of the polarisation…
We present preliminary results on the proton spin structure function in full QCD. The measurement has been done using 4 flavours of staggered fermions and an improved definition of the lattice topological charge density.
The spin and flavor fractions of constituent quarks in the proton are obtained from their chiral fluctuations involving Goldstone bosons. SU(3) flavor symmetry breaking suggested by the mass difference between the strange and up, down…
It is demonstrated how in the soliton approach to baryons a small but non-vanishing matrix element of the axial singlet current is obtained. Furthermore it is shown that these models also provide a mechanism to disentangle the ``matter" and…