Gluon spin in a quark model

  title={Gluon spin in a quark model},
  author={Vincenzo Barone and Tommaso Calarco and Alessandro Drago},
  journal={Physics Letters B},

Exploring the polarization of gluons in the nucleon

We give an overview of the current status of investigations of the polarization of gluons in the nucleon. We describe some of the physics of the spin-dependent gluon parton distribution and its

The spin structure of the nucleon

We give an overview of some of the current activities and results in theory and experiment in QCD spin physics. We focus in particular on investigations of gluon polarization in the nucleon, and on

The target asymmetry in hard vector-meson electroproduction and parton angular momenta

The target asymmetry for electroproduction of vector mesons is investigated within the handbag approach. While the generalized parton distribution (GPD) H is taken from a previous analysis of the

Spin budget of the proton at NNLO and beyond

We revisit the scale evolution of the quark and gluon spin contributions to the proton spin, $\frac{1}{2}\Delta \Sigma$ and $\Delta G$, using the three-loop results for the spin-dependent evolution

The Spin Structure of the Nucleon

Attempting to understand the origin of the intrinsic spin of the proton and neutron has been an active area of both experimental and theoretical research for the past twenty years. With the

Magnetic Polarizability of Virtual (ss¯) and (cc¯) Pairs in the Nucleon

We suggest 3P0 quantum state of virtual (ss¯) pairs in the nucleon can be polarised by the internal fields permeating the volume of the nucleon (proton or neutron). Due to the quadratic Zeeman



How much of the nucleon spin is carried by glue

The authors 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

Gauge-Invariant Decomposition of Nucleon Spin

I introduce a gauge invariant decomposition of the nucleon spin into quark helicity, quark orbital, and gluon contributions. The total quark (and hence the quark orbital) contribution is shown to be

Spin structure of the nucleon in the asymptotic limit.

An evolution equation for quark and gluon orbital angular momenta is derived for the nucleon spin using the QCD expression for the generators of Lorentz transformations as the theoretical basis for separating the spin of theucleon into different contributions.

Spin structure of the proton from polarized inclusive deep-inelastic muon-proton scattering

We have measured the spin-dependent structure function $g_1~p$ in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003 < x < 0.7$ and $1 GeV~2 <

The Electromagnetic shift of energy levels

B very beautiful experiments, Lamb and Retherford1 have shown that the fine structure of the second quantum state of hydrogen does not agree with the prediction of the Dirac theory. The 2s level,