Related papers: The proton spin puzzle: where are we today ?
We point out that the measurement of target spin depolarization $D_{nn}$ in the $\bar{p}p\to\bar{\Lambda}\Lambda$ reaction may test dynamical mechanisms invoked to explain the proton spin puzzle revealed by polarized deep--inelastic…
I review the current status of the determination of helicity-dependent, or polarized, parton distribution functions from a comprehensive analysis of experimental data in perturbative quantum chromodynamics. I illustrate the latest…
This talk consists of four parts. In part one, I give an elementary discussion on constructing a Lorentz-invariant spin sum rule for the nucleon. In part two, I discuss a gauge-dependent spin sum rule, explore its relation with the…
Polarized proton-proton collisions at the Relativistic Heavy Ion Collider (RHIC) provide unique opportunities to study the spin structure of the nucleon. We will highlight recent results on the nucleon spin structure from the STAR and…
We briefly review some of the recent developments in QCD spin physics.
Spin effects in exclusive and inclusive reactions provide an essential new dimension for testing QCD and unraveling hadron structure. Remarkable new experiments from SLAC, HERMES (DESY), and the Jefferson Laboratory present many challenges…
Opening talk presented at the Adriatico Research Conference -- Trends in Collider Spin Physics and at the RIKEN Symposium -- Spin Structure of the Nucleon. We present an overview of the opportunities to explore QCD at a very high energy…
The discrepancy between the measured Lamb shift in muonic hydrogen and expectations from electron-proton scattering and regular hydrogen spectroscopy has become known as the proton radius puzzle, whose most "mundane" resolution requires a…
How quarks and gluons conspire to provide the total spin of proton is a long-standing puzzle in quantum chromodynamics (QCD). The unique capability of RHIC, that can provide longitudinally polarized $p+p$ collisions at both $\sqrt{s} = 200$…
The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton's bound…
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…
We investigate the spin structure of the nucleon in an extended Jaffe-Lipkin quark model. In addition to the conventional $3q$ structure, different $(3q)(Q\bar{Q})$ admixtures in the nucleon wavefunction are also taken into account. The…
Recent progress in the understanding of the nucleon is presented. The unpolarised structure functions are obtained with unprecedented precision from the combined H1 and ZEUS data and are used to extract proton parton distribution functions…
We review recent experimental and theoretical progress in spin physics, as presented in the spin parallel session of DIS2006. In particular, we discuss the status of the nucleon spin structure, transverse polarized asymmetries, and recent…
The nucleons (protons and neutrons) are by far the most abundant form of matter in our visible Universe; they are composite particles made of quarks and gluons, the fundamental quanta of Quantum Chromo Dynamics (QCD). The usual…
The flavor-dependent valence, sea quark and antiquark spin distributions can be determined separately from theoretical assumptions and experimental data. We have determined the valence distributions using the Bjorken sum rule and have…
The quark-gluon plasma produced by collisions between ultra-relativistic heavy nuclei is well described in the language of hydrodynamics. Non-central collisions are characterized by very large angular momentum, which in a fluid system…
We have extracted polarized nucleon distributions from recent data at CERN, SLAC and DESY. The flavor-dependent valence and sea quark spin distributions are determined for each experiment. The up and down distributions are comparable, but…
Comments on the recent lattice QCD calculations of the flavor-singlet axial coupling constant $g_A^0$ and individual quark and gluon spin contributions to the proton spin is given. I point out the physics learned from these calculations as…
We briefly summarize the important and critical roles that PHENIX Experiment has played in determining the proton's internal structure in terms of quarks and gluons, and their dynamics. Some pioneering measurements by PHENIX Experiment on…