Related papers: Exploring the Spin Structure of the Nucleon at STA…
Jets, clusters of collimated particles produced in high energy proton-proton ($pp$) collisions, are an excellent tool to study the internal structure of the proton. According to perturbative QCD (pQCD) calculations, for center-of-mass…
Acceleration of polarized protons in the Relativistic Heavy Ion Collider (RHIC) provides a unique tool to study the spin structure of the nucleon. We give a brief overview of the PHENIX program to investigate the unknown gluon and flavor…
We review what is currently known about the transverse spin structure of hadrons, in particular from observables that can be analyzed within a collinear framework. These effects have been around for 40 years and represent a critical test of…
This paper contains three parts relating to the nucleon spin structure in a simple picture of the nucleon: (i) The polarized gluon distribution in the proton is dynamically predicted starting from a low scale by using a nonlinear QCD…
We present a detailed assessment of how well a future Electron-Ion Collider could constrain helicity parton distributions in the nucleon and, therefore, unveil the role of the intrinsic spin of quarks and gluons in the proton's spin budget.…
It is shown that the proton "spin crisis'' or "spin puzzle" can be understood by the relativistic effect of quark transversal motions due to the Melosh-Wigner rotation. The quark helicity $\Delta q$ measured in polarized deep inelastic…
The main focus of the physics program at PHENIX and STAR that makes use of RHIC's polarized proton beams is to figure out how and if at all the gluons inside protons are polarized, or to put it another way, do the spin 1 gluons prefer to…
This article gives an overview over recent results on quark and gluon helicity distributions obtained in deep inelastic lepton nucleon scattering and proton proton interactions. Future experimental programs to study the nucleon structure…
This contribution presents the most recent mid-rapidity inclusive jet results from 3 pb^-1 of data collected from longitudinally polarized proton collisions at sqrt(s)=200 GeV during the 2005 RHIC run. The inclusive jet asymmetry, a_LL,…
This article reviews our present understanding of QCD spin physics: the proton spin puzzle and new developments aimed at understanding the transverse structure of the nucleon. We discuss present experimental investigations of the nucleon's…
Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to perform precision studies of the transverse spin and transverse-momentum-dependent structure in the valence quark region for both the proton and the neutron. In…
Within a generalized parton model approach, with inclusion of spin and intrinsic transverse momentum effects, we show how the latest, highly precise, midrapidity data on the transverse single spin asymmetry measured in $pp\to\pi^0\, X$ by…
At RHIC kinematics, polarized jet hadroproduction is dominated by $gg$ and $qg$ scattering, making the jet longitudinal double-spin asymmetry, $A_{LL}$, sensitive to gluon polarization in the nucleon. I will present STAR results of $A_{LL}$…
A summary is given of the experimental and theoretical results presented in the working group on spin physics. New data on inclusive and semi-inclusive deep-inelastic scattering, combined with theoretical studies of the polarized…
One of the primary goals of the RHIC spin program is to determine the spin-dependent gluon distribution, $\Delta g(x)$, of the proton. The measurements of the 2009 longitudinal double-helicity asymmetry, $A_{LL}$, for mid-rapidity inclusive…
At RHIC kinematics, polarized jet hadroproduction is dominated by $gg$ and $qg$ scattering, making the jet double longitudinal spin asymmetry, $A_{LL}$, sensitive to gluon polarization in the nucleon. I will present STAR results of $A_{LL}$…
New results for the double spin asymmetry $A_1^{\rm p}$ and the proton longitudinal spin structure function $g_1^{\rm p}$ are presented. They were obtained by the COMPASS collaboration using polarised 200 GeV muons scattered off a…
Measurements of single-spin asymmetries for semi-inclusive electro-production of pions and kaons in deep-inelastic scattering with transverse target polarization open a new window on the transverse quark and gluon structure of the nucleon.…
The STAR detector will bring unique capabilities to the study of $\vec{p}+\vec{p}$ collisions up to total center of mass energies of 500 GeV at RHIC. The large acceptance of the time projection chamber and the electromagnetic calorimeter…
By assuming that there is no significant intrinsic polarization of the gluon, we have computed the polarized quark contributions to the proton's spin under SU(3) flavor symmetry breaking for the polarized sea and have performed a global…