scholarly journals Gluon-Spin Contribution to the Proton Spin from the Double-Helicity Asymmetry in Inclusiveπ0Production in Polarizedp+pCollisions ats=200  GeV

2009 ◽  
Vol 103 (1) ◽  
Author(s):  
A. Adare ◽  
S. Afanasiev ◽  
C. Aidala ◽  
N. N. Ajitanand ◽  
Y. Akiba ◽  
...  
Keyword(s):  
Proton Spin ◽  
Gluon Spin ◽  
200 Gev ◽  
Spin Contribution

Gluon Spin Contribution to The Nucleon Spin

2010 ◽  
Vol 207-208 ◽  
pp. 57-60
Author(s):  
Firooz Arash ◽  
Abolfazl Shahveh ◽  
Fateme Taghavi-Shahri
Keyword(s):  
Nucleon Spin ◽  
Gluon Spin ◽  
Spin Contribution

scholarly journals RECENT RESULTS ON HIGH-ENERGY SPIN PHENOMENA OF GLUONS AND SEA-QUARKS IN POLARIZED PROTON-PROTON COLLISIONS AT RHIC AT BNL

2014 ◽  
Vol 25 ◽  
pp. 1460033 ◽  
Author(s):  
BERND SURROW
Keyword(s):  
Heavy Ion ◽  
High Energy ◽  
Proton Spin ◽  
Relativistic Heavy Ion Collider ◽  
Spin Physics ◽  
Proton Collisions ◽  
Physics Program ◽  
Quark Spin ◽  
Polarized Proton ◽  
Spin Contribution

The STAR experiment at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is carrying out a spin physics program in high-energy polarized proton collisions at [Formula: see text] GeV and [Formula: see text] GeV to gain a deeper insight into the spin structure and dynamics of the proton. One of the main objectives of the spin physics program at RHIC is the precise determination of the polarized gluon distribution function. The STAR detector is well suited for the reconstruction of various final states involving jets, π0, π±, e± and γ, which allows to measure several different processes. Recent results suggest a gluon spin contribution to the proton spin at the same level as the quark spin contribution itself. The production of W bosons in polarized p+p collisions at [Formula: see text] GeV opens a new era in the study of the spin-flavor structure of the proton. W-(+) bosons are produced in [Formula: see text] collisions and can be detected through their leptonic decays, [Formula: see text], where only the respective charged lepton is measured. Results of W-(+) production suggest a large asymmetry between the polarization of anti-u and anti-d quarks.

scholarly journals Gluon polarization measurements from longitudinally polarized proton-proton collisions at STAR

2020 ◽  
Vol 1643 (1) ◽  
pp. 012184
Author(s):  
Zilong Chang
Keyword(s):  
Spin Asymmetry ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Proton Spin ◽  
Gluon Polarization ◽  
Relativistic Heavy Ion Collider ◽  
Center Of Mass Energy ◽  
Double Spin ◽  
200 Gev ◽  
Inclusive Jet

Abstract The gluon polarization contribution to the proton spin is an integral part to solve the longstanding proton spin puzzle. At the Relativistic Heavy Ion Collider (RHIC), the STAR experiment has measured jets produced in mid-pseudo-rapidity, |η| < 1.0, and full azimuth, ϕ, from longitudinally polarized pp collisions to study the gluon polarization in the proton. At center of mass energies s = 200 and 510 GeV, jet production is dominated by hard QCD scattering processes such as gluon-gluon (gg) and quark-gluon (qg), thus making the longitudinal double-spin asymmetry (ALL ) sensitive to the gluon polarization. Early STAR inclusive jet ALL results at s = 200 GeV provided the first evidence of the non-zero gluon polarization at momentum fraction x > 0.05. The higher center of mass energy s = 510 GeV allows to explore the gluon polarization as low as x ∼ 0.015. In this talk we will present the recent STAR inclusive jet and dijet ALL results at s = 510 GeV, and discuss the relevant new analysis techniques for the estimation of trigger bias and reconstruction uncertainty, the underlying event correction on the jet energy and its effect on jet ALL . Dijet results are shown for different topologies in regions of pseudo-rapidity, effectively scanning the x-dependence of the gluon polarization.

scholarly journals STATUS OF THE PROTON SPIN PROBLEM

1996 ◽  
Vol 11 (29) ◽  
pp. 5109-5181 ◽  
Author(s):  
HAI-YANG CHENG
Keyword(s):  
Cross Section ◽  
Proton Spin ◽  
Nucleon Structure ◽  
Spin Component ◽  
Hard Photon ◽  
Axial Anomaly ◽  
Quark Spin ◽  
Nucleon Structure Function ◽  
Gluon Spin ◽  
First Moment

The proton spin problem triggered by the EMC experiment and its present status are closely examined. Recent experimental and theoretical progresses and their implications are reviewed. It is pointed out that the sign of the sea quark polarization generated perturbatively by hard gluons via the anomaly mechanism is predictable. It is negative if the gluon spin component is positive. We stress that the polarized nucleon structure function g1(x) is independent of the k⊥ factorization scheme chosen in defining the quark spin density and the hard photon–gluon scattering cross-section. Consequently, the anomalous gluon and sea quark interpretations for Γ1, the first moment of g1(x), are equivalent. It is the axial anomaly that accounts for the observed suppression of [Formula: see text].

Dispersion of proton spin-lattice relaxation in a cholesteric liquid crystal

1983 ◽  
Vol 44 (10) ◽  
pp. 1179-1184 ◽  
Author(s):  
M. Vilfan ◽  
R. Blinc ◽  
J. Dolinšek ◽  
M. Ipavec ◽  
G. Lahajnar ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Spin Lattice
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