scholarly journals Leading and next-to-leading order gluon polarization in the nucleon and longitudinal double spin asymmetries from open charm muoproduction

2013 ◽  
Vol 87 (5) ◽  
Author(s):  
C. Adolph ◽  
M. G. Alekseev ◽  
V. Yu. Alexakhin ◽  
Yu. Alexandrov ◽  
G. D. Alexeev ◽  
...  
Keyword(s):  
Open Charm ◽  
Leading Order ◽  
Gluon Polarization ◽  
Spin Asymmetries ◽  
Double Spin

LONGITUDINALLY POLARIZED HADRO- AND PHOTOPRODUCTION OF HEAVY QUARKS

2009 ◽  
Vol 24 (35n37) ◽  
pp. 3045-3051
Author(s):  
JOHANN RIEDL
Keyword(s):  
Spin Structure ◽  
Heavy Quarks ◽  
Monte Carlo Code ◽  
Heavy Flavor ◽  
Gluon Polarization ◽  
Order Accuracy ◽  
Spin Asymmetries ◽  
Double Spin ◽  
Heavy Flavor Production ◽  
Phenomenological Studies

Measurements of double-spin asymmetries for single-inclusive heavy flavor production and for heavy quark correlations are expected to provide valuable information about the spin structure of the nucleon, in particular, the elusive gluon polarization. We discuss progress towards a versatile parton-level Monte-Carlo code for the production and decay of heavy quarks in longitudinally polarized hadron-hadron and photon-hadron collisions at next-to-leading order accuracy of QCD. Phenomenological studies are presented for BNL-RHIC and COMPASS.

scholarly journals SPIN PHYSICS WITH STAR

2003 ◽  
Vol 18 (08) ◽  
pp. 1335-1342 ◽  
Author(s):  
◽  
JOANNA KIRYLUK
Keyword(s):  
Star Collaboration ◽  
Gluon Polarization ◽  
Proton Proton ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Double Spin ◽  
Single Spin Asymmetries ◽  
Polarized Proton ◽  
First Time ◽  
Proton Proton Collisions

The STAR collaboration aims to study polarized proton-proton collisions at RHIC. The emphasis of the spin run this year is on transverse single spin asymmetries. Beyond 2001, we aim to determine directly and precisely the gluon polarization, as well as the polarizations of the u, [Formula: see text], d and [Formula: see text] quarks in the proton by measuring in addition longitudinal and double spin asymmetries. Furthermore, we aim to measure for the first time the quark transversity distributions. These measurements will improve substantially the knowledge and understanding of the spin structure of the nucleon.

scholarly journals HERMES AND THE SPIN OF THE PROTON

2002 ◽  
Vol 17 (25) ◽  
pp. 3551-3570 ◽  
Author(s):  
H. E. JACKSON
Keyword(s):  
Spin Structure ◽  
Total Angular Momentum ◽  
Virtual Compton Scattering ◽  
Gluon Polarization ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Double Spin ◽  
Azimuthal Asymmetries ◽  
Deep Virtual Compton Scattering ◽  
Hadron Pairs

HERMES is a second generation experiment to study the spin structure of the nucleon, in which measurements of the spin dependent properties of semi-inclusive deep-inelastic lepton scattering are emphasized. Data have been accumulated for semi-inclusive pion, kaon, and proton double-spin asymmetries, as well as for high-pT hadron pairs, and single-spin azimuthal asymmetries for pion electroproduction and deep virtual Compton scattering. These results provide information on the flavor decomposition of the polarized quark distributions in the nucleon and a first glimpse of the gluon polarization, while the observation of the azimuthal asymmetries show promise for probing the tensor spin of the nucleon and isolating the total angular momentum carried by the quarks.

scholarly journals Gluon polarisation in the nucleon and longitudinal double spin asymmetries from open charm muoproduction

2009 ◽  
Vol 676 (1-3) ◽  
pp. 31-38 ◽  
Author(s):  
M. Alekseev ◽  
V.Yu. Alexakhin ◽  
Yu. Alexandrov ◽  
G.D. Alexeev ◽  
A. Amoroso ◽  
...  
Keyword(s):  
Open Charm ◽  
Spin Asymmetries ◽  
Double Spin

MEASUREMENT OF POLARIZED QUARK DISTRIBUTIONS AT HERMES

2003 ◽  
Vol 18 (08) ◽  
pp. 1185-1192
Author(s):  
◽  
STEFAN BERNREUTHER
Keyword(s):  
Cross Section ◽  
Kinematic Range ◽  
Spin Asymmetries ◽  
Double Spin ◽  
Hermes Experiment ◽  
Down Quark ◽  
Up Quark ◽  
Rich Detector ◽  
The Individual ◽  
Quark Flavors

The HERMES experiment has measured double spin asymmetries in the cross section for deep–inelastic scattering of longitudinally polarized positrons on longitudinally polarized 3 He (1995), 1 H (1996/97), and 2 D (1998) targets. A kinematic range of 0.023 < x < 0.6, and 1 GeV 2 < Q2 < 15 GeV 2 has been covered. From these asymmetries, based on inclusive and semi–inclusive measurements, polarized quark distributions are extracted as a function of x for up [Formula: see text] and down [Formula: see text] flavors as well as for valence and sea quarks. In the measured range, the up quark polarization is positive while the down quark polarization is negative. The sea quark polarization is compatible with zero. In this analysis all sea quark polarizations have been assumed to be flavor symmetric. Presently HERMES is analyzing a high statistics 2 D data sample taken in 1999-2000. For these data it is possible to identify pions and kaons with a RICH detector which was installed in 1998. This will enable an extraction of the individual sea quark flavors [Formula: see text], [Formula: see text], and [Formula: see text] without any symmetry assumptions.

scholarly journals Double spin asymmetries through QCD instantons

2014 ◽  
Vol 90 (11) ◽  
Author(s):  
Yachao Qian ◽  
Ismail Zahed
Keyword(s):  
Spin Asymmetries ◽  
Double Spin

SCALE DEPENDENCE OF TWIST-3 CORRELATION FUNCTIONS

2011 ◽  
Vol 04 ◽  
pp. 146-156
Author(s):  
Zhong-Bo Kang ◽  
Jian-Wei Qiu
Keyword(s):  
Correlation Functions ◽  
Evolution Equations ◽  
Scale Dependence ◽  
Leading Order ◽  
Coupling Constant ◽  
Parton Distributions ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Similarities And Differences

In this talk, we introduce two sets of twist-3 quark-gluon correlation functions that are relevant to transverse single spin asymmetries, and present corresponding evolution equations at the leading order in strong coupling constant, αs. The similarities and differences between the evolution of the leading power parton distributions and that of the twist-3 multiparton correlation functions are also discussed.

scholarly journals Introduction to the Transverse-Momentum-Weighted Technique in the Twist-3 Collinear Factorization Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Hongxi Xing ◽  
Shinsuke Yoshida
Keyword(s):  
Transverse Momentum ◽  
Leading Order ◽  
Precise Description ◽  
Collinear Factorization ◽  
Factorization Approach ◽  
Hard Part ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Successful Approach

The twist-3 collinear factorization framework has drawn much attention in recent decades as a successful approach in describing the data for single spin asymmetries (SSAs). Many SSAs data have been experimentally accumulated in a variety of energies since the first measurement was done in the late 1970s and it is expected that the future experiments like Electron-Ion-Collider will provide us with more data. In order to perform a consistent and precise description of the data taken in different kinematic regimes, the scale evolution of the collinear twist-3 functions and the perturbative higher-order hard part coefficients are mandatory. In this paper, we introduce the techniques for next-to-leading order (NLO) calculation of transverse-momentum-weighted SSAs, which can be served as a useful tool to derive the QCD evolution equation for twist-3 functions and to verify the QCD collinear factorization for twist-3 observables at NLO, as well as obtain the finite NLO hard part coefficients.

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