scholarly journals Asymmetry Effects in Polarized Hadron Scattering

1997 ◽  
Vol 12 (32) ◽  
pp. 5827-5846
Author(s):  
Yaw-Hwang Chen ◽  
Su-Long Nyeo ◽  
Chung-Yi Wu
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Helicity Amplitude ◽  
Spin Asymmetry ◽  
Distribution Functions ◽  
Differential Cross Sections ◽  
Parton Distribution Functions ◽  
Double Spin Asymmetry ◽  
Single Spin ◽  
Double Spin

We calculate the single-spin and double-spin asymmetry differential cross sections for the polarized hadron scattering PP → l+ l- + jet up to O(αs) by the helicity amplitude method. Numerical results of the differential cross sections, which can be used to probe the spin contents of the proton, are obtained from several sets of polarized parton distribution functions.

scholarly journals Single-spin asymmetry ATsin(2ϕ−ϕS) in π−p Drell-Yan process within TMD factorization

2022 ◽  
Vol 258 ◽  
pp. 03002
Author(s):  
Hui Li ◽  
Xiaoyu Wang ◽  
Zhun Lu
Keyword(s):  
Spin Asymmetry ◽  
Distribution Functions ◽  
Single Spin Asymmetry ◽  
Parton Distribution Functions ◽  
Sudakov Form Factor ◽  
Transverse Momentum Dependent ◽  
Single Spin ◽  
Mulders Function ◽  
Light Cone Wave Function ◽  
The Asymmetry

We study the single-spin asymmetry ATsin(2ϕ−ϕS) in the pion-induced Drell-Yan process within the transverse momentum dependent factorization (TMD factorization). The asymmetry can be expressed as the convolution of the Boer-Mulders function and the transversity function. We numerically estimate the asymmetry ATsin(2ϕ−ϕS) at the COMPASS kinematics with the model results for the pion meson distributions from the light-cone wave function approach and the available parametrization for the proton distributions. We also include the TMD evolution formalism both proton and pion parton distribution functions by using two different parametrizations on nonperturbative Sudakov form factor. We find that the asymmetry ATsin(2ϕ−ϕS) as functions of xp, xπ, xF and q⊥ is qualitatively consistent with the recent COMPASS measurement.

scholarly journals Longitudinal Double Spin Asymmetries of π0 - Jet Correlations in Polarized Proton Collisions at s = 510 GeV at STAR

2018 ◽  
Vol 46 ◽  
pp. 1860011
Author(s):  
Yaping Wang
Keyword(s):  
Spin Asymmetry ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Final State ◽  
Model Calculations ◽  
Spin Asymmetries ◽  
Proton Collisions ◽  
Rapidity Region ◽  
Double Spin ◽  
Polarized Proton

One of the primary goals of the spin physics program at STAR is to constrain the polarized gluon distribution function, [Formula: see text], by measuring the longitudinal double-spin asymmetry ([Formula: see text]) of various final-state channels. Using a jet in the mid-rapidity region [Formula: see text] correlated with an azimuthally back-to-back [Formula: see text] in the forward rapidity region [Formula: see text] provides a new possibility to access the [Formula: see text] distribution at Bjorken-[Formula: see text] down to 0.01. Compared to inclusive jet or inclusive [Formula: see text] measurements, this channel also allows to constrain the initial parton kinematics. In these proceedings, we will present the status of the analysis of the [Formula: see text]-jet [Formula: see text] in longitudinally polarized proton+proton collisions at [Formula: see text] =510 GeV with 80 pb[Formula: see text] of data taken during the 2012 RHIC run. We also compare the projected [Formula: see text] uncertainties to theoretical predictions of the [Formula: see text] by next-to-leading order (NLO) model calculations with different polarized parton distribution functions.

scholarly journals THE QCD PARTON MODEL: A USEFUL APPROXIMATION

2007 ◽  
Vol 22 (24) ◽  
pp. 1787-1795 ◽  
Author(s):  
ELVIO DI SALVO
Keyword(s):  
Spin Asymmetry ◽  
Equations Of Motion ◽  
Quark Distribution ◽  
Parton Model ◽  
Energy Scale ◽  
Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Double Spin Asymmetry ◽  
Double Spin ◽  
Azimuthal Asymmetries

Approximate relations among transverse momentum dependent quark distribution functions are established in the framework of the QCD parton model. The validity of such results survives QCD evolution effects, owing to the Politzer theorem on equations of motion. Furthermore the model fixes an energy scale, involved in the parametrization of the correlator, which determines the Q2 dependence of the azimuthal asymmetries in inclusive reactions. Some of the present data — in particular the sin 2ϕ single spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) and the cos ϕ asymmetry in unpolarized SIDIS — support model predictions. Further measurements of SIDIS and Drell–Yan asymmetries are suggested, in particular the SIDIS double spin asymmetry, which allows to determine approximately the proton transversity.

SPIN-DEPENDENT DIFFERENTIAL CROSS SECTIONS AT SMALL ANGLES AT RHIC ENERGIES

1999 ◽  
Vol 14 (02) ◽  
pp. 253-269 ◽  
Author(s):  
N. AKCHURIN ◽  
S. V. GOLOSKOKOV ◽  
O. V. SELYUGIN
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
Differential Cross ◽  
Spin Correlation ◽  
Heavy Ion ◽  
Differential Cross Sections ◽  
Relativistic Heavy Ion Collider ◽  
Double Spin ◽  
Proton Coupling ◽  
Correlation Parameters

Spin-dependent pomeron effects are analyzed for elastic pp scattering and calculations for spin-dependent differential cross sections, analyzing power and double-spin correlation parameters are carried out for the energy range of the Relativistic Heavy Ion Collider (RHIC) at BNL. In this energy range, [Formula: see text], the structure of pomeron–proton coupling can be measured at RHIC with colliding polarized proton beams.

DOUBLE SPIN ASYMMETRY ALT IN THE PRODUCTION OF PHOTONS, HADRONS, AND JETS

2012 ◽  
Vol 20 ◽  
pp. 29-36
Author(s):  
DANIEL PITONYAK
Keyword(s):  
Spin Asymmetry ◽  
Pp Collisions ◽  
Proton Proton ◽  
Spin Asymmetries ◽  
Double Spin Asymmetry ◽  
Single Spin ◽  
Double Spin ◽  
Single Spin Asymmetries ◽  
Complete Set ◽  
First Time

We calculate the double spin asymmetry (DSA) ALT in proton-proton (pp) collisions for the production of photons, hadrons, and jets in the collinear twist-3 framework. These processes allows us for the first time to access a complete set of collinear twist-3 functions. We also give numerical estimates for the asymmetries of which photon production shows the most promise of a measurable effect. Furthermore, we comment on how these asymmetries would allow us to probe the gluon helicity down to as of yet unexplored x values, remark on the importance of these effects in determining the evolution of the Efremov-Teryaev-Qiu-Sterman (ETQS) function TF(x, x), and discuss their usefulness in resolving the true mechanism behind the large transverse single spin asymmetries (SSAs) measured in pp collisions.

scholarly journals SINGLE/DOUBLE-SPIN ASYMMETRY MEASUREMENTS OF SEMI-INCLUSIVE PION ELECTRO-PRODUCTION ON A TRANSVERSELY POLARIZED 3He TARGET THROUGH DEEP INELASTIC SCATTERING

2012 ◽  
Vol 27 (21) ◽  
pp. 1230021
Author(s):  
◽  
XIN QIAN
Keyword(s):  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Parton Distribution ◽  
Spin Asymmetry ◽  
Valence Quark ◽  
Distribution Functions ◽  
Scattered Electron ◽  
Parton Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Double Spin

Parton distribution functions, which represent the flavor and spin structure of the nucleon, provide invaluable information in illuminating quantum chromodynamics in the confinement region. Among various processes that measure such parton distribution functions, semi-inclusive deep inelastic scattering is regarded as one of the golden channels to access transverse momentum dependent parton distribution functions, which provide a 3D view of the nucleon structure in momentum space. The Jefferson Lab experiment E06-010 focuses on measuring the target single and double spin asymmetries in the [Formula: see text] reaction with a transversely polarized 3 He target in Hall A with a 5.89 GeV electron beam. A leading pion and the scattered electron are detected in coincidence by the left High-Resolution Spectrometer at 16° and the BigBite spectrometer at 30° beam right, respectively. The kinematic coverage concentrates in the valence quark region, x ~ 0.1–0.4, at Q2 ~ 1–3 GeV 2. The Collins and Sivers asymmetries of 3 He and neutron are extracted. In this review, an overview of the experiment and the final results are presented. Furthermore, an upcoming 12-GeV program with a large acceptance solenoidal device and the future possibilities at an electron–ion collider are discussed.

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