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 The Sivers asymmetry in hadronic dijet production

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Zhong-Bo Kang ◽  
Kyle Lee ◽  
Ding Yu Shao ◽  
John Terry
Keyword(s):  
Spin Asymmetry ◽  
Star Collaboration ◽  
Heavy Ion ◽  
Distribution Functions ◽  
Relativistic Heavy Ion Collider ◽  
Parton Distribution Functions ◽  
Dijet Production ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Polarized Proton

Abstract We study the single spin asymmetry in the back-to-back dijet production in transversely polarized proton-proton collisions. Such an asymmetry is generated by the Sivers functions in the incoming polarized proton. We propose a QCD formalism in terms of the transverse momentum dependent parton distribution functions, which allow us to resum the large logarithms that arise in the perturbative calculations. We make predictions for the Sivers asymmetry of hadronic dijet production at the kinematic region that is relevant to the experiment at the Relativistic Heavy Ion Collider (RHIC). We further compute the spin asymmetries in the selected positive and negative jet charge bins, to separate the contributions from u- and d-quark Sivers functions. We find that both the sign and size of our numerical results are roughly consistent with the preliminary results from the STAR collaboration at the RHIC.

scholarly journals ANALYTIC PROPERTIES OF MULTI-PARTON POLE MATRIX ELEMENTS AND UNIVERSALITY OF FRAGMENTATION FUNCTIONS

2011 ◽  
Vol 04 ◽  
pp. 115-125
Author(s):  
LEONARD GAMBERG ◽  
ASMITA MUKHERJEE ◽  
P. J. MULDERS
Keyword(s):  
High Energy ◽  
Distribution Functions ◽  
Analytic Structure ◽  
Matrix Elements ◽  
Parton Distribution Functions ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Fragmentation Functions ◽  
High Energy Scattering

Gluonic pole matrix elements explain the appearance of single spin asymmetries (SSA) in high-energy scattering processes. They involve a combination of operators which are odd under time reversal (T-odd). Such matrix elements appear in principle both for parton distribution functions and parton fragmentation functions. We show that for parton fragmentation functions these gluonic pole matrix elements vanish as a consequence of the analytic structure of scattering amplitudes in Quantum Chromodynamics. We extend this analysis to the case of multi-partonic pole matrix elements. This result is important in the study of the universality of transverse momentum dependent (TMD) fragmentation functions.

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 Asymmetries AULsinϕh in Semi-Inclusive Pions Production

2016 ◽  
Vol 40 ◽  
pp. 1660045 ◽  
Author(s):  
Zhun Lu ◽  
Wenjuan Mao
Keyword(s):  
Pion Production ◽  
Neutral Pion ◽  
Spin Asymmetry ◽  
Distribution Functions ◽  
Proton Target ◽  
Deuteron Target ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries

The single-spin asymmetry [Formula: see text] of charged and neutral pion production in semi-inclusive deep-inelastic scattering on longitudinally polarized nucleon targets is studied. We particularly consider the effects of the twist-3 transverse-momentum dependent distribution functions [Formula: see text] and [Formula: see text], which are calculated in two different spectator-diquark models. We estimate the asymmetry for [Formula: see text], [Formula: see text] and [Formula: see text] produced off the proton target at HERMES and compare the results with the HERMES measurements. We also predict the same asymmetric moment for different pions at the kinematics of CLAS 5.5 GeV on a proton target, as well as at COMPASS on a deuteron target for comparison.

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.

scholarly journals SIVERS ASYMMETRY IN e + p↑ → e + J/ψ + X

2012 ◽  
Vol 20 ◽  
pp. 162-167
Author(s):  
ASMITA MUKHERJEE
Keyword(s):  
Spin Asymmetry ◽  
Single Spin Asymmetry ◽  
Evaporation Model ◽  
Single Spin ◽  
Sivers Function ◽  
The Asymmetry

A recent investigation of the single spin asymmetry (SSA) in low virtuality electroproduction/photoproduction of J/ψ in color evaporation model is presented. It is shown that the asymmetry is sizable and can be used as a probe for the still unknown gluon Sivers function.

scholarly journals Measurement of Longitudinal Single-Spin Asymmetry for W± Production in Polarized Proton+Proton Collisions at STAR

2020 ◽  
Vol 1643 (1) ◽  
pp. 012197
Author(s):  
Qinghua Xu
Keyword(s):  
Spin Asymmetry ◽  
Global Analysis ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Distribution Functions ◽  
Single Spin Asymmetry ◽  
Nucleon Spin ◽  
Single Spin ◽  
Double Spin ◽  
Helicity Distribution

Abstract The contribution from the sea quark polarization to the nucleon spin is an important piece for the complete understanding of the nucleon spin structure. The production of W ± bosons in longitudinally polarized p+p collisions at the RHIC collider at Brookhaven National Laboratory provides a unique probe of the sea quark polarization, through the parity-violating single-spin asymmetry, AL . At the STAR experiment, the W bosons that decay through the W → ev channel at mid-rapidity (|η <1.3) can be effectively determined with the Electromagnetic Calorimeters and Time Projection Chamber. The STAR measurements of AL for W boson from datasets taken in 2011 and 2012 at s =510 GeV have been included in the global analysis of polarized parton distribution functions, and provided significant constraints on the helicity distribution functions of u ¯ and d ¯ quarks. The final AL results from 2013 STAR data sample are reported, which is about three times larger than the total integrated luminosity of previous years. The combined results of AL for 2011-2013 data are also given. A flavor asymmetry of light sea quark helicity distribution, Δ u ¯ ( x )   −   Δ d ¯ ( x ) > 0 , is confirmed from a re-weighting of global analysis NNPDFpol1.1 after including the new AL results. In addition, results on the double-spin asymmetries ALL for W ±, and AL for Z/γ* production are also reported.

scholarly journals Measurement of the beam-normal single-spin asymmetry for elastic electron scattering from C12 and Al27

2021 ◽  
Vol 104 (1) ◽  
Author(s):  
D. Androić ◽  
D. S. Armstrong ◽  
A. Asaturyan ◽  
K. Bartlett ◽  
R. S. Beminiwattha ◽  
...  
Keyword(s):  
Electron Scattering ◽  
Spin Asymmetry ◽  
Single Spin Asymmetry ◽  
Elastic Electron ◽  
Elastic Electron Scattering ◽  
Single Spin
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