Transverse target spin asymmetries on a proton target at COMPASS - on behalf of the COMPASS collaboration

The study of Drell–Yan (DY) processes involving the collision of an (un)polarised hadron beam on an (un)polarised proton target can result in a fundamental improvement of our knowledge on the transverse momentum dependent (TMDs) parton distribution functions (PDFs) of hadrons. The production mechanism of J/ψ and J/ψ - DY duality can also be addressed. One of the forthcoming polarised DY experiments (COMPASS (SPS, CERN)) is discussed in this context. The most important features of this project are briefly reviewed, as well as its sensitivity to the various transverse momentum dependent spin asymmetries.

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Single and Double Spin Asymmetries for Deeply Virtual Exclusive π0 Production on Longitudinally Polarized Proton Target with CLAS

10.2172/1432786 ◽

2013 ◽

Author(s):

Andrew Kim

Keyword(s):

Proton Target ◽

Spin Asymmetries ◽

Double Spin ◽

Polarized Proton ◽

Polarized Proton Target

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Single and double spin asymmetries for deeply virtual Compton scattering measured with CLAS and a longitudinally polarized proton target

Physical Review D ◽

10.1103/physrevd.91.052014 ◽

2015 ◽

Vol 91 (5) ◽

Cited By ~ 33

Author(s):

S. Pisano ◽

A. Biselli ◽

S. Niccolai ◽

E. Seder ◽

M. Guidal ◽

...

Keyword(s):

Compton Scattering ◽

Deeply Virtual Compton Scattering ◽

Virtual Compton Scattering ◽

Proton Target ◽

Spin Asymmetries ◽

Double Spin ◽

Polarized Proton ◽

Polarized Proton Target

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Single-Spin Asymmetries AULsinϕh in Semi-Inclusive Pions Production

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194516600454 ◽

2016 ◽

Vol 40 ◽

pp. 1660045 ◽

Cited By ~ 1

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.

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TRANSVERSITY AND AZIMUTHAL SPIN ASYMMETRY OF PION ELECTROPRODUCTION

International Journal of Modern Physics A ◽

10.1142/s0217751x03014745 ◽

2003 ◽

Vol 18 (08) ◽

pp. 1381-1390

Author(s):

BO-QIANG MA

Keyword(s):

Inelastic Scattering ◽

Light Cone ◽

Charged Lepton ◽

Pion Production ◽

Neutral Pion ◽

Spin Asymmetry ◽

Proton Target ◽

Diquark Model ◽

Spin Asymmetries ◽

Fragmentation Functions

The quark transversity distributions are discussed in a light-cone SU(6) quark-diquark model and in a perturbative QCD based analysis. The azimuthal spin asymmetries, both for charged and neutral pion production in semi-inclusive deep inelastic scattering of unpolarized charged lepton beams on longitudinally and transversely polarized nucleon targets, are analyzed. It is found that different approaches to the distribution and fragmentation functions may lead to quite different predictions. It is also found that the unfavored quark to pion fragmentation functions should be taken into account for π- production from a proton target.

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Gluon Sivers function and transverse single spin asymmetries in e+p↑→γ+X

Physical Review D ◽

10.1103/physrevd.103.036008 ◽

2021 ◽

Vol 103 (3) ◽

Author(s):

Siddhesh Padval ◽

Rohini M. Godbole ◽

Abhiram Kaushik ◽

Anuradha Misra ◽

Vaibhav S. Rawoot

Keyword(s):

Spin Asymmetries ◽

Single Spin ◽

Single Spin Asymmetries ◽

Sivers Function

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Global analysis of the Sivers functions at NLO+NNLL in QCD

Journal of High Energy Physics ◽

10.1007/jhep01(2021)126 ◽

2021 ◽

Vol 2021 (1) ◽

Cited By ~ 2

Author(s):

Miguel G. Echevarria ◽

Zhong-Bo Kang ◽

John Terry

Keyword(s):

Pair Production ◽

Global Analysis ◽

Vector Boson ◽

Lepton Pair ◽

Transverse Spin ◽

Dglap Evolution ◽

Spin Asymmetries ◽

Lepton Pair Production ◽

Asymmetry Data ◽

The Impact

Abstract We perform global fit to the quark Sivers function within the transverse momentum dependent (TMD) factorization formalism in QCD. We simultaneously fit Sivers asymmetry data from Semi-Inclusive Deep Inelastic Scattering (SIDIS) at COMPASS, HERMES, and JLab, from Drell-Yan lepton pair production at COMPASS, and from W/Z boson at RHIC. This extraction is performed at next-to-leading order (NLO) and next-to-next-to leading logarithmic (NNLL) accuracy. We find excellent agreement between our extracted asymmetry and the experimental data for SIDIS and Drell-Yan lepton pair production, while tension arises when trying to describe the spin asymmetries of W/Z bosons at RHIC. We carefully assess the situation, and we study in details the impact of the RHIC data and their implications through different ways of performing the fit. In addition, we find that the quality of the description of W/Z vector boson asymmetry data could be strongly sensitive to the DGLAP evolution of Qiu-Sterman function, besides the usual TMD evolution. We present discussion on this and the implications for measurements of the transverse-spin asymmetries at the future Electron Ion Collider.

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