scholarly journals Unique Description for Single Transverse Spin Asymmetries in DIS and Hadronic Collisions

2007 ◽  
Author(s):  
Feng Yuan
Keyword(s):  
Transverse Spin ◽  
Spin Asymmetries ◽  
Hadronic Collisions

scholarly journals The Gluon Sivers Distribution: Status and Future Prospects

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Daniël Boer ◽  
Cédric Lorcé ◽  
Cristian Pisano ◽  
Jian Zhou
Keyword(s):  
Current Data ◽  
Transverse Spin ◽  
Opportunities To Learn ◽  
Linear Combinations ◽  
Spin Asymmetries ◽  
Polarized Protons ◽  
Sivers Function ◽  
Indirect Information ◽  
Hadronic Collisions

We review what is currently known about the gluon Sivers distribution and what are the opportunities to learn more about it. Because single transverse spin asymmetries inp↑p→πXprovide only indirect information about the gluon Sivers function through the relation with the quark-gluon and tri-gluon Qiu-Sterman functions, current data from hadronic collisions at RHIC have not yet been translated into a solid constraint on the gluon Sivers function. SIDIS data, including the COMPASS deuteron data, allow for a gluon Sivers contribution of natural size expected from largeNcarguments, which isO(1/Nc)times the nonsinglet quark Sivers contribution. Several very promising processes to measure the gluon Sivers effect directly have been suggested, which besides RHIC investigations, would strongly favor experiments at AFTER@LHC and a possible future Electron-Ion Collider. Due to the inherent process dependence of TMDs, the gluon Sivers TMD probed in the various processes are different linear combinations of two universal gluon Sivers functions that have different behavior under charge conjugation and that therefore satisfy different theoretical constraints. For this reason both hadronic and DIS type of collisions are essential in the study of the role of gluons in transversely polarized protons.

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

2021 ◽  
Vol 2021 (1) ◽  
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.

scholarly journals Azimuthal and Transverse Single Spin Asymmetries in Hadronic Collisions

2010 ◽  
Author(s):  
Francesco Murgia ◽  
Leonardo Angelini ◽  
Pietro Colangelo ◽  
Fulvia De Fazio ◽  
G. E. Bruno ◽  
...  
Keyword(s):  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Hadronic Collisions

Single transverse spin asymmetries

1991 ◽  
Vol 67 (17) ◽  
pp. 2264-2267 ◽  
Author(s):  
Jianwei Qiu ◽  
George Sterman
Keyword(s):  
Transverse Spin ◽  
Spin Asymmetries
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