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Title: Single-spin asymmetries in semi-inclusive deep inelastic scattering and Drell-Yan processes

Abstract

We examine in detail the diagrammatic mechanisms which provide the change of sign between the single transverse spin asymmetries measured in semi-inclusive deep inelastic scattering (SIDIS) and in the Drell-Yan process (DY). This asymmetry is known to arise due to the transverse spin dependence of the target proton combined with a T-odd complex phase. Using the discrete symmetry properties of transverse spinors, we show that the required complex phase originates in the denominators of rescattering diagrams and their respective cuts. For simplicity, we work in a model where the proton consists of a valence quark and a scalar diquark. We then show that the phases generated in SIDIS and in DY originate from distinctly different cuts in the amplitudes, which at first appears to obscure the relationship between the single-spin asymmetries in the two processes. Nevertheless, further analysis demonstrates that the contributions of these cuts are identical in the leading-twist Bjorken kinematics considered, resulting in the standard sign-flip relation between the Sivers functions in SIDIS and DY. Physically, this fundamental, but yet untested, prediction occurs because the Sivers effect in the Drell-Yan reaction is modified by the initial-state “lensing” interactions of the annihilating antiquark, in contrast to the final-state lensingmore » which produces the Sivers effect in deep inelastic scattering.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1076821
Report Number(s):
SLAC-PUB-15408
Journal ID: ISSN 1550-7998; PRVDAQ; arXiv:1304.5237
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 88; Journal Issue: 1; Journal ID: ISSN 1550-7998
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Theory-Nucl; Phenomenology-HEP; HEPPH

Citation Formats

Brodsky, Stanley J., Hwang, Dae Sung, Kovchegov, Yuri V., Schmidt, Ivan, and Sievert, Matthew D. Single-spin asymmetries in semi-inclusive deep inelastic scattering and Drell-Yan processes. United States: N. p., 2013. Web. doi:10.1103/PhysRevD.88.014032.
Brodsky, Stanley J., Hwang, Dae Sung, Kovchegov, Yuri V., Schmidt, Ivan, & Sievert, Matthew D. Single-spin asymmetries in semi-inclusive deep inelastic scattering and Drell-Yan processes. United States. doi:10.1103/PhysRevD.88.014032.
Brodsky, Stanley J., Hwang, Dae Sung, Kovchegov, Yuri V., Schmidt, Ivan, and Sievert, Matthew D. Mon . "Single-spin asymmetries in semi-inclusive deep inelastic scattering and Drell-Yan processes". United States. doi:10.1103/PhysRevD.88.014032. https://www.osti.gov/servlets/purl/1076821.
@article{osti_1076821,
title = {Single-spin asymmetries in semi-inclusive deep inelastic scattering and Drell-Yan processes},
author = {Brodsky, Stanley J. and Hwang, Dae Sung and Kovchegov, Yuri V. and Schmidt, Ivan and Sievert, Matthew D.},
abstractNote = {We examine in detail the diagrammatic mechanisms which provide the change of sign between the single transverse spin asymmetries measured in semi-inclusive deep inelastic scattering (SIDIS) and in the Drell-Yan process (DY). This asymmetry is known to arise due to the transverse spin dependence of the target proton combined with a T-odd complex phase. Using the discrete symmetry properties of transverse spinors, we show that the required complex phase originates in the denominators of rescattering diagrams and their respective cuts. For simplicity, we work in a model where the proton consists of a valence quark and a scalar diquark. We then show that the phases generated in SIDIS and in DY originate from distinctly different cuts in the amplitudes, which at first appears to obscure the relationship between the single-spin asymmetries in the two processes. Nevertheless, further analysis demonstrates that the contributions of these cuts are identical in the leading-twist Bjorken kinematics considered, resulting in the standard sign-flip relation between the Sivers functions in SIDIS and DY. Physically, this fundamental, but yet untested, prediction occurs because the Sivers effect in the Drell-Yan reaction is modified by the initial-state “lensing” interactions of the annihilating antiquark, in contrast to the final-state lensing which produces the Sivers effect in deep inelastic scattering.},
doi = {10.1103/PhysRevD.88.014032},
journal = {Physical Review. D, Particles, Fields, Gravitation and Cosmology},
issn = {1550-7998},
number = 1,
volume = 88,
place = {United States},
year = {2013},
month = {7}
}