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Title: Observation concerning the process dependence of the Sivers functions

Abstract

The k{sub perpendicular} moment of a quark's Sivers function is known to be related to the corresponding twist-three quark-gluon correlation function T{sub q,F}(x,x). The two functions have been extracted from data for single-spin asymmetries in semi-inclusive deep-inelastic scattering and in single-inclusive hadron production in pp collisions, respectively. Performing a consistent comparison of the extracted functions, we find that they show a ''sign mismatch'': while the magnitude of the functions is roughly consistent, the k{sub perpendicular} moment of the Sivers function has opposite sign from that of T{sub q,F}(x,x), both for up and for down quarks. Barring any inconsistencies in our theoretical understanding of the Sivers functions and their process dependence, the implication of this mismatch is that either the Sivers effect is not dominantly responsible for the observed single-spin asymmetries in pp collisions or the current semi-inclusive lepton scattering data do not sufficiently constrain the k{sub perpendicular} moment of the quark Sivers functions. Both possibilities strengthen the case for further experimental investigations of single-spin asymmetries in high-energy pp and ep scattering.

Authors:
 [1];  [2];  [3];  [4]
  1. RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  2. Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  3. Institute for Theoretical Physics, Universitaet Tuebingen, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)
  4. Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Publication Date:
OSTI Identifier:
21541588
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 83; Journal Issue: 9; Other Information: DOI: 10.1103/PhysRevD.83.094001; (c) 2011 American Institute of Physics; Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; COMPARATIVE EVALUATIONS; CORRELATION FUNCTIONS; D QUARKS; DEEP INELASTIC SCATTERING; ELECTRON-PROTON INTERACTIONS; GLUONS; LEPTONS; PARTICLE PRODUCTION; PROTON-PROTON INTERACTIONS; SPIN; ANGULAR MOMENTUM; BARYON-BARYON INTERACTIONS; BOSONS; ELECTRON-NUCLEON INTERACTIONS; ELEMENTARY PARTICLES; EVALUATION; FERMIONS; FUNCTIONS; HADRON-HADRON INTERACTIONS; INELASTIC SCATTERING; INTERACTIONS; LEPTON-BARYON INTERACTIONS; LEPTON-HADRON INTERACTIONS; LEPTON-NUCLEON INTERACTIONS; NUCLEON-NUCLEON INTERACTIONS; PARTICLE INTERACTIONS; PARTICLE PROPERTIES; PROTON-NUCLEON INTERACTIONS; QUARKS; SCATTERING

Citation Formats

Zhongbo, Kang, Jianwei, Qiu, C.N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, New York 11794, Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, Vogelsang, Werner, Feng, Yuan, and RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973. Observation concerning the process dependence of the Sivers functions. United States: N. p., 2011. Web. doi:10.1103/PHYSREVD.83.094001.
Zhongbo, Kang, Jianwei, Qiu, C.N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, New York 11794, Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, Vogelsang, Werner, Feng, Yuan, & RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973. Observation concerning the process dependence of the Sivers functions. United States. doi:10.1103/PHYSREVD.83.094001.
Zhongbo, Kang, Jianwei, Qiu, C.N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, New York 11794, Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, Vogelsang, Werner, Feng, Yuan, and RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973. Sun . "Observation concerning the process dependence of the Sivers functions". United States. doi:10.1103/PHYSREVD.83.094001.
@article{osti_21541588,
title = {Observation concerning the process dependence of the Sivers functions},
author = {Zhongbo, Kang and Jianwei, Qiu and C.N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, New York 11794 and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 and Vogelsang, Werner and Feng, Yuan and RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973},
abstractNote = {The k{sub perpendicular} moment of a quark's Sivers function is known to be related to the corresponding twist-three quark-gluon correlation function T{sub q,F}(x,x). The two functions have been extracted from data for single-spin asymmetries in semi-inclusive deep-inelastic scattering and in single-inclusive hadron production in pp collisions, respectively. Performing a consistent comparison of the extracted functions, we find that they show a ''sign mismatch'': while the magnitude of the functions is roughly consistent, the k{sub perpendicular} moment of the Sivers function has opposite sign from that of T{sub q,F}(x,x), both for up and for down quarks. Barring any inconsistencies in our theoretical understanding of the Sivers functions and their process dependence, the implication of this mismatch is that either the Sivers effect is not dominantly responsible for the observed single-spin asymmetries in pp collisions or the current semi-inclusive lepton scattering data do not sufficiently constrain the k{sub perpendicular} moment of the quark Sivers functions. Both possibilities strengthen the case for further experimental investigations of single-spin asymmetries in high-energy pp and ep scattering.},
doi = {10.1103/PHYSREVD.83.094001},
journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 9,
volume = 83,
place = {United States},
year = {2011},
month = {5}
}