Transverse quark spin effects and the flavor dependence of the Boer-Mulders function
- Division of Science, Penn State Berks, Reading, Pennsylvania 19610 (United States)
- Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)
- Theory Center, Jefferson Lab, Newport News, Virginia 23608 (United States)
The naive time-reversal-odd (''T-odd'') parton distribution h{sub 1}{sup perpendicular}, the so-called Boer-Mulders function, for both up (u) and down (d) quarks is considered in the diquark spectator model. While the results of different articles in the literature suggest that the signs of the Boer-Mulders function in semi-inclusive deep inelastic scattering (SIDIS) for both flavors u and d are the same and negative, a previous calculation in the diquark spectator model found that h{sub 1}{sup perpendicular(u)} and h{sub 1}{sup perpendicular(d)} have different signs. The flavor dependence is of significance for the analysis of the azimuthal cos(2{phi}) asymmetries in unpolarized SIDIS and Drell-Yan processes, as well as for the overall physical understanding of the distribution of transversely polarized quarks in unpolarized nucleons. We find substantial differences with previous work. In particular, we obtain half and first moments of the Boer-Mulders function that are negative over the full range in Bjorken x for both the u and d quarks. In conjunction with the Collins function, we then predict the cos(2{phi}) azimuthal asymmetry for {pi}{sup +} and {pi}{sup -} in this framework. We also find that the Sivers u and d quarks are negative and positive, respectively. As a by-product of the formalism, we calculate the chiral-odd but ''T-even'' function h{sub 1L}{sup perpendicular}, which allows us to present a prediction for the single-spin asymmetry A{sub UL}{sup sin(2{phi})} for a longitudinally polarized target in SIDIS.
- OSTI ID:
- 21250122
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 77, Issue 9; Other Information: DOI: 10.1103/PhysRevD.77.094016; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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