QCD predictions for the azimuthal asymmetry in charm leptoproduction for the COMPASS kinematics
| Autor: | Efremov, A. V., Ivanov, N. Ya., Teryaev, O. V. |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | Phys. Lett. B 772 (2017) 283-289 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1016/j.physletb.2017.06.057 |
| Popis: | We present the QCD predictions for the azimuthal $\cos 2\varphi$ asymmetry in charm leptoproduction for the kinematics of the COMPASS experiment at CERN. The asymmetry is predicted to be large, about 15%. The radiative corrections to the QCD predictions for the $\cos 2\varphi$ distribution are estimated to be small, less than 10%. Our calculations show that the azimuthal asymmetry in charm production is well defined in pQCD: it is stable both perturbatively and parametrically, and practically insensitive to theoretical uncertainties in the input parameters. We analyze the nonperturbative contributions to the $\cos 2\varphi$ distribution due to the gluon transverse motion in the target and the $c$-quark fragmentation. Because of the $c$-quark low mass, the nonperturbative contributions are expected to be sizable, about (30--40)%. We conclude that extraction of the azimuthal asymmetries from available COMPASS data will provide valuable information about the transverse momentum dependent distribution of the gluon in the proton and the $c$-quark hadronization mechanism. Finally, we discuss the $\cos 2\varphi$ asymmetry as a probe of the gluonic analogue of the Boer-Mulders function, $h_{1}^{\perp g}$, describing the linear polarization of gluons inside unpolarized proton. Comment: 9 pages, 4 figures, LaTeX, journal version |
| Databáze: | arXiv |
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