https://doi.org/10.1140/epjc/s10052-021-09457-2
Regular Article - Theoretical Physics
Boer–Mulders function of the pion and pretzelosity distribution of the proton in the polarized pion-proton Drell–Yan process at COMPASS
1
School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, 100871, Beijing, China
2
Center for High Energy Physics, Peking University, 100871, Beijing, China
3
Collaborative Innovation Center of Quantum Matter, Beijing, China
Received:
25
May
2021
Accepted:
14
July
2021
Published online:
20
July
2021
We present a phenomenological analysis of the 
-weighted transverse spin dependent azimuthal asymmetry recently measured by the COMPASS Collaboration in polarized pion-proton Drell–Yan process. In the kinematical regimes explored by experiments, we consider the leading-twist contributions from the Boer–Mulders distribution functions 
of both the pion and the proton, the transversity distribution 
and the pretzelosity distribution 
of the proton, with the unpolarized transverse-momentum-dependent distribution function 
of the proton being also involved in the calculation. By comparing the data reported by the COMPASS Collaboration with theoretical calculated results, we find that the COMPASS measurements represent the first experimental evidence of the Boer–Mulders effect in polarized Drell–Yan process. We also test the universality between proton and pion Boer–Mulders functions.
© The Author(s) 2021
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Funded by SCOAP3
