https://doi.org/10.1140/epjc/s10052-018-6114-4
Regular Article - Theoretical Physics
Boer-Mulders effect in the unpolarized pion induced Drell–Yan process at COMPASS within TMD factorization
1
School of Physics, Southeast University, Nanjing, 211189, China
2
School of Physics and Engineering, Zhengzhou University, Zhengzhou, 450001, Henan, China
3
School of Physics and Telecommunication Engineering, Zhoukou Normal University, Zhoukou, 466000, China
* e-mail: zhunlu@seu.edu.cn
Received:
9
May
2018
Accepted:
27
July
2018
Published online:
11
August
2018
We investigate the theoretical framework of the 
azimuthal asymmetry contributed by the coupling of two Boer-Mulders functions in the dilepton production unpolarized 
Drell–Yan process by applying the transverse momentum dependent factorization at leading order. We adopt the model calculation results of the unpolarized distribution function 
and Boer-Mulders function 
of pion meson from the light-cone wave functions. We take into account the transverse momentum dependent evolution effects for both the distribution functions of pion and proton by adopting the existed extraction of the nonperturbative Sudakov form factor for the pion and proton distribution functions. An approximate kernel is included to deal with the energy dependence of the Boer-Mulders function related twist-3 correlation function 
needed in the calculation. We numerically estimate the Boer-Mulders asymmetry 
as the functions of 
, 
, 
and 
considering the kinematics at COMPASS Collaboration.
© The Author(s), 2018
