Title: QCD corrections to the $J/\psi$ production in deeply inelastic scattering at HERA 

Speaker: Dr.Hongfei Zhang (Chongqing University of Posts and Telecommunications) 

Time: 10:00 AM, May 19th, 2017(Friday) 

Place: Theoretical Physics Division，319
 
Abstract:  The speaker will first talk about the leptonic tensor in deeply inelastic scattering (DIS),which can reduce to a simple form if the azimuthal angle in the virtual-photon-proton rest frame is integrated over.However, in the laboratory frame, such reduced form will lead to wrong results when the transverse momentum or the rapidityof one particle is observed. This mistake is common in the phenomenological study of many semi-inclusive DIS processes.Some Monte Carlo generators even made the same mistake. Then, he will talk about the first phenomenological study of the $J/\psi$ production in DIS at QCD next-to-leading order, and its implication for the $J/\psi$ hadroproduciton at QCD next-to-next-to-leading order. We find that the K-factor is quite small in low $p_t$ region, and with the QCD corrections, the color-singlet contribution is still too small to describe the HERA data.