J/ψ production at \sqrt{s}=1.96 and 7 TeV: colour-singlet model, NNLO⋆and polarization

J P Lansberg
2011 Journal of Physics G: Nuclear and Particle Physics  
We study J/psi production in pp collisions at sqrt(s)=1.96 and 7 TeV using the Colour-Singlet Model (CSM), including next-to-leading order (NLO) corrections and dominant alphaS^5 contributions (NNLO*). We find that the CSM reproduces the existing data if the upper range of the NNLO* is near the actual --but presently unknown-- NNLO. The direct yield polarisation for the NLO and NNLO* is increasingly longitudinal in the helicity frame when P_T gets larger. Contrary to what is sometimes claimed
more » ... the literature, the prompt J/psi yield polarisation in the CSM is compatible with the experimental data from the CDF collaboration, when one combines the direct yield with a data-driven range for the polarisation of J/psi from chi(c).
doi:10.1088/0954-3899/38/12/124110 fatcat:bts3tki27jgjxja25uafr2p6yu