J/ψ polarization in the CGC+NRQCD approach
Abstract
We compute the J/ψ polarization observables λ θ , λ ϕ , λ θϕ in a Color Glass Condensate (CGC) + nonrelativistic QCQ (NRQCD) formalism that includes contributions from both color singlet and color octet intermediate states. Our results are compared to low p T data on J/ψ polarization from the LHCb and ALICE experiments on proton-proton collisions at center-of-mass energies of √{s}=7 TeV and 8 TeV. Our CGC+NRQCD computation provides a better description of data for p T ≤ 15 GeV relative to extant next-to-leading (NLO) calculations within the collinear factorization framework. These results suggest that higher order computations in the CGC+NRQCD framework have the potential to greatly improve the accuracy of extracted values of the NRQCD universal long distance matrix elements.
- Publication:
-
Journal of High Energy Physics
- Pub Date:
- December 2018
- DOI:
- 10.1007/JHEP12(2018)057
- arXiv:
- arXiv:1809.03573
- Bibcode:
- 2018JHEP...12..057M
- Keywords:
-
- QCD Phenomenology;
- High Energy Physics - Phenomenology;
- Nuclear Experiment;
- Nuclear Theory
- E-Print:
- 26 pages, 8 figures, accepted for publication in JHEP