2017/11/20 by Anna Cisek, Wolfgang Schäfer, Antoni Szczurek · 17 citations
Mathematics · Physics and Astronomy · #Algorithm #Gluon #Hadron #High-Energy Particle Collisions Research #Mathematics #Meson #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quark #hep-ph
paper · pdf · doi:10.1103/physrevd.97.114018
published in Physical review. D/Physical review. D. 97(11) (American Physical Society) · 15 pages, 8 figures
arxiv created 2017/11/20 · openalex created_date 2017/12/04 · openalex publication_date 2018/06/18 · arxiv updated 2018/06/27 · openalex updated_date 2026/08/05
We calculate the production of pairs of \ensuremathχcJ mesons with all possible combinations of J=0, 1, 2. The production mechanism which we consider is the crossed-channel gluon exchange in the gluon-gluon fusion reaction, the mechanism relevant for large rapidity separations between \ensuremathχc mesons. The salient features of the t and u-channel gluon exchange are the broad distributions in rapidity difference \mathrm\ensuremathΔy between \ensuremathχc mesons. The building blocks are the vertices g*g*\ensuremath→\ensuremathχcJ for off-shell gluons. We stick to the color-singlet model and calculate the gluon fusion vertices in the limit of heavy quarks with nonrelativistic motion in the bound state. These vertices are used to construct the g*g*\ensuremath→\ensuremathχ_cJ1\ensuremathχ_cJ2 amplitudes. We then calculate hadron-level cross sections using the kT-factorization approach. Several differential distributions at the pp center of mass energy √(s)=8 TeV are shown. We briefly discuss the contribution to J/\ensuremathψJ/\ensuremathψ production at large rapidity separation. For reference we show some distributions for production of \ensuremathχ_cJ1\ensuremathχ_cJ2 pairs in double parton scattering. The discussed single parton scattering mechanisms yield similar shapes of different distributions as the double parton scattering mechanisms.