Gluon distribution at very small x from C-even quarkonia production at the LHC

Abstract

C-parity-even quarkonia eta_b,c and chi_b,c with spin 0 and 2 are produced via two-gluon fusion. The expected cross section of the inclusive production of the quarkonia at the LHC, times the branching ratios of convenient decays, is up to tens of nanobarn per unit rapidity in the case of charmonia and around one nanobarn for the bottomonia. Measuring the quarkonia production as function of rapidity will allow to determine the gluon distribution function in nucleons in a very broad range of the Bjorken x from x~10^(-2) where it is already known, down to x~10^(-6) where it is totally unknown. The scale of the gluon distribution found from such measurements turns out to be rather low, Q^2 ~ 2.5 - 3 GeV^2, for charmonia and rather large, Q^2 ~ 20 GeV^2$, for bottomonia. We evaluate the scale by studying the next-to-leading-order production cross sections.

20 pages, 5 figures. A new section on bottomonia production, and additional discussion and references added

References in corpus (5)

• Parton distributions for the LHC
• New parton distributions for collider physics
• Parton Distributions for LHC
• Quarkonium Physics at a Fixed-Target Experiment using the LHC Beams
• Drell-Yan as a probe of small x partons at the LHC

Cited by in corpus (11)

• Lattice QCD and QCD Sum Rule determination of the decay constants of eta_c, J/psi and hc states
• Transverse single spin asymmetry in hadronic ${\eta }_{c,b}$ production
• Hadroproduction of scalar $P$-wave quarkonia in the light-front $k_T$-factorization approach
• Prompt hadroproduction of ${\eta }_c(1S,2S)$ in the $k_T$-factorization approach
• Spin physics and TMD studies at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)
• Two Photon Decays of ${\eta }_c$ from Lattice QCD
• AFTER@LHC: a precision machine to study the interface between particle and nuclear physics
• Improving the Drell-Yan probe of small x partons at the LHC via a k_t cut
• Multiplicity dependence of ${\chi }_c$ and ${\chi }_b$ meson production
• Prospectives for A Fixed-Target ExpeRiment at the LHC: AFTER@LHC
• Inclusive prompt ${\chi }_{c,b}(1^{++})$ production at the LHC