Constraints on Nonrelativistic-QCD Long-Distance Matrix Elements from J/ψ Plus W/Z Production at the LHC.

We study the associated production of prompt J/ψ mesons and W or Z bosons within the factorization approach of nonrelativistic QCD (NRQCD) at next-to-leading order in α_{s}, via intermediate color singlet ^{3}S_{1}^{[1]} and ^{3}P_{J}^{[1]} and color octet ^{1}S_{0}^{[8]}, ^{3}S_{1}^{[8]}, and ^{3}P_{J}^{[8]} states. Requiring for our predictions to be compatible with recent ATLAS measurements yields stringent new constraints on charmonium long-distance matrix elements (LDMEs) being nonperturbative, process-independent input parameters. Considering four popular LDME sets fitted to data of single J/ψ inclusive production, we find that one is marginally compatible with the data, with central predictions typically falling short by a factor of 3, one is unfavored, the factor of shortfall being about 1 order of magnitude, and two violate cross section positivity for direct J/ψ+W/Z production.

Nonplanar Cusp and Transcendental Anomalous Dimension at Four Loops in N=4 Supersymmetric Yang-Mills Theory.

We compute the nonplanar contribution to the universal anomalous dimension of the SU(4)-singlet twist-two operators in N=4 supersymmetric Yang-Mills theory at four loops through Lorentz spin 18. From this, we numerically evaluate the nonplanar contribution to the four-loop lightlike cusp anomalous dimension and derive the transcendental ζ_{3} and ζ_{5} parts of the universal anomalous dimension for arbitrary Lorentz spin in analytic form. As for the lightlike cusp anomalous dimension and the ζ_{5} part of the universal anomalous dimension, we confirm previous results.

Double Prompt J/ψ Hadroproduction in the Parton Reggeization Approach with High-Energy Resummation.

We study double prompt J/ψ hadroproduction within the nonrelativistic-QCD factorization formalism adopting the parton Reggeization approach to treat initial-state radiation in a gauge invariant and infrared-safe way. We present first predictions for the cross section distributions in the transverse momenta of the subleading J/ψ meson and the J/ψ pair. Already at leading order in α_{s}, these predictions as well as those for the total cross section and its distributions in the invariant mass m_{ψψ} and the rapidity separation |Y| of the J/ψ pair nicely agree with recent ATLAS and CMS Collaboration measurements, except for the large-m_{ψψ} and large-|Y| regions, where the predictions substantially undershoot the data.

Deciphering the X(3872) via its Polarization in Prompt Production at the CERN LHC.

Based on the hypothesis that the X(3872) exotic hadron is a mixture of χ_{c1}(2P) and other states and that its prompt hadroproduction predominately proceeds via its χ_{c1}(2P) component, we calculate the prompt-X(3872) polarization at the CERN LHC through next-to-leading order in α_{s} within the factorization formalism of nonrelativistic QCD, including both the color-singlet ^{3}P_{1}^{[1]} and color-octet ^{3}S_{1}^{[8]} cc[over ¯] Fock states. We also consider the polarization of the J/ψ produced by the subsequent X(3872) decay. We predict that, under ATLAS, CMS, and LHCb experimental conditions, the X(3872) is largely longitudinally polarized, while the J/ψ is largely transversely polarized.

Breakdown of Nonrelativistic QCD Factorization in Processes Involving Two Quarkonia and its Cure.

We study inclusive processes involving two heavy quarkonia in nonrelativistic QCD (NRQCD) and demonstrate that, in the presence of two P-wave Fock states, NRQCD factorization breaks down, leaving uncanceled infrared singularities. As phenomenologically important examples, we consider the decay ϒ→χ_{cJ}+X via bb[over ¯](^{3}P_{J_{b}}^{[8]})→cc[over ¯](^{3}P_{J}^{[1]})+gg and the production process e^{+}e^{-}→J/ψ+χ_{cJ}+X via e^{+}e^{-}→cc[over ¯](^{3}P_{J_{1}}^{[8]})+cc[over ¯](^{3}P_{J}^{[1]})+g. We infer that such singularities will appear for double quarkonium hadroproduction at next-to-leading order.