J.C. Lee

Inclusive double-quarkonium production at the Large Hadron Collider

Based on the nonrelativistic QCD (NRQCD) factorization formalism, we investigate inclusive productions of two spin-triplet S-wave quarkonia pp → 2J/ψ + X, 2Υ + X, and J/ψ + Υ + X at the CERN Large Hadron Collider. The total production rates integrated over the rapidity (y) and transverse-momentum (pT) ranges |y| < 2.4 and pT< 50GeV are predicted to be σ[pp → 2J/ψ + X] = 22 (35) nb, σ[pp → 2Υ + X ]= 24 (49) pb, and σ[pp → J/ψ + Υ + X ] = 7 (13) pb at the center-of-momentum energy

Optimal spin-quantization axes for the polarization of dileptons with large transverse momentum

\sqrt {s} = 7\left( {14} \right)\;{\text{TeV}}

Factorization in exclusive quarkonium production

. In order to provide predictions that can be useful in both small- and large-pT regions, we do not employ the fragmentation approximation and we include the spin-triplet S-wave color-singlet and color-octet channels for each quarkonium final state at leading order in the strong coupling. The pT distributions of pp → 2J/ψ + X and 2Υ + X in the low-pT region are dominated by the color-singlet contributions. At leading order in the strong coupling, the color-singlet channel is absent for pp → J/ψ + Υ + X. Therefore, the process pp → J/ψ + Υ + X may provide a useful probe to the color-octet mechanism of NRQCD.

Reconciling the light-cone and nonrelativistic QCD approaches to calculating e+ e- → J/ψ + ηc

The leading-order parton processes that produce a dilepton with large transverse momentum predict that the transverse polarization should increase with the transverse momentum for almost any choice of the quantization axis for the spin of the virtual photon. The rate of approach to complete transverse polarization depends on the choice of spin quantization axis. We propose axes that optimize that rate of approach. They are determined by the momentum of the dilepton and the direction of the jet that provides most of the balancing transverse momentum.

Higher-order relativistic corrections to gluon fragmentation into spin-triplet S-wave quarkonium

We present factorization theorems for two exclusive heavy-quarkonium production processes: production of two quarkonia in

Fragmentation contributions to hadroproduction of prompt J/ψ , χ

{e}^{+}{e}^{\ensuremath{-}}

_{cJ}

annihilation and production of a quarkonium and a light meson in

, and ψ(2S) states

B

NRQCD matrix elements for S-wave bottomonia and Γ[ηb(nS)→γγ] with relativistic corrections

-meson decays. We describe the general proofs of factorization and supplement them with explicit one-loop analyses, which illustrate some of the features of the soft-gluon cancellations. We find that violations of factorization are generally suppressed relative to the factorized contributions by a factor

New techniques for emulsion analysis in a hybrid experiment

{v}^{2}{m}_{c}/Q