Virtual photon fragmentation functions

Abstract

We introduce operator definitions for virtual photon fragmentation functions, which are needed for reliable calculations of Drell-Yan transverse momentum ($Q_T$) distributions when $Q_T$ is much larger than the invariant mass $Q$. We derive the evolution equations for these fragmentation functions. We calculate the leading order evolution kernels for partons to fragment into a unpolarized as well as a polarized virtual photon. We find that fragmentation functions to a longitudinally polarized virtual photon are most important at small $z$, and the fragmentation functions to a transversely polarized virtual photon dominate the large $z$ region. We discuss the implications of this finding to the J/$\psi$ mesons' polarization at large transverse momentum.

Latex, 19 pages including 6 figures. An error in the first version has been corrected, and references updated

References in corpus (3)

• Role of the nonperturbative input in QCD resummed Drell-Yan $Q_T$-distributions
• QCD prediction for heavy boson transverse momentum distributions
• Drell-Yan Massive Lepton-Pair's Angular Distributions at Large $Q_T$

Cited by in corpus (15)

• Theory of hard photoproduction
• Heavy Quarkonium Production at Collider Energies: Factorization and Evolution
• The hadronization of partons
• QCD Factorized Drell-Yan Cross Section at Large Transverse Momentum
• High Momentum Dilepton Production from Jets in a Quark Gluon Plasma
• Cosmic Ray Signals from Mini Black Holes in Models with Extra Dimensions: An Analytical/Monte Carlo Study
• Single transverse spin asymmetry of prompt photon production
• Low-mass lepton pair production at large transverse momentum
• Full transverse-momentum spectra of low-mass Drell-Yan pairs at LHC energies
• Strong nuclear enhancement in intermediate mass Drell-Yan production
• Fragmentation Functions for Lepton Pairs
• Low-mass dilepton production in $pp$ and $AA$ collisions
• Probing small-$x$ gluons by low-mass Drell-Yan pairs at colliders
• Hadronic production of $W$ and $Z$ bosons at large transverse momentum
• Intermediate mass dileptons in relativistic nuclear collisions