J/psi polarization from fixed-target to collider energies

Dec, 2008
7 pages
Published in:
  • Phys.Rev.Lett. 102 (2009) 151802
e-Print:
Report number:
  • CERN-PH-EP-2008-024

Citations per year

20092013201720212023024681012
Abstract: (arXiv)
The determination of the magnitude and 'sign' of the J/psi polarization crucially depends on the reference frame used in the analysis of the data and a full understanding of the polarization phenomenon requires measurements reported in two 'orthogonal' frames, such as the Collins-Soper and helicity frames. Moreover, the azimuthal anisotropy can be, in certain frames, as significant as the polar one. The seemingly contradictory J/psi polarization results reported by E866, HERA-B and CDF can be consistently described assuming that the most suitable axis for the measurement is along the direction of the relative motion of the colliding partons, and that directly produced J/psi's are longitudinally polarized at low momentum and transversely polarized at high momentum. We make specific predictions that can be tested on existing CDF data and by LHC measurements, which should show a full transverse polarization for direct J/psi mesons of pT > 25 GeV/c.
  • 13.88.+e
  • 13.20.Gd
  • anti-p p: interaction
  • p nucleus: inclusive reaction
  • J/psi(3100): hadroproduction
  • J/psi(3100): polarization
  • polarization: transverse
  • polarization: longitudinal
  • CDF
  • CERN LHC Coll