Nature of hyperthermal surface ionization

Exploring the polarization of gluons in the nucleon

“…These are heavy-flavor production, p → ccX, and single-or di-hadron production, p → hX or p → h 1 h 2 X, where the hadrons have large transverse momentum. Figure 7 compiles the current results [20,37,38,39] for extractions of ∆g from these reactions. We note that, unlike at RHIC, the success of the perturbative-QCD hard-scattering description has not been established for these observables in the kinematic regimes of interest here.…”

“…. SMC [37], COMPASS [38], and HERMES [39] results for gluon polarization, extracted from photon-gluon fusion. Taken from [20].…”

COMPASS experiment at CERN: hadron spectroscopy and open charm results

“…In the first method ("open charm" [5]) the events where the charmed quark hadronized into a D 0 or a D * meson are selected. In the second method (low [6] and high Q 2 [7] "high-p T pairs"), the PGF events are identified by requiring that two oppositely charged hightransverse momentum hadrons are detected in coincidence. In the "high-p T pairs" analysis the spin helicity asymmetry is calculated by selecting events containing hadrons with p T above 0.7 and 0.4 GeV/c, for the first and for the second hadron with respect to the virtual photon direction.…”

COMPASS experiment at CERN: open charm results and future hadron program

“…In the first method ("open charm" [4]) the events where the charmed quark hadronises into a D 0 or a D * meson are selected. In the second one (low [5] and high Q 2 [6] "high-p T pairs"), the PGF events are identified by requiring that two opposite-charge high-transverse momentum hadrons are detected in coincidence. Since this method selects light quarks as well, its counting rate is high; however, competing background processes play an important role introducing model dependence of its description.…”