High p_T Direct Photon and pi^0 Triggered Azimuthal Jet Correlations in sqrt(s)=200 GeV p+p Collisions

Understand

Correlations of charged hadrons of 1 < pT < 10 GeV/c with high pT direct photons and pi^ 0 mesons in the range 5 <pT < 15 GeV/c are used to study jet fragmentation in the photon+jet and di-jet channels, respectively.

• The magnitude of the partonic transverse momentum, kT, is obtained by comparing to a model incorporating a Gaussian kT smearing.
• The sensitivity of the associated charged hadron spectra to the underlying fragmentation function is tested and the data are compared to calculations using recent global fit results.
• The shape of the direct photon-associated hadron spectrum as well as its charge asymmetry are found to be consistent with a sample dominated by quark-gluon Compton scattering.