Measurement of the cross section for production of two isolated prompt photons in<i>pp¯</i>collisions at √<i>s</i>=1.8 TeV

Abstract

We present measurements from events with two isolated prompt photons in p\ifmmode\bar\else\textasciimacron\fi{}p collisions at \ensuremath{\surd}s =1.8 TeV. The differential cross section, measured as a function of transverse momentum (${\mathit{P}}_{\mathit{T}}$) of each photon, is about 3 times what next-to-leading-order QCD calculations predict. The cross section for photons with ${\mathit{P}}_{\mathit{T}}$ in the range 10--19 GeV is 86\ifmmode\pm\else\textpm\fi{}27(stat${)}_{\mathrm{\ensuremath{-}}23}^{+32}$(syst) pb. We also study the correlation between the two photons in both azimuthal angle and ${\mathit{P}}_{\mathit{T}}$. The magnitude of the vector sum of the transverse momenta of both photons, ${\mathit{K}}_{\mathit{T}}$=\ensuremath{\Vert}${\mathbf{P}}_{\mathit{T}1}$+${\mathbf{P}}_{\mathit{T}2}$\ensuremath{\Vert}, has a mean value of 〈${\mathit{K}}_{\mathit{T}}$〉=5.1\ifmmode\pm\else\textpm\fi{}1.1 GeV.