| Resumen |
We present measurements of direct photon pair production cross sections using 8.5 fb-1 of data collected with the D0 detector at the Fermilab Tevatron pp collider. The results are presented as differential distributions of the photon pair invariant mass dσ/dMγγ, pair transverse momentum dσ/dpTγγ, azimuthal angle between the photons dσ/dδφγγ, and polar scattering angle in the Collins-Soper frame dσ/d|cosθ*|. Measurements are performed for isolated photons with transverse momenta pTγ>18(17) GeV for the leading (next-to-leading) photon in pT, pseudorapidities |ηγ|<0.9, and a separation in η-φ space δRγγ>0.4. We present comparisons with the predictions from Monte Carlo event generators diphox and resbos implementing QCD calculations at next-to-leading order, 2γnnlo at next-to-next-to-leading order, and sherpa using matrix elements with higher-order real emissions matched to parton shower. |
