Bertram, Iain and Borissov, Guennadi and Fox, Harald and Ratoff, Peter and Ross, Anthony and Williams, Mark and D0 Collaboration, The (2013) Measurement of the differential cross sections for isolated direct photon pair production in pp collisions at. Physics Letters B, 725 (1-3). pp. 6-14. ISSN 0370-2693
Full text not available from this repository.Abstract
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 collider. The results are presented as differential distributions of the photon pair invariant mass dσ/dMγγ, pair transverse momentum , azimuthal angle between the photons dσ/dΔϕγγ, and polar scattering angle in the Collins–Soper frame . Measurements are performed for isolated photons with transverse momenta 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.