The ATLAS experiment has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at root s = 7 TeV. The full data set acquired in 2010 is used, corresponding to an integrated luminosity of 37 pb(-1). The background, consisting of hadronic jets and isolated electrons, is estimated with fully data-driven techniques and subtracted. The differential cross sections, as functions of the di-photon mass (m(gamma gamma)), total transverse momentum (p(T),(gamma gamma)), and azimuthal separation (Delta phi(gamma gamma)), are presented and compared to the predictions of next-to-leading-order QCD. RI Ferrando, James/A-9192-2012; collins-tooth, christopher/A-9201-2012; Perrino, Roberto/B-4633-2010; Laurelli, Paolo/B-1432-2012; De Cecco, Sandro/B-1016-2012; Stoicea, Gabriel/B-6717-2011; branchini, paolo/A-4857-2011; della Volpe, Domenico/B-4482-2012; Wolter, Marcin/A-7412-2012; valente, paolo/A-6640-2010; O'Shea, Val/G-1279-2010; Doyle, Anthony/C-5889-2009; Li, Xuefei/C-3861-2012; Buttar, Craig/D-3706-2011; Pina, Joao /C-4391-2012; Takai, Helio/C-3301-2012; St.Denis, Richard/C-8997-2012; Jones, Roger/H-5578-2011; Robson, Aidan/G-1087-2011; Britton, David/F-2602-2010; Fazio, Salvatore /G-5156-2010; Smirnova, Lidia/D-8089-2012; Sivoklokov, Sergey/D-8150-2012; Smirnov, Sergei/F-1014-2011; Gladilin, Leonid/B-5226-2011; Barreiro, Fernando/D-9808-2012; Kramarenko, Victor/E-1781-2012; Prokoshin, Fedor/E-2795-2012; Alexa, Calin/F-6345-2010; Gutierrez, Phillip/C-1161-2011; Pacheco Pages, Andres/C-5353-2011; Moorhead, Gareth/B-6634-2009; Livan, Michele/D-7531-2012; Petrucci, Fabrizio/G-8348-2012; Wemans, Andre/A-6738-2012; Fabbri, Laura/H-3442-2012; Kurashige, Hisaya/H-4916-2012; Villa, Mauro/C-9883-2009; Kuzhir, Polina/H-8653-2012; Delmastro, Marco/I-5599-2012

Measurement of the isolated diphoton cross section in pp collisions at root s=7 TeV with the ATLAS detector

CAPUA, Marcella;Crosetti G;Fazio S;LA ROTONDA, Laura;MASTROBERARDINO, Anna;Meoni E;