%0 Journal Article %T Measurement of the gamma(1S) production cross-section in pp collisions at sqrt(s)=7 TeV in ATLAS ATLAS Collaboration %A ATLAS Collaboration (Aad, G. et al %A Amoros, G. %A Cabrera Urban, S. %A Castillo Gimenez, V. %A Costa, M. J. %A Escobar, C. %A Ferrer, A. %A Fiorini, L. %A Fuster, J. %A Garcia, C. %A Gonzalez de la Hoz, S. %A Hernandez Jimenez, Y. %A Higon-Rodriguez, E. %A Irles Quiles, A. %A Kaci, M. %A Lacasta, C. %A Lacuesta, V. R. %A Marti-Garcia, S. %A Miñano, M. %A Mitsou, V. A. %A Moles-Valls, R. %A Moreno Llacer, M. %A Oliver Garcia, E. %A Perez Garcia-Estañ, M. T. %A Ros, E. %A Salt, J. %A Solans, C. A. %A Soldevila, U. %A Sanchez, J. %A Torro Pastor, E. %A Valladolid Gallego, E. %A Valls Ferrer, J. A. %A Villaplana Perez, M. %A Vos, M. %A Wildauer, A. %J Physics Letters B %D 2011 %V 705 %N 1-2 %I Elsevier Science Bv %@ 0370-2693 %G English %F ATLASCollaborationAad_etal2011 %O WOS:000296937000003 %O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=805), last updated on Fri, 20 Jan 2012 12:56:37 +0000 %X A measurement of the cross-section for gamma(1S) -> mu(+)mu(-) production in proton-proton collisions at centre of mass energy of 7 TeV is presented. The cross-section is measured as a function of the gamma(1S) transverse momentum in two bins of rapidity, vertical bar y(gamma(1S))vertical bar < 1.2 and 1.2 < vertical bar y(gamma(1S))vertical bar < 2.4. The measurement requires that both muons have transverse momentum p(T)(mu) > 4 GeV and pseuclorapidity vertical bar eta(mu)vertical bar < 2.5 in order to reduce theoretical uncertainties on the acceptance, which depend on the poorly known polarisation. The results are based on an integrated luminosity of 1.13 pb(-1), collected with the ATLAS detector at the Large Hadron Collider. The cross-section measurement is compared to theoretical predictions: it agrees to within a factor of two with a prediction based on the NRQCD model including colour-singlet and colour-octet matrix elements as implemented in PYTHIA while it disagrees by up to a factor of ten with the next-to-leading order prediction based on the colour-singlet model. %R 10.1016/j.physletb.2011.09.092 %U http://arxiv.org/abs/1106.5325 %U https://doi.org/10.1016/j.physletb.2011.09.092 %P 9-27