TY - JOUR AU - ATLAS Collaboration (Aad, G. et al AU - Amoros, G. AU - Cabrera Urban, S. AU - Castillo Gimenez, V. AU - Costa, M. J. AU - Escobar, C. AU - Ferrer, A. AU - Fiorini, L. AU - Fuster, J. AU - Garcia, C. AU - Gonzalez de la Hoz, S. AU - Hernandez Jimenez, Y. AU - Higon-Rodriguez, E. AU - Irles Quiles, A. AU - Kaci, M. AU - Lacasta, C. AU - Lacuesta, V. R. AU - Marti-Garcia, S. AU - Miñano, M. AU - Mitsou, V. A. AU - Moles-Valls, R. AU - Moreno Llacer, M. AU - Oliver Garcia, E. AU - Perez Garcia-Estañ, M. T. AU - Ros, E. AU - Salt, J. AU - Solans, C. A. AU - Soldevila, U. AU - Sanchez, J. AU - Torro Pastor, E. AU - Valladolid Gallego, E. AU - Valls Ferrer, J. A. AU - Villaplana Perez, M. AU - Vos, M. AU - Wildauer, A. PY - 2011 DA - 2011// TI - Measurement of the gamma(1S) production cross-section in pp collisions at sqrt(s)=7 TeV in ATLAS ATLAS Collaboration T2 - Phys. Lett. B JO - Physics Letters B SP - 9 EP - 27 VL - 705 IS - 1-2 PB - Elsevier Science Bv AB - 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. SN - 0370-2693 UR - http://arxiv.org/abs/1106.5325 UR - https://doi.org/10.1016/j.physletb.2011.09.092 DO - 10.1016/j.physletb.2011.09.092 LA - English N1 - WOS:000296937000003 ID - ATLASCollaborationAad_etal2011 ER -