A measurement of the cross-section for Upsilon(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. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved. RI Jones, Roger/H-5578-2011; Marti-Garcia, Salvador/F-3085-2011; collins-tooth, christopher/A-9201-2012; Ferrando, James/A-9192-2012; Perrino, Roberto/B-4633-2010; De Cecco, Sandro/B-1016-2012; Stoicea, Gabriel/B-6717-2011; branchini, paolo/A-4857-2011; Wolter, Marcin/A-7412-2012; McKee, Shawn/B-6435-2012; Rotaru, Marina/A-3097-2011; O'Shea, Val/G-1279-2010; Doyle, Anthony/C-5889-2009; Buttar, Craig/D-3706-2011; Robson, Aidan/G-1087-2011; Takai, Helio/C-3301-2012; St.Denis, Richard/C-8997-2012; Britton, David/F-2602-2010; Pina, Joao /C-4391-2012; Li, Xuefei/C-3861-2012; Fazio, Salvatore /G-5156-2010; Smirnova, Lidia/D-8089-2012; 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; Price, Darren/E-6162-2012; Alexa, Calin/F-6345-2010; Pacheco Pages, Andres/C-5353-2011; 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; Delmastro, Marco/I-5599-2012

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. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved.

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. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved.

Measurement of the upsilon(1S) production cross-section in pp collisions at root s = 7 TeV

Capua M;Crosetti G;Fazio S;LA ROTONDA, Laura;Mastroberardino A;Meoni E;