6533b82efe1ef96bd1292f09

RESEARCH PRODUCT

Measurement of the Upsilon(1S) production cross-section in pp collisions at sqrt(s) = 7 TeV in ATLAS

Atlas CollaborationVasiliki MitsouAntonio Ferrer SoriaJuan Antonio Valls FerrerMaría Victoria Castillo GiménezMaría José Costa MezquitaJuan A. Fuster VerdúLuca FioriniEduardo Ros MartínezYesenia Hernández JiménezCarlos Lacasta LlácerEmilio Higón RodríguezJosé Salt CairolsSantiago González De La HozAdrián Irles QuilesMohammed KaciSalvador Martí GarcíaVicente Lacuesta MiquelMercedes Miñano MoyaMiguel Villaplana Pérez

subject

Col·lisions (Física nuclear)High Energy Physics::PhenomenologyHigh Energy Physics::ExperimentFísica nuclearNuclear Experiment

description

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 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.

10.1016/j.physletb.2011.09.092http://hdl.handle.net/10550/36020