INVESTIGADORES
MONTICELLI Fernando Gabriel
artículos
Título:
Measurement of Upsilon production in 7 TeV pp collisions at ATLAS
Autor/es:
ATLAS COLLABORATION, G. AAD, F. MONTICELLI, ET AL
Revista:
PHYSICAL REVIEW D
Editorial:
AMER PHYSICAL SOC
Referencias:
Lugar: New York; Año: 2012 vol. 87 p. 1 - 54
ISSN:
1550-7998
Resumen:
Using 1.8 fb-1 of pp collisions at a center-of-mass energy of 7 TeV
recorded by the ATLAS detector at the Large Hadron Collider, we present
measurements of the production cross sections of Upsilon(1S,2S,3S)
mesons. Upsilon mesons are reconstructed using the di-muon decay mode.
Total production cross sections for p_T<70 GeV and in the rapidity
interval |Upsilon|<2.25 are measured to be 8.01+-0.02+-0.36+-0.31 nb,
2.05+-0.01+-0.12+-0.08 nb, 0.92+-0.01+-0.07+-0.04 nb respectively, with
uncertainties separated into statistical, systematic, and luminosity
measurement effects. In addition, differential cross section times
di-muon branching fractions for Upsilon(1S), Upsilon(2S), and
Upsilon(3S) as a function of Upsilon transverse momentum p_T and
rapidity are presented. These cross sections are obtained assuming
unpolarized production. If the production polarization is fully
transverse or longitudinal with no azimuthal dependence in the helicity
frame the cross section may vary by approximately +-20%. If a
non-trivial azimuthal dependence is considered, integrated cross
sections may be significantly enhanced by a factor of two or more. We
compare our results to several theoretical models of Upsilon meson
production, finding that none provide an accurate description of our
data over the full range of Upsilon transverse momenta accessible with
this dataset.