Measurement of the transverse polarization of Λ and Λ ¯ hyperons produced in proton-proton collisions at √s = 7 TeV using the ATLAS detector

The transverse polarization of Λ and Λ¯ hyperons produced in proton-proton collisions at a center-of-mass energy of 7 TeV is measured. The analysis uses 760 μb-1 of minimum bias data collected by the ATLAS detector at the LHC in the year 2010. The measured transverse polarization averaged over Feynm...

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Autor principal: Aad, G.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_15507998_v91_n3_p_Aad
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Sumario:The transverse polarization of Λ and Λ¯ hyperons produced in proton-proton collisions at a center-of-mass energy of 7 TeV is measured. The analysis uses 760 μb-1 of minimum bias data collected by the ATLAS detector at the LHC in the year 2010. The measured transverse polarization averaged over Feynman xF from 5×10-5 to 0.01 and transverse momentum pT from 0.8 to 15 GeV is -0.010±0.005(stat)±0.004(syst) for Λ and 0.002±0.006(stat)±0.004(syst) for Λ¯. It is also measured as a function of xF and pT, but no significant dependence on these variables is observed. Prior to this measurement, the polarization was measured at fixed-target experiments with center-of-mass energies up to about 40 GeV. The ATLAS results are compatible with the extrapolation of a fit from previous measurements to the xF range covered by this measurement. © 2015 CERN, for the ATLAS Collaboration.