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

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

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Bibliographic Details
Main Author: Taylor, Frank E.
Other Authors: Massachusetts Institute of Technology. Department of Physics
Format: Article
Language:en_US
Published: American Physical Society 2015
Online Access:http://hdl.handle.net/1721.1/97387
https://orcid.org/0000-0002-7586-7253
Description
Summary:The transverse polarization of Λ and [bar over Λ] hyperons produced in proton-proton collisions at a center-of-mass energy of 7 TeV is measured. The analysis uses 760  μb[superscript −1] of minimum bias data collected by the ATLAS detector at the LHC in the year 2010. The measured transverse polarization averaged over Feynman x[subscript F] from 5 × 10[superscript −5] to 0.01 and transverse momentum p[subscript T] 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 [bar over Λ]. It is also measured as a function of x[subscript F] and p[subscript T], 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 x[subscript F] range covered by this measurement.