Measurement of the transverse polarization of Lambda and (Lambda)over-bar hyperons produced in proton-proton collisions at root s=7 TeV using the ATLAS detector


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Aad G., Abbott B., Abdallah J., Khalek S. A. , Abdinov O., Aben R., ...Daha Fazla

PHYSICAL REVIEW D, cilt.91, 2015 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

The transverse polarization of Lambda and (Lambda) over bar hyperons produced in proton-proton collisions at a center-of-mass energy of 7 TeV is measured. The analysis uses 760 mu b(-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(F) from 5 x 10(-5) to 0.01 and transverse momentum p(T) from 0.8 to 15 GeV is -0.010 +/- 0.005(stat) +/- 0.004(syst) for Lambda and 0.002 +/- 0.006(stat) +/- 0.004(syst) for (Lambda) over bar. It is also measured as a function of x(F) and p(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(F) range covered by this measurement.