Observation of Polarization in Bottomonium Production at sqrt(s)=38.8 GeV
Preprint
- 9 November 2000
Abstract
We present a measurement of the polarization observed for bottomonium states produced in p-Cu collisions at sqrt(s)=38.8 GeV. The angular distribution of the decay dimuons of the Upsilon(1S) state show no polarization at small xF and pT but significant positive transverse production polarization for either pT > 1.8 GeV/c or for xF > 0.35. The Upsilon(2S+3S) unresolved states show a large transverse production polarization at all values of xF and pT measured. These observations are compared with an NRQCD calculation that predicts a transverse polarization in bottomonium production arising from quark-antiquark fusion and gluon-gluon fusion diagrams.Keywords
All Related Versions
- Version 1, 2000-11-09, ArXiv
- Published version: Physical Review Letters, 86 (12), 2529.
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