Refine
Year of publication
Document Type
- Article (21)
Language
- English (21)
Has Fulltext
- yes (21)
Is part of the Bibliography
- no (21)
Keywords
- BESIII (9)
- Branching fractions (4)
- Hadronic decays (3)
- Initial state radiation (3)
- Branching fraction (2)
- Charmonium (2)
- Cross section (2)
- Hadronic cross section (2)
- Muon anomaly (2)
- Pion form factor (2)
We report on a polarization measurement of inclusive J/ψ mesons in the di-electron decay channel at mid-rapidity at 2 < pT < 6 GeV/c in p + p collisions at √s = 200 GeV. Data were taken with the STAR detector at RHIC. The J/ψ polarization measurement should help to distinguish between different models of the J/ψ production mechanism since they predict different pT dependences of the J/ψ polarization. In this analysis, J/ψ polarization is studied in the helicity frame. The polarization parameter λθ measured at RHIC becomes smaller towards high pT , indicating more longitudinal J/ψ polarization as pT increases. The result is compared with predictions of presently available models.