Physics Letters B.
We report on a polarization measurement of inclusive J/Ѱ 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/Ѱ polarization measurement should help to distinguish between different models of the J/Ѱ production mechanism since they predict different pT dependences of the J/Ѱ polarization. In this analysis, J/Ѱ is studied in the helicity frame. The polarization parameter λθ measured at RHIC becomes smaller towards high pT, indicating more longitudinal J/Ѱ polarization as pT increases. The result is compared with predictions of presently available models.
Original Publication Citation
Adamczyk, L., Adkins, J. K., Agakishiev, G., Aggarwal, M. M., Ahammed, Z., Alekseev, I., . . . Zyzak, M. (2014). J/Ѱ polarization in p plus p collisions at √s=200 GeV in STAR. Physics Letters B, 739, 180-188. doi: 10.1016/j.physletb.2014.10.049
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; and Bültmann, S., "J/Ѱ polarization in p+p collisions at √s = 200 GeV in STAR" (2014). Physics Faculty Publications. 55.