We report on a polarization measurement of inclusive J/psi mesons in the di-electron decay channel at mid-rapidity at 2 < p(T) < 6 GeV/c in p + p collisions at root s = 200 GeV. Data were taken with the STAR detector at RHIC. The J/psi polarization measurement should help to distinguish between different models of the J/psi production mechanism since they predict different p(T) dependences of the J/psi polarization. In this analysis, J/psi is studied in the helicity frame. The polarization parameter lambda(theta) measured at RHIC becomes smaller towards high p(T), indicating more longitudinal J/psi polarization as p(T) increases. The result is compared with predictions of presently available models. (C) 2014 The Authors. Published by Elsevier B.V.

J/psi polarization in p plus p collisions at root s=200 GeV in STAR

di Ruzza B;
2014-01-01

Abstract

We report on a polarization measurement of inclusive J/psi mesons in the di-electron decay channel at mid-rapidity at 2 < p(T) < 6 GeV/c in p + p collisions at root s = 200 GeV. Data were taken with the STAR detector at RHIC. The J/psi polarization measurement should help to distinguish between different models of the J/psi production mechanism since they predict different p(T) dependences of the J/psi polarization. In this analysis, J/psi is studied in the helicity frame. The polarization parameter lambda(theta) measured at RHIC becomes smaller towards high p(T), indicating more longitudinal J/psi polarization as p(T) increases. The result is compared with predictions of presently available models. (C) 2014 The Authors. Published by Elsevier B.V.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11369/426406
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 10
social impact