Di-electron spectrum at mid-rapidity in p+p collisions at s=200 GeV Academic Article uri icon


  • We report on the mid-rapidity mass spectrum of di-electrons and cross sections of pseudoscalar and vector mesons via e+e- decays, from √s=200 GeV p+p collisions, measured by the large-acceptance experiment STAR at the Relativistic Heavy Ion Collider. The ratio of the di-electron continuum to the combinatorial background is larger than 10% over the entire mass range. Simulations of di-electrons from light-meson decays and heavy-flavor decays (charmonium and open charm correlation) are found to describe the data. The extracted ω→e+e- invariant yields are consistent with previous measurements. The mid-rapidity yields (dN/dy) of φ and J/ψ are extracted through their di-electron decay channels and are consistent with the previous measurements of φ→K+K- and J/ψ→e+e -. Our results suggest a new upper limit of the branching ratio of the η→e+e- of 1.7×10-5 at the 90% confidence level. © 2012 American Physical Society.

author list (cited authors)

  • Adamczyk, L., Agakishiev, G., Aggarwal, M. M., Ahammed, Z., Alakhverdyants, A. V., Alekseev, I., ... Zoulkarneeva, Y.

citation count

  • 24

publication date

  • August 2012