Physical Review C
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 eta -> e(+) e(-) of 1.7 x 10-5 at the 90% confidence level.
Original Publication Citation
Adamczyk, L., Agakishiev, G., Aggarwal, M. M., Ahammed, Z., Alakhverdyants, A. V., Alekseev, I., . . . Zoulkarneeva, Y. (2012). Di-electron spectrum at mid-rapidity in p+p collisions at √s=200 GeV. Physical Review C, 86(2), 024906. doi:10.1103/PhysRevC.86.024906
Adamczyk, L.; Bueltmann, S.; Koralt, I.; Plyku, D.; Zoulkarneeva, Y.; and STAR Collaboration, "Di-Electron Spectrum at Mid-Rapidity in p+p Collisions at √s=200 GeV" (2012). Physics Faculty Publications. 179.