Di-electron spectrum at mid-rapidity in p+p collisions at root s=200 GeV
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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 e+e- invariant yields are consistent with previous measurements. The mid-rapidity yields (dN/dy) of and J/ are extracted through their di-electron decay channels and are consistent with the previous measurements of K+K- and J/e+e -. Our results suggest a new upper limit of the branching ratio of the e+e- of 1.710-5 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.