Search for High-Mass e+e- Resonances in p anti-p Collisions at s**(1/2) =1.96 TeV

A search for high-mass resonances in the e+e- final state is presented based on s**(1/2) =1.96 TeV p anti-p collision data from the CDF II detector at the Fermilab Tevatron from an integrated luminosity of 2.5 fb-1. The largest excess over the standard model prediction is at an e+e- invariant mass of 240 GeV/c2. The probability of observing such an excess arising from fluctuations in the standard model anywhere in the mass range of 150-1,000 GeV/c2 is 0.6% (equivalent to 2.5 sigma). We set Bayesian upper limits on sigma(p anti-p --> X) . B(X --> e+e-) at the 95% credibility level, where X is a spi+n 1 or spi+n 2 particle, and we exclude the standard model coupling Z' and the Randall-Sundrum graviton for k/M_Pl 0.1 with masses below 963 and 848 GeV/c2, respectively.