We report on a search for new particles in the diphoton channel using a data sample of $p\bar p$ collisions at $\sqrt{ s} = 1.96$ TeV collected by the CDF II detector at the Fermilab Tevatron, with an integrated luminosity of 5.4 fb$^{ -1}$. The diphoton invariant mass spectrum of the data agrees well with the standard model expectation. We set upper limits on the production cross section times branching ratio for the Randall-Sundrum graviton, as a function of diphoton mass. We subsequently derive lower limits on the graviton mass of 459 GeV$/c^{ 2}$ and 963 GeV$/c^{ 2}$, at the 95% confidence level, for coupling parameters ($k/\bar{ M}_{ Pl}$) of 0.01 and 0.1 respectively.
Categories: hep-ex