Search for Large Extra Spatial Dimensions in the Dielectron and Diphoton Channels in $p\overline{p}$ Collisions at $\sqrt{s}=1.96\mathrm{TeV}$

We report on a search for large extra spatial dimensions in the dielectron and diphoton channels using a data sample of $1.05{\mathrm{fb}}^{-1}$ of $p\overline{p}$ collisions at a center-of-mass energy of 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. The invariant mass spectrum of the data agrees well with the prediction of the standard model. We find the most restrictive 95% C.L. lower limits on the effective Planck scale between 2.1 and 1.3 TeV for 2 to 7 extra dimensions.

Figure 1

The di-EM invariant mass distributions for CC-CC (a) and CC-EC (b) events. The data are shown by points with error bars, the filled histograms represent the Drell-Yan, diphoton, and multijet backgrounds, and the solid line represents the total background. The broken lines show the invariant mass distributions for two different values of $M_s$ for $n_d=4$. The error bars for the total background include both statistical and systematic uncertainties.

Figure 2

The distributions of the center-of-mass scattering angle $\cos {\theta }^{*}$ of the two final state EM candidates in CC-CC (a) and CC-EC (b) events. The data are shown by points with error bars, the filled histogram represent the multijet background, and the solid line represents the total background. The broken lines show the $\cos {\theta }^{*}$ distributions for two different values of $M_s$ for $n_d=4$. The error bars for the total background include both statistical and systematic uncertainties.

Figure 3

Observed and expected limits on the effective Planck scale, $M_s$, in the di-EM channel along with previously published limits in di-EM channel.