Limits on Extra Dimensions and New Particle Production in the Exclusive Photon and Missing Energy Signature in p pbar Collisions at sqrt(s) = 1.8 TeV

TL;DR

This paper searches for signs of extra dimensions and new particles in proton-antiproton collisions using a photon and missing energy signature, setting limits on model parameters with Tevatron data.

Contribution

It provides the first experimental limits on large extra dimensions and superlight gravitinos using the exclusive gamma plus missing energy channel at the Tevatron.

Findings

Limit of 221 GeV on the supersymmetry scale |F|^{1/2}.

Limits on the fundamental mass scale M_D: 549, 581, and 602 GeV for 4, 6, and 8 extra dimensions.

Introduces a pseudo-model-independent method for comparing experimental results to theory.

Abstract

The exclusive gamma-met signal has a small standard model cross-section and is thus a good channel in which to look for signs of new physics. This signature is predicted by models with a superlight gravitino or with large extra spatial dimensions. We search for such signals at the CDF detector at the Tevatron, using 87 pb^-1 of data at sqrt(s) = 1.8 TeV, and extract 95% C.L. limits on these processes. A limit of 221 GeV is set on the scale |F|^{1/2} in supersymmetry models. For 4, 6, and 8 extra dimensions, limits on the fundamental mass scale M_D of 549, 581, and 602 GeV, respectively, are found. We also specify a `pseudo-model-independent' method of comparing the results to theoretical predictions.